Changeset 191378 in webkit

Timestamp:

Oct 21, 2015 12:05:21 AM (9 years ago)

Author:

fred.wang@free.fr

Message:

[FreeType] Add support for the USE_TYPO_METRICS flag
​https://bugs.webkit.org/show_bug.cgi?id=150340

Reviewed by Martin Robinson.

Source/WebCore:

Test: fonts/use-typo-metrics-1.html

Make the FreeType backend use the typo metrics when the OS/2 USE_TYPO_METRICS flag is set.
Similar work should be done for other backends, see bug 131839.

• platform/graphics/freetype/SimpleFontDataFreeType.cpp:

(WebCore::Font::platformInit): Verify whether the OS/2 USE_TYPO_METRICS flag is set and use the typo metrics if that's the case.

LayoutTests:

Add a test to verify that the line height of a font is calculated from the typo metrics when the OS/2 USE_TYPO_METRICS flag is set. Currently, the test only passes with the FreeType backend.

• fonts/lineheight5000-typolineheight2300.woff: Added.
• fonts/use-typo-metrics-1-expected.html: Added.
• fonts/use-typo-metrics-1.html: Added.
• platform/mac/TestExpectations: Mark as failing.
• platform/win/TestExpectations: Mark as failing.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fonts/lineheight5000-typolineheight2300.woff (added)
• LayoutTests/fonts/use-typo-metrics-1-expected.html (added)
• LayoutTests/fonts/use-typo-metrics-1.html (added)
• LayoutTests/platform/mac/TestExpectations (modified) (1 diff)
• LayoutTests/platform/win/TestExpectations (modified) (1 diff)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2015-10-21  Frederic Wang  <fred.wang@free.fr>
+
+        [FreeType] Add support for the USE_TYPO_METRICS flag
+        https://bugs.webkit.org/show_bug.cgi?id=150340
+
+        Reviewed by Martin Robinson.
+
+        Add a test to verify that the line height of a font is calculated from the typo metrics when the OS/2 USE_TYPO_METRICS flag is set. Currently, the test only passes with the FreeType backend.
+
+        * fonts/lineheight5000-typolineheight2300.woff: Added.
+        * fonts/use-typo-metrics-1-expected.html: Added.
+        * fonts/use-typo-metrics-1.html: Added.
+        * platform/mac/TestExpectations: Mark as failing.
+        * platform/win/TestExpectations: Mark as failing.
+
 2015-10-20  Ryan Haddad  <ryanhaddad@apple.com>
 

trunk/LayoutTests/platform/mac/TestExpectations

@@ -1349 +1349 @@
 # Imported Blink tests which have not been investigated.
 imported/blink/compositing/video/video-controls-layer-creation-squashing.html [ Pass ImageOnlyFailure ]
+
+# USE_TYPO_METRICS is not implemented on mac.
+webkit.org/b/131839 fonts/use-typo-metrics-1.html [ Failure ]

trunk/LayoutTests/platform/win/TestExpectations

@@ -3265 +3265 @@
 # The following tests are not relevant on the Windows platform:
 fast/forms/hidpi-textfield-background-bleeding.html [ Skip ]
+
+# USE_TYPO_METRICS is not implemented on the Windows platform
+webkit.org/b/131839 fonts/use-typo-metrics-1.html [ Failure ]

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2015-10-21  Frederic Wang  <fred.wang@free.fr>
+
+        [FreeType] Add support for the USE_TYPO_METRICS flag
+        https://bugs.webkit.org/show_bug.cgi?id=150340
+
+        Reviewed by Martin Robinson.
+
+        Test: fonts/use-typo-metrics-1.html
+
+        Make the FreeType backend use the typo metrics when the OS/2 USE_TYPO_METRICS flag is set.
+        Similar work should be done for other backends, see bug 131839.
+
+        * platform/graphics/freetype/SimpleFontDataFreeType.cpp:
+        (WebCore::Font::platformInit): Verify whether the OS/2 USE_TYPO_METRICS flag is set and use the typo metrics if that's the case.
+
 2015-10-20  Hunseop Jeong  <hs85.jeong@samsung.com>
 

trunk/Source/WebCore/platform/graphics/freetype/SimpleFontDataFreeType.cpp

@@ -65 +65 @@
     float capHeight = narrowPrecisionToFloat(fontExtents.height);
     float lineGap = narrowPrecisionToFloat(fontExtents.height - fontExtents.ascent - fontExtents.descent);
+
+    // If the USE_TYPO_METRICS flag is set in the OS/2 table then we use typo metrics instead.
+    FT_Face freeTypeFace = cairo_ft_scaled_font_lock_face(m_platformData.scaledFont());
+    if (TT_OS2* OS2Table = static_cast<TT_OS2*>(FT_Get_Sfnt_Table(freeTypeFace, ft_sfnt_os2))) {
+        const FT_Short kUseTypoMetricsMask = 1 << 7;
+        if (OS2Table->fsSelection & kUseTypoMetricsMask) {
+            // FT_Size_Metrics::y_scale is in 16.16 fixed point format.
+            // Its (fractional) value is a factor that converts vertical metrics from design units to units of 1/64 pixels.
+            double yscale = (freeTypeFace->size->metrics.y_scale / 65536.0) / 64.0;
+            ascent = narrowPrecisionToFloat(yscale * OS2Table->sTypoAscender);
+            descent = -narrowPrecisionToFloat(yscale * OS2Table->sTypoDescender);
+            lineGap = narrowPrecisionToFloat(yscale * OS2Table->sTypoLineGap);
+        }
+    }
+    cairo_ft_scaled_font_unlock_face(m_platformData.scaledFont());
 
     m_fontMetrics.setAscent(ascent);