new tools to generate screenshots for the widget gallery. added the tools

* devel-docs/tools/*: new tools to generate screenshots for the widget gallery.
* devel-docs/Makefile.am: added the tools subdir.
* configure.in: modified accordingly.

devel-docs/tools/shadow.c

@@ -0,0 +1,149 @@
+#include "shadow.h"
+#include <math.h>
+
+#define BLUR_RADIUS 5
+#define SHADOW_OFFSET (BLUR_RADIUS * 4 / 5)
+#define SHADOW_OPACITY 0.75
+
+typedef struct {
+  int size;
+  double *data;
+} ConvFilter;
+
+static double
+gaussian (double x, double y, double r)
+{
+    return ((1 / (2 * M_PI * r)) *
+	    exp ((- (x * x + y * y)) / (2 * r * r)));
+}
+
+static ConvFilter *
+create_blur_filter (int radius)
+{
+  ConvFilter *filter;
+  int x, y;
+  double sum;
+  
+  filter = g_new0 (ConvFilter, 1);
+  filter->size = radius * 2 + 1;
+  filter->data = g_new (double, filter->size * filter->size);
+
+  sum = 0.0;
+  
+  for (y = 0 ; y < filter->size; y++)
+    {
+      for (x = 0 ; x < filter->size; x++)
+	{
+	  sum += filter->data[y * filter->size + x] = gaussian (x - (filter->size >> 1),
+								y - (filter->size >> 1),
+								radius);
+	}
+    }
+
+  for (y = 0; y < filter->size; y++)
+    {
+      for (x = 0; x < filter->size; x++)
+	{
+	  filter->data[y * filter->size + x] /= sum;
+	}
+    }
+
+  return filter;
+  
+}
+
+static GdkPixbuf *
+create_shadow (GdkPixbuf *src)
+{
+  int x, y, i, j;
+  int width, height;
+  GdkPixbuf *dest;
+  static ConvFilter *filter = NULL;
+  int src_rowstride, dest_rowstride;
+  int src_bpp, dest_bpp;
+  
+  guchar *src_pixels, *dest_pixels;
+
+  if (!filter)
+    filter = create_blur_filter (BLUR_RADIUS);
+  
+  width = gdk_pixbuf_get_width (src) + BLUR_RADIUS * 2 + SHADOW_OFFSET;
+  height = gdk_pixbuf_get_height (src) + BLUR_RADIUS * 2 + SHADOW_OFFSET;
+
+  dest = gdk_pixbuf_new (gdk_pixbuf_get_colorspace (src),
+			 gdk_pixbuf_get_has_alpha (src),
+			 gdk_pixbuf_get_bits_per_sample (src),
+			 width, height);
+  gdk_pixbuf_fill (dest, 0);  
+  src_pixels = gdk_pixbuf_get_pixels (src);
+  src_rowstride = gdk_pixbuf_get_rowstride (src);
+  src_bpp = gdk_pixbuf_get_has_alpha (src) ? 4 : 3;
+  
+  dest_pixels = gdk_pixbuf_get_pixels (dest);
+  dest_rowstride = gdk_pixbuf_get_rowstride (dest);
+  dest_bpp = gdk_pixbuf_get_has_alpha (dest) ? 4 : 3;
+  
+  for (y = 0; y < height; y++)
+    {
+      for (x = 0; x < width; x++)
+	{
+	  int sumr = 0, sumg = 0, sumb = 0, suma = 0;
+
+	  for (i = 0; i < filter->size; i++)
+	    {
+	      for (j = 0; j < filter->size; j++)
+		{
+		  int src_x, src_y;
+
+		  src_y = -(BLUR_RADIUS + SHADOW_OFFSET) + y - (filter->size >> 1) + i;
+		  src_x = -(BLUR_RADIUS + SHADOW_OFFSET) + x - (filter->size >> 1) + j;
+
+		  if (src_y < 0 || src_y > gdk_pixbuf_get_height (src) ||
+		      src_x < 0 || src_x > gdk_pixbuf_get_width (src))
+		    continue;
+
+		  sumr += src_pixels [src_y * src_rowstride +
+				      src_x * src_bpp + 0] *
+		    filter->data [i * filter->size + j];
+		  sumg += src_pixels [src_y * src_rowstride +
+				      src_x * src_bpp + 1] * 
+		    filter->data [i * filter->size + j];
+
+		  sumb += src_pixels [src_y * src_rowstride +
+				      src_x * src_bpp + 2] * 
+		    filter->data [i * filter->size + j];
+		  
+		  if (src_bpp == 4)
+		    suma += src_pixels [src_y * src_rowstride +
+					src_x * src_bpp + 3] *
+		    filter->data [i * filter->size + j];
+
+		    
+		}
+	    }
+
+	  if (dest_bpp == 4)
+	    dest_pixels [y * dest_rowstride +
+			 x * dest_bpp + 3] = suma * SHADOW_OPACITY;
+
+	}
+    }
+  
+  return dest;
+}
+
+GdkPixbuf *
+create_shadowed_pixbuf (GdkPixbuf *src)
+{
+  GdkPixbuf *dest;
+  
+  dest = create_shadow (src);
+
+  gdk_pixbuf_composite (src, dest,
+			BLUR_RADIUS, BLUR_RADIUS,
+			gdk_pixbuf_get_width (src),
+			gdk_pixbuf_get_height (src),
+			BLUR_RADIUS, BLUR_RADIUS, 1.0, 1.0,
+			GDK_INTERP_NEAREST, 255);
+  return dest;
+}