vcl/skia/gdiimpl.cxx | 52 +++++++++++++++++++++++++++++++++++----------------
1 file changed, 36 insertions(+), 16 deletions(-)
New commits:
commit 4de9f35aef7a96a3c034e8a7ed5006ab36e5984a
Author: Luboš Luňák <l.lu...@collabora.com>
AuthorDate: Wed Nov 18 16:30:52 2020 +0100
Commit: Caolán McNamara <caol...@redhat.com>
CommitDate: Mon Nov 23 21:39:53 2020 +0100
avoid Skia floating point position fixups for rectangles (tdf#137329)
Avoid to toSkX()/toSkY() tweaks for rectangular areas, so with AA
enabled it leads to fuzzy edges, and rectangles should line up
perfectly with all pixels even without tweaks.
Change-Id: I45bf5a57a9f2d941eb7ec224992fc452481a2f98
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/106060
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lu...@collabora.com>
(cherry picked from commit 5b292e878703ebc32e875406f4116cba145a9042)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/106434
Reviewed-by: Caolán McNamara <caol...@redhat.com>
diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index 40bd2181c9b1..bd497d7f8f6e 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -50,7 +50,8 @@ namespace
// bottom-most line of pixels of the bounding rectangle (see
//
https://lists.freedesktop.org/archives/libreoffice/2019-November/083709.html).
// So be careful with rectangle->polygon conversions (generally avoid them).
-void addPolygonToPath(const basegfx::B2DPolygon& rPolygon, SkPath& rPath)
+void addPolygonToPath(const basegfx::B2DPolygon& rPolygon, SkPath& rPath,
+ bool* hasOnlyOrthogonal = nullptr)
{
const sal_uInt32 nPointCount(rPolygon.count());
@@ -85,6 +86,11 @@ void addPolygonToPath(const basegfx::B2DPolygon& rPolygon,
SkPath& rPath)
else if (!bHasCurves)
{
rPath.lineTo(aCurrentPoint.getX(), aCurrentPoint.getY());
+ // If asked for, check whether the polygon has a line that is not
+ // strictly horizontal or vertical.
+ if (hasOnlyOrthogonal != nullptr && aCurrentPoint.getX() !=
aPreviousPoint.getX()
+ && aCurrentPoint.getY() != aPreviousPoint.getY())
+ *hasOnlyOrthogonal = false;
}
else
{
@@ -105,6 +111,8 @@ void addPolygonToPath(const basegfx::B2DPolygon& rPolygon,
SkPath& rPath)
rPath.cubicTo(aPreviousControlPoint.getX(),
aPreviousControlPoint.getY(),
aCurrentControlPoint.getX(),
aCurrentControlPoint.getY(),
aCurrentPoint.getX(), aCurrentPoint.getY());
+ if (hasOnlyOrthogonal != nullptr)
+ *hasOnlyOrthogonal = false;
}
aPreviousPoint = aCurrentPoint;
nPreviousIndex = nCurrentIndex;
@@ -115,7 +123,8 @@ void addPolygonToPath(const basegfx::B2DPolygon& rPolygon,
SkPath& rPath)
}
}
-void addPolyPolygonToPath(const basegfx::B2DPolyPolygon& rPolyPolygon, SkPath&
rPath)
+void addPolyPolygonToPath(const basegfx::B2DPolyPolygon& rPolyPolygon, SkPath&
rPath,
+ bool* hasOnlyOrthogonal = nullptr)
{
const sal_uInt32 nPolygonCount(rPolyPolygon.count());
@@ -124,7 +133,7 @@ void addPolyPolygonToPath(const basegfx::B2DPolyPolygon&
rPolyPolygon, SkPath& r
for (const auto& rPolygon : rPolyPolygon)
{
- addPolygonToPath(rPolygon, rPath);
+ addPolygonToPath(rPolygon, rPath, hasOnlyOrthogonal);
}
}
@@ -815,36 +824,47 @@ void SkiaSalGraphicsImpl::performDrawPolyPolygon(const
basegfx::B2DPolyPolygon&
preDraw();
SkPath polygonPath;
- addPolyPolygonToPath(aPolyPolygon, polygonPath);
+ bool hasOnlyOrthogonal = true;
+ addPolyPolygonToPath(aPolyPolygon, polygonPath, &hasOnlyOrthogonal);
polygonPath.setFillType(SkPathFillType::kEvenOdd);
addXorRegion(polygonPath.getBounds());
SkPaint aPaint;
aPaint.setAntiAlias(useAA);
- // We normally use pixel at their center positions, but slightly off (see
toSkX/Y()).
- // With AA lines that "slightly off" causes tiny changes of color, making
some tests
- // fail. Since moving AA-ed line slightly to a side doesn't cause any real
visual
- // difference, just place exactly at the center. tdf#134346
- const SkScalar posFix = useAA ? toSkXYFix : 0;
+
+ // For lines we use toSkX()/toSkY() in order to pass centers of pixels to
Skia,
+ // as that leads to better results with floating-point coordinates
+ // (e.g. https://bugs.chromium.org/p/skia/issues/detail?id=9611).
+ // But that means that we generally need to use it also for areas, so that
they
+ // line up properly if used together (tdf#134346).
+ // On the other hand, with AA enabled and rectangular areas, this leads to
fuzzy
+ // edges (tdf#137329). But since rectangular areas line up perfectly to
pixels
+ // everywhere, it shouldn't be necessary to do this for them.
+ // So if AA is enabled, avoid this fixup for rectangular areas.
+ if (!useAA || !hasOnlyOrthogonal)
+ {
+ // We normally use pixel at their center positions, but slightly off
(see toSkX/Y()).
+ // With AA lines that "slightly off" causes tiny changes of color,
making some tests
+ // fail. Since moving AA-ed line slightly to a side doesn't cause any
real visual
+ // difference, just place exactly at the center. tdf#134346
+ const SkScalar posFix = useAA ? toSkXYFix : 0;
+ polygonPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, nullptr);
+ }
if (mFillColor != SALCOLOR_NONE)
{
- SkPath path;
- polygonPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, &path);
aPaint.setColor(toSkColorWithTransparency(mFillColor, fTransparency));
aPaint.setStyle(SkPaint::kFill_Style);
// HACK: If the polygon is just a line, it still should be drawn. But
when filling
// Skia doesn't draw empty polygons, so in that case ensure the line
is drawn.
- if (mLineColor == SALCOLOR_NONE && path.getBounds().isEmpty())
+ if (mLineColor == SALCOLOR_NONE && polygonPath.getBounds().isEmpty())
aPaint.setStyle(SkPaint::kStroke_Style);
- getDrawCanvas()->drawPath(path, aPaint);
+ getDrawCanvas()->drawPath(polygonPath, aPaint);
}
if (mLineColor != SALCOLOR_NONE)
{
- SkPath path;
- polygonPath.offset(toSkX(0) + posFix, toSkY(0) + posFix, &path);
aPaint.setColor(toSkColorWithTransparency(mLineColor, fTransparency));
aPaint.setStyle(SkPaint::kStroke_Style);
- getDrawCanvas()->drawPath(path, aPaint);
+ getDrawCanvas()->drawPath(polygonPath, aPaint);
}
postDraw();
#if defined LINUX
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