[gimp] app: port GimpColorBar drawing to cairo

[Michael Natterer <mitch src gnome org>]

commit 208096bc7cc498195839eeb53d23a32f560af05e
Author: Michael Natterer <mitch gimp org>
Date:   Fri Jul 30 14:58:55 2010 +0200

    app: port GimpColorBar drawing to cairo

 app/widgets/gimpcolorbar.c |   86 +++++++++++++++++++++++---------------------
 1 files changed, 45 insertions(+), 41 deletions(-)
---
diff --git a/app/widgets/gimpcolorbar.c b/app/widgets/gimpcolorbar.c
index 92e7dd8..516573e 100644
--- a/app/widgets/gimpcolorbar.c
+++ b/app/widgets/gimpcolorbar.c
@@ -21,6 +21,8 @@
 
 #include <gtk/gtk.h>
 
+#include "libgimpwidgets/gimpwidgets.h"
+
 #include "libgimpmath/gimpmath.h"
 #include "libgimpcolor/gimpcolor.h"
 #include "libgimpconfig/gimpconfig.h"
@@ -153,14 +155,20 @@ static gboolean
 gimp_color_bar_expose (GtkWidget      *widget,
                        GdkEventExpose *event)
 {
-  GimpColorBar  *bar   = GIMP_COLOR_BAR (widget);
-  GtkStyle      *style = gtk_widget_get_style (widget);
-  GtkAllocation  allocation;
-  guchar        *buf;
-  guchar        *b;
-  gint           x, y;
-  gint           width, height;
-  gint           i, j;
+  GimpColorBar    *bar = GIMP_COLOR_BAR (widget);
+  cairo_t         *cr;
+  GtkAllocation    allocation;
+  cairo_surface_t *surface;
+  cairo_pattern_t *pattern;
+  guchar          *b;
+  gint             x, y;
+  gint             width, height;
+  gint             i;
+
+  cr = gdk_cairo_create (event->window);
+
+  gdk_cairo_region (cr, event->region);
+  cairo_clip (cr);
 
   gtk_widget_get_allocation (widget, &allocation);
 
@@ -172,46 +180,42 @@ gimp_color_bar_expose (GtkWidget      *widget,
   if (width < 1 || height < 1)
     return TRUE;
 
-  buf = g_alloca (width * height * 3);
+  cairo_translate (cr, allocation.x + x, allocation.y + y);
+  cairo_rectangle (cr, 0, 0, width, height);
+  cairo_clip (cr);
 
-  switch (bar->orientation)
-    {
-    case GTK_ORIENTATION_HORIZONTAL:
-      for (i = 0, b = buf; i < width; i++, b += 3)
-        {
-          const guchar *src = bar->buf + 3 * ((i * 256) / width);
+  surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, 256, 1);
 
-          b[0] = src[0];
-          b[1] = src[1];
-          b[2] = src[2];
-        }
+  for (i = 0, b = cairo_image_surface_get_data (surface);
+       i < 256;
+       i++, b += 4)
+    {
+      const guchar *src = bar->buf + 3 * i;
 
-      for (i = 1; i < height; i++)
-        memcpy (buf + i * width * 3, buf, width * 3);
+      GIMP_CAIRO_RGB24_SET_PIXEL(b, src[0], src[1], src[2]);
+    }
 
-      break;
+  pattern = cairo_pattern_create_for_surface (surface);
+  cairo_pattern_set_extend (pattern, CAIRO_EXTEND_REFLECT);
+  cairo_surface_destroy (surface);
 
-    case GTK_ORIENTATION_VERTICAL:
-      for (i = 0, b = buf; i < height; i++, b += 3 * width)
-        {
-          const guchar *src  = bar->buf + 3 * (255 - ((i * 256) / height));
-          guchar       *dest = b;
-
-          for (j = 0; j < width; j++, dest += 3)
-            {
-              dest[0] = src[0];
-              dest[1] = src[1];
-              dest[2] = src[2];
-            }
-        }
-      break;
+  if (bar->orientation == GTK_ORIENTATION_HORIZONTAL)
+    {
+      cairo_scale (cr, (gdouble) width / 256.0, 1.0);
+    }
+  else
+    {
+      cairo_translate (cr, 0, height);
+      cairo_scale (cr, 1.0, (gdouble) height / 256.0);
+      cairo_rotate (cr, - G_PI / 2);
     }
 
-  gdk_draw_rgb_image (gtk_widget_get_window (widget), style->black_gc,
-                      allocation.x + x, allocation.y + y,
-                      width, height,
-                      GDK_RGB_DITHER_NORMAL,
-                      buf, 3 * width);
+  cairo_set_source (cr, pattern);
+  cairo_pattern_destroy (pattern);
+
+  cairo_paint (cr);
+
+  cairo_destroy (cr);
 
   return TRUE;
 }