From fd6a2d1c8ff0488757378080f6003c434fd68de2 Mon Sep 17 00:00:00 2001 From: Allan Sandfeld Jensen Date: Wed, 11 Mar 2015 17:14:50 +0100 Subject: Improve rounding in QCosmeticStroker MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fixes the drawn position of end points in drawLine. Based on a patch by Jørgen Lind, and modified so that it caused no test regressions. Task-number: QTBUG-38144 Change-Id: I24aa28480cc6ae09abf91d80378970565a29b254 Reviewed-by: Gunnar Sletta --- src/gui/painting/qcosmeticstroker.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'src/gui/painting') diff --git a/src/gui/painting/qcosmeticstroker.cpp b/src/gui/painting/qcosmeticstroker.cpp index 93c95e4a86..f82b098012 100644 --- a/src/gui/painting/qcosmeticstroker.cpp +++ b/src/gui/painting/qcosmeticstroker.cpp @@ -437,8 +437,9 @@ void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal int y = (y1 + 32) >> 6; int ys = (y2 + 32) >> 6; + int round = (xinc > 0) ? 32 : 0; if (y != ys) { - x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; + x += ( ((((y << 6) + round - y1))) * xinc ) >> 6; if (swapped) { lastPixel.x = x >> 16; @@ -468,8 +469,9 @@ void QCosmeticStroker::calculateLastPoint(qreal rx1, qreal ry1, qreal rx2, qreal int x = (x1 + 32) >> 6; int xs = (x2 + 32) >> 6; + int round = (yinc > 0) ? 32 : 0; if (x != xs) { - y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; + y += ( ((((x << 6) + round - x1))) * yinc ) >> 6; if (swapped) { lastPixel.x = x; @@ -762,9 +764,10 @@ static bool drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, int y = (y1 + 32) >> 6; int ys = (y2 + 32) >> 6; + int round = (xinc > 0) ? 32 : 0; if (y != ys) { - x += ( ((((y << 6) + 32 - y1))) * xinc ) >> 6; + x += ( ((((y << 6) + round - y1))) * xinc ) >> 6; // calculate first and last pixel and perform dropout control QCosmeticStroker::Point first; @@ -837,9 +840,10 @@ static bool drawLine(QCosmeticStroker *stroker, qreal rx1, qreal ry1, qreal rx2, int x = (x1 + 32) >> 6; int xs = (x2 + 32) >> 6; + int round = (yinc > 0) ? 32 : 0; if (x != xs) { - y += ( ((((x << 6) + 32 - x1))) * yinc ) >> 6; + y += ( ((((x << 6) + round - x1))) * yinc ) >> 6; // calculate first and last pixel to perform dropout control QCosmeticStroker::Point first; -- cgit v1.2.3