AnimatedSprite: set implicit size based on implicit frame size

By doing so, users no longer need to set an implicit or explicit size
for AnimatedSprite.

[ChangeLog][QtQuick][AnimatedSprite] AnimatedSprite's implicitWidth and
implicitHeight are now based on frameWidth and frameHeight,
respectively. This means it is no longer necessary to explicitly size
AnimatedSprite.

Task-number: QTBUG-36341
Change-Id: I3eb87e9b1c6bb93b3c667123c345341f34e2eee8
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

3 files changed, 52 insertions, 3 deletions

diff --git a/examples/quick/imageelements/animatedsprite.qml b/examples/quick/imageelements/animatedsprite.qml
index ba3d8ffdbc..0c6bf5e28d 100644
--- a/examples/quick/imageelements/animatedsprite.qml
+++ b/examples/quick/imageelements/animatedsprite.qml
@@ -60,8 +60,6 @@ Item {
 //! [sprite]
     AnimatedSprite {
         id: sprite
-        width: 170
-        height: 170
         anchors.centerIn: parent
         source: "content/speaker.png"
         frameCount: 60
diff --git a/src/quick/items/qquickanimatedsprite.cpp b/src/quick/items/qquickanimatedsprite.cpp
index c644433115..8e486add44 100644
--- a/src/quick/items/qquickanimatedsprite.cpp
+++ b/src/quick/items/qquickanimatedsprite.cpp
@@ -210,7 +210,6 @@ QT_BEGIN_NAMESPACE
     Stops, then starts the sprite animation.
 */
 
-//TODO: Implicitly size element to size of sprite
 QQuickAnimatedSprite::QQuickAnimatedSprite(QQuickItem *parent) :
     QQuickItem(*(new QQuickAnimatedSpritePrivate), parent)
 {
@@ -516,6 +515,7 @@ void QQuickAnimatedSprite::setFrameHeight(int arg)
     if (d->m_sprite->m_frameHeight != arg) {
         d->m_sprite->setFrameHeight(arg);
         Q_EMIT frameHeightChanged(arg);
+        setImplicitHeight(frameHeight());
         reloadImage();
     }
 }
@@ -527,6 +527,7 @@ void QQuickAnimatedSprite::setFrameWidth(int arg)
     if (d->m_sprite->m_frameWidth != arg) {
         d->m_sprite->setFrameWidth(arg);
         Q_EMIT frameWidthChanged(arg);
+        setImplicitWidth(frameWidth());
         reloadImage();
     }
 }
@@ -641,6 +642,17 @@ QSGSpriteNode* QQuickAnimatedSprite::initNode()
     if (image.isNull())
         return nullptr;
 
+    // If frameWidth or frameHeight are not explicitly set, frameWidth
+    // will be set to the width of the image divided by the number of frames,
+    // and frameHeight will be set to the height of the image.
+    // In this case, QQuickAnimatedSprite currently won't emit frameWidth/HeightChanged
+    // at all, so we have to do this here, as it's the only place where assembledImage()
+    // is called (which calculates the "implicit" frameWidth/Height.
+    // In addition, currently the "implicit" frameWidth/Height are only calculated once,
+    // even after changing to a different source.
+    setImplicitWidth(frameWidth());
+    setImplicitHeight(frameHeight());
+
     QSGSpriteNode *node = d->sceneGraphContext()->createSpriteNode();
 
     d->m_sheetSize = QSize(image.size());
diff --git a/tests/auto/quick/qquickanimatedsprite/tst_qquickanimatedsprite.cpp b/tests/auto/quick/qquickanimatedsprite/tst_qquickanimatedsprite.cpp
index 368779f52f..d24ebd9878 100644
--- a/tests/auto/quick/qquickanimatedsprite/tst_qquickanimatedsprite.cpp
+++ b/tests/auto/quick/qquickanimatedsprite/tst_qquickanimatedsprite.cpp
@@ -53,6 +53,7 @@ private slots:
     void test_largeAnimation();
     void test_reparenting();
     void test_changeSourceToSmallerImgKeepingBigFrameSize();
+    void test_implicitSize();
 };
 
 void tst_qquickanimatedsprite::initTestCase()
@@ -318,6 +319,44 @@ void tst_qquickanimatedsprite::test_changeSourceToSmallerImgKeepingBigFrameSize(
     killer->wait();
 }
 
+void tst_qquickanimatedsprite::test_implicitSize()
+{
+    QQuickView window;
+    window.setSource(testFileUrl("basic.qml"));
+    window.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&window));
+    QVERIFY(window.rootObject());
+
+    QQuickAnimatedSprite* sprite = window.rootObject()->findChild<QQuickAnimatedSprite*>("sprite");
+    QVERIFY(sprite);
+    QCOMPARE(sprite->frameWidth(), 31);
+    QCOMPARE(sprite->frameHeight(), 30);
+    QCOMPARE(sprite->implicitWidth(), 31);
+    QCOMPARE(sprite->implicitHeight(), 30);
+
+    // Ensure that implicitWidth matches frameWidth.
+    QSignalSpy frameWidthChangedSpy(sprite, SIGNAL(frameWidthChanged(int)));
+    QVERIFY(frameWidthChangedSpy.isValid());
+
+    QSignalSpy frameImplicitWidthChangedSpy(sprite, SIGNAL(implicitWidthChanged()));
+    QVERIFY(frameImplicitWidthChangedSpy.isValid());
+
+    sprite->setFrameWidth(20);
+    QCOMPARE(frameWidthChangedSpy.count(), 1);
+    QCOMPARE(frameImplicitWidthChangedSpy.count(), 1);
+
+    // Ensure that implicitHeight matches frameHeight.
+    QSignalSpy frameHeightChangedSpy(sprite, SIGNAL(frameHeightChanged(int)));
+    QVERIFY(frameHeightChangedSpy.isValid());
+
+    QSignalSpy frameImplicitHeightChangedSpy(sprite, SIGNAL(implicitHeightChanged()));
+    QVERIFY(frameImplicitHeightChangedSpy.isValid());
+
+    sprite->setFrameHeight(20);
+    QCOMPARE(frameHeightChangedSpy.count(), 1);
+    QCOMPARE(frameImplicitHeightChangedSpy.count(), 1);
+}
+
 QTEST_MAIN(tst_qquickanimatedsprite)
 
 #include "tst_qquickanimatedsprite.moc"