Account for non-pixel-aligned current transforms when snapping to pixel coordinates. b=369882 r=vlad

gfx/src/thebes/nsThebesImage.cpp

@@ -346,9 +346,6 @@ nsThebesImage::Draw(nsIRenderingContext &aContext,
              mDecoded.x, mDecoded.y, mDecoded.width, mDecoded.height);
 #endif
 
-    gfxMatrix savedCTM(ctx->CurrentMatrix());
-    PRBool doSnap = !(savedCTM.HasNonTranslation());
-
     if (mSinglePixel) {
         // if a == 0, it's a noop
         if (mSinglePixelColor.a == 0.0)
@@ -362,14 +359,6 @@ nsThebesImage::Draw(nsIRenderingContext &aContext,
         return NS_OK;
     }
 
-    // See comment inside ThebesDrawTile
-    if (doSnap) {
-        gfxMatrix roundedCTM(savedCTM);
-        roundedCTM.x0 = ::floor(roundedCTM.x0 + 0.5);
-        roundedCTM.y0 = ::floor(roundedCTM.y0 + 0.5);
-        ctx->SetMatrix(roundedCTM);
-    }
-
     gfxFloat xscale = aDestRect.size.width / aSourceRect.size.width;
     gfxFloat yscale = aDestRect.size.height / aSourceRect.size.height;
 
@@ -410,12 +399,9 @@ nsThebesImage::Draw(nsIRenderingContext &aContext,
 
     ctx->NewPath();
     ctx->SetPattern(pat);
-    ctx->Rectangle(destRect, doSnap);
+    ctx->Rectangle(destRect);
     ctx->Fill();
 
-    if (doSnap)
-        ctx->SetMatrix(savedCTM);
-
     return NS_OK;
 }
 

layout/base/nsLayoutUtils.cpp

@@ -63,6 +63,7 @@
 #include "gfxIImageFrame.h"
 #include "imgIContainer.h"
 #include "gfxRect.h"
+#include "gfxContext.h"
 #include "nsIImage.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsCSSRendering.h"
@@ -2043,6 +2044,10 @@ nsLayoutUtils::DrawImage(nsIRenderingContext* aRenderingContext,
   aRenderingContext->GetDeviceContext(*getter_AddRefs(dc));
   PRInt32 d2a = dc->AppUnitsPerDevPixel();
 
+  nsRefPtr<gfxContext> ctx = NS_STATIC_CAST(gfxContext*,
+    aRenderingContext->GetNativeGraphicData(
+      nsIRenderingContext::NATIVE_THEBES_CONTEXT));
+
   // the dest rect is affected by the current transform; that'll be
   // handled by Image::Draw(), when we actually set up the rectangle.
   
@@ -2050,15 +2055,12 @@ nsLayoutUtils::DrawImage(nsIRenderingContext* aRenderingContext,
   // pixel, but then convert back to gfxFloats for the rest of the math.
   gfxRect pxDest;
   {
-    nsIntRect r;
-    r.x = NSAppUnitsToIntPixels(aDestRect.x, d2a);
-    r.y = NSAppUnitsToIntPixels(aDestRect.y, d2a);
-    r.width = NSAppUnitsToIntPixels(aDestRect.XMost(), d2a) - r.x;
-    r.height = NSAppUnitsToIntPixels(aDestRect.YMost(), d2a) - r.y;
-    pxDest.pos.x = gfxFloat(r.x);
-    pxDest.pos.y = gfxFloat(r.y);
-    pxDest.size.width = gfxFloat(r.width);
-    pxDest.size.height = gfxFloat(r.height);
+    pxDest.pos.x = NSAppUnitsToFloatPixels(aDestRect.x, d2a);
+    pxDest.pos.y = NSAppUnitsToFloatPixels(aDestRect.y, d2a);
+    pxDest.size.width = NSAppUnitsToFloatPixels(aDestRect.width, d2a);
+    pxDest.size.height = NSAppUnitsToFloatPixels(aDestRect.height, d2a);
+    if (ctx->UserToDevicePixelSnapped(pxDest))
+      pxDest = ctx->DeviceToUser(pxDest);
   }
 
   // And likewise for the dirty rect.  (Is should be OK to round to
@@ -2067,15 +2069,12 @@ nsLayoutUtils::DrawImage(nsIRenderingContext* aRenderingContext,
   // been intersected with, and we should be rounding those consistently.)
   gfxRect pxDirty;
   {
-    nsIntRect r;
-    r.x = NSAppUnitsToIntPixels(dirtyRect.x, d2a);
-    r.y = NSAppUnitsToIntPixels(dirtyRect.y, d2a);
-    r.width = NSAppUnitsToIntPixels(dirtyRect.XMost(), d2a) - r.x;
-    r.height = NSAppUnitsToIntPixels(dirtyRect.YMost(), d2a) - r.y;
-    pxDirty.pos.x = gfxFloat(r.x);
-    pxDirty.pos.y = gfxFloat(r.y);
-    pxDirty.size.width = gfxFloat(r.width);
-    pxDirty.size.height = gfxFloat(r.height);
+    pxDirty.pos.x = NSAppUnitsToFloatPixels(dirtyRect.x, d2a);
+    pxDirty.pos.y = NSAppUnitsToFloatPixels(dirtyRect.y, d2a);
+    pxDirty.size.width = NSAppUnitsToFloatPixels(dirtyRect.width, d2a);
+    pxDirty.size.height = NSAppUnitsToFloatPixels(dirtyRect.height, d2a);
+    if (ctx->UserToDevicePixelSnapped(pxDirty))
+      pxDirty = ctx->DeviceToUser(pxDirty);
   }
 
   // Reduce the src rect to what's needed for the dirty rect.

layout/reftests/bugs/369882-ref.xul

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <hbox height="18" align="center">
+    <deck>
+      <image width="16" height="16"
+             src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVR42mP4z8AAAAMBAQD3A0FDAAAAAElFTkSuQmCC"/>
+    </deck>
+  </hbox>
+</window>

layout/reftests/bugs/369882.xul

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <hbox height="17" align="center">
+    <deck>
+      <image width="16" height="16"
+             style="background:blue"
+             src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVR42mP4z8AAAAMBAQD3A0FDAAAAAElFTkSuQmCC"/>
+    </deck>
+  </hbox>
+</window>

layout/reftests/bugs/reftest.list

@@ -209,6 +209,7 @@ fails == 368020-4.html 368020-4-ref.html # bug 368085
 fails == 368504-1.html 368504-1-ref.html # bug 368504
 == 368622-1.html 368622-1-ref.html
 == 368622-1.html 368622-1-ref.html
+== 369882.xul 369882-ref.xul
 == 370422-1.html 370422-1-ref.html
 == 370586-1.xhtml 370586-1-ref.xhtml
 == 370629-1.html 370629-1-ref.html

layout/reftests/pixel-rounding/reftest.list

@@ -138,7 +138,7 @@ random == image-width-left-6.html image-width-6.html
 == offscreen-background-color-size-5.html offscreen-10-ref.html
 == offscreen-background-color-size-6.html offscreen-10-ref.html
 == offscreen-image-pos-4.html offscreen-0-ref.html
-fails-if(MOZ_WIDGET_TOOLKIT!="cocoa") == offscreen-image-pos-5.html offscreen-10-ref.html # bug 368280
+== offscreen-image-pos-5.html offscreen-10-ref.html
 == offscreen-image-pos-6.html offscreen-10-ref.html
 random == offscreen-image-size-4.html offscreen-0-ref.html # bug 371316
 random == offscreen-image-size-5.html offscreen-10-ref.html # bug 371316