[GTK] Bump freetype version to 2.8.0

https://bugs.webkit.org/show_bug.cgi?id=176351

Source/WebCore:

Patch by Dominik Röttsches <dominik.rottsches@intel.com> on 2017-09-06
Reviewed by Carlos Alberto Lopez Perez.

Retrieving line spacing info without metrics hinting - FreeType's metric hinting
uses rounding which results in the sum of ascent and descent being larger
than the line height. To work around this without globally disabling font metrics
hinting, I am temporarily creating a new cairo scaled font with metrics hinting
off and retrieving the height values from this one.

* platform/graphics/freetype/SimpleFontDataFreeType.cpp:
(WebCore::scaledFontWithoutMetricsHinting): New function to clone the existing font, only with metrics hinting
disabled.
(WebCore::Font::platformInit): Get height info from non-metrics hinted font, disable rounding for linespacing.

Tools:

Reviewed by Carlos Alberto Lopez Perez.

Remove the patch we were using since it was reverted upstream.

* gtk/jhbuild.modules:
* gtk/patches/freetype6-2.4.11-truetype-font-height-fix.patch: Removed.

Canonical link: https://commits.webkit.org/193031@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@221670 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/ChangeLog

@@ -1,3 +1,21 @@
+2017-09-06  Dominik Röttsches  <dominik.rottsches@intel.com>
+
+        [GTK] Bump freetype version to 2.8.0
+        https://bugs.webkit.org/show_bug.cgi?id=176351
+
+        Reviewed by Carlos Alberto Lopez Perez.
+
+        Retrieving line spacing info without metrics hinting - FreeType's metric hinting
+        uses rounding which results in the sum of ascent and descent being larger
+        than the line height. To work around this without globally disabling font metrics
+        hinting, I am temporarily creating a new cairo scaled font with metrics hinting
+        off and retrieving the height values from this one.
+
+        * platform/graphics/freetype/SimpleFontDataFreeType.cpp:
+        (WebCore::scaledFontWithoutMetricsHinting): New function to clone the existing font, only with metrics hinting
+        disabled.
+        (WebCore::Font::platformInit): Get height info from non-metrics hinted font, disable rounding for linespacing.
+
 2017-09-06  Frédéric Wang  <fwang@igalia.com>
 
         Introduce ScrollingTreeScrollingNodeDelegateIOS to share code between overflow and frame scrolling

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

@@ -33,13 +33,15 @@
 #include "config.h"
 #include "Font.h"
 
+#include "CairoUniquePtr.h"
 #include "CairoUtilities.h"
 #include "FloatConversion.h"
 #include "FloatRect.h"
 #include "FontCache.h"
 #include "FontDescription.h"
 #include "GlyphBuffer.h"
 #include "OpenTypeTypes.h"
+#include "RefPtrCairo.h"
 #include "UTF16UChar32Iterator.h"
 #include <cairo-ft.h>
 #include <cairo.h>
@@ -52,14 +54,30 @@
 
 namespace WebCore {
 
+static RefPtr<cairo_scaled_font_t> scaledFontWithoutMetricsHinting(cairo_scaled_font_t* scaledFont)
+{
+    CairoUniquePtr<cairo_font_options_t> fontOptions(cairo_font_options_create());
+    cairo_scaled_font_get_font_options(scaledFont, fontOptions.get());
+    cairo_font_options_set_hint_metrics(fontOptions.get(), CAIRO_HINT_METRICS_OFF);
+    cairo_matrix_t fontMatrix;
+    cairo_scaled_font_get_font_matrix(scaledFont, &fontMatrix);
+    cairo_matrix_t fontCTM;
+    cairo_scaled_font_get_ctm(scaledFont, &fontCTM);
+    return adoptRef(cairo_scaled_font_create(cairo_scaled_font_get_font_face(scaledFont), &fontMatrix, &fontCTM, fontOptions.get()));
+}
+
 void Font::platformInit()
 {
     if (!m_platformData.size())
         return;
 
     ASSERT(m_platformData.scaledFont());
+    // Temporarily create a clone that doesn't have metrics hinting in order to avoid incorrect
+    // rounding resulting in incorrect baseline positioning since the sum of ascent and descent
+    // becomes larger than the line height.
+    auto fontWithoutMetricsHinting = scaledFontWithoutMetricsHinting(m_platformData.scaledFont());
     cairo_font_extents_t fontExtents;
-    cairo_scaled_font_extents(m_platformData.scaledFont(), &fontExtents);
+    cairo_scaled_font_extents(fontWithoutMetricsHinting.get(), &fontExtents);
 
     float ascent = narrowPrecisionToFloat(fontExtents.ascent);
     float descent = narrowPrecisionToFloat(fontExtents.descent);
@@ -88,9 +106,7 @@ void Font::platformInit()
     m_fontMetrics.setAscent(ascent);
     m_fontMetrics.setDescent(descent);
     m_fontMetrics.setCapHeight(capHeight);
-
-    // Match CoreGraphics metrics.
-    m_fontMetrics.setLineSpacing(lroundf(ascent) + lroundf(descent) + lroundf(lineGap));
+    m_fontMetrics.setLineSpacing(ascent + descent + lineGap);
     m_fontMetrics.setLineGap(lineGap);
 
     cairo_text_extents_t textExtents;

Tools/ChangeLog

@@ -1,3 +1,15 @@
+2017-09-06  Carlos Garcia Campos  <cgarcia@igalia.com>
+
+        [GTK] Bump freetype version to 2.8.0
+        https://bugs.webkit.org/show_bug.cgi?id=176351
+
+        Reviewed by Carlos Alberto Lopez Perez.
+
+        Remove the patch we were using since it was reverted upstream.
+
+        * gtk/jhbuild.modules:
+        * gtk/patches/freetype6-2.4.11-truetype-font-height-fix.patch: Removed.
+
 2017-09-06  Yoshiaki Jitsukawa  <Yoshiaki.Jitsukawa@sony.com>
 
         [Win] Tools/TestWebKitAPI/Tests/WTF/PriorityQueue.cpp fails to compile with MSVC 2015

Tools/gtk/jhbuild.modules

@@ -119,12 +119,9 @@
   </autotools>
 
   <autotools id="freetype6" autogen-sh="configure">
-    <branch module="freetype/freetype-2.4.11.tar.bz2" version="2.4.11"
+    <branch module="freetype/freetype-2.8.tar.bz2" version="2.8"
             repo="savannah.gnu.org"
-            hash="sha256:ef9d0bcb64647d9e5125dc7534d7ca371c98310fec87677c410f397f71ffbe3f"
-            md5sum="b93435488942486c8d0ca22e8f768034">
-      <patch file="freetype6-2.4.11-truetype-font-height-fix.patch" strip="1"/>
-    </branch>
+            hash="sha256:a3c603ed84c3c2495f9c9331fe6bba3bb0ee65e06ec331e0a0fb52158291b40b"/>
   </autotools>
 
   <autotools id="harfbuzz" autogen-sh="configure">