[Webkit-unassigned] [Bug 97824] New: OpenTypeVerticalData issue with DroidSansFallback.ttf on chromium-android and chromium-linux

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=97824

           Summary: OpenTypeVerticalData issue with DroidSansFallback.ttf
                    on chromium-android and chromium-linux
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: Unspecified
        OS/Version: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Platform
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: wangxianzhu at chromium.org
                CC: tony at chromium.org, senorblanco at chromium.org,
                    tkent at chromium.org, peter at chromium.org,
                    bashi at chromium.org, kojiishi at gmail.com


Bug 97227 enabled OpenTypeVerticalData on Linux. However, if replace the fonts used in layout tests (/usr/share/fonts/truetype/kochi/kochi-gothic.ttf, /usr/share/fonts/truetype/kochi/kochi-mincho.ttf) with Android's font DroidSansFallback.ttf (containing CJK glyphs and others), DumpRenderTree generates incorrect result for verticle CJK text.

Steps to reproduce:
1. Apply the attached patch and build DumpRenderTree
2. Save the attached DroidSansFallback.ttf to /tmp
3. Run new-run-webkit-tests --no-new-test-results testvert.html

Expected result: see the attached expected result
Actual result: see the attached actual result 1. The CJK glyphs are only displayed small parts of them

Reason: On chromium-linux unitsPerEm() has only a default value 1000, so the OpenTypeVerticalData::advanceHeight() computes incorrect height advance (4.096).

For the default fonts kochi-gothic.ttf and kochi-mincho.ttf, m_advanceHeights is empty, so the default height is returned, and it happens to be correct.

With the 'if' block in OpenTypeVerticalData::advanceHeight() commented out (forced to use the default height), it produces another incorrect result (see attached actual result 2): The punctuations are not correctly substituted.

The results are the same on chromium-android with the font.

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