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Graphics Programming Black Book (Special Edition)
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chapter35
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l35-2.c
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C/C++ Source or Header
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1997-06-18
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91 lines
/*
* Sample program to illustrate EGA/VGA line drawing routines.
*
* Compiled with Borland C++ 4.02
* Checked by Jim Mischel 11/21/94
*
* Must be linked with L14-1.C or L14-3.ASM. Build with either
* of these command lines:
* bcc l14-2.c l14-1.c, or
* bcc l14-2.c l14-3.asm
*
* By Michael Abrash.
*/
#include <dos.h> /* contains geninterrupt */
#define GRAPHICS_MODE 0x10
#define TEXT_MODE 0x03
#define BIOS_VIDEO_INT 0x10
#define X_MAX 640 /* working screen width */
#define Y_MAX 348 /* working screen height */
extern void EVGALine();
/*
* Subroutine to draw a rectangle full of vectors, of the specified
* length and color, around the specified rectangle center.
*/
void VectorsUp(XCenter, YCenter, XLength, YLength, Color)
int XCenter, YCenter; /* center of rectangle to fill */
int XLength, YLength; /* distance from center to edge
of rectangle */
int Color; /* color to draw lines in */
{
int WorkingX, WorkingY;
/* Lines from center to top of rectangle */
WorkingX = XCenter - XLength;
WorkingY = YCenter - YLength;
for ( ; WorkingX < ( XCenter + XLength ); WorkingX++ )
EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
/* Lines from center to right of rectangle */
WorkingX = XCenter + XLength - 1;
WorkingY = YCenter - YLength;
for ( ; WorkingY < ( YCenter + YLength ); WorkingY++ )
EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
/* Lines from center to bottom of rectangle */
WorkingX = XCenter + XLength - 1;
WorkingY = YCenter + YLength - 1;
for ( ; WorkingX >= ( XCenter - XLength ); WorkingX-- )
EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color);
/* Lines from center to left of rectangle */
WorkingX = XCenter - XLength;
WorkingY = YCenter + YLength - 1;
for ( ; WorkingY >= ( YCenter - YLength ); WorkingY-- )
EVGALine(XCenter, YCenter, WorkingX, WorkingY, Color );
}
/*
* Sample program to draw four rectangles full of lines.
*/
void main()
{
char temp;
/* Set graphics mode */
_AX = GRAPHICS_MODE;
geninterrupt(BIOS_VIDEO_INT);
/* Draw each of four rectangles full of vectors */
VectorsUp(X_MAX / 4, Y_MAX / 4, X_MAX / 4,
Y_MAX / 4, 1);
VectorsUp(X_MAX * 3 / 4, Y_MAX / 4, X_MAX / 4,
Y_MAX / 4, 2);
VectorsUp(X_MAX / 4, Y_MAX * 3 / 4, X_MAX / 4,
Y_MAX / 4, 3);
VectorsUp(X_MAX * 3 / 4, Y_MAX * 3 / 4, X_MAX / 4,
Y_MAX / 4, 4);
/* Wait for the enter key to be pressed */
scanf("%c", &temp);
/* Back to text mode */
_AX = TEXT_MODE;
geninterrupt(BIOS_VIDEO_INT);
}