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The The The TextView TextView TextView DLL DLL DLL Version 1.00 Version 1.00 Version 1.00 The TextView DLL The TextView DLL The TextView DLL I I INTRODUCTION TO NTRODUCTION TO NTRODUCTION TO T T TEXT EXT EXTV V VIEW IEW IEW Thank you for using the TextView TextView TextView system. The author hopes that it will prove to be a powerful and useful tool to Windows applications writers, providing a facility that is both useful in the final application, and helpful in the development phase. This manual covers all aspects of the system. It assumes that you are an experienced Windows application developer, and are conversant with the use of the Windows API. The author is always interested to hear any reports about how you find TextView, what further facilities you would like it to include, and any problems you may find when using it. Contact addresses are given later in this manual. What is TextView? What is TextView? What is TextView? TextView TextView TextView is a system that provides a Windows 3 application with the ability to write lines of text to a window with the minimum of effort. TextView TextView TextView itself handles all the many operations needed to manage the window displaying the text; you need only call the function that writes the text, in exactly the same way as you would call printf printf printf in a DOS application. You can create as many TextView TextView TextView windows as you require, and all will operate independently. TextView TextView TextView windows can be resized by the user, minimized, maximized and scrolled horizontally and vertically with no work needed by the application. They can also have File menus that notify the application when the user requests that the window contents be written to disk. TextView TextView TextView windows can, of course, be used for an infinite variety of purposes. One possibility is to use TextView TextView TextView to provide a way of outputting tracing and debugging information when developing an application. Included with the system are the sources for a demonstration application that contain a flexible tracing system that may be incorporated into your own code. TextView TextView TextView is supplied as a Dynamic Link Library or DLL. In this form it is not added to the application's code at link time, but instead is bound to it dynamically by Windows whenever an application needing it is run. All applications using TextView TextView TextView will share the same code segments, making it very efficient in memory utilisation. What you need to use TextView What you need to use TextView What you need to use TextView In order to use TextView TextView TextView you will need to have a suitable compiler that can generate Windows 3 code, such as Microsoft C 6.0. The TextView TextView TextView functions follow the same conventions as used in the Windows API, and their descriptions later in this guide use the same layout as in the Microsoft Windows Programmer's Reference. Page Page Page 1 1 1 The TextView DLL The TextView DLL The TextView DLL Distribution and Use of TextView Distribution and Use of TextView Distribution and Use of TextView TextView TextView TextView is Copyright (c) Alan Phillips 1991. It may be freely distributed by anyone, to anyone. Apart from reasonable media and handling costs, no charge may be levied for its distribution. It may be stored on Bulletin Board systems and other archives so long as all the files comprising the original distribution are included. It may be repackaged to suit the storage conventions in use for the system concerned. It may not be distributed as part of commercial disk libraries without the prior agreement of the author. TextView TextView TextView may be freely used in any non-commercial Windows application. Authors of such applications may include the TextView TextView TextView DLL with the products either with or without the other files comprising the full distribution set. However, such application should include in their documentation (or should display in their About dialog box or in their online help) that they are using TextView TextView TextView, and should list the author's copyright. The demonstration sources supplied with TextView TextView TextView may be freely adapted and included in other applications as required. Authors of ShareWare or commercial products may not use TextView TextView TextView without the author's written permission. Disclaimer Disclaimer Disclaimer TextView TextView TextView is distributed on an as is basis. No guarantee is offered, and none should be inferred, of its correct functionality, nor of its suitability for any task whatsoever. The author accepts no liability for any loss or damage whatsoever caused as a result of using TextView TextView TextView with any application, whether written by the user or a third party. TextView TextView TextView is written as a private activity by the author, unconnected in any way with his employment at the University of Lancaster. Contacting the Author Contacting the Author Contacting the Author The author may be contacted c/o The Computer Centre, Lancaster The Computer Centre, Lancaster The Computer Centre, Lancaster University, Lancaster LA1 4YW, United Kingdom University, Lancaster LA1 4YW, United Kingdom University, Lancaster LA1 4YW, United Kingdom . Electronic mail may be addressed to one of the following addresses: alan@uk.ac.lancaster alan@uk.ac.lancaster alan@uk.ac.lancaster JANET network JANET network JANET network alan@lancaster.ac.uk alan@lancaster.ac.uk alan@lancaster.ac.uk Internet or BITNET Internet or BITNET Internet or BITNET alan%uk.ac.lancaster@ukc alan%uk.ac.lancaster@ukc alan%uk.ac.lancaster@ukc UUCP network UUCP network UUCP network Page Page Page 2 2 2 The TextView DLL The TextView DLL The TextView DLL I I INSTALLING NSTALLING NSTALLING T T TEXT EXT EXTV V VIEW IEW IEW There are three components to the TextView TextView TextView system. The DLL itself, textview.dll textview.dll textview.dll, should be copied to your Windows directory. The model-independent import library textview.lib textview.lib textview.lib should be copied to one of the directories named in your LIB LIB LIB environment variable - the directory containing your Windows SDK libraries or your C compiler libraries would normally be suitable. The header file textview.h textview.h textview.h should be copied to one of the directories named in your INCLUDE INCLUDE INCLUDE environment variable - the directory containing your windows.h windows.h windows.h header file would be suitable. Page Page Page 3 3 3 The TextView DLL The TextView DLL The TextView DLL U U USING SING SING T T TEXT EXT EXTV V VIEW IEW IEW The TextView TextView TextView DLL extends the Windows API with a number of specific functions, which you call from your application. All the functions have names beginning with TV TV TV, to avoid clashes with Windows functions, those in your application or in other DLLs. All the functions use the Pascal calling convention, and must be declared FAR FAR FAR. Full function prototypes are contained in the include file textview.h textview.h textview.h; including this in your source will automatically select the right calling mode, and will also perform any necessary casts to far pointers. You must take two additional steps when building your application: - Include the TextView TextView TextView import library textview.lib textview.lib textview.lib in the list of libraries that you name for the linker to scan. - Make sure you declare sufficient stack size in your application's .DEF .DEF .DEF file. As a rough guide, try increasing the size by 2Kbytes over what your application itself uses. You must not use the Windows LoadLibrary LoadLibrary LoadLibrary and GetProcAddress GetProcAddress GetProcAddress functions to link TextView routines at run-time. This is because some of the functions are actually within the import library and must be statically-linked. The sections below describe how to use TextView TextView TextView in your application. The text assumes that you're familiar with the Windows API and with how to program Windows applications: there is general information on this in the documentation supplied with the Microsoft Windows Software Developer's Kit, and in several other published books. Besides this manual, there is a comprehensively-commented set of C source routines supplied in the distribution set. These show you how you can use TextView TextView TextView to add a dynamic tracing utility to your application, which provides you with a very powerful development aid that enables you to keep a log of your application's activity that can be scrolled back and consulted when necessary. A Summary of TextView Usage A Summary of TextView Usage A Summary of TextView Usage Although it offers your application powerful facilities, TextView TextView TextView's API is very straightforward, and has been written to parallel closely the way you use the Windows API. The basic concepts of how the system works are these: The TextView Window The TextView Window The TextView Window A window created by TextView TextView TextView is an ordinary overlapped window that belongs to your application. Within certain limits you have full control over the appearance of the window: you can allow the user to resize it or not, supply it with maximize and minimize boxes, and so on. Page Page Page 4 4 4 The TextView DLL The TextView DLL The TextView DLL Creation of a TextView TextView TextView window is done with the TVCreateWindow TVCreateWindow TVCreateWindow function, which looks similar to the Windows CreateWindow CreateWindow CreateWindow function. The major difference is that for a TextView TextView TextView window the message loop is handled within the DLL and not by your application, so that you do not need to concern yourself with managing the window. TextView TextView TextView will look after aspects such as text scrolling on your behalf. Although your application does not supply the message loop, it can still interact fully with the window. A set of functions allow you to test what state the window in and to change that state, and to destroy the window when you've finished with it. If you choose, you can specify that a TextView TextView TextView window displays a File menu with Save, Save As and Print options. You do not see clicks on these menu items directly, since you do not supply the message loop, but you can arrange for TextView TextView TextView to call back into a routine in your application to notify you when menu items are selected. How Text is Stored How Text is Stored How Text is Stored TextView TextView TextView maintains the lines written to each window in a cyclic buffer held in an area of memory private to that window. Each window operates independently of the others, and the only practical limit to the total amount of data stored will be how much memory your system has available. When you create a window by calling TVCreateWindow TVCreateWindow TVCreateWindow you specify the maximum number of lines that each window can store, up to a limit of 4096 lines. Specifying a larger number requires TextView TextView TextView to allocate more control memory for the window, so you should not request a larger capacity that you need. Whenever a line is written, TextView TextView TextView stores the contents in dynamically-allocated memory. When the window contains the specified maximum number of lines, the next to be written will replace the oldest line, and so on. A line can be up to 512 characters long. Scrolling Scrolling Scrolling When you create a TextView TextView TextView window it will be in automatic scrolling state. In this state TextView TextView TextView will automatically move existing lines of text up to make room as new ones are written, without your application needing to be aware of what is happening. Old lines, of course, will disappear off the top of the window, but they will remain stored in memory until the window reaches its set capacity and they are overwritten with new lines of text. If the user wishes to look at older messages that are no longer visible in the window, he can put the window into manual scrolling state. TextView TextView TextView will draw horizontal and Page Page Page 5 5 5 The TextView DLL The TextView DLL The TextView DLL vertical scroll bars on the window (you may select either or both) and the user may use them to scroll around the stored text. You can specify when you create the window that it is to have a Scrolling menu to enable the user to select manual scrolling mode, or you may choose to control the window from your own application using the TVSetScrollMode TVSetScrollMode TVSetScrollMode function. When the window is in manual scroll mode it is unable to display any text written to it. However, it will count the number of messages lost should this occur, and will add a line itself to the window to warn the user when the window returns to automatic scroll mode. Registering a TextView Window Class Registering a TextView Window Class Registering a TextView Window Class As with the Windows CreateWindow CreateWindow CreateWindow function, you must have registered a suitable window class before you can create a TextView TextView TextView window using TVCreateWindow TVCreateWindow TVCreateWindow. Since most of the details of the window class have to be supplied by TextView TextView TextView itself, you must call a TextView TextView TextView function TVRegisterClass TVRegisterClass TVRegisterClass to do this, and must not use the ordinary Windows technique. When you call TVRegisterClass TVRegisterClass TVRegisterClass you specify four arguments: for example TVRegisterClass(hInstance,"TV_WINCLASS", TVRegisterClass(hInstance,"TV_WINCLASS", TVRegisterClass(hInstance,"TV_WINCLASS", LoadIcon(hInstance,"TV_WINICON"), LoadIcon(hInstance,"TV_WINICON"), LoadIcon(hInstance,"TV_WINICON"), GetStockObject(WHITE_BRUSH)); GetStockObject(WHITE_BRUSH)); GetStockObject(WHITE_BRUSH)); will register a class using an icon defined in your application's resource area, and will use a white background for the window. The function will return FALSE FALSE FALSE if it fails to register the window class, or if you pass incorrect arguments. Creating a TextView Window Creating a TextView Window Creating a TextView Window Creating a Window with TextView TextView TextView is closely analogous to how you use Windows' own CreateWindow CreateWindow CreateWindow function. The routine you call is TVCreateWindow TVCreateWindow TVCreateWindow, and many of the arguments you need to pass are have exact CreateWindow CreateWindow CreateWindow equivalents. The lpClassName, lpWindowTitle, X, Y, nWidth, nHeight and hInstance arguments are used in the same way as the CreateWindow CreateWindow CreateWindow arguments of the same name. The one restriction is that the window class you specify with lpClassName must have been registered with the TVRegisterClass TVRegisterClass TVRegisterClass function. The remaining arguments are specific to TextView and have no CreateWindow CreateWindow CreateWindow equivalents. hFont specifies a handle to the font that you want text written in the window to appear in. If you specify the argument as NULL NULL NULL, TextView TextView TextView will use the system font; otherwise, you can use any font created with the CreateFont CreateFont CreateFont function. Page Page Page 6 6 6 The TextView DLL The TextView DLL The TextView DLL The dWflags argument specifies a series of bit settings that describe the appearance you want the window to take, and what facilities it provides. These are described in detail below. The nTabSize value specifies how you want tabs to be expanded in lines written to the window. You give the value as a number of characters; TextView multiplies this by the width of the average character in the selected font to calculate the actual spacing. If you give a value of zero, tabs will be expanded to a width of 8 characters. The nMaxLines argument tells TextView how many lines of text should be stored with the window (note that this is not the size of the actual window, but the size of its data storage area). You can set this value to be from 128 to 4096. If you write more lines than this to the window, the oldest lines will be progressively overwritten. The lpMenuHandler argument is the procedure instance address of a function within your application that is to receive notification of things happening in the window. This is discussed in more detail below in the section on Receiving Menu Notifications. The value you pass as this argument must have been obtained by using the MakeProcInstance MakeProcInstance MakeProcInstance function. Depending on the values you have specifies in the dwFlags argument, you may be allowed to give a NULL NULL NULL value. The return value from TVCreateWindow TVCreateWindow TVCreateWindow is a normal window handle, which you use in other TextView TextView TextView functions. You can also pass this handle to Windows functions to manipulate the window; however you should avoid calling DestroyWindow DestroyWindow DestroyWindow to close it. Instead, use the TextView TextView TextView equivalent TVDestroyWindow TVDestroyWindow TVDestroyWindow, which is guaranteed to work in future releases. The dwFlags Argument The dwFlags Argument The dwFlags Argument This argument is a collection of bit settings that tells TextView TextView TextView details of how you want the window to appear, and what facilities it should support. The TVS_MAXIMIZE TVS_MAXIMIZE TVS_MAXIMIZE, TVS_MINIMIZE TVS_MINIMIZE TVS_MINIMIZE and TVS_SYSMENU TVS_SYSMENU TVS_SYSMENU settings correspond directly to dwStyle settings in CreateWindow CreateWindow CreateWindow, and control whether the window has a maximize box, a minimize box, and a system menu. The TVS_NOCLOSE TVS_NOCLOSE TVS_NOCLOSE setting can be used to disable the close option in the system menu; if you select this, your application must destroy the window, as the user will have no way to do so. If you specify a system menu, and do not disable the close option, you must supply a procedure address with the lpMenuHandler argument so that TextView TextView TextView can notify your application when the user closes the window. The TVS_NORESIZE TVS_NORESIZE TVS_NORESIZE setting allows you to create the window without a thick "resizing" frame. The user will not be able to alter the size of the window other than by minimizing or maximizing it. Page Page Page 7 7 7 The TextView DLL The TextView DLL The TextView DLL TVS_HSCROLL TVS_HSCROLL TVS_HSCROLL and TVS_VSCROLL TVS_VSCROLL TVS_VSCROLL specify whether the window is to show horizontal and vertical scroll bars if the user or your application puts it into manual scroll mode. If you don't include either of the settings, manual scroll mode cannot be selected, and the user will be unable to scroll back to look at text no longer in the window. TVS_TIMESTAMP TVS_TIMESTAMP TVS_TIMESTAMP controls whether TextView is to timestamp text written to the window. If you specify it, all lines will be prefixed with the current Windows time (that is, the number of milliseconds since Windows started, obtained from the GetCurrentTime GetCurrentTime GetCurrentTime function). Timestamping messages can be useful if you are using TextView to trace the path taken by your application in response to external events. The other settings all control what menu items should appear in the window's menu bar. TVS_SCROLLMENU TVS_SCROLLMENU TVS_SCROLLMENU selects a Scrolling menu item, which will let the user switch between manual and automatic scroll modes. You can use this setting only if you've also given either or both of TVS_HSCROLL TVS_HSCROLL TVS_HSCROLL and TVS_VSCROLL TVS_VSCROLL TVS_VSCROLL. If you specify a procedure address with the lpMenuHandler argument, your application will be notified when the user clicks these menu items. TVS_FILESAVE TVS_FILESAVE TVS_FILESAVE, TVS_FILESAVEAS TVS_FILESAVEAS TVS_FILESAVEAS and TVS_FILEPRINT TVS_FILEPRINT TVS_FILEPRINT specify that the window is to have a File menu, which should include Save, Save As and Print options respectively. You can use the three settings independently. If you use any of these settings you must specify a procedure address in the lpMenuHandler argument to receive notification when the items are clicked. Writing Text to a TextView Window Writing Text to a TextView Window Writing Text to a TextView Window Once a TextView TextView TextView window is created, writing text to it is simply done with the TVOutputText TVOutputText TVOutputText function. This takes three arguments: hWnd This is the handle to the TextView TextView TextView window. lpBuffer This is a long pointer to a buffer containing the line you wish to write. nSize This is the number of characters in the buffer. If you set this value to zero, TVOutputText TVOutputText TVOutputText will assume the text is a zero-terminated string and will write it out completely. You can write up to 512 bytes in a line, less the length of the timestamp details if you used the TVS_TIMESTAMP TVS_TIMESTAMP TVS_TIMESTAMP option in the dwFlags argument to TVCreateWindow TVCreateWindow TVCreateWindow. If you supply a longer line than that, TextView TextView TextView will truncate it. What happens to the text depends on the current state of the TextView TextView TextView window you are writing it to. If the window is in automatic scroll mode, it will be displayed in the window, which will be scrolled up by one line if necessary to make room for it. The text will be written in the colour last specified with Page Page Page 8 8 8 The TextView DLL The TextView DLL The TextView DLL the TVSetTextColor TVSetTextColor TVSetTextColor function (or in black, if you haven't set another colour). If the window is in manual scroll mode, the text will be discarded. TextView TextView TextView will record the fact that a line has been lost, and when the user (or your application) returns the window to automatic scroll mode will add a line itself noting the number of lines that have ben lost. If the window has been suspended with a call to TVSuspendWindow TVSuspendWindow TVSuspendWindow, or you are currently calling the TVReturnData TVReturnData TVReturnData function to read back the data stored in the window, the text will also be discarded. Here, though, TextView TextView TextView will not record the fact. If you choose, you can determine the status of the window by calling the TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus function, and so avoid making calls to TVOutputText TVOutputText TVOutputText at inappropriate moments. Receiving Menu Notifications Receiving Menu Notifications Receiving Menu Notifications A TextView TextView TextView window is an independent entity, all of whose functions are controlled within the TextView TextView TextView DLL itself. Your application does not provide the message loop for the window, and is normally unaware of what the user is doing to the window: TextView TextView TextView handles window resizing, scrolling, iconizing and so on. However, you may wish to make your application aware of what the window is doing for one of two reasons. Firstly, you may wish to allow the user to control the window from either its own menu or from the application's menu - for example, you might include in your application's menu the ability for the user to switch the TextView TextView TextView window between manual and automatic scrolling. In order to keep the application's menu state in line with the window, it will be necessary for the application to be informed whenever the state is changed using the window's own menu. The application will probably also wish to be informed when the user closes the window with the Close option in its System menu, so that it can keep track of which windows are still active. The second reason is that some services must be provided by the application. TextView allows you to specify that the window should possess a File menu with options such as Save and Print, but it does not itself handle these functions. Instead, it notifies the application when one of these menu items is clicked, so that it may then perform the required operations. All these examples of menu notifications are done via the menu handler routine specified when you create the window with TVCreateWindow TVCreateWindow TVCreateWindow. Whenever the user clicks a menu item (including the Close option in the System menu) the TextView TextView TextView DLL will call this routine, passing it the handle of the window concerned, and a code indicating the menu item. Your code can then take what action it wishes. For example, if the user clicked on File Save As , you might run a dialog to ask the user for a file name, open it, and then copy the data Page Page Page 9 9 9 The TextView DLL The TextView DLL The TextView DLL currently in the window to the file using the TVSaveWindowToFile TVSaveWindowToFile TVSaveWindowToFile function. The example sources contained in the distribution set contain examples of how you use menu notification. The code keeps the main window's menu in line with the current state of the window, graying some items when the window is destroyed and checking the relevant scroll state selections. Saving Data in a Window to File Saving Data in a Window to File Saving Data in a Window to File TextView TextView TextView allows you to save the contents of a window to a file on disk at any time. There are two techniques for doing this, depending on how much processing of the data you wish your application to do before it is written. If you application created the window and specified a File menu with File Save or File Save As options, it will be notified when they are clicked, as described above, but you can, of course, initiate a file save at any time and not solely when this occurs. The first technique for saving the data is the simplest. TextView TextView TextView provides a function TVSaveWindowToFile TVSaveWindowToFile TVSaveWindowToFile which will write a range of lines to a file exactly as they as stored, and if you don't need to process the data yourself this will be the easiest option. Your application will need to determine the name of the file to be written, probably by giving the user a dialog box to choose it, and open the file for writing; then it can call TVSaveWindowToFile TVSaveWindowToFile TVSaveWindowToFile. For example, if the name of the file is stored in file_name file_name file_name, you could use code like this to save all the data stored for the window: int int int hFile; hFile; hFile; /* handle to file */ /* handle to file */ /* handle to file */ ... ... ... hFile = _lcreat(file_name,0); hFile = _lcreat(file_name,0); hFile = _lcreat(file_name,0); TVSaveWindowToFile(hWnd,hFile,0,-1,0L); TVSaveWindowToFile(hWnd,hFile,0,-1,0L); TVSaveWindowToFile(hWnd,hFile,0,-1,0L); Specifying the start line as 0 and the number of lines to write as -1 causes all the stored data to be saved. The demonstration program sources in the distribution set show you this technique in use. The second technique for saving data allows you to process the lines before they are written. You can obtain successive lines from the window by calling the TVReturnData TVReturnData TVReturnData function, described in a following section, perform the actions required, and write to the file yourself. If you wish to save only the data that is actually visible in the window, you can use the TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus function to obtain the required line numbers, as shown here: Page Page Page 10 10 10 The TextView DLL The TextView DLL The TextView DLL TVWSTATUS TVWSTATUS TVWSTATUS status; status; status; /* window status details */ /* window status details */ /* window status details */ int int int hFile; hFile; hFile; /* handle to file */ /* handle to file */ /* handle to file */ ... ... ... /* Get details of the window */ /* Get details of the window */ /* Get details of the window */ TVGetWindowStatus(hWnd,&status); TVGetWindowStatus(hWnd,&status); TVGetWindowStatus(hWnd,&status); /* Open the file and write the data that is visible now */ /* Open the file and write the data that is visible now */ /* Open the file and write the data that is visible now */ hFile hFile hFile = _lcreat(file_name,0); = _lcreat(file_name,0); = _lcreat(file_name,0); TVSaveWindowToFile(hWnd,hFile,status.nTopLine, TVSaveWindowToFile(hWnd,hFile,status.nTopLine, TVSaveWindowToFile(hWnd,hFile,status.nTopLine, status.nRows,0L); status.nRows,0L); status.nRows,0L); Giving the number of lines to be written as the number of rows in the window ensures that all the visible data is written. If the window is not actually full, the function will adjust the number requested itself. Printing Data in a Window Printing Data in a Window Printing Data in a Window TextView TextView TextView does not itself provide facilities to print the contents of a window to file. If you wish your application to do this, you will need to use the TVReturnData TVReturnData TVReturnData function described below to read back the window's contents, and handle the printer yourself. If you create the window to have a File menu with a Print option, TextView TextView TextView will notify your application when the user requests a print action by clicking it. Reading Back the Contents of a TextView Window Reading Back the Contents of a TextView Window Reading Back the Contents of a TextView Window Your application can call the TextView TextView TextView DLL at any time to read back the data stored with any TextView TextView TextView window, using the TVReturnData TVReturnData TVReturnData function. The initial call to TVReturnData TVReturnData TVReturnData nominates a buffer that you wish to use to receive the contents of the window, one line at a time. You also specify the address of a callback function; TextView TextView TextView will copy the text of one line into your buffer and call this function to allow you to process it, repeatedly until either every line has been processed, or you terminate the sequence. For example, the callback function might be declared like this: int int intFAR FAR FAR PASCAL PASCAL PASCAL data_handler(HWND hWnd, LPSTR lpBuffer, data_handler(HWND hWnd, LPSTR lpBuffer, data_handler(HWND hWnd, LPSTR lpBuffer, int nCount, BOOL nTruncated) int nCount, BOOL nTruncated) int nCount, BOOL nTruncated) { { { /* Make sure we didn't lose any bit of the line */ /* Make sure we didn't lose any bit of the line */ /* Make sure we didn't lose any bit of the line */ if ( nTruncated ) if ( nTruncated ) if ( nTruncated ) { { { Page Page Page 11 11 11 The TextView DLL The TextView DLL The TextView DLL /* Buffer was too short, so a line has been cut /* Buffer was too short, so a line has been cut /* Buffer was too short, so a line has been cut * short. Warn the user and abort the process * short. Warn the user and abort the process * short. Warn the user and abort the process */ */ */ MessageBox(NULL,"Buffer too short",NULL, MessageBox(NULL,"Buffer too short",NULL, MessageBox(NULL,"Buffer too short",NULL, MB_ICONSTOP | MB_TASKMODAL); MB_ICONSTOP | MB_TASKMODAL); MB_ICONSTOP | MB_TASKMODAL); return(0); return(0); return(0); } } } /* Got all the line, so process it */ /* Got all the line, so process it */ /* Got all the line, so process it */ process_line(lpBuffer); process_line(lpBuffer); process_line(lpBuffer); /* And return non-zero to get the next line */ /* And return non-zero to get the next line */ /* And return non-zero to get the next line */ return(1); return(1); return(1); } } } This routine will be called once for every line of text in the window. It checks that no data was lost due to the buffer being too small, and if it was it terminates the read of data by returning a value of zero to the DLL. If not, it calls some routine called process_file process_file process_file to do something to the data, and returns a non-zero value requesting the DLL to pass the next line to it. While your application is engaged in reading back lines of text from a window, any calls to TVOutputText TVOutputText TVOutputText to add more text to it, and most of the functions controlling the window, will be disabled. The example sources supplied in the distribution give you a full example of how to use TVReturnData TVReturnData TVReturnData. In this case, they read back the data from one window and make a copy of it in another. Destroying a TextView Window Destroying a TextView Window Destroying a TextView Window A TextView TextView TextView window may be destroyed in one of two ways. Your application may simply call the TVDestroyWindow TVDestroyWindow TVDestroyWindow function, which will remove the window from the screen and release all its memory resources. This may be done at any time. Alternatively, if you specified in the TVCreateWindow TVCreateWindow TVCreateWindow call that the window was to have a System Menu, and did not inhibit the Close option, the user may close the window directly by clicking that option. In this case, TextView TextView TextView will remove the window from the screen and release the memory resources used by the window. It will then notify your application that the window has been destroyed by calling the menu handler function, passing it a code of TVMI_CLOSE TVMI_CLOSE TVMI_CLOSE. You should not use the normal Windows DestroyWindow DestroyWindow DestroyWindow function to destroy a TextView window as this may be incompatible with future releases. Page Page Page 12 12 12 The TextView DLL The TextView DLL The TextView DLL Control Functions Control Functions Control Functions TextView TextView TextView provides your application with a range of control functions that control the operation of its windows, as described below: Setting Text and Background Colour Setting Text and Background Colour Setting Text and Background Colour By default, text will be displayed in a TextView TextView TextView window in black. The TVSetTextColor TVSetTextColor TVSetTextColor function allows you to specify any RGB value to be used for subsequent output. The TVSetBKColor TVSetBKColor TVSetBKColor function allows you to set the text background colour. Setting the Scroll State Setting the Scroll State Setting the Scroll State If you specify the TVS_SCROLLMENU TVS_SCROLLMENU TVS_SCROLLMENU setting in the dwFlags argument to TVCreateWindow TVCreateWindow TVCreateWindow, the window will have a Scrolling menu that will permit the user to switch between manual and automatic scroll modes at will. If you wish, your application can force a particular scroll state itself with the TVSetScrollState TVSetScrollState TVSetScrollState function. If you do not specify a Scrolling menu, this is the only way to change scroll modes. Suspending Text Output Suspending Text Output Suspending Text Output At some point in your application you may wish to suppress output to a TextView TextView TextView window. One way of doing so would, of course, be to set a global flag in your application's data segment that is checked by every routine that calls TVOutputText TVOutputText TVOutputText, and this technique is used in the demonstration application to activate or disable tracing. An alternative that does not involve a global flag is to use the TVSuspendWindow TVSuspendWindow TVSuspendWindow function. When a window is marked as suspended, TVOutputText TVOutputText TVOutputText functions as normal, but the text is discarded. Temporarily Inhibiting Window Updates Temporarily Inhibiting Window Updates Temporarily Inhibiting Window Updates Writing text to a window, particularly if the existing contents must be scrolled to make room, can be an expensive operation in terms of processor power. If your application has to write a large number of lines to a TextView TextView TextView window at one time, it will be considerably slowed while the data is scrolled up through the display. The TVSetRedraw TVSetRedraw TVSetRedraw function allows you to configure a window so that text lines are stored as normal, but the window is not updated as they are received, letting you write the data with TVOutputText TVOutputText TVOutputText very rapidly. Then, when you have written all the lines, you can tell TextView TextView TextView to update the window: it Page Page Page 13 13 13 The TextView DLL The TextView DLL The TextView DLL will display only the final windowfull of lines, which will involve no scrolling. The demonstration program supplied with TextView TextView TextView lets you see the effect of suppressing window updates: the Write Batch menu option writes 200 lines to the window, scrolling for each one; the Write Batch Fast option disables window updating, writes 200 lines and then updates the window. Clearing a Window Clearing a Window Clearing a Window The TVResetWindow TVResetWindow TVResetWindow will destroy all data stored for a window, and it will be redrawn empty. The window will be set into automatic scroll mode, and the text colour used will be set to be black. Information Functions Information Functions Information Functions You can find out the exact status of a TextView TextView TextView window at any time by calling the TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus routine. This fills in a TVWSTATUS TVWSTATUS TVWSTATUS struct that you supply; the details of the format are shown in the Data Types and Structures section. Page Page Page 14 14 14 The TextView DLL The TextView DLL The TextView DLL F F FUNCTIONS UNCTIONS UNCTIONS D D DIRECTORY IRECTORY IRECTORY This chapter contains an alphabetical list of functions comprising the TextView TextView TextView system. The specifications are laid out in the same way as those in the Microsoft Windows Programmer's reference Manual. All TextView TextView TextView functions use the Pascal calling convention, and must be declared FAR FAR FAR. Including the header file textview.h textview.h textview.h in sources using these interfaces will declare their prototypes automatically, and will ensure that they are being correctly used. Applications that make use TextView TextView TextView routines must be linked with the TextView TextView TextView import library textview.lib textview.lib textview.lib. Page Page Page 15 15 15 The TextView DLL The TextView DLL The TextView DLL TVCreateWindow TVCreateWindow TVCreateWindow Syntax Syntax Syntax BOOL BOOL BOOL TVCreateWindow TVCreateWindow TVCreateWindow(lpClassName, lpWindowName, X, Y, nWidth, nHeight, hInstance, hFont, dwFlags, dwUnused, nTabSize, nMaxLines, lpMenuHandler) This function creates a TextView TextView TextView window. Many of the arguments are similar to those used with the CreateWindow function, but there are some extra values appropriate to TextView TextView TextView, and some inappropriate arguments may not be specified. TVCreateWindow TVCreateWindow TVCreateWindow will always create an overlapped window. Option flags allow the selection of minimize and maximize boxes, and whether the user will be able to resize it by dragging its borders. TextView TextView TextView allows the application to interact with the window in a controlled way. All message handling for the window is performed by TextView TextView TextView, but the application can specify that it wished to be notified when events such as menu item clicks occur. For example, this allows the window to appear to the user as a normal application window complete with a File menu, but for handling of the corresponding functions to be done by the application. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description lpClassName LPSTR LPSTR LPSTR Points to a null-terminated string that names the window class. This class must have been previously registered with a call to TVRegisterClass. TVRegisterClass. TVRegisterClass. lpWindowName LPSTR LPSTR LPSTR Points to a null-terminated character string that represents the window name. X int int int Specifies the initial x-position of the window. The value is the initial x-coordinate of the upper left corner, in screen coordinates. If the value is CW_USEDEFAULT, Windows selects the default position for the window's upper-left corner. Y int int int Specifies the initial y-position of the window. The value is the initial y-coordinate of the upper left corner, in screen coordinates. Page Page Page 16 16 16 The TextView DLL The TextView DLL The TextView DLL nWidth int int int Specifies the width of the window in device units. If the value is CW_USEDEFAULT, Windows selects a default width and height for the window, and the nHeight argument is ignored. nHeight int int int Specifies the height of the window in device units. The argument is ignored if nWidth is CW_USEDEFAULT. hInstance HANDLE HANDLE HANDLE Identifies the instance of the module to be associated with the window. hFont HFONT HFONT HFONT Specifies a handle to the font to be used when text is written to the window. If the value is NULL, the system font is used. dwFlags DWORD DWORD DWORD Specifies various facilities required in the window. It can be any combination of the values given in the list below. dwUnused DWORD DWORD DWORD Must be zero. nTabSize int int int Specifies the width of a tab stop to be used when writing text to the window. nMaxLines int int int Specifies how many lines of text are to be stored in the window's buffers. The value must be between 128 and 4096; values outside this range will be silently adjusted. lpMenuHandler FARPROC FARPROC FARPROC A procedure instance of a routine to be called when the user clicks on an item in the window's menu. See the "Comments" section for details. Return Value Return Value Return Value The return value is a handle to the new window. It is NULL if the window could not be created. Comments Comments Comments Where the X argument is CW_USEDEFAULT, the Y argument can be one of the show-style parameters described with the ShowWindow ShowWindow ShowWindow function. The address passed as the lpMenuHandler argument must be created by using the MakeProcInstance MakeProcInstance MakeProcInstance function. The callback function must use the Pascal calling convention and be declared FAR FAR FAR. The dwFlags argument should contain values from the list below: Page Page Page 17 17 17 The TextView DLL The TextView DLL The TextView DLL TVS_FILESAVE Specifies that the window is to have a File menu that will incorporates a Save option. If this option is specified the lpMenuHandler argument must not be NULL. TVS_FILESAVEASSpecifies that the window is to have a File menu that will incorporates a Save As option. If this option is specified the lpMenuHandler argument must not be NULL. TVS_FILEPRINT Specifies that the window is to have a File menu that includes a Print option. If this option is specified the lpMenuHandler argument must not be NULL. TVS_HSCROLL Specifies that the window is to permit horizontal scrolling by the user. TVS_MAXIMIZE Specifies that the window is to have a maximize box. TVS_MINIMIZE Specifies that the window is to have a minimize box. TVS_NOCLOSE Specifies that the Close option on the window's system menu is to be inhibited. If this option is used the window can only be destroyed by a call to TVDestroyWindow TVDestroyWindow TVDestroyWindow. This option is ignored if TVS_SYSMENU is not specified also. TVS_NORESIZE Specifies that the window is not to have a thick frame allowing the user to resize it. TVS_SCROLLMENU Specifies that the window is to have a Scroll menu, allowing the user to switch between manual and automatic scrolling. This option requires one or both of TVS_HSCROLL and TVS_VSCROLL to also be defined. If this option is omitted, the application must switch scrolling modes if required with a call to TVSetScrollState TVSetScrollState TVSetScrollState. TVS_SYSMENU Specifies that the window is to have a system menu. If this option is used and the TVS_NOCLOSE option is not used, the lpMenuHandler argument must not be NULL. Page Page Page 18 18 18 The TextView DLL The TextView DLL The TextView DLL TVS_TIMESTAMP Specifies that lines written to the window are to automatically be timestamped. TextView TextView TextView will prepend the current Windows time (the number of milliseconds since Windows was started) to the text supplied. TVS_VSCROLL Specifies that the window is to permit vertical scrolling by the user. Callback Callback Callback void FAR PASCAL void FAR PASCAL void FAR PASCAL MenuHandler(hWnd,nMenuItem) HWND HWND HWND hWnd; ; ; WORD WORD WORD nMenuItem; ; ; MenuHandler is a place-holder for the application- supplied function name. The actual name must be exported by including it in an EXPORTS EXPORTS EXPORTS statement in the application's module definition file. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Identifies the window whose menu item has been selected nMenuItem WORD WORD WORD Identifies the menu item concerned. The value will be one of those in the table below. The menu handler callback function will be informed of which menu option has been clicked in the nMenuItem argument. The value will be one of those in the list below; if the dwFlags argument to TVCreateWindow TVCreateWindow TVCreateWindow did not enable a menu item the corresponding notification value will not occur. TVMI_AUTOSCROLL Specifies that the user has clicked the Automatic option in the window's Scrolling menu. TextView will have already set the window into automatic scrolling state and hidden any scroll bars. TVMI_CLOSE Specifies that the user has clicked the Close option on the window's system menu. The window will already have been destroyed when this event is notified. TVMI_FILESAVE Specifies that the user has clicked the Save option in the window's File menu. TVMI_FILESAVEAS Specifies that the user has clicked the Save As option in the window's File menu. Page Page Page 19 19 19 The TextView DLL The TextView DLL The TextView DLL TVMI_FILEPRINTSpecifies that the user has clicked the Print option in the window's File menu. TVMI_MANUALSCROLL Specifies that the user has clicked the Manual option in the window's Scrolling menu. TextView will already have set the window into manual scrolling mode and drawn the required scroll bars. Page Page Page 20 20 20 The TextView DLL The TextView DLL The TextView DLL TVDestroyWindow TVDestroyWindow TVDestroyWindow Syntax Syntax Syntax BOOL BOOL BOOL TVDestroyWindow TVDestroyWindow TVDestroyWindow(hWnd) Destroys a window created with the TVCreateWindow TVCreateWindow TVCreateWindow function. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window to be destroyed. . . Return Value Return Value Return Value The function returns TRUE TRUE TRUE if the window has been destroyed. . . Page Page Page 21 21 21 The TextView DLL The TextView DLL The TextView DLL TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus Syntax Syntax Syntax BOOL BOOL BOOL TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus(hWnd,lpStatusBlock) This function returns status information for a TextView TextView TextView window. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. lpStatusBlock LPTVWSTATUS LPTVWSTATUS LPTVWSTATUS A FAR pointer to a TVWSTATUS TVWSTATUS TVWSTATUS block whose values will be filled in by this call. Return Value Return Value Return Value The return value will be TRUE if the call succeeded and the status information was returned. Page Page Page 22 22 22 The TextView DLL The TextView DLL The TextView DLL TVOutputText TVOutputText TVOutputText Syntax Syntax Syntax BOOL BOOL BOOL TVOutputText TVOutputText TVOutputText(hWnd,lpString,nCount) Writes one line of text to a TextView TextView TextView window. The text is stored in the window's buffer; if this contains the maximum number of lines specified when the window was created, the oldest stored line will be replaced. If the TVS_TIMESTAMP TVS_TIMESTAMP TVS_TIMESTAMP option was specified when the window was created, TextView TextView TextView will prefix the supplied text with the current Windows time before displaying it. Tab characters will be expanded to the width specified when the window was created. The text will be written using the colour defined by the last call to TVSetTextColor TVSetTextColor TVSetTextColor, or in black by default. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. lpString LPSTR LPSTR LPSTR Points to the string to be written. nCount int int int Specifies the number of characters in the string. If the value is zero the string will be assumed to be null- terminated and will be written in its entirety. Return Value Return Value Return Value The return value will be TRUE TRUE TRUE if the text was successfully displayed. Comments Comments Comments There are three conditions in which the text will not be displayed in the window as requested: 1. If the window has been put into suspended state with a call to TVSuspendWindow TVSuspendWindow TVSuspendWindow, the call to TVOutputText TVOutputText TVOutputText will be silently ignored. 2. If the application has called TVReturnData TVReturnData TVReturnData to read back the lines stored in the window, and has not yet ended the call-back loop, the call to TVOutputText TVOutputText TVOutputText will be silently ignored. 3. If the window is in manual scroll mode, the call will also be silently ignored. However, TextView TextView TextView records the number of lines lost when this occurs, and will add a line to the window itself to notify the user when the window returns to automatic scroll mode. Page Page Page 23 23 23 The TextView DLL The TextView DLL The TextView DLL In all these cases, TVOutputText TVOutputText TVOutputText returns a value of TRUE TRUE TRUE to the caller. A FALSE FALSE FALSE value is used solely to indicate a system problem such as insufficient memory. Text longer than 512 bytes will be truncated. Page Page Page 24 24 24 The TextView DLL The TextView DLL The TextView DLL TVRegisterClass TVRegisterClass TVRegisterClass Syntax Syntax Syntax BOOL BOOL BOOL TVRegisterClass TVRegisterClass TVRegisterClass(hInstance,lpClassName,hIcon,h brBackground) This function registers a window class that can subsequently be passed to TVCreateWindow TVCreateWindow TVCreateWindow to create a TextView TextView TextView window. The use of the function is similar to that of the RegisterClass RegisterClass RegisterClass function, with the exception that TextView TextView TextView itself will supply most of the details required. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hInstance HANDLE HANDLE HANDLE Specifies the application's instance handle. lpClassName LPSTR LPSTR LPSTR Points to a null-terminated string containing the name to be given to the window class. hIcon HICON HICON HICON Specifies a handle to the icon to be used when the TextView TextView TextView window is minimized. It must not be NULL. hbrBackground HBRUSH HBRUSH HBRUSH Specifies the class background brush to be applied to the window. The meaning is as defined for the hbrBackground item of the WNDCLASS WNDCLASS WNDCLASS structure, with the exception that the value must not be NULL. Return Value Return Value Return Value The function returns TRUE TRUE TRUE if the class was registered successfully. Comments Comments Comments An error return value of FALSE FALSE FALSE will result both from the class name already having been registered, and from invalid arguments being supplied. Page Page Page 25 25 25 The TextView DLL The TextView DLL The TextView DLL TVResetWindow TVResetWindow TVResetWindow Syntax Syntax Syntax BOOL BOOL BOOL TVResetWindow TVResetWindow TVResetWindow(hWnd) This functions resets a TextView TextView TextView window to an 'empty' state. All stored text is discarded, and the window is redrawn empty. The window will be put into automatic scroll mode, and will be marked as not suspended. The text colour will be set to black. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle of the window concerned. Return Value Return Value Return Value The function will return TRUE TRUE TRUE if the operation succeeded. Page Page Page 26 26 26 The TextView DLL The TextView DLL The TextView DLL TVReturnData TVReturnData TVReturnData Syntax Syntax Syntax int int int TVReturnData TVReturnData TVReturnData(hWnd,lpBuffer,nSize,lpNotifyFunc ) This function requests TextView to return the data stored in a TextView window into an application- supplied buffer. TextView TextView TextView will copy successive lines into the buffer, and will call back into a notification function to inform the application that each line is ready. The process continues until either all the lines have been returned or the callback function returns zero. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. lpBuffer LPSTR LPSTR LPSTR Points to the application's buffer into which TextView TextView TextView will copy successive lines. nSize int int int Specifies the size of the application's buffer. lpNotifyFunc FARPROC FARPROC FARPROC The procedure-instance address of the callback function used to notify the application when each line has been copied into the buffer. Return Value Return Value Return Value The return value specifies the last value returned by the callback function. Its meaning is user-defined. Comments Comments Comments The address passed as the lpNotifyFunc argument must be created by using the MakeProcInstance MakeProcInstance MakeProcInstance function. The callback function must use the Pascal calling convention and be declared FAR FAR FAR. Callback Callback Callback int FAR PASCAL int FAR PASCAL int FAR PASCAL NotifyFunc(hWnd,lpBuffer,nCount,nTruncated) HWND HWND HWND hWnd; LPSTR LPSTR LPSTR lpBuffer; int int int nCount; BOOL BOOL BOOL nTruncated; NotifyFunc is a placeholder for the application- supplied function name. The actual name must be exported by including it in an EXPORTS statement in the application's module definition file. Page Page Page 27 27 27 The TextView DLL The TextView DLL The TextView DLL _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. lpBuffer LPSTR LPSTR LPSTR Points to the application- supplied buffer that now contains the text of a line of text from the window. nCount int int int Specifies the line number within the window corresponding to this call. The first line is numbered zero. nTruncated BOOL BOOL BOOL This value will be TRUE if the text had to be truncated to fit into the supplied buffer. Page Page Page 28 28 28 The TextView DLL The TextView DLL The TextView DLL TVSaveWindowToFile TVSaveWindowToFile TVSaveWindowToFile Syntax Syntax Syntax BOOL BOOL BOOL TVSaveWindowToFile TVSaveWindowToFile TVSaveWindowToFile(hWnd,hFile,nStart,nLines,d wFlags) This function writes the data stored for a TextView TextView TextView window into a file. It can be called at any time, and not only in response to the user clicking an item in the window's File menu. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. hFile int int int Specifies the MSDOS handle to the file to which the data is to be written. The file must have been opened for writing. nStart int int int Specifies the number of the first stored line to be written to the file. The first line is numbered zero. nLines int int int Specifies the number of lines to be written. A value of -1 will write all the lines stored from the first specified to the end of the buffer. dwFlags DWORD DWORD DWORD Must be set to 0L. Return Value Return Value Return Value The function returns TRUE TRUE TRUE if the operation succeeded. A value of FALSE FALSE FALSE indicates either that the range of lines requested was invalid, or that an error occurred writing the file. In the latter case, TextView TextView TextView will display a message to alert the user. Page Page Page 29 29 29 The TextView DLL The TextView DLL The TextView DLL TVSetBkColor TVSetBkColor TVSetBkColor Syntax Syntax Syntax DWORD DWORD DWORD TVSetBkColor TVSetBkColor TVSetBkColor(hWnd,crColor) This function sets the background colour used when text is written to a TextView TextView TextView window. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. crColor COLORREF COLORREF COLORREF Specifies the new background colour. Return Value Return Value Return Value The function will return the previously set colour, or -1 if an error occurs. Comments Comments Comments TextView TextView TextView does not record background colours with individual messages. As the screen is scrolled messages that are written will use the text colour defined when they were stored, but the current background colour value. Page Page Page 30 30 30 The TextView DLL The TextView DLL The TextView DLL TVSetRedraw TVSetRedraw TVSetRedraw Syntax Syntax Syntax WORD WORD WORD TVSetRedraw TVSetRedraw TVSetRedraw(hWnd,nNewState) This function sets the redraw of a TextView TextView TextView window. If the state is set to FALSE FALSE FALSE, lines written to the window with TVOutputText TVOutputText TVOutputText will be stored, but the screen will not be updated until the state is changed to TRUE TRUE TRUE. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. nNewState BOOL BOOL BOOL Specifies the new state to be set. Return Value Return Value Return Value The function will return the previous redraw state of the window. Page Page Page 31 31 31 The TextView DLL The TextView DLL The TextView DLL TVSetScrollState TVSetScrollState TVSetScrollState Syntax Syntax Syntax WORD WORD WORD TVSetScrollState TVSetScrollState TVSetScrollState(hWnd,nNewState) This function sets the scrolling state of a TextView TextView TextView window. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. nNewState WORD WORD WORD Specifies the new state to be set. The value should be TV_SCR_AUTO TV_SCR_AUTO TV_SCR_AUTO to set automatic scrolling, or TV_SCR_MANUAL TV_SCR_MANUAL TV_SCR_MANUAL to set manual scrolling. Return Value Return Value Return Value The function will return the previous scrolling state of the window as wither TV_SCR_AUTO TV_SCR_AUTO TV_SCR_AUTO or TV_SCR_MANUAL TV_SCR_MANUAL TV_SCR_MANUAL. It will return zero if an error occurs, or if the call to TVCreateWindow TVCreateWindow TVCreateWindow did not specify one or both of the TVS_HSCROLL TVS_HSCROLL TVS_HSCROLL and TVS_VSCROLL TVS_VSCROLL TVS_VSCROLL options. Page Page Page 32 32 32 The TextView DLL The TextView DLL The TextView DLL TVSetTextColor TVSetTextColor TVSetTextColor Syntax Syntax Syntax DWORD DWORD DWORD TVSetTextColor TVSetTextColor TVSetTextColor(hWnd,crColor) This function sets the colour in which text is written to a TextView TextView TextView window. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. crColor COLORREF COLORREF COLORREF Specifies the colour in which text is to be written. Return Value Return Value Return Value The function will return the previously set colour, or -1 if an error occurs. Comments Comments Comments Using this function does not affect the colour of text that has already been written. Page Page Page 33 33 33 The TextView DLL The TextView DLL The TextView DLL TVSuspendWindow TVSuspendWindow TVSuspendWindow Syntax Syntax Syntax BOOL BOOL BOOL TVSuspendWindow TVSuspendWindow TVSuspendWindow(hWnd,nNewState) Sets the suspend state of a TextView TextView TextView window. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description hWnd HWND HWND HWND Specifies the handle to the window concerned. nNewState BOOL BOOL BOOL Specifies the state to be set. It should be TRUE TRUE TRUE to suspend the window, and FALSE FALSE FALSE to desuspend it. Return Value Return Value Return Value The return value is the previous suspend state of the window. Page Page Page 34 34 34 The TextView DLL The TextView DLL The TextView DLL TVVersion TVVersion TVVersion Syntax Syntax Syntax void void void TVVersion TVVersion TVVersion(lpMark,lpVersion,lpCycle) Returns the version identification of the TextView TextView TextView DLL. This consists of a mark number, a version number within that mark, and a compilation cycle number within that version. _________ Parameter _________ Parameter _________ Parameter ________________ Type/Description ________________ Type/Description ________________ Type/Description lpMark LPINT LPINT LPINT Pointer to an int int int to receive the mark number. lpVersion LPINT LPINT LPINT Pointer to an int int int to receive the version number. lpCycle LPINT LPINT LPINT Pointer to an int int int to receive the cycle number. Return Value Return Value Return Value The function has no return value. Page Page Page 35 35 35 The TextView DLL The TextView DLL The TextView DLL D D DATA ATA ATA T T TYPES AND YPES AND YPES AND S S STRUCTURES TRUCTURES TRUCTURES This section describes the data types and structures that are defined by TextView TextView TextView. Definitions of all the items described here are contain in the header file textview.h textview.h textview.h. Data types Data types Data types The data types in the following list are key words that define the size and meaning of arguments and return values associated with TextView TextView TextView functions. ____ Type ____ Type ____ Type __________ Definition __________ Definition __________ Definition LPTVWSTATUS LPTVWSTATUS LPTVWSTATUS Long pointer to a TVWSTATUS TVWSTATUS TVWSTATUS data structure. Data structures Data structures Data structures This section lists data structures that are used by TextView TextView TextView. TVWSTATUS TVWSTATUS TVWSTATUS Status Information for a TextView Window Status Information for a TextView Window Status Information for a TextView Window The TVWSTATUS TVWSTATUS TVWSTATUS structure contains information giving the current status of a TextView TextView TextView window. typedef struct sTVWSTATUS typedef struct sTVWSTATUS typedef struct sTVWSTATUS { { { DWORD DWORD DWORD dwFlags; dwFlags; dwFlags; int int int nMaxLines; nMaxLines; nMaxLines; int int int nLinesStored; nLinesStored; nLinesStored; BOOL BOOL BOOL nSuspended; nSuspended; nSuspended; BOOL BOOL BOOL nReturningData; nReturningData; nReturningData; BOOL BOOL BOOL nRedraw; nRedraw; nRedraw; WORD WORD WORD nScrollState; nScrollState; nScrollState; int int int nTabSize; nTabSize; nTabSize; int int int nMessagesLost; nMessagesLost; nMessagesLost; int int int nRows; nRows; nRows; int int int nColumns; nColumns; nColumns; int int int nTopLine; nTopLine; nTopLine; int int int nNextRow; nNextRow; nNextRow; COLORREF COLORREF COLORREF crColor; crColor; crColor; COLORREF COLORREF COLORREF crBkColor; crBkColor; crBkColor; } TVWSTATUS; } TVWSTATUS; } TVWSTATUS; The TVWSTATUS structure has the following fields: Page Page Page 36 36 36 The TextView DLL The TextView DLL The TextView DLL _________ Parameter _________ Parameter _________ Parameter ___________ Description ___________ Description ___________ Description dwFlags dwFlags dwFlags Contains a copy of the dwFlags argument passed to the TVCreateWindow TVCreateWindow TVCreateWindow call that created the window. nMaxLines nMaxLines nMaxLines Specifies the maximum number of lines that may be stored with the window. nLinesStored nLinesStored nLinesStored Specifies the number of lines currently stored with the window. nSuspended nSuspended nSuspended Specifies whether the window is currently in suspended state. nReturningDat nReturningDat nReturningDat Specifies whether TextView TextView TextView is currently a a a servicing a TVReturnData TVReturnData TVReturnData call for this window. nRedraw nRedraw nRedraw Specifies whether lines written to the window are being displayed immediately, or are being held until a window redraw is permitted. nScrollState nScrollState nScrollState Specifies the current scroll state of the window. The value will be either TV_SCR_AUTO TV_SCR_AUTO TV_SCR_AUTO or TV_SCR_MANUAL TV_SCR_MANUAL TV_SCR_MANUAL. nTabSize nTabSize nTabSize Specifies the width of a tab stop, in characters. nMessagesLost nMessagesLost nMessagesLost Specifies the number of messages that have been lost by being written to the window while it is in manual scroll state. The value is cleared whenever the scroll state is set to automatic. nRows nRows nRows Specifies the current depth of the window, in text rows. nColumns nColumns nColumns Specifies the current width of the window, in average characters. nTopLine nTopLine nTopLine Specifies the line number of the line currently displayed at the top of the window. nNextRow nNextRow nNextRow Specifies the window row to which the next line of text will be written (the first row is numbered zero). If the value is negative, the window is full and will need to be scrolled to accept the next line. crColor crColor crColor The current text colour. crBkColor crBkColor crBkColor The current background colour. Page Page Page 37 37 37 The TextView DLL The TextView DLL The TextView DLL Page Page Page 38 38 38 The TextView DLL The TextView DLL The TextView DLL A A APPENDIX PPENDIX PPENDIX : T : T : THE HE HE D D DEMONSTRATION EMONSTRATION EMONSTRATION P P PROGRAM ROGRAM ROGRAM Supplied with the TextView TextView TextView DLL in the full distribution set are full sources for a demonstration program that both show you what the system can do, and supplement the information in this guide on how to program with it. The sources are Copyright (c) Alan Phillips 1991. However, the techniques shown within them may be freely used and adopted for any non-commercial applications. A real-time program trace facility A real-time program trace facility A real-time program trace facility The purpose of the demonstration program is to show you how you can use TextView TextView TextView to add a real-time tracing facility to your application. Of course, there are many ways to debug a program while you are developing it. You can use Microsoft's CodeView system to monitor it; but this is relatively clumsy and, until CodeView 3.05, required you to have two monitors attached to your system. Even with single monitor capability, CodeView debugging can be a time-consuming business. If you know the area where a bug is occurring, you might plant MessageBox MessageBox MessageBox calls at suitable points to stop the program and display details. This, though, is very laborious, requiring you to click an OK box every time; and if your bug is deep inside a loop might well be totally impractical. TextView TextView TextView lets you add a real-time trace facility to your program with ease. In essence, you can regard it as giving you the ability you have in DOS programs of performing printf printf printf calls to the screen: the messages appear as you write them, and scroll off the top of the screen to make room for new ones. However, with TextView TextView TextView you have a permanent record of as many of the lines as you choose, and can at any time scroll back through them. Typically, you would add simple text output calls to your program as you develop it, writing out progress records and useful values as you go. The trace trace trace routine in the supplied sources is a basic example of such a routine. Its action is controlled by a simple on or off flag that is settable from a menu, so you can activate or de-activate tracing whenever you want. Of course, you could add more sophisticated criteria, to allow you to trace, for example, only certain categories of events or at certain debug levels. Running the demonstration Running the demonstration Running the demonstration To run the demonstration you must first have installed the TextView TextView TextView DLL as described earlier. Then, you can start it from the Program Manager, the File Manager or any other program launcher you may have. Page Page Page 39 39 39 The TextView DLL The TextView DLL The TextView DLL Trace menu items Trace menu items Trace menu items All the actions of the demonstration program are controlled by options in the trace menu. Some of the options control the trace system's operation; others simulate an application writing messages as it runs. Start tracing Start tracing Start tracing This option activates tracing. If a trace window does not already exist, it causes a call to TVCreateWindow TVCreateWindow TVCreateWindow to create one. The global tracing flag is set to on, so that the trace routine becomes active. Stop tracing Stop tracing Stop tracing Sets the global tracing flag to off, so that the trace routine does nothing. The trace window is not affected. These two options show on way of controlling the system from your application. Write one message Write one message Write one message Causes one call to the trace routine to write a message. Depending on the setting of the global tracing flag, text either will or will not appear in the trace window. Write batch Write batch Write batch Writes a batch of 200 messages in a loop, to demonstrate how the TextView TextView TextView window scrolls. Write batch fast Write batch fast Write batch fast Writes a batch of 200 messages in a loop. Unlike the previous option, the TVSetRedraw TVSetRedraw TVSetRedraw function is called to inhibit updating of the TextView TextView TextView window while this is being done. The effect is that the messages are written substantially faster. Reset trace window Reset trace window Reset trace window Calls the TVResetWindow TVResetWindow TVResetWindow function to clear all data stored in the TextView TextView TextView window. Show trace window Show trace window Show trace window This option uses normal Windows API functions to make the TextView TextView TextView window visible, and bring it to the top of the screen. It shows you one case in which you can manipulate the window with normal Windows functions as well as with TextView TextView TextView functions. Show trace status Show trace status Show trace status Calls the TVGetWindowStatus TVGetWindowStatus TVGetWindowStatus function to display some details of what the TextView TextView TextView window is doing. Page Page Page 40 40 40 The TextView DLL The TextView DLL The TextView DLL Trace window scrolling Trace window scrolling Trace window scrolling This menu option shows you a further popup menu item containing two items: Automatic and Manual. These let you change the scrolling state of the TextView TextView TextView window from the application's menu. You can also change the scrolling state from the Scrolling item in the TextView TextView TextView window's own menu. Note how the application uses the menu notification facility to keep the check marks on its menu item in line with the window state when this is done. Copy trace window Copy trace window Copy trace window This menu item creates a second TextView TextView TextView window, and uses the TVReturnData TVReturnData TVReturnData function to copy all the data from the first one into it. Kill trace window Kill trace window Kill trace window This destroys the TextView TextView TextView window and deletes all the stored data. Source files Source files Source files The demonstration program source comprises a number of modules, which are described briefly below. For full details you should consult the actual sources, which contain a large amount of explanatory comment. main.c main.c main.c This is the entry point module for the demonstration program. It contains the message processing routine that services messages sent to the main window. Note, of course, that the application contains no code at all to service messages sent to the TextView TextView TextView window - the DLL handles all of this itself. trace.c trace.c trace.c This module contains the routines that service most of the Trace menu items, and the trace routine itself. This routine is written to accept a format string, such as you pass to printf, and a variable number of arguments of any type. Also in this module is the menu handler function. This routine is called back from the Windows DLL to notify the application when the user clicks an item in the TextView TextView TextView window's menu. Page Page Page 41 41 41 The TextView DLL The TextView DLL The TextView DLL copy.c copy.c copy.c This module handles the Copy Trace Window menu item. It sets up a second TextView TextView TextView window and calls TVReturnData TVReturnData TVReturnData to read the contents of the first. utils.c utils.c utils.c This contains a few small utility routines. Building the program Building the program Building the program The demonstration sources are written to be compiled with Microsoft C 6.00A. You may need to make adjustments if you have a different compiler. The makefile is written for a UNIX-compatible make program such as ndmake. If you use the Microsoft nmake utility in the Programmer's Work Bench you will need to amend it. Page Page Page 42 42 42 
