diff options
| author | Mark Hung <marklh9@gmail.com> | 2021-05-02 15:12:46 +0800 |
|---|---|---|
| committer | Mark Hung <marklh9@gmail.com> | 2021-05-05 16:06:15 +0200 |
| commit | dd0d0b44fd1c6c0292d7b2eb3f5cf2baa21e4481 (patch) | |
| tree | 4acf78cce5976019116b99cfa4830074eea223ce | |
| parent | bb9a3f1cd2912b836deb9f73c2010bf03a1438c9 (diff) | |
vcl: adjust LayoutText() for vertical writing.
Revert 58af692e2814 "tdf#111967 translate offsets
so it is relative to vorigin", which use
hb_font_add_glyph_origin_for_direction to change
the origin for vertical writing. This caused major
problem in Y-axis.
For X-axis, align the baseline of the vertical run
to the center of the rotated horizontal run,
by adding "(ascender + descener) / 2.
Besides the alignment mentioned above, underlying text
rendering code should be able to render properly based
on the positions that Harfbuzz API creates.
Change-Id: Ic1ef1f734686d0e61c4b2a6bf7feb7c870bba84f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115014
Tested-by: Jenkins
Reviewed-by: Mark Hung <marklh9@gmail.com>
| -rw-r--r-- | vcl/source/gdi/CommonSalLayout.cxx | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/vcl/source/gdi/CommonSalLayout.cxx b/vcl/source/gdi/CommonSalLayout.cxx index 5565b3eb4d69..801abdd16670 100644 --- a/vcl/source/gdi/CommonSalLayout.cxx +++ b/vcl/source/gdi/CommonSalLayout.cxx @@ -325,6 +325,18 @@ bool GenericSalLayout::LayoutText(ImplLayoutArgs& rArgs, const SalLayoutGlyphsIm pTextLayout = pNewScriptRun.get(); } + // nBaseOffset is used to align vertical text to the center of rotated + // horizontal text. That is the offset from original baseline to + // the center of EM box. Maybe we can use OpenType base table to improve this + // in the future. + DeviceCoordinate nBaseOffset = 0; + if (rArgs.mnFlags & SalLayoutFlags::Vertical) + { + hb_font_extents_t extents; + if (hb_font_get_h_extents(pHbFont, &extents)) + nBaseOffset = ( extents.ascender + extents.descender ) / 2; + } + hb_buffer_t* pHbBuffer = hb_buffer_create(); hb_buffer_pre_allocate(pHbBuffer, nGlyphCapacity); #if !HB_VERSION_ATLEAST(1, 1, 0) @@ -583,16 +595,9 @@ bool GenericSalLayout::LayoutText(ImplLayoutArgs& rArgs, const SalLayoutGlyphsIm { nGlyphFlags |= GlyphItemFlags::IS_VERTICAL; - // We have glyph offsets that is relative to h origin now, - // add the origin back so it is relative to v origin. - hb_font_add_glyph_origin_for_direction(pHbFont, - nGlyphIndex, - HB_DIRECTION_TTB, - &pHbPositions[i].x_offset , - &pHbPositions[i].y_offset ); nAdvance = -pHbPositions[i].y_advance; nXOffset = -pHbPositions[i].y_offset; - nYOffset = -pHbPositions[i].x_offset; + nYOffset = -pHbPositions[i].x_offset - nBaseOffset; } else { |