ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

home *** CD-ROM | disk | FTP | other *** search

/ ProfitPress Mega CDROM2 …eeware (MSDOS)(1992)(Eng) / ProfitPress-MegaCDROM2.B6I / PROG / PASCAL / TPPCX.ZIP / PCX.DOC < prev next >

Wrap

Text File | 1991-01-29 | 25.7 KB | 562 lines

PCX.TPU - TPv6.0 Object-Oriented unit for displaying or saving PCX format picture files on Hercules, EGA, VGA, or compatible adapters. ╔═════════╗ ║ BasePCX ║█ ╚═════════╝█ ▀▀▀▀▀▀▀▀▀▀ The BasePCX object provides basic PCX functions that are independant of the adapter type. This object is used in the abstract to create device dependant objects. RESTRICTIONS ───────────────────────────────────────────────────────────────── This unit is for use only with EGA/ECM, VGA, and Hercules compatible devices. Extended image files, ones exceeding the displaying device resolution, cannot be read at this time and will generate a PCXError. Future versions will handle panning. When reading a file which was created by a higher resolution device than the device displaying the file, it may still be read as long as the image dimensions do not exceed the display device resolution. The image size can be set in the paint program before creating the picture if you wish to make the PCX file compatible with several devices. FIELDS ─────────────────────────────────────────────────────────────────────── PCXError PcxError: byte; Read only Set to constant equivalent if an error is encountered in reading writing from object. See: BasePCX.GetPCXError Loaded Loaded: boolean; Read/Write Set to false at object initialization, it is set to true after a picture has been loaded. It tells internal methods that a picture has been loaded and if the image or portion of the image is saved as another file, the existing color mapping is written to the new file. See: BasePCX.PCXLoaded Hdr Hdr: Header; Read only Record containing information pertaining to the picture file. The record is filled when reading a PCX file from a 128 byte file header that precedes the actual image data. The last 58 bytes of the file header are just filler, so these are ignored. The header record contains the following fields: Maker: integer; Code that specifies the picture generating program conforms to PCX format. PCXError set if incorrect maker, further methods halted. Version: integer; Code stating what PCX format version the following picture file was created with. PCXError set if incor- rect version, further methods halted. Encoding: integer; Code indicating the compression type of the following picture file. PCXError set if not run-length encoded, further methods halted. bpp: integer; Number indicating the number of bits per pixel per plane. Not used in this unit version. xmn: integer; Number setting the upper left horizontal coordinate of following picture. See: BasePCX.GetXmn ymn: integer; Number setting the upper left vertical coordinate of following picture. See: BasePCX.GetYmn xmx: integer; Number setting the lower right horizontal coordinate of following picture. See: BasePCX.GetXmx ymx: integer; Number setting the lower right vertical coordinate of following picture. See: BasePCX.GetYmx HRes: integer; Number indicating the horizontal resolution of the device that the created the picture file. VRes: integer; Number indicating the vertical resolution of the device that created the picture file. CMap: TripletArray; 2-dimensional array ( 16 triplets ) containing palette information for the following picture. If the following image is color and the displaying device is an EGA/VGA, the color map is used and the palette is set accordingly, if requested in the Show method. Otherwise CMap is ignored. Reserved: byte; Filler number reserved by ZSoft. NPlanes: byte; Number of picture planes used to create the image. Essentially establishes the differance between a mono and color picture. See: BasePCX.IsMultiPlane NBpl: integer; Number telling the object how many bytes are used to store a single horizontal line of the picture in memory. Palett: integer; Number for interpreting the palette. 0 = gray scale iamge. 1 = color image. Page Page: byte; Read only Used when reading PCX files, it determines which video page the image is written to. Since the object uses direct memory, the picture is written to the page requested regardless of the active page setting. The visual page setting still maintains display control. PFile PFile: pointer; Read only Points to dynamic memory area where entire PCX file has been read into ram. This increases decoding speed by reading the compressed image data from ram instead of thru file I/O. PCXError will be set if there is not enough memory available. See: BasePCX.Done SizeF SizeF: longint; Read only Size of PCX file read into ram. Used for disposing memory when destructing the object. Buf Buf: PBuf; Read only Pointer to dynamic variable (128 byte) which holds one complete decoded/encoded scan line during the decoding or encoding method. Offset Offset: POffset; Read only One-dimensional 480 byte array holding the video memory offset address to the beginning of each horizontal scan line. The offsets are calculated based on the object and not the creating device. Display Display: DisplayRec; Read/Write Record variable set by descendant objects upon initialization containing display adapter information. Correct information is set based on the descendant type and not the creating device. The record contains the following fields: SegBase: word; Base address to video memory. Page0: word; Offset from SegBase for start of video page 0. Page1: word; Offset from SegBase for start of video page 1. HorizRes: integer; Horizontal resolution of specific adapter. Informative only, not used. VertRes: integer; Vertical resolution of specific adapter. Informative only, not used. BytesPerLine: integer; Number of bytes required for one scan line per plane. Informative only, not used. See: Hdr field. NoColors: integer; Number of palette entries available. Informative only, not used. f f: file; Read only Assigned to PCX file and used during decoding or encoding. During decoding, the file variable is closed immediately after reading into ram. While encoding, however, the file must remain open until the process is completed thus requiring it to be a field of the object. METHODS, PUBLIC ────────────────────────────────────────────────────────────── Init constructor Init; Initializes all internal pointers to nil. Calls the FillOffsets procedure. Sets PCXError to PCXError0. OverRide: Always Done destructor Done; virtual; Disposes of the Offset and PFile allocations. OverRide: Mostly Show procedure Show( Filename: FStr; PageNo: byte; UsePal: boolean ); Displays requested PCX file as assigned by Filename on the page specified by PageNo (0 or 1 only) using the color mapping as specified in the PCX file header if UsePal is set to true. If errors are encountered, PCXError is set accordingly and the procedure is exited. Only pages 0 and 1 are valid in this version. If UsePal is set to false, the object uses the default settings as specified in the EGA_Pal constant. These settings are the same as a paint program's default settings. Any PCX file created on a Hercules, EGA, or VGA adapter can be displayed on any one of the same adapters. That is to say, you can display a monochrome image on an EGA adapter, or display an EGA image on a Hercules adapter, or etc. with the following limitations/conditions: The PCX file vertical size cannot exceed the display adapter's resolution. Images will be distorted when displayed on an adapter differant then the creating device. When displaying a mono picture on a color adapter, set UsePal to false. It is important to note the following: When UsePal is set to true, the PCX file may change the palette. All occurances of a specific color within the program will be immediately set to the new value. Also, the object instance does not reset the palette when it it destructed. It remains more versatile to control the palette outside the object. Some paint programs, for unknown reasons, do some strange things with the palette settings. So if a display doesn't turn out as expected, try setting UsePal to false. See EGA.DOC for procedure on resetting the palette to the default condition. See also: BasePCX.Save This method calls OpenFile; if the file opens without errors, calls GetHeader, SetPal (if requested), Decode. See also: BasePCX Page field description Save procedure Save( x1, y1, x2, y2: integer; Filename: FStr ); Saves image in viewport specified by upper left coordinates (x1,y1) and lower right coordinates (x2,y2) to disk in PCX format with the specified Filename. At this time, it saves only an image displayed on page 0 of any adapter. If a PCX picture has been previously loaded and all/portion of the same picture is being saved, the same color mapping information is written to the new file IF it was displayed with UsePal set to true AND the object was not destructed between the calls to Show and Save. Otherwise the default EGA palette is written. This method is graphics adapter specific, the correct object must be used depending on the graphics card of creating device. A VGA adapter can be set to 640x350 or 640x480 resolution. It is important to note that the image saved will, most of the time, not be to the exacting coordinates specified. This is due to the fact that each bit represents one pixel (8 pixels per byte). Since there are always an integral number of bytes, the image must start and stop at multiples of 8. This method calls OpenFile with a newfile request; if no errors are reported, calls WriteHeader, Encode. See also: BasePCX.Show GetPicVp procedure GetPicVp( var PicVp: viewporttype ); Returns displayed image boundaries in the PicVp variable. These coordinates are read from the PCX header information. GetXmn function GetXmn: integer; Returns upper left horizontal corner of picture. GetYmn function GetYmn: integer; Returns upper left vertical corner of picture. GetXmx function GetXmx: integer; Returns lower right horizontal corner of picture. GetYmx function GetYmx: integer; Returns lower right vertical corner of picture. IsMulti- Plane function IsMultiPlane: boolean; Returns true if picture read is a multi-plane image. Generally used to determine the differance between a color or B/W image. GetPCXError function GetPCXError: byte; Returns with numeric code cooresponding to type of error encountered during object implementation, if any, and can be compared to the following constants: 0 = No error 1 = File not found 2 = Not enough memory for picture buffer 3 = Error reading PCX file into RAM 4 = Multi-plane image encountered,display adapter for single plane only 5 = Not a valid PCX file 6 = Incorrect PCX version. Must be v3.0 or greater 7 = Not enough memory for Offset Buffer 8 = Unable to open new file 9 = Encoding error 10 = Image exceeds 64k limit. 11 = Image exceeds display capabilities. PCXLoaded function PCXLoaded: boolean; Returns true if a PCX picture has been loaded from disk and is currently displayed. ( whether invisble or not ) Primarily used internally for resetting the EGA. METHODS, PRIVATE ───────────────────────────────────────────────────────────── OpenFile procedure OpenFile( Filename: FStr; NewFile: boolean; var Ok: boolean ); Opens requested PCX file. When reading a file, Newfile is set to false and the file is read into ram and then closed. When writing a file, NewFile is set to true and the file is rewritten. No action is taken if the file currently exists and the method overwrites, always. Action should be taken prior to writing a PCX file to determine if an existing file exists. Ok returns true if normal file procedures (IOResult) performed correctly. GetHeader procedure GetHeader; When reading a PCX file, method decodes header information and sets internal fields accordingly. SetPal procedure SetPal; virtual; Abstract method only. OverRide: Always Decode procedure Decode; virtual; Abstract method only. OverRide: Always DecodeRow procedure DecodeRow( var Index: integer ); Decodes compressed image data contained in the memory area pointed to by Buf. Index is a counter variable keeping track of the current position in memory pointed to by PFile. WriteRow procedure WriteRow( row: integer ); Writes uncompressed image data to video memory at the page requested and plane setting. The row cooresponds to the Offset array index for addressing. ReadRow procedure ReadRow( row, sbyt: integer; var inBuf: PBuf ); Reads a single scan line, starting at offset row + sbyt, into the inBuf variable based on the row requested and plane setting. Row cooresponds to the Offset array index for addressing. Sbyt is the byte number within the row to start reading from. WriteHeader procedure WriteHeader; Writes header infromation to a new PCX file. Palette information is written as a default configuration, normal to the creating device. Future versions will allow for palette manipulation. FillOffsets function FillOffsets: boolean; virtual; Abstract method only. OverRide: Always. Encode function Encode(SRow, ERow: integer; sbyt: byte): integer;virtual; Abstract method only. OverRide: Always EncPut function EncPut( byt, cnt: byte ): integer; Writes a data byte (byt) to the PCX file (f). Cnt is a repeat rate of the data byte. If the repeat rate is greater than one, the cnt variable is coded and written to the file prior to the data byte. EncPut returns with the number of bytes written to the file (1 or 2) for keeping track of the total number written. EncodeLine function EncodeLine( inBuf: PBuf; inLen: integer ): boolean; Compresses the data contained in the inBuf variable. The amount of data to compress is determined by the inLen variable. Reads the data in inBuf a byte at a time and counts the number of times the data is repeated, if any. It calls EncPut when the data stops repeating (byte mismatch) to write to the PCX file. EncodeLine returns true if the encoding process was successful. GetByte function GetByte( n: integer ): byte; Retrieves the byte value from the memory pointed to by PFile at position n. GetInteger function GetInteger( n1, n2: integer ): integer; Retrieves the integer value from the memory pointed to by PFile at positions n1 and n2. FillOffsets function FillOffsets: boolean; virtual; First determines if enough memory is available for reading the PCX file into ram, then calculates video memory offset addresses based on descendant type. Calculations are stored in the Offset field with each horizontal scan line number cooresponding with the array number. ie: scanline 0 = Offset[0], scanline 1 = Offset[1] Method returns true if memory was allocated. If not enough memory is available, the method returns false and the Init constructor fails, returning NIL to the host. Decode procedure Decode; virtual; Decodes compressed image data based on header information. Allocates memory for Buf, determines if image is multiplane, calls EGA_SetPlane_Write, DecodeRow, WriteRow. OverRide: Always ┌─────────┐ │ BasePCX │ └────┬────┘ ┌─────┘ ╔════╧════╗ ║ HercPCX ║█ ╚═════════╝█ ▀▀▀▀▀▀▀▀▀▀ The HercPCX object provides the device dependant methods for creating PCX format files on Hercules graphics adapters. It can create PCX files on any monochrome graphics devices whose base video address is $B000, however if multiple pages are not supported you must be sure to pass only page 0 to the inherited Show method. METHODS, PUBLIC ────────────────────────────────────────────────────────────── Init constructor Init; Checks for the presence of an EGA/VGA adapter by seeing if the EGACard variable in the EGA unit is true or false. If EGACard is true the Init contructor fails, since a HercPCX instance on an EGA/VGA adapter would not display properly. If an EGA/VGA is not detected, the PCX units Display constant is set to equal the HERC_Attr constant and BasePCX.Init is called. If the BasePCX.Init method returns false, this constructor fails. Done destructor Done; virtual; Calls BasPCX.Done destructor. METHODS, PRIVATE ───────────────────────────────────────────────────────────── Decode procedure Decode; virtual; Allocates/disposes of memory for the Buf pointer. Checks with the IsMultiPlane method and if true decodes the compressed data based on a multi-plane image else decodes normally. Loops thru DecodeRow and WriteRow for each scan line from Hdr.ymn to Hdr.ymx. GetRow procedure GetRow( r, sbyt: integer; var inBuf: PBuf ); Calls ReadRow with r (row to read), sbyt (starting byte in row), and inBuf (memory area to read into). Encode function Encode(SRow, ERow: integer; sbyt: byte): integer;virtual; Loops from SRow to ERow calling GetRow with scan line number cooresponding to the loop count and sbyt starting postion. Calls EncodeLine with the data retrieved from GetRow. If EncodeLine returned true, goes to top of loop, else sets itself to PCXError9 and exits. If Encode completes correctly it returns to the calling method set to 0. FillOffsets function FillOffsets: boolean; virtual; Fills the Offset variable with the video memory address to the start of each scan line. The Offset array elements coorespond to the scan line number. ie: Offset^[0] = scan line 0, Offset^[1] = scan line 1, etc. These addresses are calculated based on the Hercules graphics adapter, which is in an interlaced pattern. ┌─────────┐ │ BasePCX │ └────┬────┘ ┌─────┴─────┐ ┌────┴────┐ ╔════╧════╗ │ HercPCX │ ║ EgaPCX ║█ └─────────┘ ╚═════════╝█ ▀▀▀▀▀▀▀▀▀▀ The EgaPCX object provides the device dependant methods for reading or creating PCX format files on EGA/VGA graphics adapters on pages 0 and 1 only in 640 x 350 resolution mode. METHODS, PUBLIC ────────────────────────────────────────────────────────────── Init constructor Init; Checks with EGA unit's EGACard constant and if not true, the constructor Fails. If EGACard returns true, Display is set to EGA_Attr and BasePcx.Init is called. Done destructor Done; virtual; Calls BasePCX.Done destructor. METHODS, PRIVATE ───────────────────────────────────────────────────────────── SetPal procedure SetPal; virtual; Sets palette to values contained in Hdr.CMap as read from the PCX file header. Calls EGA unit, EGA_SetRGBPalette procedure with Hdr.CMap component values. Decode procedure Decode; virtual; Allocates/disposes of memory for the Buf pointer. Checks with the IsMultiPlane method and if true decodes the compressed data based on a multi-plane image else decodes according to single plane data. Loops thru DecodeRow and WriteRow for each scan line from Hdr.ymn to Hdr.ymx. GetRow procedure GetRow( Plane, r, sbyt: integer; var inBuf: PBuf ); Retrieves video memory data for compressing. Calls EGA unit, EGA_SetPlane_Read with Plane (bit plane to read), calls ReadRow with r (scanline/row to read), sbyt (starting byte in row) and inBuf (memory area to read into). Encode function Encode(SRow, ERow: integer; sbyt: byte): integer;virtual; Loops from SRow to ERow calling GetRow with scan line number cooresponding to the loop count and sbyt starting position. Calls EncodeLine with the data retrieved from GetRow. If EncodeLine returned true, goes to top of loop, else sets itself to PCXError9 and exits. If Encode completes correctly it returns to the calling method set to 0. FillOffsets function FillOffsets: boolean; virtual; Fills the Offset variable with the video memory address to the start of each scan line. The Offset array elements coorespond to the scan line number. ie: Offset^[0] = scan line 0, Offset^[1] = scan line 1, etc. These addresses are calculated based on the EGA/VGA graphics adapter, which is in a non-interlaced pattern. ┌─────────┐ │ BasePCX │ └────┬────┘ ┌─────┴─────┐ ┌────┴────┐ ┌────┴────┐ │ HercPCX │ │ EgaPCX │ └─────────┘ └────┬────┘ ╔════╧════╗ ║ VgaPCX ║█ ╚═════════╝█ ▀▀▀▀▀▀▀▀▀▀ The VgaPCX object provides the device dependant methods for reading or creating PCX format files on VGA graphics adapters on pages 0 and 1 only in 640 x 350 or 640 x 480 resolution modes. Init constructor Init; Checks with EGA unit's VGACard constant and if not true, the constructor Fails. If VGACard returns true, Display is set to EGA_Attr with VertRes set to 480 and BasePcx.Init is called. Done destructor Done; virtual; Calls BasePCX.Done destructor. ────────────────────────────────────────────────────────────────────────────── Compiled with Borland's Turbo Pascal v6.0 Designed for ZSoft Corporation's PCX file format 29Jan91