#define PACK_RGB32(r, g, b) \
((((r) & 0xff) << 16) | (((g) & 0xff) << 8) | ((b) & 0xff))
+#define UNPACK_R32(c) (((c) >> 16) & 0xff)
+#define UNPACK_G32(c) (((c) >> 8) & 0xff)
+#define UNPACK_B32(c) ((c) & 0xff)
+
int clip_line(int *x0, int *y0, int *x1, int *y1, int xmin, int ymin, int xmax, int ymax);
void draw_line(int x0, int y0, int x1, int y1, unsigned short color);