Scale to DIPs in ppb_graphics2d_impl for proper invalidation

webkit/plugins/ppapi/ppb_graphics_2d_impl_unittest.cc

+// Copyright (c) 2012 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/basictypes.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/rect.h"
+#include "webkit/plugins/ppapi/ppb_graphics_2d_impl.h"
+
+static const int kSentinel = -500;
+
+TEST(PpapiGraphics2DImplTest, ScaleMetrics) {
+  static const struct {
+    int x1;
+    int y1;
+    int w1;
+    int h1;
+    int x2;
+    int y2;
+    int w2;
+    int h2;
+    int dx1;
+    int dy1;
+    int dx2;
+    int dy2;
+    float scale;
+    bool result;
+  } tests[] = {
+    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1.0, true },
+    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2.0, true },
+    { 0, 0, 4, 4, 0, 0, 2, 2, 0, 0, 0, 0, 0.5, true },
+    { 1, 1, 4, 4, 0, 0, 3, 3, 0, 0, 0, 0, 0.5, false },
+    { 53, 75, 100, 100, 53, 75, 100, 100, 0, 0, 0, 0, 1.0, true },
+    { 53, 75, 100, 100, 106, 150, 200, 200, 0, 0, 0, 0, 2.0, true },
+    { 53, 75, 100, 100, 26, 37, 51, 51, 0, 0, 0, 0, 0.5, false },
+    { 53, 74, 100, 100, 26, 37, 51, 50, 0, 0, 0, 0, 0.5, false },
+    { -1, -1, 100, 100, -1, -1, 51, 51, 0, 0, 0, 0, 0.5, false },
+    { -2, -2, 100, 100, -1, -1, 50, 50, 4, -4, 2, -2, 0.5, true },
+    { -101, -100, 50, 50, -51, -50, 26, 25, 0, 0, 0, 0, 0.5, false },
+
+    { 10, 10, 20, 20, 5, 5, 10, 10, 0, 0, 0, 0, 0.5, true },
+      // Cannot scroll due to partial coverage on sides
+    { 11, 10, 20, 20, 5, 5, 11, 10, 0, 0, 0, 0, 0.5, false },
+      // Can scroll since backing store is actually smaller/scaling up
+    { 11, 20, 100, 100, 22, 40, 200, 200, 7, 3, 14, 6, 2.0, true },
+      // Can scroll due to delta and bounds being aligned
+    { 10, 10, 20, 20, 5, 5, 10, 10, 6, 4, 3, 2, 0.5, true },
+      // Cannot scroll due to dx
+    { 10, 10, 20, 20, 5, 5, 10, 10, 5, 4, 2, 2, 0.5, false },
+      // Cannot scroll due to dy
+    { 10, 10, 20, 20, 5, 5, 10, 10, 6, 3, 3, 1, 0.5, false },
+      // Cannot scroll due to top
+    { 10, 11, 20, 20, 5, 5, 10, 11, 6, 4, 3, 2, 0.5, false },
+      // Cannot scroll due to left
+    { 7, 10, 20, 20, 3, 5, 11, 10, 6, 4, 3, 2, 0.5, false },
+      // Cannot scroll due to width
+    { 10, 10, 21, 20, 5, 5, 11, 10, 6, 4, 3, 2, 0.5, false },
+      // Cannot scroll due to height
+    { 10, 10, 20, 51, 5, 5, 10, 26, 6, 4, 3, 2, 0.5, false },
+      // Not checking scrolling
+    { 20, 20, 100, 100, 10, 10, 50, 50, kSentinel, kSentinel, kSentinel,
+      kSentinel, 0.5, true },
+    { 20, 21, 100, 100, 10, 10, 50, 51, kSentinel, kSentinel, kSentinel,
+      kSentinel, 0.5, true },
+      // Check negative scroll deltas
+    { 10, 10, 20, 20, 5, 5, 10, 10, -6, -4, -3, -2, 0.5, true },
+    { 10, 10, 20, 20, 5, 5, 10, 10, -6, -3, -3, -1, 0.5, false },
+
+  };
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(tests); ++i) {
+    gfx::Rect r1(tests[i].x1, tests[i].y1, tests[i].w1, tests[i].h1);
+    gfx::Rect r2(tests[i].x2, tests[i].y2, tests[i].w2, tests[i].h2);
+    gfx::Rect orig = r1;
+    int dx = tests[i].dx1;
+    int dy = tests[i].dy1;
+    bool res = webkit::ppapi::PPB_Graphics2D_Impl::ScaleMetrics(
+          tests[i].scale,
+          r1,
+          dx != kSentinel ? &dx : NULL,
+          dy != kSentinel ? &dy : NULL);
+    EXPECT_TRUE(r1.Equals(r2));
+    EXPECT_EQ(res, tests[i].result);
+    if (res) {
+      EXPECT_EQ(dx, tests[i].dx2);
+      EXPECT_EQ(dy, tests[i].dy2);
+    }
+    // Reverse the scale and ensure all the original pixels are still inside
+    // the result.
+    webkit::ppapi::PPB_Graphics2D_Impl::ScaleMetrics(
+        1.0f / tests[i].scale, r1, NULL, NULL);
+    EXPECT_TRUE(r1.Contains(orig));
+  }
+}