Fix sizing when auto-scaling a missing resource at a non-integer scale factor. Matches the rounding rules used by UX when scaling resources at non-integer scale factors.

BUG=223928


Review URL: https://chromiumcodereview.appspot.com/12939015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@190970 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 32 insertions, 2 deletions

diff --git a/ui/base/resource/resource_bundle.cc b/ui/base/resource/resource_bundle.cc
index 3c03ee8..c1687f8 100644
--- a/ui/base/resource/resource_bundle.cc
+++ b/ui/base/resource/resource_bundle.cc
@@ -86,8 +86,8 @@ class ResourceBundle::ResourceBundleImageSource : public gfx::ImageSkiaSource {
       image = skia::ImageOperations::Resize(
           image,
           skia::ImageOperations::RESIZE_LANCZOS3,
-          gfx::ToFlooredInt(image.width() * scale),
-          gfx::ToFlooredInt(image.height() * scale));
+          gfx::ToCeiledInt(image.width() * scale),
+          gfx::ToCeiledInt(image.height() * scale));
       // If --highlight-missing-scaled-resources is specified, log the resource
       // id and blend the created resource with red.
       if (ShouldHighlightMissingScaledResources()) {
diff --git a/ui/base/resource/resource_bundle_unittest.cc b/ui/base/resource/resource_bundle_unittest.cc
index ab1c2094..c6f4910 100644
--- a/ui/base/resource/resource_bundle_unittest.cc
+++ b/ui/base/resource/resource_bundle_unittest.cc
@@ -498,6 +498,36 @@ TEST_F(ResourceBundleImageTest, GetImageNamedFallback1x) {
   EXPECT_EQ(20, image_rep.pixel_height());
 }
 
+// Tests GetImageNamed() behaves properly when the size of a scaled image
+// requires rounding as a result of using a non-integer scale factor.
+TEST_F(ResourceBundleImageTest, GetImageNamedFallback1xRounding) {
+  base::FilePath data_path = dir_path().AppendASCII("sample.pak");
+  base::FilePath data_140P_path = dir_path().AppendASCII("sample_140P.pak");
+  base::FilePath data_180P_path = dir_path().AppendASCII("sample_180P.pak");
+
+  CreateDataPackWithSingleBitmap(data_path, 8, base::StringPiece());
+  // Mark 140% and 180% images as requiring 1x fallback.
+  CreateDataPackWithSingleBitmap(data_140P_path, 8, base::StringPiece(
+    reinterpret_cast<const char*>(kPngScaleChunk),
+    arraysize(kPngScaleChunk)));
+  CreateDataPackWithSingleBitmap(data_180P_path, 8, base::StringPiece(
+    reinterpret_cast<const char*>(kPngScaleChunk),
+    arraysize(kPngScaleChunk)));
+
+  ResourceBundle* resource_bundle = CreateResourceBundleWithEmptyLocalePak();
+  resource_bundle->AddDataPackFromPath(data_path, SCALE_FACTOR_100P);
+  resource_bundle->AddDataPackFromPath(data_140P_path, SCALE_FACTOR_140P);
+  resource_bundle->AddDataPackFromPath(data_180P_path, SCALE_FACTOR_180P);
+
+  // Non-integer dimensions should be rounded up.
+  gfx::ImageSkia* image_skia = resource_bundle->GetImageSkiaNamed(3);
+  gfx::ImageSkiaRep image_rep =
+    image_skia->GetRepresentation(ui::SCALE_FACTOR_140P);
+  EXPECT_EQ(12, image_rep.pixel_width());
+  image_rep = image_skia->GetRepresentation(ui::SCALE_FACTOR_180P);
+  EXPECT_EQ(15, image_rep.pixel_width());
+}
+
 TEST_F(ResourceBundleImageTest, FallbackToNone) {
   base::FilePath data_default_path = dir_path().AppendASCII("sample.pak");