static int
_fill_polygon_rgb(uint8_t *img,
int npoints, Edge *e, uint32_t color,
int w, int h, int rowstride)
{
int i, j;
float *xx;
int ymin, ymax;
float y;
if (npoints <= 0) return 0;
/* Find upper and lower polygon boundary (within image) */
ymin = e[0].ymin;
ymax = e[0].ymax;
for (i = 1; i < npoints; i++) {
if (e[i].ymin < ymin) ymin = e[i].ymin;
if (e[i].ymax > ymax) ymax = e[i].ymax;
}
if (ymin < 0) ymin = 0;
if (ymax >= h) ymax = h-1;
/* Process polygon edges */
xx = malloc(npoints * sizeof(float));
if (!xx) return -1;
for (;ymin <= ymax; ymin++) {
y = ymin+0.5F;
for (i = j = 0; i < npoints; i++) {
if (y >= e[i].ymin && y <= e[i].ymax) {
if (e[i].d == 0)
draw_hline_rgb(img, e[i].xmin, ymin, e[i].xmax, color,
w, h, rowstride);
else
xx[j++] = (y-e[i].y0) * e[i].dx + e[i].x0;
}
}
if (j == 2) {
if (xx[0] < xx[1])
draw_hline_rgb(img, CEIL(xx[0]-0.5), ymin, FLOOR(xx[1]+0.5),
color, w, h, rowstride);
else
draw_hline_rgb(img, CEIL(xx[1]-0.5), ymin, FLOOR(xx[0]+0.5),
color, w, h, rowstride);
} else {
qsort(xx, j, sizeof(float), x_cmp);
for (i = 0; i < j-1 ; i += 2)
draw_hline_rgb(img, CEIL(xx[i]-0.5), ymin, FLOOR(xx[i+1]+0.5),
color, w, h, rowstride);
}
}
free(xx);
return 0;
}
int main(int argc, char **argv)
{
uint32_t w = 600;
uint32_t h = 400;
uint32_t rs = w * 3;
uint8_t *img = (uint8_t*)malloc( h * rs );
memset(img, 0, h*rs);
draw_line_rgb(img, 0, 0, 600, 400, 0xFFFF00, w, h, rs);
draw_hline_rgb(img, 0, 200, 200, 0xFF00FF, w, h, rs);
draw_hline_rgb(img, 200, 300, 0, 0xFF00FF, w, h, rs);
int triangle[] = { 300, 200,
300, 100,
400, 200 };
draw_polygon_rgb(img, 3, triangle, 0x00FF00, 0, w, h, rs);
draw_rect_rgb(img, 300, 300, 390, 390, 0xFFFFFF, 1, w, h, rs);
draw_rect_rgb(img, 350, 250, 450, 330, 0x80FF0000, 1, w, h, rs);
draw_rect_rgb(img, 400, 200, 500, 300, 0xa00000FF, 1, w, h, rs);
draw_ellipse_rgb(img, 500, 100, 575, 150, 0x00FFFF, 1, 0,
w, h, rs);
draw_ellipse_rgb(img, 450, 25, 525, 100, 0x00FFFF, 0, 0,
w, h, rs);
draw_ellipse_rgb(img, -50,-50,50,50, 0xFFFF00, 1, 0, w, h, rs);
FILE *fp = fopen("out.ppm", "wb");
ppm_write( fp, img, w, h, w*3 );
fclose( fp );
free( img );
printf("created out.ppm\n");
return 0;
}
void
draw_line_rgb(int x0, int y0, int x1, int y1,
DrawColor color, DrawImage* img)
{
int xs;
int ys;
int dx = x1-x0;
if (dx < 0)
{
dx = -dx;
xs = -1;
}
else
xs = 1;
int dy = y1-y0;
if (dy < 0)
{
dy = -dy;
ys = -1;
}
else
ys = 1;
int n = (dx > dy) ? dx : dy;
if (dx == 0) {
for (int i = 0; i < dy; i++) {
draw_point_rgb(x0, y0, color, img);
y0 += ys;
}
} else if (dy == 0) {
draw_hline_rgb(x0, y0, x1, color, img);
} else if (dx > dy) {
n = dx;
dy += dy;
int e = dy - dx;
dx += dx;
for(int i = 0; i < n; i++) {
draw_point_rgb(x0, y0, color, img);
if (e >= 0) {
y0 += ys;
e -= dx;
}
e += dy;
x0 += xs;
}
} else {
n = dy;
dx += dx;
int e = dx - dy;
dy += dy;
for(int i = 0; i < n; i++) {
draw_point_rgb(x0, y0, color, img);
if (e >= 0) {
x0 += xs;
e -= dy;
}
e += dx;
y0 += ys;
}
}
}
void draw_box_rgb(int x0, int y0, int x1, int y1,
DrawColor color, DrawImage* img)
{
for(int y=y0; y<=y1; y++)
draw_hline_rgb(x0, y, x1, color, img);
}
void
draw_line_rgb(uint8_t *img, int x0, int y0, int x1, int y1,
uint32_t color,
int w, int h, int rowstride)
{
int i, n, e;
int dx, dy;
int xs, ys;
/* normalize coordinates */
dx = x1-x0;
if (dx < 0) dx = -dx, xs = -1;
else xs = 1;
dy = y1-y0;
if (dy < 0) dy = -dy, ys = -1;
else ys = 1;
n = (dx > dy) ? dx : dy;
if (dx == 0) {
/* vertical */
for (i = 0; i < dy; i++) {
draw_point_rgb(img, x0, y0, color, w, h, rowstride);
y0 += ys;
}
} else if (dy == 0) {
/* horizontal */
draw_hline_rgb(img, x0, y0, x1, color, w, h, rowstride);
} else if (dx > dy) {
/* bresenham, horizontal slope */
n = dx;
dy += dy;
e = dy - dx;
dx += dx;
for (i = 0; i < n; i++) {
draw_point_rgb(img, x0, y0, color, w, h, rowstride);
if (e >= 0) {
y0 += ys;
e -= dx;
}
e += dy;
x0 += xs;
}
} else {
/* bresenham, vertical slope */
n = dy;
dx += dx;
e = dx - dy;
dy += dy;
for (i = 0; i < n; i++) {
draw_point_rgb(img, x0, y0, color, w, h, rowstride);
if (e >= 0) {
x0 += xs;
e -= dy;
}
e += dx;
y0 += ys;
}
}
}
