QQuickIconImage: prevent color from being applied twice

QQuickIconImage::componentComplete() calls
QQuickIconImagePrivate::updateIcon(), which loads the icon's image via
QQuickImageBase::load(). That eventually calls
QQuickImageBase::requestFinished(), which calls
QQuickIconImage::pixmapChange(). That then calls
QQuickIconImagePrivate::updateFillMode(), which can in turn cause
QQuickIconImage::pixmapChange() to be called again, causing recursion.

This recursion resulted in icon.color being applied twice.

We already have a recursion check in place in
QQuickIconImagePrivate::updateFillMode(), so we can reuse that in
QQuickIconImage::pixmapChange() to know whether or not we should apply
the color to the image.

Task-number: QTBUG-69506
Change-Id: I5cd9edaa524c7ceb9c41c53a9efefcc4c647e246
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

3 files changed, 101 insertions, 2 deletions

diff --git a/src/quickcontrols2/qquickiconimage.cpp b/src/quickcontrols2/qquickiconimage.cpp
index c8357647..d86afd7f 100644
--- a/src/quickcontrols2/qquickiconimage.cpp
+++ b/src/quickcontrols2/qquickiconimage.cpp
@@ -198,7 +198,8 @@ void QQuickIconImage::pixmapChange()
     QQuickImage::pixmapChange();
     d->updateFillMode();
 
-    if (d->color.alpha() > 0) {
+    // Don't apply the color if we're recursing (updateFillMode() can cause us to recurse).
+    if (!d->updatingFillMode && d->color.alpha() > 0) {
         QImage image = d->pix.image();
         if (!image.isNull()) {
             QPainter painter(&image);
diff --git a/tests/auto/qquickiconimage/data/translucentColors.qml b/tests/auto/qquickiconimage/data/translucentColors.qml
new file mode 100644
index 00000000..49178d76
--- /dev/null
+++ b/tests/auto/qquickiconimage/data/translucentColors.qml
@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.10
+import QtQuick.Controls 2.3
+import QtQuick.Controls.impl 2.3
+
+ApplicationWindow {
+    width: 500
+    height: 500
+    visible: true
+
+    IconImage {
+        width: Math.min(250, parent.width)
+        height: Math.min(250, parent.height)
+        source: "qrc:/icons/testtheme/22x22/actions/color-test-original.png"
+        sourceSize: Qt.size(250, 0)
+        color: Qt.rgba(0, 0, 0, 0.5)
+    }
+}
diff --git a/tests/auto/qquickiconimage/tst_qquickiconimage.cpp b/tests/auto/qquickiconimage/tst_qquickiconimage.cpp
index 1dab0784..bc24c4fb 100644
--- a/tests/auto/qquickiconimage/tst_qquickiconimage.cpp
+++ b/tests/auto/qquickiconimage/tst_qquickiconimage.cpp
@@ -1,4 +1,4 @@
-/****************************************************************************
+/****************************************************************************
 **
 ** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
@@ -30,6 +30,7 @@
 #include <QtTest/qsignalspy.h>
 
 #include <QtCore/qmath.h>
+#include <QtQml/qqmlapplicationengine.h>
 #include <QtQml/qqmlengine.h>
 #include <QtQml/qqmlcomponent.h>
 #include <QtQml/qqmlfileselector.h>
@@ -69,6 +70,7 @@ private slots:
     void color();
     void fileSelectors();
     void imageProvider();
+    void translucentColors();
 
 private:
     void setTheme();
@@ -528,6 +530,35 @@ void tst_qquickiconimage::imageProvider()
     QCOMPARE(image.pixelColor(image.width() / 2, image.height() / 2), QColor(Qt::red));
 }
 
+/*
+    QQuickIconImage::componentComplete() calls QQuickIconImagePrivate::updateIcon(),
+    which loads the icon's image via QQuickImageBase::load(). That eventually calls
+    QQuickImageBase::requestFinished(), which calls QQuickIconImage::pixmapChange().
+    That then calls QQuickIconImagePrivate::updateFillMode(), which can in turn
+    cause QQuickIconImage::pixmapChange() to be called again, causing recursion.
+
+    This was a problem because it resulted in icon.color being applied twice.
+
+    This test checks that that doesn't happen.
+*/
+void tst_qquickiconimage::translucentColors()
+{
+    if (QGuiApplication::platformName() == QLatin1String("offscreen"))
+        QSKIP("grabToImage() doesn't work on the \"offscreen\" platform plugin (QTBUG-63185)");
+
+    // Doesn't reproduce with QQuickView.
+    QQmlApplicationEngine engine;
+    engine.load(testFileUrl("translucentColors.qml"));
+    QQuickWindow *window = qobject_cast<QQuickWindow*>(engine.rootObjects().first());
+
+    QQuickIconImage *iconImage = qobject_cast<QQuickIconImage*>(window->findChild<QQuickIconImage*>());
+    QVERIFY(iconImage);
+
+    const QImage image = grabItemToImage(iconImage);
+    QVERIFY(!image.isNull());
+    QCOMPARE(image.pixelColor(image.width() / 2, image.height() / 2), QColor::fromRgba(0x80000000));
+}
+
 int main(int argc, char *argv[])
 {
     QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);