From 72aaba336c7afe6d79d59995bfb31a8effca4e9e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Samuel=20R=C3=B8dal?= Date: Thu, 20 Sep 2012 15:30:24 +0200 Subject: Fixed inconsistent rounding of square cap pens. A horizontal line should round up at the same time as a vertical line with square cap, when rendering at subpixel coordinates. Thus, the special casing in the cosmetic stroker of offsetting by half a pixel should be for flat caps instead of for square caps. Task-number: QTBUG-26013 Change-Id: Ic09249337f814c7de95a17976ec9e651561a744b Reviewed-by: Lars Knoll --- src/gui/painting/qcosmeticstroker.cpp | 20 ++++++++-------- tests/auto/gui/painting/qpainter/tst_qpainter.cpp | 29 +++++++++++++++++++++++ 2 files changed, 39 insertions(+), 10 deletions(-) diff --git a/src/gui/painting/qcosmeticstroker.cpp b/src/gui/painting/qcosmeticstroker.cpp index 6f7b69f7b0..8bfa6d6c92 100644 --- a/src/gui/painting/qcosmeticstroker.cpp +++ b/src/gui/painting/qcosmeticstroker.cpp @@ -409,7 +409,7 @@ void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal if (clipLine(rx1, ry1, rx2, ry2)) return; - const int half = 32; + const int half = 31; int x1 = toF26Dot6(rx1) + half; int y1 = toF26Dot6(ry1) + half; int x2 = toF26Dot6(rx2) + half; @@ -429,8 +429,8 @@ void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal int xinc = F16Dot16FixedDiv(x2 - x1, y2 - y1); int x = x1 << 10; - int y = y1 >> 6; - int ys = y2 >> 6; + int y = (y1 + 32) >> 6; + int ys = (y2 + 32) >> 6; if (y != ys) { x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; @@ -460,8 +460,8 @@ void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal int yinc = F16Dot16FixedDiv(y2 - y1, x2 - x1); int y = y1 << 10; - int x = x1 >> 6; - int xs = x2 >> 6; + int x = (x1 + 32) >> 6; + int xs = (x2 + 32) >> 6; if (x != xs) { y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; @@ -702,7 +702,7 @@ static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, if (stroker->clipLine(rx1, ry1, rx2, ry2)) return; - static const int half = 32; + static const int half = 31; int x1 = toF26Dot6(rx1) + half; int y1 = toF26Dot6(ry1) + half; int x2 = toF26Dot6(rx2) + half; @@ -735,8 +735,8 @@ static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, capAdjust(caps, y1, y2, x, xinc); - int y = y1 >> 6; - int ys = y2 >> 6; + int y = (y1 + 32) >> 6; + int ys = (y2 + 32) >> 6; if (y != ys) { x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; @@ -810,8 +810,8 @@ static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, capAdjust(caps, x1, x2, y, yinc); - int x = x1 >> 6; - int xs = x2 >> 6; + int x = (x1 + 32) >> 6; + int xs = (x2 + 32) >> 6; if (x != xs) { y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; diff --git a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp index 14e83adfd0..029bbb8df3 100644 --- a/tests/auto/gui/painting/qpainter/tst_qpainter.cpp +++ b/tests/auto/gui/painting/qpainter/tst_qpainter.cpp @@ -278,6 +278,7 @@ private slots: void drawTextOutsideGuiThread(); void drawTextWithComplexBrush(); + void QTBUG26013_squareCapStroke(); private: void fillData(); @@ -4361,6 +4362,34 @@ void tst_QPainter::drawTextWithComplexBrush() QVERIFY(paintedPixels > 0); } +void tst_QPainter::QTBUG26013_squareCapStroke() +{ + QImage image(4, 4, QImage::Format_RGB32); + + QPainter p(&image); + p.setPen(QPen(Qt::black, 0, Qt::SolidLine, Qt::SquareCap)); + + for (int i = 0; i < 3; ++i) { + qreal d = i / 3.0; + + image.fill(0xffffffff); + + p.drawLine(QLineF(0, d, 0, d + 2)); + p.drawLine(QLineF(1, d, 3, d)); + + // ensure that a horizontal line and a vertical line with square cap round up (downwards) at the same time + QCOMPARE(image.pixel(0, 0), image.pixel(1, 0)); + + image.fill(0xffffffff); + + p.drawLine(QLineF(d, 0, d + 2, 0)); + p.drawLine(QLineF(d, 1, d, 3)); + + // ensure that a vertical line and a horizontal line with square cap round up (to the right) at the same time + QCOMPARE(image.pixel(0, 0), image.pixel(0, 1)); + } +} + QTEST_MAIN(tst_QPainter) #include "tst_qpainter.moc" -- cgit v1.2.3