Attachment 263903 Details for Bug 131839 – Patch iOS

[patch] Patch iOS

use-typo-ios.patch (text/plain), 4.14 KB, created by Frédéric Wang Nélar on 2015-10-22 22:49:45 PDT

(hide)

Description:

Filename:

MIME Type:

Creator: Frédéric Wang Nélar

Created: 2015-10-22 22:49:45 PDT

Size: 4.14 KB

patch

obsolete

>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index b648fe0..9c3e06d 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,18 @@
>+2015-10-22  Frederic Wang  <fred.wang@free.fr>
>+
>+        Add support for the USE_TYPO_METRICS flag on iOS
>+        https://bugs.webkit.org/show_bug.cgi?id=131839
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Make the iOS Font service use typo the typo metrics for fonts with a MATH table when the OS/2 USE_TYPO_METRICS flag is set.
>+
>+        No new tests because this is already tested by fonts/use-typo-metrics-1.html
>+
>+        * platform/graphics/ios/FontServicesIOS.mm:
>+        (WebCore::fontHasMathTable):
>+        (WebCore::FontServicesIOS::FontServicesIOS):
>+
> 2015-10-22  Alex Christensen  <achristensen@webkit.org>
> 
>         Initial NSURLSession WebResourceLoader implementation
>diff --git a/Source/WebCore/platform/graphics/ios/FontServicesIOS.mm b/Source/WebCore/platform/graphics/ios/FontServicesIOS.mm
>index 15483c1..e30760c 100644
>--- a/Source/WebCore/platform/graphics/ios/FontServicesIOS.mm
>+++ b/Source/WebCore/platform/graphics/ios/FontServicesIOS.mm
>@@ -28,12 +28,25 @@
> #import "CoreGraphicsSPI.h"
> #import "DynamicLinkerSPI.h"
> #import "FontMetrics.h"
>+#import "OpenTypeTypes.h"
> #import <wtf/RetainPtr.h>
> 
> namespace WebCore {
> 
> static const float kLineHeightAdjustment = 0.15f;
> 
>+static bool fontHasMathTable(CTFontRef ctFont)
>+{
>+    RetainPtr<CFArrayRef> tableTags = adoptCF(CTFontCopyAvailableTables(ctFont, kCTFontTableOptionNoOptions));
>+    CFIndex numTables = CFArrayGetCount(tableTags.get());
>+    for (CFIndex index = 0; index < numTables; ++index) {
>+        CTFontTableTag tag = (CTFontTableTag)(uintptr_t)CFArrayGetValueAtIndex(tableTags.get(), index);
>+        if (tag == kCTFontTableMATH)
>+            return true;
>+    }
>+    return false;
>+}
>+
> static bool shouldUseAdjustment(CTFontRef font, bool isiOS7OrLater)
> {
>     RetainPtr<NSString> familyName = adoptNS((NSString *)CTFontCopyFamilyName(font));
>@@ -95,6 +108,31 @@ FontServicesIOS::FontServicesIOS(CTFontRef font)
>             descent = (scaleEmToUnits(615, 2048) * pointSize);
>         }
>     }
>+    // The Open Font Format describes the OS/2 USE_TYPO_METRICS flag as follows:
>+    // "If set, it is strongly recommended to use OS/2.sTypoAscender - OS/2.sTypoDescender+ OS/2.sTypoLineGap as a value for default line spacing for this font."
>+    // We only apply this rule in the important case of fonts with a MATH table.
>+    if (fontHasMathTable(font)) {
>+        if (CFDataRef os2Table = CGFontCopyTableForTag(cgFont.get(), kCTFontTableOS2)) {
>+            // For the structure of the OS/2 table, see
>+            // https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6OS2.html
>+            const CFIndex fsSelectionOffset = 16 * 2 + 10 + 4 * 4 + 4 * 1;
>+            const CFIndex sTypoAscenderOffset = fsSelectionOffset + 3 * 2;
>+            const CFIndex sTypoDescenderOffset = sTypoAscenderOffset + 2;
>+            const CFIndex sTypoLineGapOffset = sTypoDescenderOffset + 2;
>+            if (CFDataGetLength(os2Table) >= sTypoLineGapOffset + 2) {
>+                const UInt8* os2Data = CFDataGetBytePtr(os2Table);
>+                const unsigned short useTypoMetricsMask = 1 << 7;
>+                if (*(reinterpret_cast<const OpenType::UInt16*>(os2Data + fsSelectionOffset)) & useTypoMetricsMask) {
>+                    unsigned unitsPerEm = CGFontGetUnitsPerEm(cgFont.get());
>+                    float pointSize = CTFontGetSize(font);
>+                    ascent = scaleEmToUnits(*(reinterpret_cast<const OpenType::Int16*>(os2Data + sTypoAscenderOffset)), unitsPerEm) * pointSize;
>+                    descent = -scaleEmToUnits(*(reinterpret_cast<const OpenType::Int16*>(os2Data + sTypoDescenderOffset)), unitsPerEm) * pointSize;
>+                    lineGap = scaleEmToUnits(*(reinterpret_cast<const OpenType::Int16*>(os2Data + sTypoLineGapOffset)), unitsPerEm) * pointSize;
>+                }
>+            }
>+            CFRelease(os2Table);
>+        }
>+    }
>     CGFloat adjustment = (shouldUseAdjustment(font, isiOS7OrLater)) ? ceil((ascent + descent) * kLineHeightAdjustment) : 0;
> 
>     m_ascent = ascent + adjustment;

Actions: View | Formatted Diff | Diff

Attachments on bug 131839: 263416 | 263497 | 263596 | 263616 | 263903 | 263907 | 264672 | 264674 | 264678 | 264680 | 264682 | 264686 | 264687 | 264688 | 264689 | 264712 | 264723