Bresenham's line algorithm

drawline.c

void draw_line(int x1, int y1, int x2, int y2) {
	
	int dx = x2 - x1;
	int dy = y2 - y1;
	float slope = (float)dy / (float)dx;
	float error = 0;
	int y = y1;

	int i;

	for (i = 0; i < x2; i++) {

		if (i == 0) {

			draw_pixel(x1 + i, y, 255);
			continue;
		}
		
		error += slope;

		if (error >= 0.5) {
		
			y++;
			error--;
		}
		
		draw_pixel(x1 + i, y, 255);
	}
}