applied some simple but effective optimizations to

2001-08-19  Sven Neumann  <sven@gimp.org>

	* pixops/pixops.c: applied some simple but effective optimizations
	to pixops_composite_nearest() and pixops_composite_color_nearest().

diff --git a/gdk-pixbuf/ChangeLog b/gdk-pixbuf/ChangeLog
index 3f0cc9457d88a5b3018bd659260a1ef88165e1bd..f8594ac75884730b79f8e9da1047acf625eec35f 100644 (file)
--- a/gdk-pixbuf/ChangeLog
+++ b/gdk-pixbuf/ChangeLog
@@ -1,3 +1,8 @@
+2001-08-19  Sven Neumann  <sven@gimp.org>
+
+       * pixops/pixops.c: applied some simple but effective optimizations 
+       to pixops_composite_nearest() and pixops_composite_color_nearest().
+
 2001-08-07  Sven Neumann  <sven@gimp.org>
 
        * gdk-pixbuf.c (gdk_pixbuf_fill): a comment asked to optimize this

diff --git a/gdk-pixbuf/pixops/pixops.c b/gdk-pixbuf/pixops/pixops.c
index 0dc51d9f75d731a8d77d2ef4120168212a7a33ae..9fc732e9a06691966f9c1d5bd86484f6e4c08fdf 100644 (file)
--- a/gdk-pixbuf/pixops/pixops.c
+++ b/gdk-pixbuf/pixops/pixops.c
@@ -176,37 +176,39 @@ pixops_composite_nearest (guchar        *dest_buf,
          else
            a0 = overall_alpha;
 
-         if (dest_has_alpha)
-           {
-             unsigned int w0 = 0xff * a0;
-             unsigned int w1 = (0xff - a0) * dest[3];
-             unsigned int w = w0 + w1;
+          switch (a0)
+            {
+            case 0:
+              break;
+            case 255:
+              dest[0] = p[0];
+              dest[1] = p[1];
+              dest[2] = p[2];
+              if (dest_has_alpha)
+                dest[3] = 0xff;
+              break;
+            default:
+              if (dest_has_alpha)
+                {
+                  unsigned int w0 = 0xff * a0;
+                  unsigned int w1 = (0xff - a0) * dest[3];
+                  unsigned int w = w0 + w1;
 
-             if (w != 0)
-               {
                  dest[0] = (w0 * p[0] + w1 * dest[0]) / w;
                  dest[1] = (w0 * p[1] + w1 * dest[1]) / w;
                  dest[2] = (w0 * p[2] + w1 * dest[2]) / w;
                  dest[3] = w / 0xff;
-               }
-             else
-               {
-                 dest[0] = 0;
-                 dest[1] = 0;
-                 dest[2] = 0;
-                 dest[3] = 0;
-               }
-           }
-         else
-           {
-             dest[0] = (a0 * p[0] + (0xff - a0) * dest[0]) / 0xff;
-             dest[1] = (a0 * p[1] + (0xff - a0) * dest[1]) / 0xff;
-             dest[2] = (a0 * p[2] + (0xff - a0) * dest[2]) / 0xff;
-             
-             if (dest_channels == 4)
-               dest[3] = 0xff;
-           }
-
+                }
+              else
+                {
+                  unsigned int a1 = 0xff - a0;
+                  
+                  dest[0] = (a0 * p[0] + a1 * dest[0]) / 0xff;
+                  dest[1] = (a0 * p[1] + a1 * dest[1]) / 0xff;
+                  dest[2] = (a0 * p[2] + a1 * dest[2]) / 0xff;
+                }
+              break;
+            }
          dest += dest_channels;
          x += x_step;
        }
@@ -283,31 +285,48 @@ pixops_composite_color_nearest (guchar        *dest_buf,
          else
            a0 = overall_alpha;
 
-         if (a0 == 255)
-           {
+          switch (a0)
+            {
+            case 0:
+              if (((j + check_x) >> check_shift) & 1)
+                {
+                  dest[0] = r2; 
+                  dest[1] = g2; 
+                  dest[2] = b2;
+                }
+              else
+                {
+                  dest[0] = r1; 
+                  dest[1] = g1; 
+                  dest[2] = b1;
+                }
+            break;
+            case 255:
              dest[0] = p[0];
              dest[1] = p[1];
              dest[2] = p[2];
-           }
-         else
-           if (((j + check_x) >> check_shift) & 1)
-             {
-               tmp = ((int) p[0] - r2) * a0;
-               dest[0] = r2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-               tmp = ((int) p[1] - g2) * a0;
-               dest[1] = g2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-               tmp = ((int) p[2] - b2) * a0;
-               dest[2] = b2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-             }
-           else
-             {
-               tmp = ((int) p[0] - r1) * a0;
-               dest[0] = r1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-               tmp = ((int) p[1] - g1) * a0;
-               dest[1] = g1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-               tmp = ((int) p[2] - b1) * a0;
-               dest[2] = b1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
-             }
+              break;
+            default:
+              if (((j + check_x) >> check_shift) & 1)
+                {
+                  tmp = ((int) p[0] - r2) * a0;
+                  dest[0] = r2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                  tmp = ((int) p[1] - g2) * a0;
+                  dest[1] = g2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                  tmp = ((int) p[2] - b2) * a0;
+                  dest[2] = b2 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                }
+              else
+                {
+                  tmp = ((int) p[0] - r1) * a0;
+                  dest[0] = r1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                  tmp = ((int) p[1] - g1) * a0;
+                  dest[1] = g1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                  tmp = ((int) p[2] - b1) * a0;
+                  dest[2] = b1 + ((tmp + (tmp >> 8) + 0x80) >> 8);
+                }
+              break;
+            }
          
          if (dest_channels == 4)
            dest[3] = 0xff;