img.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "img.h"
static unsigned char buf[HEIGHT][WIDTH][3];
static int filecnt = 0;
static char fname[100];
void img_clear(void) {
    int i, j;
    for(j = 0; j < HEIGHT; ++j){
        for(i = 0; i < WIDTH; ++i) {
            buf[j][i][0] = buf[j][i][1] = buf[j][i][2] = 255;
        }
    }
}
void img_write(void) {
    sprintf(fname, "img%04d.ppm", ++filecnt);
    FILE *f = fopen(fname, "wb");
    if(f == NULL) {
        fprintf(stderr, "can't open %s\n", fname);
        exit(1);
    }
    fprintf(f, "P6\n%d %d\n255\n", WIDTH, HEIGHT);
    fwrite(buf, sizeof(buf), 1, f);
    fclose(f);
}
void img_putpixel(struct color c, int x, int y) {
    if(x < 0 || x >= WIDTH || y < 0 || y >= HEIGHT) {
        return;
    }
    buf[HEIGHT-y-1][x][0] = c.r;
    buf[HEIGHT-y-1][x][1] = c.g;
    buf[HEIGHT-y-1][x][2] = c.b;
}
void img_fillrect(struct color c, double x, double y, double w, double h) {
    int imin = (int)(x - w/2), imax = (int)(x + w/2);
    int jmin = (int)(y - h/2), jmax = (int)(y + h/2);
    int i, j;
    for(j = jmin; j <= jmax; ++j) {
        for(i = imin; i <= imax; ++i) { img_putpixel(c, i, j); }
    }
}