#18078: B_MITER_JOIN implementation differs from common miter semantics
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Reporter: thebuck | Owner: axeld
Type: bug | Status: new
Priority: low | Milestone: Unscheduled
Component: Servers/app_server | Version: R1/beta4
Keywords: | Blocked By:
Blocking: | Platform: All
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=== Flow of information when viewing SVG in WebPositive
`stroke-linejoin: miter` in SVG file
↓ some Webkit code, presumably
`LineJoin::Miter`
↓ `void GraphicsContextHaiku::setLineJoin(LineJoin lineJoin)`
in
haikuwebkit/Source/WebCore/platform/graphics/haiku/GraphicsContextHaiku.cpp
`B_MITER_JOIN`
↓ `inline agg::line_join_e agg_line_join_mode_for(join_mode mode)`
in haiku/src/servers/app/drawing/Painter/Painter.cpp
`agg::miter_join`
=== Semantic difference
`agg::miter_join` cuts off the corner exactly where the miter limit is
located, resulting in a semi-bevelled look.
But `agg::miter_join_revert` is what provides the correct behaviour:\\
Switching to bevel when miter limit is exceeded.
=== Conflicting semantics
SVG, PDF, ... the modern world.
Not observed in BePDF: does it have its own stroking implementation?
=== Proposed fix:
If BeOS `B_MITER_JOIN` means `agg::miter_join_revert`, or the difference
would not be noticeable in any other application, just map it that way.
Otherwise, introduce a new
`B_BINARY_MITER_JOIN`/`B_MITER_BEVEL_JOIN`/`B_MITER_REVERT_JOIN` style...
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Ticket URL: <https://dev.haiku-os.org/ticket/18078>
Haiku <https://dev.haiku-os.org>
The Haiku operating system.
