Enable <use> elements in <mask> and propagate state to mask children

The use node could not be created within a mask due to a missing entry
in a switch statement. This is corrected with this patch.

The mask element was implemented such that states do not propagate to
it's children. This is not correct and states are propagated correctly
with this patch.

Pick-to: 6.7 6.7.0
Fixes: QTBUG-123010
Change-Id: I4aab070c73b2e8a9bd0c642c70ea5b28eaef3416
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

6 files changed, 60 insertions, 15 deletions

diff --git a/src/svg/qsvghandler.cpp b/src/svg/qsvghandler.cpp
index 99c6a4f..666865c 100644
--- a/src/svg/qsvghandler.cpp
+++ b/src/svg/qsvghandler.cpp
@@ -4146,6 +4146,7 @@ static QSvgNode *createUseNode(QSvgNode *parent,
     case QSvgNode::Defs:
     case QSvgNode::Group:
     case QSvgNode::Switch:
+    case QSvgNode::Mask:
         group = static_cast<QSvgStructureNode*>(parent);
         break;
     default:
diff --git a/src/svg/qsvgnode.cpp b/src/svg/qsvgnode.cpp
index deb4d71..f6b52e9 100644
--- a/src/svg/qsvgnode.cpp
+++ b/src/svg/qsvgnode.cpp
@@ -233,6 +233,22 @@ void QSvgNode::applyStyle(QPainter *p, QSvgExtraStates &states) const
     m_style.apply(p, this, states);
 }
 
+/*!
+    \internal
+
+    Apply the styles of all parents to the painter and the states.
+    The styles are applied from the top level node to the current node.
+    This function can be used to set the correct style for a node
+    if it's draw function is triggered out of the ordinary draw context,
+    for example the mask node, that is cross-referenced.
+*/
+void QSvgNode::applyStyleRecursive(QPainter *p, QSvgExtraStates &states) const
+{
+    if (parent())
+        parent()->applyStyleRecursive(p, states);
+    applyStyle(p, states);
+}
+
 void QSvgNode::revertStyle(QPainter *p, QSvgExtraStates &states) const
 {
     m_style.revert(p, states);
@@ -591,6 +607,16 @@ qreal QSvgNode::strokeWidth(QPainter *p)
     return pen.widthF();
 }
 
+void QSvgNode::initPainter(QPainter *p)
+{
+    QPen pen(Qt::NoBrush, 1, Qt::SolidLine, Qt::FlatCap, Qt::SvgMiterJoin);
+    pen.setMiterLimit(4);
+    p->setPen(pen);
+    p->setBrush(Qt::black);
+    p->setRenderHint(QPainter::Antialiasing);
+    p->setRenderHint(QPainter::SmoothPixmapTransform);
+}
+
 bool QSvgNode::shouldDrawNode(QPainter *p, QSvgExtraStates &states) const
 {
     static bool alwaysDraw = qEnvironmentVariableIntValue("QT_SVG_DISABLE_SIZE_LIMIT");
diff --git a/src/svg/qsvgnode_p.h b/src/svg/qsvgnode_p.h
index c0fa35c..f616a45 100644
--- a/src/svg/qsvgnode_p.h
+++ b/src/svg/qsvgnode_p.h
@@ -101,6 +101,7 @@ public:
 
     void appendStyleProperty(QSvgStyleProperty *prop, const QString &id);
     void applyStyle(QPainter *p, QSvgExtraStates &states) const;
+    void applyStyleRecursive(QPainter *p, QSvgExtraStates &states) const;
     void revertStyle(QPainter *p, QSvgExtraStates &states) const;
     QSvgStyleProperty *styleProperty(QSvgStyleProperty::Type type) const;
     QSvgPaintStyleProperty *styleProperty(const QString &id) const;
@@ -169,6 +170,8 @@ protected:
     mutable QSvgStyle m_style;
 
     static qreal strokeWidth(QPainter *p);
+    static void initPainter(QPainter *p);
+
 private:
     QSvgNode   *m_parent;
 
diff --git a/src/svg/qsvgstructure.cpp b/src/svg/qsvgstructure.cpp
index 02e6b64..01fe1f5 100644
--- a/src/svg/qsvgstructure.cpp
+++ b/src/svg/qsvgstructure.cpp
@@ -743,17 +743,17 @@ QImage QSvgMask::createMask(QPainter *p, QSvgExtraStates &states, const QRectF &
 
     mask.fill(Qt::transparent);
     QPainter painter(&mask);
+    initPainter(&painter);
 
-    painter.setRenderHints(p->renderHints());
+    QSvgExtraStates maskNodeStates;
+    applyStyleRecursive(&painter, maskNodeStates);
+
+    // The transformation of the mask node is not relevant. What matters are the contentUnits
+    // and the position/scale of the node that the mask is applied to.
+    painter.resetTransform();
     painter.translate(-imageBound.topLeft());
     painter.setTransform(p->transform(), true);
 
-    // This is required because the QPen is scaled if contentUnits is objectBoundingBox,
-    // which does not match Chrome and Firefox.
-    painter.setPen(Qt::NoPen);
-
-    QSvgExtraStates states2; // Fake states so scopes do not propagate
-
     QTransform oldT = painter.transform();
     if (m_contentUnits == QtSvg::UnitTypes::objectBoundingBox){
         painter.translate(localRect.topLeft());
@@ -765,7 +765,7 @@ QImage QSvgMask::createMask(QPainter *p, QSvgExtraStates &states, const QRectF &
     while (itr != m_renderers.end()) {
         QSvgNode *node = *itr;
         if ((node->isVisible()) && (node->displayMode() != QSvgNode::NoneMode))
-            node->draw(&painter, states2);
+            node->draw(&painter, maskNodeStates);
         ++itr;
     }
 
diff --git a/src/svg/qsvgtinydocument.cpp b/src/svg/qsvgtinydocument.cpp
index e45a4fd..246df7b 100644
--- a/src/svg/qsvgtinydocument.cpp
+++ b/src/svg/qsvgtinydocument.cpp
@@ -235,12 +235,7 @@ void QSvgTinyDocument::draw(QPainter *p, const QRectF &bounds)
     //sets default style on the painter
     //### not the most optimal way
     mapSourceToTarget(p, bounds);
-    QPen pen(Qt::NoBrush, 1, Qt::SolidLine, Qt::FlatCap, Qt::SvgMiterJoin);
-    pen.setMiterLimit(4);
-    p->setPen(pen);
-    p->setBrush(Qt::black);
-    p->setRenderHint(QPainter::Antialiasing);
-    p->setRenderHint(QPainter::SmoothPixmapTransform);
+    initPainter(p);
     QList<QSvgNode*>::iterator itr = m_renderers.begin();
     applyStyle(p, m_states);
     while (itr != m_renderers.end()) {
@@ -311,7 +306,6 @@ void QSvgTinyDocument::draw(QPainter *p, const QString &id,
     p->restore();
 }
 
-
 QSvgNode::Type QSvgTinyDocument::type() const
 {
     return Doc;
diff --git a/tests/baseline/data/bugs/maskuseandinheritance.svg b/tests/baseline/data/bugs/maskuseandinheritance.svg
new file mode 100644
index 0000000..84df8c5
--- /dev/null
+++ b/tests/baseline/data/bugs/maskuseandinheritance.svg
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="200" height="200" viewBox="0 0 20 20" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+    <defs>
+        <polygon id="path-1" points="0 0 20 0 20 10 0 20"></polygon>
+    </defs>
+    <g id="g1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
+        <g id="g2" transform="translate(-1000, -1000)">
+            <g id="g3" transform="translate(1000, 1000)">
+                <g id="g4" transform="translate(0, 0)">
+                    <g id="g5" transform="translate(0, 0)">
+                        <mask id="mask-2" fill="white">
+                            <use xlink:href="#path-1"></use>
+                        </mask>
+                        <g id="Clip-2"></g>
+                        <path d="M 2 2 l 16 0 l 0 16 l -16 0 z" id="Fill-1" fill="#CECECE" mask="url(#mask-2)"></path>
+                    </g>
+                </g>
+            </g>
+        </g>
+    </g>
+</svg>
\ No newline at end of file