Fix regions generation on windows.

ui/gfx/path_win_unittest.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 "base/win/scoped_gdi_object.h"
+#include "skia/ext/skia_utils_win.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkRRect.h"
+#include "ui/gfx/path.h"
+#include "ui/gfx/path_win.h"

[Alexei Svitkine (slow), 2014/10/28 13:21:02]

Nit: This should be first include followed by an empty line.

[alex-ac, 2014/10/28 13:32:57]

Done.

+
+namespace {
+
+std::vector<SkIRect> GetRectsFromHRGN(HRGN region) {

[Alexei Svitkine (slow), 2014/10/28 13:21:02]

Add a comment explaining what this method does.

[alex-ac, 2014/10/28 13:32:57]

Done.

+  // Determine the size of output buffer required to receive the region.
+  DWORD bytes_size = GetRegionData(region, 0, NULL);
+  CHECK_NE(0, bytes_size);
+
+  // Fetch the Windows RECTs that comprise the region.
+  std::vector<char> buffer(bytes_size);
+  LPRGNDATA region_data = reinterpret_cast<LPRGNDATA>(buffer.data());
+  DWORD result = GetRegionData(region, bytes_size, region_data);
+  CHECK_EQ(bytes_size, result);
+
+  // Pull out the rectangles into a SkIRect vector to return to caller.
+  const LPRECT rects = reinterpret_cast<LPRECT>(&region_data->Buffer[0]);
+  std::vector<SkIRect> sk_rects(region_data->rdh.nCount);
+  std::transform(rects, rects + region_data->rdh.nCount,

[Alexei Svitkine (slow), 2014/10/28 13:21:02]

Nit: Please run git cl lint and include the std library headers it suggests you
to include.

[alex-ac, 2014/10/28 13:32:57]

Done.

+                 sk_rects.begin(), skia::RECTToSkIRect);
+
+  return sk_rects;
+}
+
+}  // namespace
+
+// Test that rectangle with round corners stil has round corners after
+// converting from SkPath to the HRGN.
+TEST(CreateHRGNFromSkPathTest, RoundCornerTest) {
+  const SkIRect rects[] = {
+      { 17, 0, 33, 1},
+      { 12, 1, 38, 2},
+      { 11, 2, 39, 3},
+      { 9, 3, 41, 4},
+      { 8, 4, 42, 5},
+      { 6, 5, 44, 6},
+      { 5, 6, 45, 8},
+      { 4, 8, 46, 9},
+      { 3, 9, 47, 11},
+      { 2, 11, 48, 12},
+      { 1, 12, 49, 17},
+      { 0, 17, 50, 33},
+      { 1, 33, 49, 38},
+      { 2, 38, 48, 39},
+      { 3, 39, 47, 41},
+      { 4, 41, 46, 42},
+      { 5, 42, 45, 44},
+      { 6, 44, 44, 45},
+      { 8, 45, 42, 46},
+      { 9, 46, 41, 47},
+      { 11, 47, 39, 48},
+      { 12, 48, 38, 49},
+      { 17, 49, 33, 50},
+  };
+
+  gfx::Path path;
+  SkRRect rrect;
+  rrect.setRectXY(SkRect::MakeWH(50, 50), 20, 20);
+  path.addRRect(rrect);
+  base::win::ScopedRegion region(gfx::CreateHRGNFromSkPath(path));
+  const std::vector<SkIRect>& region_rects = GetRectsFromHRGN(region);
+  EXPECT_EQ(arraysize(rects), region_rects.size());
+  for (size_t i = 0; i < arraysize(rects) && i < region_rects.size(); ++i)
+    EXPECT_EQ(rects[i], region_rects[i]);
+}
+
+// Check that a path enclosing two non-adjacent areas is correctly translated
+// to a non-contiguous region.
+TEST(CreateHRGNFromSkPathTest, NonContiguousPath) {
+  const SkIRect rects[] = {
+      { 0, 0, 50, 50},
+      { 100, 100, 150, 150},
+  };
+
+  gfx::Path path;

[Alexei Svitkine (slow), 2014/10/28 13:21:02]

Put the test inside the gfx namespace and remove the gfx:: prefixes.

[alex-ac, 2014/10/28 13:32:57]

Done.

+  for (const SkIRect& rect : rects) {
+    path.addRect(SkRect::Make(rect));
+  }
+  base::win::ScopedRegion region(gfx::CreateHRGNFromSkPath(path));
+  const std::vector<SkIRect>& region_rects = GetRectsFromHRGN(region);
+  EXPECT_EQ(arraysize(rects), region_rects.size());
+  for (size_t i = 0; i < arraysize(rects) && i < region_rects.size(); ++i)

[Alexei Svitkine (slow), 2014/10/28 13:21:02]

Nit: Change the EXPECT_EQ above to ASSERT_EQ and then you just need to check
only one of the two conditions here since they'll be guaranteed to be
equivalent.

[alex-ac, 2014/10/28 13:32:57]

Done.

+    EXPECT_EQ(rects[i], region_rects[i]);
+}
+
+// Check that empty region is returned for empty path.
+TEST(CreateHRGNFromSkPathTest, EmptyPath) {
+  gfx::Path path;
+  base::win::ScopedRegion empty_region(::CreateRectRgn(0, 0, 0, 0));
+  base::win::ScopedRegion region(gfx::CreateHRGNFromSkPath(path));
+  EXPECT_TRUE(::EqualRgn(empty_region, region));
+}
+