else
color->a = round_channel (color->a, PIXMAN_FORMAT_A (format));
}
+
+/* Check whether @pixel is a valid quantization of the a, r, g, b
+ * parameters. Some slack is permitted.
+ */
+void
+pixel_checker_init (pixel_checker_t *checker, pixman_format_code_t format)
+{
+ assert (PIXMAN_FORMAT_VIS (format));
+
+ checker->format = format;
+
+ switch (PIXMAN_FORMAT_TYPE (format))
+ {
+ case PIXMAN_TYPE_A:
+ checker->bs = 0;
+ checker->gs = 0;
+ checker->rs = 0;
+ checker->as = 0;
+ break;
+
+ case PIXMAN_TYPE_ARGB:
+ checker->bs = 0;
+ checker->gs = checker->bs + PIXMAN_FORMAT_B (format);
+ checker->rs = checker->gs + PIXMAN_FORMAT_G (format);
+ checker->as = checker->rs + PIXMAN_FORMAT_R (format);
+ break;
+
+ case PIXMAN_TYPE_ABGR:
+ checker->rs = 0;
+ checker->gs = checker->rs + PIXMAN_FORMAT_R (format);
+ checker->bs = checker->gs + PIXMAN_FORMAT_G (format);
+ checker->as = checker->bs + PIXMAN_FORMAT_B (format);
+ break;
+
+ case PIXMAN_TYPE_BGRA:
+ /* With BGRA formats we start counting at the high end of the pixel */
+ checker->bs = PIXMAN_FORMAT_BPP (format) - PIXMAN_FORMAT_B (format);
+ checker->gs = checker->bs - PIXMAN_FORMAT_B (format);
+ checker->rs = checker->gs - PIXMAN_FORMAT_G (format);
+ checker->as = checker->rs - PIXMAN_FORMAT_R (format);
+ break;
+
+ case PIXMAN_TYPE_RGBA:
+ /* With BGRA formats we start counting at the high end of the pixel */
+ checker->rs = PIXMAN_FORMAT_BPP (format) - PIXMAN_FORMAT_R (format);
+ checker->gs = checker->rs - PIXMAN_FORMAT_R (format);
+ checker->bs = checker->gs - PIXMAN_FORMAT_G (format);
+ checker->as = checker->bs - PIXMAN_FORMAT_B (format);
+ break;
+
+ default:
+ assert (0);
+ break;
+ }
+
+ checker->am = ((1 << PIXMAN_FORMAT_A (format)) - 1) << checker->as;
+ checker->rm = ((1 << PIXMAN_FORMAT_R (format)) - 1) << checker->rs;
+ checker->gm = ((1 << PIXMAN_FORMAT_G (format)) - 1) << checker->gs;
+ checker->bm = ((1 << PIXMAN_FORMAT_B (format)) - 1) << checker->bs;
+
+ checker->aw = PIXMAN_FORMAT_A (format);
+ checker->rw = PIXMAN_FORMAT_R (format);
+ checker->gw = PIXMAN_FORMAT_G (format);
+ checker->bw = PIXMAN_FORMAT_B (format);
+}
+
+void
+pixel_checker_split_pixel (const pixel_checker_t *checker, uint32_t pixel,
+ int *a, int *r, int *g, int *b)
+{
+ *a = (pixel & checker->am) >> checker->as;
+ *r = (pixel & checker->rm) >> checker->rs;
+ *g = (pixel & checker->gm) >> checker->gs;
+ *b = (pixel & checker->bm) >> checker->bs;
+}
+
+static int32_t
+convert (double v, uint32_t width, uint32_t mask, uint32_t shift, double def)
+{
+ int32_t r;
+
+ if (!mask)
+ v = def;
+
+ r = (v * ((mask >> shift) + 1));
+ r -= r >> width;
+
+ return r;
+}
+
+static void
+get_limits (const pixel_checker_t *checker, double limit,
+ color_t *color,
+ int *ao, int *ro, int *go, int *bo)
+{
+ *ao = convert (color->a + limit, checker->aw, checker->am, checker->as, 1.0);
+ *ro = convert (color->r + limit, checker->rw, checker->rm, checker->rs, 0.0);
+ *go = convert (color->g + limit, checker->gw, checker->gm, checker->gs, 0.0);
+ *bo = convert (color->b + limit, checker->bw, checker->bm, checker->bs, 0.0);
+}
+
+/* The acceptable deviation in units of [0.0, 1.0]
+ */
+#define DEVIATION (0.004)
+
+void
+pixel_checker_get_max (const pixel_checker_t *checker, color_t *color,
+ int *am, int *rm, int *gm, int *bm)
+{
+ get_limits (checker, DEVIATION, color, am, rm, gm, bm);
+}
+
+void
+pixel_checker_get_min (const pixel_checker_t *checker, color_t *color,
+ int *am, int *rm, int *gm, int *bm)
+{
+ get_limits (checker, - DEVIATION, color, am, rm, gm, bm);
+}
+
+pixman_bool_t
+pixel_checker_check (const pixel_checker_t *checker, uint32_t pixel,
+ color_t *color)
+{
+ int32_t a_lo, a_hi, r_lo, r_hi, g_lo, g_hi, b_lo, b_hi;
+ int32_t ai, ri, gi, bi;
+ pixman_bool_t result;
+
+ pixel_checker_get_min (checker, color, &a_lo, &r_lo, &g_lo, &b_lo);
+ pixel_checker_get_max (checker, color, &a_hi, &r_hi, &g_hi, &b_hi);
+ pixel_checker_split_pixel (checker, pixel, &ai, &ri, &gi, &bi);
+
+ result =
+ a_lo <= ai && ai <= a_hi &&
+ r_lo <= ri && ri <= r_hi &&
+ g_lo <= gi && gi <= g_hi &&
+ b_lo <= bi && bi <= b_hi;
+
+ return result;
+}
void
round_color (pixman_format_code_t format, color_t *color);
+
+typedef struct
+{
+ pixman_format_code_t format;
+ uint32_t am, rm, gm, bm;
+ uint32_t as, rs, gs, bs;
+ uint32_t aw, rw, gw, bw;
+} pixel_checker_t;
+
+void
+pixel_checker_init (pixel_checker_t *checker, pixman_format_code_t format);
+
+void
+pixel_checker_split_pixel (const pixel_checker_t *checker, uint32_t pixel,
+ int *a, int *r, int *g, int *b);
+
+void
+pixel_checker_get_max (const pixel_checker_t *checker, color_t *color,
+ int *a, int *r, int *g, int *b);
+
+void
+pixel_checker_get_min (const pixel_checker_t *checker, color_t *color,
+ int *a, int *r, int *g, int *b);
+
+pixman_bool_t
+pixel_checker_check (const pixel_checker_t *checker,
+ uint32_t pixel, color_t *color);