gdk: Add gdk_color_state_clamp()

Allows clamping values into the correct range to construct valid colors.

gdk/gdkcolorstate.c

@@ -331,6 +331,68 @@ gdk_default_color_state_get_cicp (GdkColorState *color_state)
   return &self->cicp;
 }
 
+static gboolean
+gdk_color_state_check_inf_nan (const float src[4],
+                               float       dest[4])
+{
+  if (isnan (src[0]) ||
+      isnan (src[1]) ||
+      isnan (src[2]) ||
+      isnan (src[3]))
+    {
+      dest = (float[4]) { 1.0, 0.0, 0.8, 1.0 };
+      return TRUE;
+    }
+  if (isinf (src[0]) ||
+      isinf (src[1]) ||
+      isinf (src[2]) ||
+      isinf (src[3]))
+    {
+      dest = (float[4]) { 0.0, 0.8, 1.0, 1.0 };
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+static void
+gdk_color_state_clamp_0_1 (GdkColorState *self,
+                           const float    src[4],
+                           float          dest[4])
+{
+  if (gdk_color_state_check_inf_nan (src, dest))
+    return;
+
+  dest[0] = CLAMP (src[0], 0.0f, 1.0f);
+  dest[1] = CLAMP (src[1], 0.0f, 1.0f);
+  dest[2] = CLAMP (src[2], 0.0f, 1.0f);
+  dest[3] = CLAMP (src[3], 0.0f, 1.0f);
+}
+
+static void
+gdk_color_state_clamp_unbounded (GdkColorState *self,
+                                 const float    src[4],
+                                 float          dest[4])
+{
+  if (gdk_color_state_check_inf_nan (src, dest))
+    return;
+
+  dest[0] = src[0];
+  dest[1] = src[1];
+  dest[2] = src[2];
+  dest[3] = CLAMP (src[3], 0.0f, 1.0f);
+}
+
+static void
+gdk_default_color_state_clamp (GdkColorState *color_state,
+                               const float    in[4],
+                               float          out[4])
+{
+  GdkDefaultColorState *self = (GdkDefaultColorState *) color_state;
+
+  self->clamp (color_state, in, out);
+}
+
 /* }}} */
 
 static const
@@ -342,6 +404,7 @@ GdkColorStateClass GDK_DEFAULT_COLOR_STATE_CLASS = {
   .get_convert_to = gdk_default_color_state_get_convert_to,
   .get_convert_from = gdk_default_color_state_get_convert_from,
   .get_cicp = gdk_default_color_state_get_cicp,
+  .clamp = gdk_default_color_state_clamp,
 };
 
 GdkDefaultColorState gdk_default_color_states[] = {
@@ -360,6 +423,7 @@ GdkDefaultColorState gdk_default_color_states[] = {
       [GDK_COLOR_STATE_ID_REC2100_PQ] = gdk_default_srgb_to_rec2100_pq,
       [GDK_COLOR_STATE_ID_REC2100_LINEAR] = gdk_default_srgb_to_rec2100_linear,
     },
+    .clamp = gdk_color_state_clamp_0_1,
     .cicp = { 1, 13, 0, 1 },
   },
   [GDK_COLOR_STATE_ID_SRGB_LINEAR] = {
@@ -377,6 +441,7 @@ GdkDefaultColorState gdk_default_color_states[] = {
       [GDK_COLOR_STATE_ID_REC2100_PQ] = gdk_default_srgb_linear_to_rec2100_pq,
       [GDK_COLOR_STATE_ID_REC2100_LINEAR] = gdk_default_srgb_linear_to_rec2100_linear,
     },
+    .clamp = gdk_color_state_clamp_0_1,
     .cicp = { 1, 8, 0, 1 },
   },
   [GDK_COLOR_STATE_ID_REC2100_PQ] = {
@@ -394,6 +459,7 @@ GdkDefaultColorState gdk_default_color_states[] = {
       [GDK_COLOR_STATE_ID_SRGB_LINEAR] = gdk_default_rec2100_pq_to_srgb_linear,
       [GDK_COLOR_STATE_ID_REC2100_LINEAR] = gdk_default_rec2100_pq_to_rec2100_linear,
     },
+    .clamp = gdk_color_state_clamp_0_1,
     .cicp = { 9, 16, 0, 1 },
   },
   [GDK_COLOR_STATE_ID_REC2100_LINEAR] = {
@@ -411,6 +477,7 @@ GdkDefaultColorState gdk_default_color_states[] = {
       [GDK_COLOR_STATE_ID_SRGB_LINEAR] = gdk_default_rec2100_linear_to_srgb_linear,
       [GDK_COLOR_STATE_ID_REC2100_PQ] = gdk_default_rec2100_linear_to_rec2100_pq,
     },
+    .clamp = gdk_color_state_clamp_unbounded,
     .cicp = { 9, 8, 0, 1 },
   },
 };
@@ -566,6 +633,7 @@ GdkColorStateClass GDK_CICP_COLOR_STATE_CLASS = {
   .get_convert_to = gdk_cicp_color_state_get_convert_to,
   .get_convert_from = gdk_cicp_color_state_get_convert_from,
   .get_cicp = gdk_cicp_color_state_get_cicp,
+  .clamp = gdk_color_state_clamp_0_1,
 };
 
 static inline float *
@@ -770,6 +838,24 @@ gdk_color_state_get_no_srgb_tf (GdkColorState *self)
   return self->klass->get_no_srgb_tf (self);
 }
 
+/*< private >
+ * gdk_color_state_clamp:
+ * @self: a `GdkColorState`
+ * @src: the values to clamp
+ * @dest: (out): location to store the result, may be identical to
+ *   the src argument
+ *
+ * Clamps the values to be within the allowed ranges for the given
+ * color state.
+ */
+void
+gdk_color_state_clamp (GdkColorState *self,
+                       const float    src[4],
+                       float          dest[4])
+{
+  self->klass->clamp (self, src, dest);
+}
+
 /* }}} */
 
 /* vim:set foldmethod=marker expandtab: */

gdk/gdkcolorstateprivate.h

@@ -46,6 +46,9 @@ struct _GdkColorStateClass
   GdkFloatColorConvert  (* get_convert_from)    (GdkColorState  *self,
                                                  GdkColorState  *source);
   const GdkCicp *       (* get_cicp)            (GdkColorState  *self);
+  void                  (* clamp)               (GdkColorState  *self,
+                                                 const float     src[4],
+                                                 float           dest[4]);
 };
 
 typedef struct _GdkDefaultColorState GdkDefaultColorState;
@@ -57,6 +60,9 @@ struct _GdkDefaultColorState
   const char *name;
   GdkColorState *no_srgb;
   GdkFloatColorConvert convert_to[GDK_COLOR_STATE_N_IDS];
+  void (* clamp) (GdkColorState  *self,
+                  const float     src[4],
+                  float           dest[4]);
 
   GdkCicp cicp;
 };
@@ -78,6 +84,10 @@ GdkColorState * gdk_color_state_get_no_srgb_tf          (GdkColorState
 GdkColorState * gdk_color_state_new_for_cicp            (const GdkCicp          *cicp,
                                                          GError                **error);
 
+void            gdk_color_state_clamp                   (GdkColorState          *self,
+                                                         const float             src[4],
+                                                         float                   dest[4]);
+
 static inline GdkColorState *
 gdk_color_state_get_rendering_color_state (GdkColorState *self)
 {
@@ -214,4 +224,3 @@ gdk_color_state_from_rgba (GdkColorState *self,
                                  self,
                                  out_color);
 }
-