diff --git a/layout/generic/nsHTMLCanvasFrame.cpp b/layout/generic/nsHTMLCanvasFrame.cpp
index 6af9bb91e9d9..0f7db3fb6e77 100644
--- a/layout/generic/nsHTMLCanvasFrame.cpp
+++ b/layout/generic/nsHTMLCanvasFrame.cpp
@@ -236,19 +236,17 @@ nsHTMLCanvasFrame::PaintCanvas(nsIRenderingContext& aRenderingContext,
if (inner.width == 0 || inner.height == 0)
return;
+ gfxRect devInner(presContext->AppUnitsToGfxUnits(inner));
+
nsIntSize sizeCSSPixels = GetCanvasSize();
- nsSize sizeAppUnits(nsPresContext::CSSPixelsToAppUnits(sizeCSSPixels.width),
- nsPresContext::CSSPixelsToAppUnits(sizeCSSPixels.height));
+ gfxFloat sx = devInner.size.width / (gfxFloat) sizeCSSPixels.width;
+ gfxFloat sy = devInner.size.height / (gfxFloat) sizeCSSPixels.height;
gfxContext *ctx = aRenderingContext.ThebesContext();
- gfxFloat sx = inner.width / (gfxFloat) sizeAppUnits.width;
- gfxFloat sy = inner.height / (gfxFloat) sizeAppUnits.height;
-
ctx->Save();
- ctx->Translate(gfxPoint(presContext->AppUnitsToGfxUnits(inner.x),
- presContext->AppUnitsToGfxUnits(inner.y)));
+ ctx->Translate(devInner.pos);
ctx->Scale(sx, sy);
canvas->RenderContexts(ctx);
diff --git a/layout/reftests/bugs/488692-1-ref.html b/layout/reftests/bugs/488692-1-ref.html
new file mode 100644
index 000000000000..d21a0da083c9
--- /dev/null
+++ b/layout/reftests/bugs/488692-1-ref.html
@@ -0,0 +1,6 @@
+
+
+
+
+
+
diff --git a/layout/reftests/bugs/488692-1.html b/layout/reftests/bugs/488692-1.html
new file mode 100644
index 000000000000..0fa0b6752b9a
--- /dev/null
+++ b/layout/reftests/bugs/488692-1.html
@@ -0,0 +1,11 @@
+
+
+
+
+
+
+
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index e5e672bfd7df..e164a05b29f0 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1229,3 +1229,4 @@ fails-if(MOZ_WIDGET_TOOLKIT=="gtk2") == 481948-3.html 481948-3-ref.html # differ
== 487539-1.html about:blank
== 488390-1.html 488390-1-ref.html
== 488685-1.html 488685-1-ref.html
+== 488692-1.html 488692-1-ref.html