graphics programming in c
TRANSCRIPT
Evaluation Criteria• Project: 40%• End Semester Examination: 60%
Course Content• Introduction to Graphics Programming in C• Points, Lines and Polygons• Line Drawing Algorithms • Circle Drawing Algorithms• Area Filling Algorithms• Geometric Transformations in 2D• Geometric Transformations in 3D• Line Clipping Algorithms in 2D• Line Clipping Algorithms in 3D
Integrated Development Environment• Turbo C++ , Version 3.0, Copyright (c) 1990, 1992 by Borland
International, Inc
Graphics Header File• Go to File New • Type initgraph in the new window and right click on it• There you will find a program and using it lets try to create a
header file to initialize and exit graphics mode• Open another file and save it as grap.h
The grap.h Header File#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
void ginit()
{
……
……
}
void gexit()
{
……
……
}
The ginit() Functionvoid ginit()
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
/* initialize graphics mode */
initgraph(&gdriver, &gmode, "D:/Tcpp/BGI");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* return with error code */
}
}
The gexit() Functionvoid gexit()
{
closegraph();
}
The First Program• Open a new file and save it as first.c• There you have to include the grap.h header file that had been
created earlier• Then your first program should look like as follows and
running it will give a black and empty screen
#include<stdio.h>
#include<conio.h>
#include"D:/GP/header/grap.h"
void main()
{
ginit();
getch();
gexit();
}
The Output Screen• Execute following code to get the maximum x and maximum
y values of the output screen
#include<stdio.h>
#include<conio.h>
#include"D:/GP/header/grap.h"
void main()
{
ginit();
printf("%d %d",getmaxx(),getmaxy());
getch();
gexit();
}
The Output Screenx
y
The Output Screen• The y-axis is upside down?• The solution:
(x,y) (x, getmaxy() - y)
x
y x
y
Better Approximation as an Integer
FLOOR (x + 0.5)
Approximating x and y Coordinatesint dpx(double x)
{
int p;
p=(int)(x+0.5);
return p;
}
int dpy(double y)
{
int p;
p=(int)(y+0.5);
p=getmaxy()-p;
return p;
}
Displaying a Pointvoid main()
{
ginit();
putpixel(dpx(50.2),dpy(70.7),15);
getch();
gexit();
}
Any Questions?
Thank You!