From 84bc219fb1e9f586c1f7ac2c10172c4da2605f96 Mon Sep 17 00:00:00 2001
From: Eirik Aavitsland <eirik.aavitsland@qt.io>
Date: Mon, 27 Jan 2020 14:22:19 +0100
Subject: Add API to enable opt-in aspect ratio feature in QSvgRenderer

[ChangeLog][QSvgRenderer] Introduced aspect ratio mode property, so
that rendering may be set to preserve the view box aspect ratio.

Task-number: QTBUG-81259
Change-Id: I9802788cdaf2c30974c1ffc34ad5b67cdc74ed57
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
---
 src/svg/qsvgrenderer.cpp                     | 35 ++++++++++++++++++++++++++++
 src/svg/qsvgrenderer.h                       |  4 ++++
 src/svg/qsvgtinydocument.cpp                 |  5 ++++
 src/svg/qsvgtinydocument_p.h                 |  4 +++-
 tests/auto/qsvgrenderer/tst_qsvgrenderer.cpp |  3 +--
 5 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/src/svg/qsvgrenderer.cpp b/src/svg/qsvgrenderer.cpp
index 40ae6ab..0097ec2 100644
--- a/src/svg/qsvgrenderer.cpp
+++ b/src/svg/qsvgrenderer.cpp
@@ -256,6 +256,41 @@ void QSvgRenderer::setFramesPerSecond(int num)
     d->fps = num;
 }
 
+/*!
+    \property QSvgRenderer::aspectRatioMode
+
+    \brief how rendering adheres to the SVG view box aspect ratio
+
+    The accepted modes are:
+    \list
+    \li Qt::IgnoreAspectRatio (the default): the aspect ratio is ignored and the
+        rendering is stretched to the target bounds.
+    \li Qt::KeepAspectRatio: rendering is centered and scaled as large as possible
+        within the target bounds while preserving aspect ratio.
+    \endlist
+
+    \since 5.15
+*/
+
+Qt::AspectRatioMode QSvgRenderer::aspectRatioMode() const
+{
+    Q_D(const QSvgRenderer);
+    if (d->render && d->render->preserveAspectRatio())
+        return Qt::KeepAspectRatio;
+    return Qt::IgnoreAspectRatio;
+}
+
+void QSvgRenderer::setAspectRatioMode(Qt::AspectRatioMode mode)
+{
+    Q_D(QSvgRenderer);
+    if (d->render) {
+        if (mode == Qt::KeepAspectRatio)
+            d->render->setPreserveAspectRatio(true);
+        else if (mode == Qt::IgnoreAspectRatio)
+            d->render->setPreserveAspectRatio(false);
+    }
+}
+
 /*!
   \property QSvgRenderer::currentFrame
   \brief the current frame of the document's animation, or 0 if the document is not animated
diff --git a/src/svg/qsvgrenderer.h b/src/svg/qsvgrenderer.h
index c7da2fb..3703b1c 100644
--- a/src/svg/qsvgrenderer.h
+++ b/src/svg/qsvgrenderer.h
@@ -65,6 +65,7 @@ class Q_SVG_EXPORT QSvgRenderer : public QObject
     Q_PROPERTY(QRectF viewBox READ viewBoxF WRITE setViewBox)
     Q_PROPERTY(int framesPerSecond READ framesPerSecond WRITE setFramesPerSecond)
     Q_PROPERTY(int currentFrame READ currentFrame WRITE setCurrentFrame)
+    Q_PROPERTY(Qt::AspectRatioMode aspectRatioMode READ aspectRatioMode WRITE setAspectRatioMode)
 public:
     QSvgRenderer(QObject *parent = nullptr);
     QSvgRenderer(const QString &filename, QObject *parent = nullptr);
@@ -81,6 +82,9 @@ public:
     void setViewBox(const QRect &viewbox);
     void setViewBox(const QRectF &viewbox);
 
+    Qt::AspectRatioMode aspectRatioMode() const;
+    void setAspectRatioMode(Qt::AspectRatioMode mode);
+
     bool animated() const;
     int framesPerSecond() const;
     void setFramesPerSecond(int num);
diff --git a/src/svg/qsvgtinydocument.cpp b/src/svg/qsvgtinydocument.cpp
index 8f6aac1..b4b9526 100644
--- a/src/svg/qsvgtinydocument.cpp
+++ b/src/svg/qsvgtinydocument.cpp
@@ -336,6 +336,11 @@ void QSvgTinyDocument::setHeight(int len, bool percent)
     m_heightPercent = percent;
 }
 
+void QSvgTinyDocument::setPreserveAspectRatio(bool on)
+{
+    m_preserveAspectRatio = on;
+}
+
 void QSvgTinyDocument::setViewBox(const QRectF &rect)
 {
     m_viewBox = rect;
diff --git a/src/svg/qsvgtinydocument_p.h b/src/svg/qsvgtinydocument_p.h
index d0c5cae..d4b92e8 100644
--- a/src/svg/qsvgtinydocument_p.h
+++ b/src/svg/qsvgtinydocument_p.h
@@ -89,6 +89,7 @@ public:
     bool heightPercent() const;
 
     bool preserveAspectRatio() const;
+    void setPreserveAspectRatio(bool on);
 
     QRectF viewBox() const;
     void setViewBox(const QRectF &rect);
@@ -128,6 +129,7 @@ private:
 
     mutable bool m_implicitViewBox = true;
     mutable QRectF m_viewBox;
+    bool m_preserveAspectRatio = false;
 
     QHash<QString, QSvgRefCounter<QSvgFont> > m_fonts;
     QHash<QString, QSvgNode *> m_namedNodes;
@@ -185,7 +187,7 @@ inline QRectF QSvgTinyDocument::viewBox() const
 
 inline bool QSvgTinyDocument::preserveAspectRatio() const
 {
-    return false;
+    return m_preserveAspectRatio;
 }
 
 inline int QSvgTinyDocument::currentElapsed() const
diff --git a/tests/auto/qsvgrenderer/tst_qsvgrenderer.cpp b/tests/auto/qsvgrenderer/tst_qsvgrenderer.cpp
index 14cb473..686c854 100644
--- a/tests/auto/qsvgrenderer/tst_qsvgrenderer.cpp
+++ b/tests/auto/qsvgrenderer/tst_qsvgrenderer.cpp
@@ -270,18 +270,17 @@ void tst_QSvgRenderer::testMapViewBoxToTarget()
         QCOMPARE(picture.boundingRect(), QRect(125, 125, 250, 250));
     }
 
-#if 0
     // Requires keep-aspectratio feature
     { // Viewport and viewBox specified -> scale 500x500 square to 1000x750 while preserving aspect ratio gives 750x750
         data = "<svg width=\"1000\" height=\"750\" viewBox=\"-250 -250 500 500\"><g><rect x=\"0\" y=\"0\" width=\"500\" height=\"500\" /></g></svg>";
         QPicture picture;
         QPainter painter(&picture);
         QSvgRenderer rend(data);
+        rend.setAspectRatioMode(Qt::KeepAspectRatio);
         rend.render(&painter);
         painter.end();
         QCOMPARE(picture.boundingRect(), QRect(500, 375, 750, 750));
     }
-#endif
 }
 
 void tst_QSvgRenderer::testRenderElement()
-- 
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