Straighten out zoom and border-image

third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp

Index: third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp b/third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp
index 338b82cc71477d547df5f69dc73423c06ca45afa..51d82366c8513042c31c0e23ca7ca5ee4d94cca8 100644
--- a/third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp
+++ b/third_party/WebKit/Source/core/paint/NinePieceImagePainter.cpp
@@ -49,13 +49,15 @@ bool NinePieceImagePainter::paint(GraphicsContext& graphicsContext, const Layout
     rectWithOutsets.expand(style.imageOutsets(ninePieceImage));
     LayoutRect borderImageRect = rectWithOutsets;
 
-    IntSize imageSize = roundedIntSize(styleImage->imageSize(m_layoutObject, 1, borderImageRect.size()));
+    LayoutSize defaultObjectSize = borderImageRect.size();
+    defaultObjectSize.scale(1 / style.effectiveZoom());
+    IntSize imageSize = roundedIntSize(styleImage->imageSize(m_layoutObject, 1, defaultObjectSize));
 
     IntRectOutsets borderWidths(style.borderTopWidth(), style.borderRightWidth(),
         style.borderBottomWidth(), style.borderLeftWidth());
     NinePieceImageGrid grid(ninePieceImage, imageSize, pixelSnappedIntRect(borderImageRect), borderWidths);
 
-    RefPtr<Image> image = styleImage->image(m_layoutObject, imageSize, style.effectiveZoom());
+    RefPtr<Image> image = styleImage->image(m_layoutObject, imageSize, 1);

[fs, 2016/03/22 14:07:23]

Maybe add a comment (or two) about why the zoom/scale factors are chosen this
way (i.e a boiled down version of the commit message or so.)

[davve, 2016/03/22 14:29:00]

I added two lines to the follow-up documentation patch I was scribbling at
anyway.

https://codereview.chromium.org/1824003002

Would that do?

 
     InterpolationQuality interpolationQuality = BoxPainter::chooseInterpolationQuality(m_layoutObject, image.get(), 0, rectWithOutsets.size());
     InterpolationQuality previousInterpolationQuality = graphicsContext.imageInterpolationQuality();