diff --git a/ChangeLog b/ChangeLog
index 6a34a79298..4cc67d20e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-12-13  Sven Neumann  <sven@gimp.org>
+
+	* app/base/tile-pyramid.c (tile_pyramid_write_quarter)
+	* app/display/gimpdisplayshell-render.c
+	(render_image_tile_fault_nearest): corrected formula used for
+	pre-multiplying the alpha value.
+
 2007-12-13  Sven Neumann  <sven@gimp.org>
 
 	Speed up our display rendering code paths by keeping data with
diff --git a/app/base/tile-pyramid.c b/app/base/tile-pyramid.c
index 84d1fb0764..b0755937a6 100644
--- a/app/base/tile-pyramid.c
+++ b/app/base/tile-pyramid.c
@@ -505,10 +505,10 @@ tile_pyramid_write_quarter (Tile *dest,
                   break;
 
                 default:
-                  dst[0] = ((src0[0] * src0[1] +
-                             src1[0] * src1[1] +
-                             src2[0] * src2[1] +
-                             src3[0] * src3[1]) >> 10);
+                  dst[0] = ((src0[0] * (src0[1] + 1) +
+                             src1[0] * (src1[1] + 1) +
+                             src2[0] * (src2[1] + 1) +
+                             src3[0] * (src3[1] + 1)) >> 10);
                   dst[1] = (a + 2) >> 2;
                   break;
                 }
@@ -557,19 +557,26 @@ tile_pyramid_write_quarter (Tile *dest,
                   break;
 
                 default:
-                  dst[0] = ((src0[0] * src0[3] +
-                             src1[0] * src1[3] +
-                             src2[0] * src2[3] +
-                             src3[0] * src3[3]) >> 10);
-                  dst[1] = ((src0[1] * src0[3] +
-                             src1[1] * src1[3] +
-                             src2[1] * src2[3] +
-                             src3[1] * src3[3]) >> 10);
-                  dst[2] = ((src0[2] * src0[3] +
-                             src1[2] * src1[3] +
-                             src2[2] * src2[3] +
-                             src3[2] * src3[3]) >> 10);
-                  dst[3] = (a + 2) >> 2;
+                  {
+                    const guint a0 = src0[3] + 1;
+                    const guint a1 = src1[3] + 1;
+                    const guint a2 = src2[3] + 1;
+                    const guint a3 = src3[3] + 1;
+
+                    dst[0] = (src0[0] * a0 +
+                              src1[0] * a1 +
+                              src2[0] * a2 +
+                              src3[0] * a3) >> 10;
+                    dst[1] = (src0[1] * a0 +
+                              src1[1] * a1 +
+                              src2[1] * a2 +
+                              src3[1] * a3) >> 10;
+                    dst[2] = (src0[2] * a0 +
+                              src1[2] * a1 +
+                              src2[2] * a2 +
+                              src3[2] * a3) >> 10;
+                    dst[3] = (a + 2) >> 2;
+                  }
                   break;
                 }
 
diff --git a/app/display/gimpdisplayshell-render.c b/app/display/gimpdisplayshell-render.c
index 28d16ec455..8e98955c58 100644
--- a/app/display/gimpdisplayshell-render.c
+++ b/app/display/gimpdisplayshell-render.c
@@ -778,6 +778,7 @@ box_filter_premult (const guint    left_weight,
     }
 }
 
+	
 /* fast paths */
 static const guchar * render_image_tile_fault_one_row  (RenderInfo *info);
 static const guchar * render_image_tile_fault_nearest  (RenderInfo *info);
@@ -1594,9 +1595,9 @@ render_image_tile_fault_nearest (RenderInfo *info)
           switch (bpp)
             {
             case 4:
-              d[0] = (s[0] * s[3]) >> 8;
-              d[1] = (s[1] * s[3]) >> 8;
-              d[2] = (s[2] * s[3]) >> 8;
+              d[0] = (s[0] * (s[3] + 1)) >> 8;
+              d[1] = (s[1] * (s[3] + 1)) >> 8;
+              d[2] = (s[2] * (s[3] + 1)) >> 8;
               d[3] = s[3];
 
               d += 4;
@@ -1604,7 +1605,7 @@ render_image_tile_fault_nearest (RenderInfo *info)
               break;
 
             case 2:
-              d[0] = (s[0] * s[1]) >> 8;
+              d[0] = (s[0] * (s[1] + 1)) >> 8;
               d[1] = s[1];
 
               d += 2;