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_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;
}
}
}
