MINMAX
__x = MINMAX(__x + x, 0, FB_WIDTH);
__y = MINMAX(__y + y, 0, FB_HEIGHT);
x = MINMAX(x, 0, FB_WIDTH);
y = MINMAX(y, 0, FB_HEIGHT);
xend = MINMAX(x + w, 0, FB_WIDTH);
yend = MINMAX(y + h , 0, FB_HEIGHT);
x0 = MINMAX(x0, 0, FB_WIDTH);
y0 = MINMAX(y0, 0, FB_HEIGHT);
x1 = MINMAX(x1, 0, FB_WIDTH);
y1 = MINMAX(y1, 0, FB_HEIGHT);
x1end = MINMAX(x1 + w, 0, FB_WIDTH);
y1end = MINMAX(y1 + h, 0, FB_HEIGHT);