Bug 213279

Summary: [WinCairo] glyph positions differ between partially selected texts and not selected texts
Product: WebKit Reporter: Fujii Hironori <fujii.hironori>
Component: TextAssignee: Nobody <webkit-unassigned>
Status: NEW    
Severity: Normal CC: mmaxfield
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
test content
none
[screenshot] WinCairo port
none
test content (abcd) none

Fujii Hironori
Reported 2020-06-16 18:22:44 PDT
Created attachment 402063 [details] test content [WinCairo] glyph positions differ between partially selected texts and not selected texts Even though WinCairo WebKit1 testing Buildbot doesn't fail, fast/text/international/hebrew-selection.html is failing on my PC with WinCairo WK1. I created a test content based on fast/text/international/hebrew-selection-expected.html.
Attachments
test content (611 bytes, text/html)
2020-06-16 18:22 PDT, Fujii Hironori 		no flags
Details
[screenshot] WinCairo port (10.67 KB, image/png)
2020-06-16 18:25 PDT, Fujii Hironori 		no flags
Details
test content (abcd) (515 bytes, text/html)
2020-06-16 23:45 PDT, Fujii Hironori 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Fujii Hironori
Comment 1 2020-06-16 18:25:00 PDT
Created attachment 402064 [details] [screenshot] WinCairo port Both סְ should look same, but first סְ has black shadow in WinCairo port. AppleWin doesn't have this issue.
Fujii Hironori
Comment 2 2020-06-16 18:40:56 PDT
(In reply to Fujii Hironori from comment #0) > Even though WinCairo WebKit1 testing Buildbot doesn't fail, > fast/text/international/hebrew-selection.html is failing on my PC with > WinCairo WK1. The test case is passing even on my PC with WinCairo WK2 because it has another bug repainting the entire content area by changing selection. Bug 213277 – [WinCairo][WK2] The entire content area is unnecessarily repainted just by clicking a text
Fujii Hironori
Comment 3 2020-06-16 23:45:01 PDT
Created attachment 402082 [details] test content (abcd) This issue can be reproduced by using alphabet.
Fujii Hironori
Comment 4 2020-06-17 21:56:11 PDT
Because the extents of glyphs "ab" are overlapped, _cairo_scaled_font_glyph_device_extents returns true for 'overlap_out'. Then, texts "abcd" and "ab" are drawn by using composite_glyphs_via_mask, while a test "cd" is drawn by composite_glyphs without a mask. This causes the tiny difference. I modified _cairo_compositor_glyphs to overwrite 'overlap' to TRUE or FALSE. I confirmed the tiny difference disappeared. diff --git a/src/cairo-compositor.c b/src/cairo-compositor.c index b31413b99..0147ed3bc 100644 --- a/src/cairo-compositor.c +++ b/src/cairo-compositor.c @@ -242,6 +242,7 @@ _cairo_compositor_glyphs (const cairo_compositor_t *compositor, clip, &overlap); if (unlikely (status)) return status; + overlap = TRUE; do { while (compositor->glyphs == NULL)
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