From 6a3ef1e796587dab0a978c4eeb78223c820e4467 Mon Sep 17 00:00:00 2001
From: Bas Schouten <bschouten@mozilla.com>
Date: Tue, 28 Sep 2010 21:52:13 +0200
Subject: [PATCH] Bug 599658: Properly deal with matrices with negative scale
 values. r=vlad a=blocking-beta7

---
 gfx/cairo/cairo/src/cairo-d2d-surface.cpp | 30 +++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/gfx/cairo/cairo/src/cairo-d2d-surface.cpp b/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
index bc3e3dc4f3e..506ab107ae4 100644
--- a/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
+++ b/gfx/cairo/cairo/src/cairo-d2d-surface.cpp
@@ -2691,8 +2691,9 @@ _cairo_d2d_blend_surface(cairo_d2d_surface_t *dst,
     rectSrc.right = (float)(x2 * transform->xx + transform->x0);
     rectSrc.bottom = (float)(y2 * transform->yy + transform->y0);
 
-    if (rectSrc.left < 0 || rectSrc.top < 0 ||
-	rectSrc.right > sourceSize.width || rectSrc.bottom > sourceSize.height) {
+    if (rectSrc.left < 0 || rectSrc.top < 0 || rectSrc.right < 0 || rectSrc.bottom < 0 ||
+	rectSrc.right > sourceSize.width || rectSrc.bottom > sourceSize.height ||
+	rectSrc.left > sourceSize.width || rectSrc.top > sourceSize.height) {
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
@@ -2702,9 +2703,31 @@ _cairo_d2d_blend_surface(cairo_d2d_surface_t *dst,
     rectDst.right = (float)x2;
     rectDst.bottom = (float)y2;
 
+    // Bug 599658 - if the src rect is inverted in either axis D2D is fine with
+    // this but it does not actually invert the bitmap. This is an easy way
+    // of doing that.
+    D2D1_MATRIX_3X2_F matrix = D2D1::IdentityMatrix();
+    bool needsTransform = false;
+    if (rectSrc.left > rectSrc.right) {
+	rectDst.left = -rectDst.left;
+	rectDst.right = -rectDst.right;
+	matrix._11 = -1.0;
+	needsTransform = true;
+    }
+    if (rectSrc.top > rectSrc.bottom) {
+	rectDst.top = -rectDst.top;
+	rectDst.bottom = -rectDst.bottom;
+	matrix._22 = -1.0;
+	needsTransform = true;
+    }
+
     D2D1_BITMAP_INTERPOLATION_MODE interpMode =
       D2D1_BITMAP_INTERPOLATION_MODE_LINEAR;
 
+    if (needsTransform) {
+	dst->rt->SetTransform(matrix);
+    }
+
     if (filter == CAIRO_FILTER_NEAREST) {
       interpMode = D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR;
     }
@@ -2714,6 +2737,9 @@ _cairo_d2d_blend_surface(cairo_d2d_surface_t *dst,
 			opacity,
 			interpMode,
 			rectSrc);
+    if (needsTransform) {
+	dst->rt->SetTransform(D2D1::IdentityMatrix());
+    }
 
     return rv;
 }