vcl/unx/generic/gdi/cairotextrender.cxx | 51 +++++++++++++++++++++++---------
1 file changed, 37 insertions(+), 14 deletions(-)
New commits:
commit bfe18cbb5eebe975bd469bb884b4c86f03fc48c0
Author: Caolán McNamara <caol...@redhat.com>
AuthorDate: Tue Nov 29 20:26:49 2022 +0000
Commit: Caolán McNamara <caol...@redhat.com>
CommitDate: Wed Nov 30 12:15:44 2022 +0100
Related: tdf#152094 experiment with snapping to a subpixel
Change-Id: Ieb4fbd135f618d7e46762b0ac297446308c75755
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143474
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caol...@redhat.com>
diff --git a/vcl/unx/generic/gdi/cairotextrender.cxx
b/vcl/unx/generic/gdi/cairotextrender.cxx
index 95e11f9614a7..0a5ae547360c 100644
--- a/vcl/unx/generic/gdi/cairotextrender.cxx
+++ b/vcl/unx/generic/gdi/cairotextrender.cxx
@@ -23,6 +23,7 @@
#include <unx/fc_fontoptions.hxx>
#include <unx/freetype_glyphcache.hxx>
+#include <headless/CairoCommon.hxx>
#include <vcl/svapp.hxx>
#include <sallayout.hxx>
#include <salinst.hxx>
@@ -167,12 +168,30 @@ void CairoTextRender::DrawTextLayout(const
GenericSalLayout& rLayout, const SalG
const bool bResolutionIndependentLayoutEnabled =
rLayout.GetTextRenderModeForResolutionIndependentLayout();
+ /*
+ * It might be ideal to cache surface and cairo context between calls and
+ * only destroy it when the drawable changes, but to do that we need to at
+ * least change the SalFrame etc impls to dtor the SalGraphics *before* the
+ * destruction of the windows they reference
+ */
+ cairo_t *cr = syncCairoContext(getCairoContext());
+ if (!cr)
+ {
+ SAL_WARN("vcl", "no cairo context for text");
+ return;
+ }
+
std::vector<cairo_glyph_t> cairo_glyphs;
std::vector<int> glyph_extrarotation;
cairo_glyphs.reserve( 256 );
+ double nSnapToSubPixelDiff = 0.0;
+ double nXScale, nYScale;
+ dl_cairo_surface_get_device_scale(cairo_get_target(cr), &nXScale,
&nYScale);
+
DevicePoint aPos;
const GlyphItem* pGlyph;
+ const GlyphItem* pPrevGlyph = nullptr;
int nStart = 0;
while (rLayout.GetNextGlyph(&pGlyph, aPos, nStart))
{
@@ -184,13 +203,30 @@ void CairoTextRender::DrawTextLayout(const
GenericSalLayout& rLayout, const SalG
const bool bVertical = pGlyph->IsVertical();
glyph_extrarotation.push_back(bVertical ? 1 : 0);
- // tdf#150507 like skia even when subpixel rendering pixel snap y
if (bResolutionIndependentLayoutEnabled)
{
+ // tdf#150507 like skia, even when subpixel rendering pixel, snap y
if (!bVertical)
aGlyph.y = std::floor(aGlyph.y + 0.5);
else
aGlyph.x = std::floor(aGlyph.x + 0.5);
+
+ // tdf#152094 snap to 1/4 of a pixel after a run of whitespace,
+ // probably a little dubious, but maybe worth a shot for lodpi
+ double& rGlyphDimension = !bVertical ? aGlyph.x : aGlyph.y;
+ const int nSubPixels = 4 * (!bVertical ? nXScale : nYScale);
+ if (pGlyph->IsSpacing())
+ nSnapToSubPixelDiff = 0;
+ else if (pPrevGlyph && pPrevGlyph->IsSpacing())
+ {
+ double nSnapToSubPixel = std::floor(rGlyphDimension *
nSubPixels) / nSubPixels;
+ nSnapToSubPixelDiff = rGlyphDimension - nSnapToSubPixel;
+ rGlyphDimension = nSnapToSubPixel;
+ }
+ else
+ rGlyphDimension -= nSnapToSubPixelDiff;
+
+ pPrevGlyph = pGlyph;
}
cairo_glyphs.push_back(aGlyph);
@@ -222,19 +258,6 @@ void CairoTextRender::DrawTextLayout(const
GenericSalLayout& rLayout, const SalG
return;
}
- /*
- * It might be ideal to cache surface and cairo context between calls and
- * only destroy it when the drawable changes, but to do that we need to at
- * least change the SalFrame etc impls to dtor the SalGraphics *before* the
- * destruction of the windows they reference
- */
- cairo_t *cr = syncCairoContext(getCairoContext());
- if (!cr)
- {
- SAL_WARN("vcl", "no cairo context for text");
- return;
- }
-
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
if (__lsan_disable)
__lsan_disable();
