Changeset 171561 in webkit

Timestamp:

Jul 24, 2014 5:27:09 PM (10 years ago)

Author:

mmaxfield@apple.com

Message:

Crash when measuring a glyphs from a fallback SVG font
​https://bugs.webkit.org/show_bug.cgi?id=135264

Reviewed by Simon Fraser.

Source/WebCore:
We can't realize font data for all fallback fonts ahead
of time, but we don't have all the necessary context to
realize SVG fallback data when it's needed. For now, we
can just bail; however, a larger, more invasive fix is
in order.

Test: svg/text/svg-fallback-font-crash.html

• platform/graphics/WidthIterator.cpp:

(WebCore::applyFontTransforms):

LayoutTests:
Render some text with a fallback SVG Font including a glyph which
only exists in that fallback font. Make sure there is no crash.

• svg/text/resources/Litherum.svg:
• svg/text/svg-fallback-font-crash-expected.txt: Added.
• svg/text/svg-fallback-font-crash.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/svg/text/resources/Litherum.svg (modified) (1 diff)
• LayoutTests/svg/text/svg-fallback-font-crash-expected.txt (added)
• LayoutTests/svg/text/svg-fallback-font-crash.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/platform/graphics/WidthIterator.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2014-07-24  Myles C. Maxfield  <mmaxfield@apple.com>
+
+        Crash when measuring a glyphs from a fallback SVG font
+        https://bugs.webkit.org/show_bug.cgi?id=135264
+
+        Reviewed by Simon Fraser.
+
+        Render some text with a fallback SVG Font including a glyph which
+        only exists in that fallback font. Make sure there is no crash.
+
+        * svg/text/resources/Litherum.svg:
+        * svg/text/svg-fallback-font-crash-expected.txt: Added.
+        * svg/text/svg-fallback-font-crash.html: Added.
+
 2014-07-24  Mihnea Ovidenie  <mihnea@adobe.com>
 

trunk/LayoutTests/svg/text/resources/Litherum.svg

@@ -7 +7 @@
 <font-face units-per-em="14" ascent="14" descent="-7"/>
 <glyph unicode="|" horiz-adv-x="14" d="M5 -7v21h4v-21z"/>
+<glyph unicode="&#x20001;" horiz-adv-x="14" d="M5 -7v21h4v-21z"/>
 </font>
 </defs>

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-07-24  Myles C. Maxfield  <mmaxfield@apple.com>
+
+        Crash when measuring a glyphs from a fallback SVG font
+        https://bugs.webkit.org/show_bug.cgi?id=135264
+
+        Reviewed by Simon Fraser.
+
+        We can't realize font data for all fallback fonts ahead
+        of time, but we don't have all the necessary context to
+        realize SVG fallback data when it's needed. For now, we
+        can just bail; however, a larger, more invasive fix is
+        in order.
+
+        Test: svg/text/svg-fallback-font-crash.html
+
+        * platform/graphics/WidthIterator.cpp:
+        (WebCore::applyFontTransforms):
+
 2014-07-24  Daniel Bates  <dabates@apple.com>
             And Alexey Proskuryakov  <ap@apple.com>

trunk/Source/WebCore/platform/graphics/WidthIterator.cpp

@@ -124 +124 @@
     // We need to handle transforms on SVG fonts internally, since they are rendered internally.
     if (fontData->isSVGFont()) {
-        ASSERT(iterator.run().renderingContext());
         // SVG font ligatures are handled during glyph selection, only kerning remaining.
-        if (typesettingFeatures & Kerning)
+        if (iterator.run().renderingContext() && (typesettingFeatures & Kerning)) {
+            // FIXME: We could pass the necessary context down to this level so we can lazily create rendering contexts at this point.
+            // However, a larger refactoring of SVG fonts might necessary to sidestep this problem completely.
             iterator.run().renderingContext()->applySVGKerning(fontData, iterator, glyphBuffer, lastGlyphCount);
+        }
     } else
 #endif