Add ability to compute text intercepts to Font

third_party/WebKit/Source/platform/fonts/FontTest.cpp

+// Copyright 2016 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 "platform/fonts/Font.h"
+
+#include "platform/testing/FontTestHelpers.h"
+#include "platform/testing/UnitTestHelpers.h"
+#include "platform/text/TextRun.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using blink::testing::createTestFont;
+
+namespace blink {
+
+static inline String fontPath(String relativePath) {
+  return testing::blinkRootDir() + "/Source/platform/testing/data/" +
+         relativePath;
+}
+
+TEST(FontTest, TextIntercepts) {
+  Font font = createTestFont("Ahem", fontPath("Ahem.woff"), 16);
+  // A sequence of LATIN CAPITAL LETTER E WITH ACUTE and LATIN SMALL LETTER P
+  // characters. E ACUTES are squares above the baseline in Ahem, while p's
+  // are rectangles below the baseline.
+  UChar ahemAboveBelowBaselineString[] = {0xc9, 0x70, 0xc9, 0x70, 0xc9,
+                                          0x70, 0xc9, 0x70, 0xc9};
+  TextRun ahemAboveBelowBaseline(ahemAboveBelowBaselineString, 9);
+  TextRunPaintInfo textRunPaintInfo(ahemAboveBelowBaseline);
+  SkPaint defaultPaint;
+  float deviceScaleFactor = 1;
+
+  std::tuple<float, float> belowBaselineBounds = std::make_tuple(2, 4);
+  Vector<Font::TextIntercept> textIntercepts;
+  // 4 intercept ranges for below baseline p glyphs in the test string
+  font.getTextIntercepts(textRunPaintInfo, deviceScaleFactor, defaultPaint,
+                         belowBaselineBounds, textIntercepts);
+  EXPECT_EQ(textIntercepts.size(), 4u);
+  for (auto textIntercept : textIntercepts) {
+    EXPECT_GT(textIntercept.m_end, textIntercept.m_begin);
+  }
+
+  std::tuple<float, float> aboveBaselineBounds = std::make_tuple(-4, -2);
+  // 5 intercept ranges for the above baseline E ACUTE glyphs
+  font.getTextIntercepts(textRunPaintInfo, deviceScaleFactor, defaultPaint,
+                         aboveBaselineBounds, textIntercepts);
+  EXPECT_EQ(textIntercepts.size(), 5u);
+  for (auto textIntercept : textIntercepts) {
+    EXPECT_GT(textIntercept.m_end, textIntercept.m_begin);
+  }
+}
+
+}  // namespace blink