Index: third_party/WebKit/Source/core/layout/ng/ng_line_height_metrics.cc |
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_line_height_metrics.cc b/third_party/WebKit/Source/core/layout/ng/ng_line_height_metrics.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..b47c9892c1c71b423a6b06592ae73e81ae25f619 |
--- /dev/null |
+++ b/third_party/WebKit/Source/core/layout/ng/ng_line_height_metrics.cc |
@@ -0,0 +1,46 @@ |
+// Copyright 2017 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 "core/layout/ng/ng_line_height_metrics.h" |
+ |
+#include "core/style/ComputedStyle.h" |
+ |
+namespace blink { |
+ |
+NGLineHeightMetrics::NGLineHeightMetrics(const ComputedStyle& style, |
+ FontBaseline baseline_type) { |
+ const SimpleFontData* font_data = style.font().primaryFont(); |
+ DCHECK(font_data); |
+ Initialize(font_data->getFontMetrics(), baseline_type, |
+ style.computedLineHeightInFloat()); |
+} |
+ |
+NGLineHeightMetrics::NGLineHeightMetrics(const FontMetrics& font_metrics, |
+ FontBaseline baseline_type) { |
+ Initialize(font_metrics, baseline_type, font_metrics.floatLineSpacing()); |
+} |
+ |
+void NGLineHeightMetrics::Initialize(const FontMetrics& font_metrics, |
+ FontBaseline baseline_type, |
+ float line_height) { |
+ ascent = font_metrics.floatAscent(baseline_type); |
+ descent = font_metrics.floatDescent(baseline_type); |
+ float half_leading = (line_height - (ascent + descent)) / 2; |
+ // Ensure the top and the baseline is snapped to CSS pixel. |
+ // TODO(kojii): How to handle fractional ascent isn't determined yet. Should |
+ // we snap top or baseline? If baseline, top needs fractional. If top, |
+ // baseline may not align across fonts. |
+ ascent_and_leading = ascent + floor(half_leading); |
+ descent_and_leading = line_height - ascent_and_leading; |
+} |
+ |
+void NGLineHeightMetrics::Unite(const NGLineHeightMetrics& other) { |
+ ascent = std::max(ascent, other.ascent); |
+ descent = std::max(descent, other.descent); |
+ ascent_and_leading = std::max(ascent_and_leading, other.ascent_and_leading); |
+ descent_and_leading = |
+ std::max(descent_and_leading, other.descent_and_leading); |
+} |
+ |
+} // namespace blink |