From 5b292e878703ebc32e875406f4116cba145a9042 Mon Sep 17 00:00:00 2001
From: Luboš Luňák <l.lunak@collabora.com>
Date: Wed, 18 Nov 2020 16:30:52 +0100
Subject: avoid Skia floating point position fixups for rectangles (tdf#137329)
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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.lunak@collabora.com>
---
 vcl/qa/cppunit/skia/skia.cxx | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

(limited to 'vcl/qa')

diff --git a/vcl/qa/cppunit/skia/skia.cxx b/vcl/qa/cppunit/skia/skia.cxx
index d13e1530f95e..1f04c5825584 100644
--- a/vcl/qa/cppunit/skia/skia.cxx
+++ b/vcl/qa/cppunit/skia/skia.cxx
@@ -35,6 +35,7 @@ public:
     void testInterpretAs8Bit();
     void testAlphaBlendWith();
     void testBitmapCopyOnWrite();
+    void testTdf137329();
 
     CPPUNIT_TEST_SUITE(SkiaTest);
     CPPUNIT_TEST(testBitmapErase);
@@ -42,6 +43,7 @@ public:
     CPPUNIT_TEST(testInterpretAs8Bit);
     CPPUNIT_TEST(testAlphaBlendWith);
     CPPUNIT_TEST(testBitmapCopyOnWrite);
+    CPPUNIT_TEST(testTdf137329);
     CPPUNIT_TEST_SUITE_END();
 
 private:
@@ -303,6 +305,27 @@ void SkiaTest::testBitmapCopyOnWrite()
     CPPUNIT_ASSERT(bitmap.unittestGetAlphaImage() != oldAlphaImage);
 }
 
+void SkiaTest::testTdf137329()
+{
+    // Draw a filled polygon in the entire device, with AA enabled.
+    // All pixels in the device should be black, even those at edges (i.e. not affected by AA).
+    ScopedVclPtr<VirtualDevice> device = VclPtr<VirtualDevice>::Create(DeviceFormat::DEFAULT);
+    device->SetOutputSizePixel(Size(10, 10));
+    device->SetBackground(Wallpaper(COL_WHITE));
+    device->SetAntialiasing(AntialiasingFlags::Enable);
+    device->Erase();
+    device->SetLineColor();
+    device->SetFillColor(COL_BLACK);
+    device->DrawPolyPolygon(
+        basegfx::B2DPolyPolygon(basegfx::B2DPolygon{ { 0, 0 }, { 10, 0 }, { 10, 10 }, { 0, 10 } }));
+    // savePNG("/tmp/tdf137329.png", device);
+    CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(0, 0)));
+    CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(9, 0)));
+    CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(9, 9)));
+    CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(0, 9)));
+    CPPUNIT_ASSERT_EQUAL(COL_BLACK, device->GetPixel(Point(4, 4)));
+}
+
 } // namespace
 
 CPPUNIT_TEST_SUITE_REGISTRATION(SkiaTest);
-- 
cgit