| From b7029fbd12c32e851ed7d81b692197176eb71d9e Mon Sep 17 00:00:00 2001 |
| From: Gunnar Sletta <gunnar.sletta@digia.com> |
| Date: Thu, 4 Jul 2013 16:20:40 +1000 |
| Subject: [PATCH] Fix drawing of 0-width polylines from outside the devicerect. |
| |
| This was broken by a previous fix which aimed to fix gaps in |
| polylines with tiny line segments. The result was that we |
| skipped updating the origin point when stroke() didn't produce |
| pixels which accidentally included the case of the line |
| being completely outside the deviceRect. I fixed this |
| by returning the value of clipLine in drawLine to the caller |
| so we could still update the origin for this case. |
| |
| Task-number: QTBUG-31579 |
| Change-Id: Iac29436f042da7658bbeaf9370351dc6f2c95065 |
| (cherry picked from qtbase/900cccfd459fcbdbc4aa3d313afe12cfbf68fd87) |
| --- |
| src/gui/painting/qcosmeticstroker.cpp | 42 ++++++++++++++++++++++------------- |
| src/gui/painting/qcosmeticstroker_p.h | 2 +- |
| 2 files changed, 27 insertions(+), 17 deletions(-) |
| |
| diff --git a/src/gui/painting/qcosmeticstroker.cpp b/src/gui/painting/qcosmeticstroker.cpp |
| index 0061ecb..4413170 100644 |
| --- a/src/gui/painting/qcosmeticstroker.cpp |
| +++ b/src/gui/painting/qcosmeticstroker.cpp |
| @@ -133,10 +133,15 @@ struct NoDasher { |
| |
| }; |
| |
| +/* |
| + * The return value is the result of the clipLine() call performed at the start |
| + * of each of the two functions, aka "false" means completely outside the devices |
| + * rect. |
| + */ |
| template<DrawPixel drawPixel, class Dasher> |
| -static void drawLine(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| +static bool drawLine(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| template<DrawPixel drawPixel, class Dasher> |
| -static void drawLineAA(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| +static bool drawLineAA(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| |
| inline void drawPixel(QCosmeticStroker *stroker, int x, int y, int coverage) |
| { |
| @@ -602,17 +607,20 @@ void QCosmeticStroker::drawPath(const QVectorPath &path) |
| caps |= CapEnd; |
| |
| QCosmeticStroker::Point last = this->lastPixel; |
| - stroke(this, p.x(), p.y(), p2.x(), p2.y(), caps); |
| + bool unclipped = stroke(this, p.x(), p.y(), p2.x(), p2.y(), caps); |
| |
| /* fix for gaps in polylines with fastpen and aliased in a sequence |
| of points with small distances: if current point p2 has been dropped |
| - out, keep last non dropped point p. */ |
| - if (fastPenAliased) { |
| - if (last.x != lastPixel.x || last.y != lastPixel.y || |
| - points == begin + 2 || points == end - 2 ) { |
| - { |
| - p = p2; |
| - } |
| + out, keep last non dropped point p. |
| + |
| + However, if the line was completely outside the devicerect, we |
| + still need to update p to avoid drawing the line after this one from |
| + a bad starting position. |
| + */ |
| + if (fastPenAliased && unclipped) { |
| + if (last.x != lastPixel.x || last.y != lastPixel.y |
| + || points == begin + 2 || points == end - 2) { |
| + p = p2; |
| } |
| } else { |
| p = p2; |
| @@ -720,10 +728,10 @@ static inline void capAdjust(int caps, int &x1, int &x2, int &y, int yinc) |
| the drawing shifts from horizontal to vertical or back. |
| */ |
| template<DrawPixel drawPixel, class Dasher> |
| -static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) |
| +static bool drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) |
| { |
| if (stroker->clipLine(rx1, ry1, rx2, ry2)) |
| - return; |
| + return false; |
| |
| static const int half = 31; |
| int x1 = toF26Dot6(rx1) + half; |
| @@ -813,7 +821,7 @@ static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, |
| } else { |
| // horizontal |
| if (!dx) |
| - return; |
| + return true; |
| |
| QCosmeticStroker::Direction dir = QCosmeticStroker::LeftToRight; |
| |
| @@ -886,14 +894,15 @@ static void drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, |
| } |
| } |
| stroker->lastPixel = last; |
| + return true; |
| } |
| |
| |
| template<DrawPixel drawPixel, class Dasher> |
| -static void drawLineAA(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) |
| +static bool drawLineAA(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, qreal ry2, int caps) |
| { |
| if (stroker->clipLine(rx1, ry1, rx2, ry2)) |
| - return; |
| + return false; |
| |
| int x1 = toF26Dot6(rx1); |
| int y1 = toF26Dot6(ry1); |
| @@ -967,7 +976,7 @@ static void drawLineAA(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx |
| } else { |
| // horizontal |
| if (!dx) |
| - return; |
| + return true; |
| |
| int yinc = F16Dot16FixedDiv(dy, dx); |
| |
| @@ -1029,6 +1038,7 @@ static void drawLineAA(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx |
| drawPixel(stroker, x, (y>>16) + 1, alpha * alphaEnd >> 6); |
| } |
| } |
| + return true; |
| } |
| |
| QT_END_NAMESPACE |
| diff --git a/src/gui/painting/qcosmeticstroker_p.h b/src/gui/painting/qcosmeticstroker_p.h |
| index 870738b..3216856 100644 |
| --- a/src/gui/painting/qcosmeticstroker_p.h |
| +++ b/src/gui/painting/qcosmeticstroker_p.h |
| @@ -56,7 +56,7 @@ QT_MODULE(Gui) |
| class QCosmeticStroker; |
| |
| |
| -typedef void (*StrokeLine)(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| +typedef bool (*StrokeLine)(QCosmeticStroker *stroker, qreal x1, qreal y1, qreal x2, qreal y2, int caps); |
| |
| class QCosmeticStroker |
| { |
| -- |
| 1.8.3.2 |
| |