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SURPAS-86 SUPPLEMENTARY DOCUMENTATION IBM PC Graphics Driver Copyright (C) 1987 Tixaku Pty Ltd On your SURPAS distribution disk you will find two files called GRAPHICS.PAS and GRAPHICS.BIN. They contain a complete set of graphic drivers for the IBM Color/Graphics Adapter and enable you to use medium and high resolution graphics in your SURPAS Pascal programs. The graphic drivers support all three graphic modes: 320 x 200 color graphics, 320 x 200 monochrome graphics and 620 x 200 monochrome graphics. If your system is not equipped with a Color/Graphics Adapter you cannot use the graphic drivers. To include the graphic drivers in a program, place the following compiler directive at the very beginning of the program: (*$I GRAPHICS*) This will include the file called GRAPHICS.PAS in the compilation of your source text. Alternatively you can copy the entire GRAP- HICS.PAS file into your source text. GRAPHICS.PAS contains a list of very short procedures, each of which calls an EXTERNAL proce- dure called GRAPHICS. The code for the GRAPHICS procedure is read from the GRAPHICS.BIN file and it contains the actual drivers. The drivers are written in machine code to optimize execution speed. The following procedures and functions are provided by the gra- phic driver package: CRTMODE Set CRT mode. WINDOW Define Window Coordinates. BCOLOR Set Background Color. PCOLOR Set Color Palette. FCOLOR Set Foreground Color. COLORMAP Define Color Map. FILLSCREEN Fill Screen. MOVETO Set Current Position. MOVEBY Set Current Position Relative. LINETO Draw Line. LINEBY Draw Line Relative. PLOTAT Plot Point. PLOTBY Plot Point Relative. PAINT Paint Area. POINT Read Color Of Dot. Each routine is described in detail below. All graphic routines operate within a window. By default the window is set to the entire graphic image, i.e. (0,0)-(319,199) for medium resolution and (0,0)-(639,199) for high resolution, but there are occations when it is handy to use only part of the screen, while safeguarding the rest from accidental use. For this purpose, the graphic drivers allow you to define any rectangle on the screen as the window. The graphic routines operate on integer coordinates. Thus, the coordinate range is -32768..32767. However, coodinates outside the window are ignored. When a line is drawn using any of the graphic routines, it is automatically clipped so that only the portion which lies within the current window is displayed. Points whose coordinates are not within the current window, even those points that would not be on the screen at all, are legal but ignored. It is possible to mix text and graphics on the screen. In 320 x 200 graphics mode the screen can display 40 x 25 characters and in 640 x 200 graphics mode it can display 80 x 25 characters. To write a text on the graphics screen, use the GOTOXY procedure or an Escape-Y sequence to move the cursor (which is not visible in graphics mode) to the relevant row/column, and output the text using a WRITE statement. Each character cell occupies 8 x 8 dots, so the actual X coordinate of the upper left corner of a charac- ter cell is the row number times 8, and the actual Y coordinate is the column number times 8. Note that the foreground color set by FCOLOR does not apply when text is written to the graphics screen. The foreground color of text is selected through an Escape-b sequence. For further details on this, please refer to the IBMPC.DOC Supplementary Documentation file on your distribu- tion disk. Function: Set CRT Mode. Header: PROCEDURE CRTMODE(M: INTEGER); Remarks: This procedure is used to set the CRT operating mode. M is an integer between 0 and 7 which selects an operating mode according to the table below: 0 = 40 x 25 Black and White. 1 = 40 x 25 Color. 2 = 80 x 25 Black and White. 3 = 80 x 25 Color. 4 = 320 x 200 Color Graphics. 5 = 320 x 200 Monochrome Graphics. 6 = 640 x 200 Monochrome Graphics. 7 = 80 x 25 Black and White (Monochrome Display). Mode 7 should only be selected if your IBM PC or XT is equipped with a Monochrome Display Adapter. When CRTMODE is called, the window is reset to the whole screen, the current position becomes (0,0) and the foreground color becomes 3 (CRT modes 4 and 5) or 1 (CRT mode 6). All of the routines described in the following operate correctly in modes 4-6 only. Function: Define Window Coordinates. Header: PROCEDURE WINDOW(X1,Y1,X2,Y2: INTEGER); Remarks: The window is the area on the screen that may be manipulated by the graphic routines. By default the window is the whole screen, but through this command the boundaries of the window may be changed. Every- thing outside the window remains unchanged during all graphic operations until it again becomes part of the window. (X1,Y1) and (X2,Y2) are the opposite corners of the window (no special ordering is required). X coordinates must be between 0 and 319 (CRT modes 4 and 5) or 639 (CRT mode 6) and Y coordinates must be between 0 and 199. If one or more of the coordinates are out of range, the window is not changed. The current position becomes the upper left corner of the window. Note that CRTMODE resets the window to the entire screen. Function: Set Background Color. Header: PROCEDURE BCOLOR(C: INTEGER); Remarks: For 320 x 200 graphics (CRT modes 4 and 5) this procedure sets the background color. For 640 x 200 graphics (CRT mode 6) it sets the color value of the foreground color (the background color is always black in this mode). C is an integer between 0 to 15 which selects a color according to the table below: 0 = Black. 8 = Dark Gray. 1 = Blue. 9 = Light Blue. 2 = Green. 10 = Light Green. 3 = Cyan. 11 = Light Cyan. 4 = Red. 12 = Light Red. 5 = Magenta. 13 = Light Magenta. 6 = Brown. 14 = Yellow. 7 = Light Gray. 15 = White. For 320 x 200 graphics, the background color defaults to black (0). For 640 x 200 graphics it defaults to white (15), since it is actually the foreground color. Function: Set Color Palette. Header: PROCEDURE PCOLOR(C: INTEGER); Remarks: This procedure has meaning only for 320 x 200 gra- phics (CRT modes 4 and 5). C is an integer between 0 and 1 which selects the foreground color palette according to the table below: 0 = Green, Red and Yellow foreground colors. 1 = Cyan, Magenta and White foreground colors. The default palette is 1. The screen can only display the colors of one palette. Thus, all foreground co- lors on the screen change instantly when an new palette is selected. Function: Set Foreground Color. Header: PROCEDURE FCOLOR(C: INTEGER); Remarks: C is an integer between -1 and 3 (320 x 200 graphics) or -1 and 1 (640 x 200 graphics). It selects the foreground color, i.e. the color to be used for lines and dots drawn by the LINETO, LINEBY, PLOTAT and PLOTBY routines. For 320 x 200 graphics, C selects a foreground color according to the table below: -1 = Use color map set by COLORMAP. 0 = Background color set by BCOLOR. 1 = Green (palette 0) or Cyan (palette 1). 2 = Red (palette 0) or Magenta (palette 1). 3 = Yellow (palette 0) or White (palette 1). For 640 x 200 graphics, C selects a foreground color according to the table below: -1 = Use color map set by COLORMAP. 0 = Black. 1 = Color set by BCOLOR. For details on color mapping (foreground color -1), see the description of the COLORMAP procedure. The default foreground color is 3 for 320 x 200 graphics and 1 for 640 x 200 graphics. Note that the fore- ground color set by FCOLOR does not apply when text is written to the graphics screen through write sta- tements (use Escape-b instead). Function: Define Color Map. Header: PROCEDURE COLORMAP(C0,C1,C2,C3: INTEGER); Remarks: When the foreground color (set by FCOLOR) is -1, the graphic routines use a color map to write dots on the screen. Essentially the color map is a translation table: When a dot is written, its current color value is used to determine its new value. C0 defines the new color that dots of color 0 should have when they are written, C1 defines the new color for color 1, etc. For instance, if the color map is (3,2,1,0) and the foreground color is -1, LINETO, LINEBY, PLOTAT and PLOTBY will complement dots when they are writ- ten. A color map of (0,2,2,2) will turn dots of all foreground colors into color 2, but it will leave dots of the background color unchanged. In 640 x 200 graphics mode the screen can only show two colors (0 and 1), so C2 and C3 are ignored in this mode. There is no default color map; the COLORMAP procedure must be called before foreground color -1 is used. Function: Fill Screen. Header: PROCEDURE FILLSCREEN(C: INTEGER); Remarks: FILLSCREEN fills the entire window with the color specified by C. C is an integer between -1 and 3 (320 x 200 graphics) or -1 and 1 (640 x 200 graphics). For a definition of the colors associated with the values of C please refer to the description of FCOLOR. When C is -1, FILLSCREEN uses the color map. This allows some dramatic effects. For example, if the color map is (3,2,1,0), FILLSCREEN(-1) makes a "negative" of the contents of the window. If the color map is (0,1,0,3), FILLSCREEN will turn all red or magenta dots into the background color. Function: Set Current Position. Header: PROCEDURE MOVETO(X,Y: INTEGER); Remarks: The current position becomes (X,Y). Function: Set Current Position Relative. Header: PROCEDURE MOVEBY(DX,DY: INTEGER); Remarks: (DX,DY) is added to the current position. Function: Draw Line. Header: PROCEDURE LINETO(X,Y: INTEGER); Remarks: Draws a line in the current foreground color from the current position to (X,Y). The current position then becomes (X,Y). Function: Draw Line Relative. Header: PROCEDURE LINEBY(DX,DY: INTEGER); Remarks: Draws a line in the current foreground color from the current position to the current position plus (DX,DY). (DX,DY) is then added to the current posi- tion. Function: Plot Point. Header: PROCEDURE PLOTAT(X,Y: INTEGER); Remarks: Plots a point in the current foreground color at (X,Y). The current position becomes (X,Y). Function: Plot Point Relative. Header: PROCEDURE PLOTBY(DX,DY: INTEGER); Remarks: Plots a point in the current foreground color at the current position plus (DX,DY). (DX,DY) is then added to the current position. Function: Paint Area. Header: PROCEDURE PAINT(X,Y,FC,BC: INTEGER); Remarks: Fills in an area on the screen with the color speci- fied by FC. (X,Y) are the coordinates of a point within the area to be painted. BC is the boundary color, i.e. the color of the edges of the area. PAINT has no effect if the starting point already has the boundary color. If the shape to be painted is not closed, the foreground color will "leak out" and fill the entire window. On the other hand, if the shape is closed but the starting point is outside it, PAINT will fill the surrounding area. PAINT never paints beyond the current window. FC and BC must be true colors, i.e. 0-3 for 320 x 200 graphics and 0-1 for 640 x 200 graphics. Color mapping is not supported by PAINT. Function: Return Color Of Dot. Header: FUNCTION POINT(X,Y: INTEGER): INTEGER; Remarks: Returns the color of the dot at (X,Y), i.e. 0-3 for 320 x 200 graphics and 0-1 for 640 x 200 graphics. If (X,Y) is outside the window, POINT returns -1.