vcl/skia/gdiimpl.cxx | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
New commits:
commit 859596233146590f7ebac1f05bbb83ce5ea8aac4
Author: Luboš Luňák <l.lu...@collabora.com>
AuthorDate: Fri Sep 18 10:19:33 2020 +0200
Commit: Luboš Luňák <l.lu...@collabora.com>
CommitDate: Mon Sep 21 14:33:11 2020 +0200
do not try to merge polygons if they do not share a point (tdf#136222)
If two polygons do not share a point, then they do not share an edge,
so they cannot be adjacent polygons. As a side-effect this avoids
the problem with tdf#136222, as it turns out
basegfx::utils::mergeToSinglePolyPolygon() is broken with polygons
that are almost but not quite adjacent.
Change-Id: Ibf290cc886d7c337fd04c925b551b2e7773a6b70
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/102985
Reviewed-by: Noel Grandin <noel.gran...@collabora.co.uk>
Reviewed-by: Luboš Luňák <l.lu...@collabora.com>
Tested-by: Jenkins
diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index f6abc2ffb6fb..a5a8b00b9b0c 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -40,6 +40,7 @@
#include <basegfx/polygon/b2dpolygontools.hxx>
#include <basegfx/polygon/b2dpolypolygontools.hxx>
#include <basegfx/polygon/b2dpolypolygoncutter.hxx>
+#include <o3tl/sorted_vector.hxx>
namespace
{
@@ -849,6 +850,19 @@ void SkiaSalGraphicsImpl::performDrawPolyPolygon(const
basegfx::B2DPolyPolygon&
#endif
}
+namespace
+{
+struct LessThan
+{
+ bool operator()(const basegfx::B2DPoint& point1, const basegfx::B2DPoint&
point2) const
+ {
+ if (basegfx::fTools::equal(point1.getX(), point2.getX()))
+ return basegfx::fTools::less(point1.getY(), point2.getY());
+ return basegfx::fTools::less(point1.getX(), point2.getX());
+ }
+};
+} // namespace
+
bool SkiaSalGraphicsImpl::delayDrawPolyPolygon(const basegfx::B2DPolyPolygon&
aPolyPolygon,
double fTransparency)
{
@@ -877,6 +891,9 @@ bool SkiaSalGraphicsImpl::delayDrawPolyPolygon(const
basegfx::B2DPolyPolygon& aP
// so they do not need joining.
if (aPolyPolygon.count() != 1)
return false;
+ // If the polygon is not closed, it doesn't mark an area to be filled.
+ if (!aPolyPolygon.isClosed())
+ return false;
// If a polygon does not contain a straight line, i.e. it's all curves,
then do not merge.
// First of all that's even more expensive, and second it's very unlikely
that it's a polygon
// split into more polygons.
@@ -889,6 +906,28 @@ bool SkiaSalGraphicsImpl::delayDrawPolyPolygon(const
basegfx::B2DPolyPolygon& aP
{
checkPendingDrawing(); // Cannot be parts of the same larger polygon,
draw the last and reset.
}
+ if (!mLastPolyPolygonInfo.polygons.empty())
+ {
+ assert(aPolyPolygon.count() == 1);
+ assert(mLastPolyPolygonInfo.polygons.back().count() == 1);
+ // Check if the new and the previous polygon share at least one point.
If not, then they
+ // cannot be adjacent polygons, so there's no point in trying to merge
them.
+ bool sharePoint = false;
+ const basegfx::B2DPolygon& poly1 = aPolyPolygon.getB2DPolygon(0);
+ const basegfx::B2DPolygon& poly2 =
mLastPolyPolygonInfo.polygons.back().getB2DPolygon(0);
+ o3tl::sorted_vector<basegfx::B2DPoint, LessThan> poly1Points; // for
O(n log n)
+ poly1Points.reserve(poly1.count());
+ for (sal_uInt32 i = 0; i < poly1.count(); ++i)
+ poly1Points.insert(poly1.getB2DPoint(i));
+ for (sal_uInt32 i = 0; i < poly2.count(); ++i)
+ if (poly1Points.find(poly2.getB2DPoint(i)) != poly1Points.end())
+ {
+ sharePoint = true;
+ break;
+ }
+ if (!sharePoint)
+ checkPendingDrawing(); // Draw the previous one and reset.
+ }
// Collect the polygons that can be possibly merged. Do the merging only
once at the end,
// because it's not a cheap operation.
mLastPolyPolygonInfo.polygons.push_back(aPolyPolygon);
@@ -908,6 +947,8 @@ void SkiaSalGraphicsImpl::checkPendingDrawing()
if (polygons.size() == 1)
performDrawPolyPolygon(polygons.front(), transparency, true);
else
+ // TODO: tdf#136222 shows that
basegfx::utils::mergeToSinglePolyPolygon() is unreliable
+ // in corner cases, possibly either a bug or rounding errors
somewhere.
performDrawPolyPolygon(basegfx::utils::mergeToSinglePolyPolygon(polygons),
transparency,
true);
}
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