vectorimage: Fix identical gradient stops in qml generator

In SVG, two subsequent identical gradient stops means a hard
transition to the color of the second at that position. However,
this is not the case in Qt and because of the way we sort the
gradient stops, the order of the two identical stops will be
wrong.

This is addressed by adding an epsilon to identical stops in
Qt Svg, but the epsilon is FLT_EPSILON, which is around 1e-7.
The default output precision for doubles in Qt is 6, so when
storing the numbers to file, the epsilon would be lost, the
two positions would be considered identical and the reordering
would happen.

This caused a visual error when running svgtoqml on the
paint-grad-16-t.svg test.

Change-Id: I857958512c3de7dc843a705893b4c2d7d2a36fd4
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
(cherry picked from commit 67d685eed9219deca960716cec2a4dfb085c5c62)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 20eb817ba2bcf38e28dc94591f048da8867beb40)

1 files changed, 4 insertions, 2 deletions

diff --git a/src/quickvectorimage/generator/qquickqmlgenerator.cpp b/src/quickvectorimage/generator/qquickqmlgenerator.cpp
index c9c94c34a3..2607a9bdb0 100644
--- a/src/quickvectorimage/generator/qquickqmlgenerator.cpp
+++ b/src/quickvectorimage/generator/qquickqmlgenerator.cpp
@@ -191,7 +191,8 @@ void QQuickQmlGenerator::generateGradient(const QGradient *grad)
         stream() << "x2: " << gradRect.right();
         stream() << "y2: " << gradRect.bottom();
         for (auto &stop : linGrad->stops())
-            stream() << "GradientStop { position: " << stop.first << "; color: \"" << stop.second.name(QColor::HexArgb) << "\" }";
+            stream() << "GradientStop { position: " << QString::number(stop.first, 'g', 7)
+                     << "; color: \"" << stop.second.name(QColor::HexArgb) << "\" }";
         m_indentLevel--;
         stream() << "}";
     } else if (grad->type() == QGradient::RadialGradient) {
@@ -205,7 +206,8 @@ void QQuickQmlGenerator::generateGradient(const QGradient *grad)
         stream() << "focalX:" << radGrad->focalPoint().x();
         stream() << "focalY:" << radGrad->focalPoint().y();
         for (auto &stop : radGrad->stops())
-            stream() << "GradientStop { position: " << stop.first << "; color: \"" << stop.second.name(QColor::HexArgb) << "\" }";
+            stream() << "GradientStop { position: " << QString::number(stop.first, 'g', 7)
+                     << "; color: \"" << stop.second.name(QColor::HexArgb) << "\" }";
         m_indentLevel--;
         stream() << "}";
     }