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Text File | 1992-10-30 | 13.4 KB | 359 lines

Turbo Vision 2.0 Programming Guide ================================== This file contains information on material added to Turbo Vision 2.0 after the Programming Guide had gone to press and also corrections to a few errors in the manual. We strongly suggest that you mark these corrections and changes in your manual for future reference. ============================================================= Changes and additions to Chapter 19, "Turbo Vision Reference" ============================================================= ============================================================= CreateFindDialog function Editors ============================================================= Declaration function CreateFindDialog: PDialog; Function Constructs and returns a pointer to the standard text search dialog box used by StdEditorDialog. If you want to customize the simpler editor dialog boxes but still use the standard text search interface, your editor dialog box function should execute the dialog box returned by CreateFindDialog for a Dialog parameter of edFind. See also EditorDialog variable, edXXXX constants, StdEditorDialog function ============================================================= CreateReplaceDialog function Editors ============================================================= Declaration function CreateReplaceDialog: PDialog; Function Constructs and returns a pointer to the standard text search-and-replace dialog box used by StdEditorDialog. If you want to customize the simpler editor dialog boxes but still use the standard text search interface, your editor dialog box function should execute the dialog box returned by CreateReplaceDialog for a Dialog parameter of edReplace. See also EditorDialog variable, edXXXX constants, StdEditorDialog function ============================================================= FailSysErrors variable Drivers ============================================================= Declaration FailSysErrors: Boolean = False; If True, causes the system error handler to behave as if the user had responded to a system error message by pressing Esc. Normally, the system error handler displays a message on the last line of the screen and waits for user input. Setting FailSysErrors to True causes the system error handler to bypass the message and user prompt, and just return as if the DOS call that produced the error failed. See also SysErrorFunc variable ============================================================= GetCtrlChar function Drivers ============================================================= Declaration function GetCtrlChar(KeyCode: Word): Char; Function Returns the character, Ch, for which Ctrl+Ch produces the 2-byte scan code given by the argument KeyCode. Gives the reverse mapping to GetCtrlCode. See also GetCtrlCode ============================================================= GetCtrlCode function Drivers ============================================================= Declaration function GetCtrlCode(Ch: Char): Word; Function Returns the 2-byte scan code (keycode) corresponding to Ctrl+Ch. This function gives the reverse mapping to GetCtrlChar. See also GetCtrlChar ============================================================= GetShiftState function Drivers ============================================================= Declaration function GetShiftState: Byte; Function Returns a byte containing the current Shift key state, as reported by DOS. The return value contains a combination of the kbXXXX constants for shift states. You should call GetShiftState instead of checking the ShiftState variable directly. ShiftState is not guaranteed to be valid in protected mode, but GetShiftState returns the correct value in either real or protected mode. See also kbXXXX constants ============================================================= RegisterMenus procedure Menus ============================================================= Declaration procedure RegisterMenus; Function Calls RegisterType for each of the object types defined in the Menus unit: TMenuBar, TMenuBox, TMenuPopup, and TStatusLine. After calling RegisterMenus, your application can read or write any of those types with streams. See also RegisterType procedure ============================================================= RegisterViews procedure Views ============================================================= Declaration procedure RegisterViews; Function Calls RegisterType for each of the object types defined in the Views unit: TView, TFrame, TScrollBar, TScroller, TListViewer, TGroup, and TWindow. After calling RegisterViews, your application can read or write any of those types with streams. See also RegisterType procedure ============================================================= ShiftState variable Drivers ============================================================= Although this variable exists to maintain compatibility with version 1.0, you should not check ShiftState directly. Rather, you should call GetShiftState, which returns a valid set of shift state flags in either real or protected mode. ============================================================= TDesktop App ============================================================= TDesktop has two additional methods not documented. Methods ========================================= Load constructor Load(var S: TStream); Constructs and loads a desktop object from the stream S by first calling the Load constructor inherited from TGroup, then calling GetSubViewPtr to set up the Background field, then reading the TileColumnsFirst field. See also: TGroup.Load, TGroup.GetSubViewPtr Store procedure Store(var S: TStream); Writes the desktop object to the stream S by first calling the Store method inherited from TGroup, then calling PutSubViewPtr to store the Background field, then writing the value of TileColumnsFirst. See also: TGroup.Store, TGroup.PutSubViewPtr ============================================================= TMemoryStream Objects ============================================================= TMemoryStream implements a stream in heap memory. The mechanics of using memory streams are simple. You construct a memory stream, specifying its initial size and a block size. The memory stream allocates as many blocks on the heap as needed to meet the initial size. Bytes stored on the stream are not guaranteed to be in contiguous memory locations unless the stream consists of a single block. Once you construct the stream, you use it like any other. Writing beyond the end of the stream causes the stream to grow in increments of the initial block size, up to a maximum of 16,384 blocks. Changing the size of a memory stream by enlarging or truncating could seriously fragment your heap. Try to set the initial size and block size of the stream to reasonable values to minimize individual allocations. Fields ========================================= BlockSize BlockSize: Integer; The size of each block allocated to the memory stream. CurSeg CurSeg: Integer; Holds the segment part of the address of the block that contains the current stream position. Position Position: Longint; The position of the stream in bytes. The first position is 0. SegCount SegCount: Integer; The number of blocks currently allocated to the memory stream. SegList SegList: PWordArray; Contains the list of segment parts used by each allocated block. The entries 0..SegCount-1 contain valid segments. Size Size: Longint; The size of the stream in bytes. Methods ========================================= Init constructor Init(ALimit: Longint; ABlockSize: Word); Constructs a memory stream object by first calling the Init constructor inherited from TStream, then allocates enough blocks of size ABlockSize to collectively contain ALimit bytes. Sets BlockSize to ABlockSize. See also: TStream.Init Done destructor Done; virtual; Disposes of the memory stream object by disposing of the memory allocated to the stream, then calling the Done destructor inherited from TStream. See also: TStream.Done GetPos function GetPos: Longint; virtual; Returns the stream's current position. The first position is 0. GetSize function GetSize: Longint; virtual; Returns the size of the stream in bytes. Read procedure Read(var Buf; Count: Word); virtual; Reads Count bytes from the stream, starting at the current position, into the buffer Buf. Seek procedure Seek(Pos: Longint); virtual; Sets the current position to Pos bytes from the start of the stream. The first position is 0. Truncate procedure Truncate; virtual; Deletes all data on the stream from the current position to the end. Sets the current position to the new end of the stream. Write procedure Write(var Buf; Count: Word); virtual; Writes Count bytes from the buffer Buf to the stream, starting at the current position. ============================================================= TStringList Objects ============================================================= In the example code in the Load constructor description, TBufStream should be PBufStream. ============================================================= TStrListMaker Objects ============================================================= In the example code in the description of how to use the string list maker, TBufStream should be PBufStream.