Fix images drawn with the NineImagePainter class in high DPI.

ui/gfx/nine_image_painter.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/nine_image_painter.h"
 
 #include <limits>
 
 #include "third_party/skia/include/core/SkPaint.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/rect_conversions.h"
+#include "ui/gfx/geometry/safe_integer_conversions.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/scoped_canvas.h"
 
 namespace gfx {
 
 namespace {
 
+// The following functions width and height of the image in pixels for the
+// scale factor in the Canvas.
+int ImageWidthInPixels(const ImageSkia& i, Canvas* c) {
+  return i.GetRepresentation(c->image_scale()).pixel_width();
+}
+
+int ImageHeightInPixels(const ImageSkia& i, Canvas* c) {
+  return i.GetRepresentation(c->image_scale()).pixel_height();
+}
+
 // Stretches the given image over the specified canvas area.
 void Fill(Canvas* c,
           const ImageSkia& i,
           int x,
           int y,
           int w,
           int h,
           const SkPaint& paint) {
-  c->DrawImageInt(i, 0, 0, i.width(), i.height(), x, y, w, h, false, paint);
+  c->DrawImageIntInPixel(i, 0, 0, ImageWidthInPixels(i, c),
+                         ImageHeightInPixels(i, c), x, y, w, h, false, paint);
 }
 
 }  // namespace
 
 NineImagePainter::NineImagePainter(const std::vector<ImageSkia>& images) {
   DCHECK_EQ(arraysize(images_), images.size());
   for (size_t i = 0; i < arraysize(images_); ++i)
     images_[i] = images[i];
 }
 
 NineImagePainter::NineImagePainter(const ImageSkia& image,
                                    const Insets& insets) {
   DCHECK_GE(image.width(), insets.width());
   DCHECK_GE(image.height(), insets.height());
 
   // Extract subsets of the original image to match the |images_| format.
   const int x[] =
-      { 0, insets.left(), image.width() - insets.right(), image.width() };

[sky, 2014/05/05 14:08:16]

nit: keep the space here. It's generally what we do for code like this (it
matches that in the openning brace).

[ananta, 2014/05/05 18:53:28]

Done.

+      { 0, insets.left(), image.width() - insets.right(), image.width()};
   const int y[] =
-      { 0, insets.top(), image.height() - insets.bottom(), image.height() };
+      { 0, insets.top(), image.height() - insets.bottom(), image.height()};
 
   for (size_t j = 0; j < 3; ++j) {
     for (size_t i = 0; i < 3; ++i) {
       images_[i + j * 3] = ImageSkiaOperations::ExtractSubset(image,
           Rect(x[i], y[j], x[i + 1] - x[i], y[j + 1] - y[j]));
     }
   }
 }
 
 NineImagePainter::~NineImagePainter() {
@@ skipping 19 matching lines @@
                              const uint8 alpha) {
   if (IsEmpty())
     return;
 
   ScopedCanvas scoped_canvas(canvas);
   canvas->Translate(bounds.OffsetFromOrigin());
 
   SkPaint paint;
   paint.setAlpha(alpha);
 
+  // Scale the bounds and convert to the smallest enclosing rectangle after
+  // scaling. This is to ensure that we paint all pixels correctly.
+  Rect scaled_enclosing_rect =
+      ToEnclosingRect(RectF(ScalePoint(bounds.origin(), canvas->image_scale()),
+                            ScaleSize(bounds.size(), canvas->image_scale())));
+
   // In case the corners and edges don't all have the same width/height, we draw
   // the center first, and extend it out in all directions to the edges of the
   // images with the smallest widths/heights.  This way there will be no
   // unpainted areas, though some corners or edges might overlap the center.
-  int w = bounds.width();
-  int i0w = images_[0].width();
-  int i2w = images_[2].width();
-  int i3w = images_[3].width();
-  int i5w = images_[5].width();
-  int i6w = images_[6].width();
-  int i8w = images_[8].width();
+  int w = scaled_enclosing_rect.width();
+  int i0w = ImageWidthInPixels(images_[0], canvas);
+  int i2w = ImageWidthInPixels(images_[2], canvas);
+  int i3w = ImageWidthInPixels(images_[3], canvas);
+  int i5w = ImageWidthInPixels(images_[5], canvas);
+  int i6w = ImageWidthInPixels(images_[6], canvas);
+  int i8w = ImageWidthInPixels(images_[8], canvas);
+
   int i4x = std::min(std::min(i0w, i3w), i6w);
   int i4w = w - i4x - std::min(std::min(i2w, i5w), i8w);
-  int h = bounds.height();
-  int i0h = images_[0].height();
-  int i1h = images_[1].height();
-  int i2h = images_[2].height();
-  int i6h = images_[6].height();
-  int i7h = images_[7].height();
-  int i8h = images_[8].height();
+  int h = scaled_enclosing_rect.height();
+
+  int i0h = ImageHeightInPixels(images_[0], canvas);
+  int i1h = ImageHeightInPixels(images_[1], canvas);
+  int i2h = ImageHeightInPixels(images_[2], canvas);
+  int i6h = ImageHeightInPixels(images_[6], canvas);
+  int i7h = ImageHeightInPixels(images_[7], canvas);
+  int i8h = ImageHeightInPixels(images_[8], canvas);
+
   int i4y = std::min(std::min(i0h, i1h), i2h);
   int i4h = h - i4y - std::min(std::min(i6h, i7h), i8h);
   if (!images_[4].isNull())
     Fill(canvas, images_[4], i4x, i4y, i4w, i4h, paint);
-  canvas->DrawImageInt(images_[0], 0, 0, paint);
+  canvas->DrawImageIntInPixel(images_[0], 0, 0, i0w, i0h,
+                              0, 0, i0w, i0h, false, paint);
   Fill(canvas, images_[1], i0w, 0, w - i0w - i2w, i1h, paint);
-  canvas->DrawImageInt(images_[2], w - i2w, 0, paint);
+  canvas->DrawImageIntInPixel(images_[2], 0, 0, i2w, i2h, w - i2w, 0,
+                              i2w, i2h, false, paint);
   Fill(canvas, images_[3], 0, i0h, i3w, h - i0h - i6h, paint);
   Fill(canvas, images_[5], w - i5w, i2h, i5w, h - i2h - i8h, paint);
-  canvas->DrawImageInt(images_[6], 0, h - i6h, paint);
+  canvas->DrawImageIntInPixel(images_[6], 0, 0, i6w, i6h, 0, h - i6h,
+                              i6w, i6h, false, paint);
   Fill(canvas, images_[7], i6w, h - i7h, w - i6w - i8w, i7h, paint);
-  canvas->DrawImageInt(images_[8], w - i8w, h - i8h, paint);
+  canvas->DrawImageIntInPixel(images_[8], 0, 0, i8w, i8h, w - i8w, h - i8h,
+                              i8w, i8h, false, paint);
 }
 
 }  // namespace gfx