* SECTION:rgba_colors
* @Short_description: RGBA colors
* @Title: RGBA Colors
+ *
+ * The #GdkRGBA struct is a convenient way to pass rgba colors around.
+ * It's based on cairo's way to deal with colors and mirrors its behavior.
+ * All values are in the range from 0.0 to 1.0 inclusive. So the color
+ * (0.0, 0.0, 0.0, 0.0) represents transparent black and
+ * (1.0, 1.0, 1.0, 1.0) is opaque white. Other values will be clamped
+ * to this range when drawing.
*/
G_DEFINE_BOXED_TYPE (GdkRGBA, gdk_rgba,
gdk_rgba_copy, gdk_rgba_free)
+/**
+ * GdkRGBA:
+ * @red: The intensity of the red channel from 0.0 to 1.0 inclusive
+ * @green: The intensity of the green channel from 0.0 to 1.0 inclusive
+ * @blue: The intensity of the blue channel from 0.0 to 1.0 inclusive
+ * @alpha: The opacity of the color from 0.0 for completely translucent to
+ * 1.0 for opaque
+ *
+ * The GdkRGBA structure is used to represent a (possibly translucent)
+ * color, in a way that is compatible with cairos notion of color.
+ */
+
/**
* gdk_rgba_copy:
* @rgba: a #GdkRGBA
*
- * Makes a copy of a #GdkRGBA structure, the result must be freed
- * through gdk_rgba_free().
+ * Makes a copy of a #GdkRGBA structure.
+ *
+ * The result must be freed through gdk_rgba_free().
+ *
+ * Returns: A newly allocated #GdkRGBA, with the same contents as @rgba
*
- * Returns: A newly allocated #GdkRGBA
- **/
+ * Since: 3.0
+ */
GdkRGBA *
-gdk_rgba_copy (GdkRGBA *rgba)
+gdk_rgba_copy (const GdkRGBA *rgba)
{
GdkRGBA *copy;
* @rgba: a #GdkRGBA
*
* Frees a #GdkRGBA struct created with gdk_rgba_copy()
- **/
+ *
+ * Since: 3.0
+ */
void
gdk_rgba_free (GdkRGBA *rgba)
{
g_slice_free (GdkRGBA, rgba);
}
+#define SKIP_WHITESPACES(s) while (*(s) == ' ') (s)++;
+
+/* Parses a single color component from a rgb() or rgba() specification
+ * according to CSS3 rules. Compared to exact CSS3 parsing we are liberal
+ * in what we accept as follows:
+ *
+ * - For non-percentage values, we accept floats in the range 0-255
+ * not just [0-9]+ integers
+ * - For percentage values we accept any float, not just
+ * [ 0-9]+ | [0-9]* '.' [0-9]+
+ * - We accept mixed percentages and non-percentages in a single
+ * rgb() or rgba() specification.
+ */
+static double
+parse_rgb_value (const char *str,
+ char **endp)
+{
+ double number;
+ const char *p;
+
+ number = g_ascii_strtod (str, endp);
+
+ p = *endp;
+
+ SKIP_WHITESPACES (p);
+
+ if (*p == '%')
+ {
+ *endp = (char *)(p + 1);
+ return CLAMP(number / 100., 0., 1.);
+ }
+ else
+ {
+ return CLAMP(number / 255., 0., 1.);
+ }
+}
+
/**
* gdk_rgba_parse:
- * @spec: the string specifying the color
* @rgba: the #GdkRGBA struct to fill in
+ * @spec: the string specifying the color
*
* Parses a textual representation of a color, filling in
* the <structfield>red</structfield>, <structfield>green</structfield>,
* </itemizedlist>
*
* Where 'r', 'g', 'b' and 'a' are respectively the red, green, blue and
- * alpha color values, parsed in the last 2 cases as double numbers in
- * the range [0..1], any other value out of that range will be clamped.
+ * alpha color values. In the last two cases, r g and b are either integers
+ * in the range 0 to 255 or precentage values in the range 0% to 100%, and
+ * a is a floating point value in the range 0 to 1.
*
* Returns: %TRUE if the parsing succeeded
- **/
+ *
+ * Since: 3.0
+ */
gboolean
-gdk_rgba_parse (const gchar *spec,
- GdkRGBA *rgba)
+gdk_rgba_parse (GdkRGBA *rgba,
+ const gchar *spec)
{
gboolean has_alpha;
gdouble r, g, b, a;
gchar *str = (gchar *) spec;
-#define SKIP_WHITESPACES(s) while (*(s) == ' ') (s)++;
-
if (strncmp (str, "rgba", 4) == 0)
{
has_alpha = TRUE;
PangoColor pango_color;
/* Resort on PangoColor for rgb.txt color
- * map and '#' prefixed colors */
+ * map and '#' prefixed colors
+ */
if (pango_color_parse (&pango_color, str))
{
if (rgba)
/* Parse red */
SKIP_WHITESPACES (str);
- r = g_ascii_strtod (str, &str);
+ r = parse_rgb_value (str, &str);
SKIP_WHITESPACES (str);
if (*str != ',')
/* Parse green */
SKIP_WHITESPACES (str);
- g = g_ascii_strtod (str, &str);
+ g = parse_rgb_value (str, &str);
SKIP_WHITESPACES (str);
if (*str != ',')
/* Parse blue */
SKIP_WHITESPACES (str);
- b = g_ascii_strtod (str, &str);
+ b = parse_rgb_value (str, &str);
SKIP_WHITESPACES (str);
if (has_alpha)
if (*str != ')')
return FALSE;
-#undef SKIP_WHITESPACES
-
if (rgba)
{
rgba->red = CLAMP (r, 0, 1);
return TRUE;
}
+#undef SKIP_WHITESPACES
+
/**
* gdk_rgba_hash:
- * @p: a #GdkRGBA pointer.
+ * @p: (type GdkRGBA): a #GdkRGBA pointer
*
* A hash function suitable for using for a hash
- * table that stores #GdkRGBA<!-- -->s.
+ * table that stores #GdkRGBAs.
*
- * Return value: The hash function applied to @p
- **/
+ * Return value: The hash value for @p
+ *
+ * Since: 3.0
+ */
guint
gdk_rgba_hash (gconstpointer p)
{
const GdkRGBA *rgba = p;
return ((guint) (rgba->red * 65535) +
- ((guint) (rgba->green * 65535) << 11) +
- ((guint) (rgba->blue * 65535) << 22) +
- ((guint) (rgba->alpha * 65535) >> 6));
+ ((guint) (rgba->green * 65535) << 11) +
+ ((guint) (rgba->blue * 65535) << 22) +
+ ((guint) (rgba->alpha * 65535) >> 6));
}
/**
* gdk_rgba_equal:
- * @p1: a #GdkRGBA pointer.
- * @p2: another #GdkRGBA pointer.
+ * @p1: (type GdkRGBA): a #GdkRGBA pointer
+ * @p2: (type GdkRGBA): another #GdkRGBA pointer
*
* Compares two RGBA colors.
*
* Return value: %TRUE if the two colors compare equal
- **/
+ *
+ * Since: 3.0
+ */
gboolean
gdk_rgba_equal (gconstpointer p1,
gconstpointer p2)
* @rgba: a #GdkRGBA
*
* Returns a textual specification of @rgba in the form
- * <literal>rgba (r, g, b, a)</literal>, where 'r', 'g',
- * 'b' and 'a' represent the red, green, blue and alpha
- * values respectively.
+ * <literal>rgb (r, g, b)</literal> or
+ * <literal>rgba (r, g, b, a)</literal>,
+ * where 'r', 'g', 'b' and 'a' represent the red, green,
+ * blue and alpha values respectively. r, g, and b are
+ * represented as integers in the range 0 to 255, and a
+ * is represented as floating point value in the range 0 to 1.
+ *
+ * These string forms are string forms those supported by
+ * the CSS3 colors module, and can be parsed by gdk_rgba_parse().
+ *
+ * Note that this string representation may loose some
+ * precision, since r, g and b are represented as 8-bit
+ * integers. If this is a concern, you should use a
+ * different representation.
*
* Returns: A newly allocated text string
- **/
+ *
+ * Since: 3.0
+ */
gchar *
-gdk_rgba_to_string (GdkRGBA *rgba)
+gdk_rgba_to_string (const GdkRGBA *rgba)
{
- return g_strdup_printf ("rgba(%f,%f,%f,%f)",
- CLAMP (rgba->red, 0, 1),
- CLAMP (rgba->green, 0, 1),
- CLAMP (rgba->blue, 0, 1),
- CLAMP (rgba->alpha, 0, 1));
+ if (rgba->alpha > 0.999)
+ {
+ return g_strdup_printf ("rgb(%d,%d,%d)",
+ (int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
+ (int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
+ (int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.));
+ }
+ else
+ {
+ gchar alpha[G_ASCII_DTOSTR_BUF_SIZE];
+
+ g_ascii_dtostr (alpha, G_ASCII_DTOSTR_BUF_SIZE, CLAMP (rgba->alpha, 0, 1));
+
+ return g_strdup_printf ("rgba(%d,%d,%d,%s)",
+ (int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
+ (int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
+ (int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.),
+ alpha);
+ }
}
projects / ~andy / gtk / blobdiff