From 3e762699d59fc230ab22de15fd4612c194b2411b Mon Sep 17 00:00:00 2001
From: Daniel Holbert <dholbert@cs.stanford.edu>
Date: Fri, 22 Oct 2010 15:55:04 -0700
Subject: [PATCH] Bug 606360: Don't double-count full-page-zoom factor when
 drawing SVG <image> element. r=longsonr a=blocking-final+

---
 layout/reftests/svg/image/image-zoom-01-ref.svg |  5 +++++
 layout/reftests/svg/image/image-zoom-01a.svg    |  8 ++++++++
 layout/reftests/svg/image/image-zoom-01b.svg    |  8 ++++++++
 layout/reftests/svg/image/image-zoom-02-ref.svg |  4 ++++
 layout/reftests/svg/image/image-zoom-02.svg     |  7 +++++++
 layout/reftests/svg/image/reftest.list          |  3 +++
 layout/svg/base/src/nsSVGImageFrame.cpp         | 13 ++++++++-----
 7 files changed, 43 insertions(+), 5 deletions(-)
 create mode 100644 layout/reftests/svg/image/image-zoom-01-ref.svg
 create mode 100644 layout/reftests/svg/image/image-zoom-01a.svg
 create mode 100644 layout/reftests/svg/image/image-zoom-01b.svg
 create mode 100644 layout/reftests/svg/image/image-zoom-02-ref.svg
 create mode 100644 layout/reftests/svg/image/image-zoom-02.svg

diff --git a/layout/reftests/svg/image/image-zoom-01-ref.svg b/layout/reftests/svg/image/image-zoom-01-ref.svg
new file mode 100644
index 000000000000..49451529c02d
--- /dev/null
+++ b/layout/reftests/svg/image/image-zoom-01-ref.svg
@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink"
+     viewBox="0 0 20 20">
+  <image width="10" height="10" xlink:href="blueRect10x10.png"/>
+</svg>
diff --git a/layout/reftests/svg/image/image-zoom-01a.svg b/layout/reftests/svg/image/image-zoom-01a.svg
new file mode 100644
index 000000000000..b77712a138e8
--- /dev/null
+++ b/layout/reftests/svg/image/image-zoom-01a.svg
@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink"
+     viewBox="0 0 20 20"
+     reftest-zoom="1.5">
+  <title>Testcase to ensure that full-page-zoom doesn't actually zoom raster
+         images, when we have a viewBox applied.</title>
+  <image width="10" height="10" xlink:href="blueRect10x10.png"/>
+</svg>
diff --git a/layout/reftests/svg/image/image-zoom-01b.svg b/layout/reftests/svg/image/image-zoom-01b.svg
new file mode 100644
index 000000000000..7aff01d2bb43
--- /dev/null
+++ b/layout/reftests/svg/image/image-zoom-01b.svg
@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink"
+     viewBox="0 0 20 20"
+     reftest-zoom="0.5">
+  <title>Testcase to ensure that full-page-zoom doesn't actually zoom raster
+         images, when we have a viewBox applied.</title>
+  <image width="10" height="10" xlink:href="blueRect10x10.png"/>
+</svg>
diff --git a/layout/reftests/svg/image/image-zoom-02-ref.svg b/layout/reftests/svg/image/image-zoom-02-ref.svg
new file mode 100644
index 000000000000..fca1d5703ee2
--- /dev/null
+++ b/layout/reftests/svg/image/image-zoom-02-ref.svg
@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink">
+  <image width="15" height="15" xlink:href="blueRect10x10.png"/>
+</svg>
diff --git a/layout/reftests/svg/image/image-zoom-02.svg b/layout/reftests/svg/image/image-zoom-02.svg
new file mode 100644
index 000000000000..6caf046558f3
--- /dev/null
+++ b/layout/reftests/svg/image/image-zoom-02.svg
@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg"
+     xmlns:xlink="http://www.w3.org/1999/xlink"
+     reftest-zoom="1.5">
+  <title>Testcase to ensure that full-page-zoom will zoom raster
+         images the right amount.</title>
+  <image width="10" height="10" xlink:href="blueRect10x10.png"/>
+</svg>
diff --git a/layout/reftests/svg/image/reftest.list b/layout/reftests/svg/image/reftest.list
index 5f7bed9ee0a9..fb685ec4ddb5 100644
--- a/layout/reftests/svg/image/reftest.list
+++ b/layout/reftests/svg/image/reftest.list
@@ -14,6 +14,9 @@
 == image-x-01.svg             image-x-01-ref.svg
 == image-xy-01.svg            image-xy-01-ref.svg
 == image-y-01.svg             image-y-01-ref.svg
+== image-zoom-01a.svg         image-zoom-01-ref.svg
+== image-zoom-01b.svg         image-zoom-01-ref.svg
+== image-zoom-02.svg          image-zoom-02-ref.svg
 
 # Tests for <image> with preserveAspectRatio
 # NOTE: The reference cases in the following tests trigger 20 assertions each
diff --git a/layout/svg/base/src/nsSVGImageFrame.cpp b/layout/svg/base/src/nsSVGImageFrame.cpp
index c4195eebde21..324534edaf61 100644
--- a/layout/svg/base/src/nsSVGImageFrame.cpp
+++ b/layout/svg/base/src/nsSVGImageFrame.cpp
@@ -255,10 +255,13 @@ nsSVGImageFrame::PaintSVG(nsSVGRenderState *aContext,
       nsSVGUtils::SetClipRect(ctx, GetCanvasTM(), clipRect);
     }
 
-    // NOTE: To ensure that |width| and |height| don't accidentally
-    // scale the user-unit size in SVG images, we apply those attributes
-    // via |destRect|, not via our gfxContext's transform.
-    ctx->Multiply(GetImageTransform());
+    nscoord appUnitsPerDevPx = PresContext()->AppUnitsPerDevPixel();
+    gfxFloat pageZoomFactor =
+      nsPresContext::AppUnitsToFloatCSSPixels(appUnitsPerDevPx);
+
+    // NOTE: We need to cancel out the effects of Full-Page-Zoom, or else
+    // it'll get applied an extra time by DrawSingleUnscaledImage.
+    ctx->Multiply(GetImageTransform().Scale(pageZoomFactor, pageZoomFactor));
 
     // fill-opacity doesn't affect <image>, so if we're allowed to
     // optimize group opacity, the opacity used for compositing the
@@ -274,7 +277,7 @@ nsSVGImageFrame::PaintSVG(nsSVGRenderState *aContext,
 
     nsRect dirtyRect; // only used if aDirtyRect is non-null
     if (aDirtyRect) {
-      dirtyRect = aDirtyRect->ToAppUnits(PresContext()->AppUnitsPerDevPixel());
+      dirtyRect = aDirtyRect->ToAppUnits(appUnitsPerDevPx);
       // Adjust dirtyRect to match our local coordinate system.
       dirtyRect.MoveBy(-mRect.TopLeft());
     }