Add a means to set the application icon where supported

On OS X the application icon can be changed at runtime, so this adds a way
to set this via the QPlatformIntegration.

[ChangeLog][OS X] QApplication::setWindowIcon now changes the icon for the
application in the dock.

Task-number: QTBUG-43999
Change-Id: Ice298c0bd52f10f4866f37c6d3f20cf5419b7a1b
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@theqtcompany.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>

src/gui/kernel/qguiapplication.cpp

@@ -2840,6 +2840,9 @@ void QGuiApplication::setWindowIcon(const QIcon &icon)
     if (!QGuiApplicationPrivate::app_icon)
         QGuiApplicationPrivate::app_icon = new QIcon();
     *QGuiApplicationPrivate::app_icon = icon;
+    if (QGuiApplicationPrivate::platform_integration
+            && QGuiApplicationPrivate::platform_integration->hasCapability(QPlatformIntegration::ApplicationIcon))
+        QGuiApplicationPrivate::platform_integration->setApplicationIcon(icon);
     if (QGuiApplicationPrivate::is_app_running && !QGuiApplicationPrivate::is_app_closing)
         QGuiApplicationPrivate::self->notifyWindowIconChanged();
 }

src/gui/kernel/qplatformintegration.cpp

@@ -231,6 +231,8 @@ QPlatformServices *QPlatformIntegration::services() const
     implementation for QOpenGLContext::getProcAddress() and support returning a function
     pointer also for the standard, non-extension functions. This capability is a
     prerequisite for dynamic OpenGL loading.
+
+    \value ApplicationIcon The platform supports setting the application icon. (since 5.5)
  */
 
 /*!
@@ -544,4 +546,16 @@ QOpenGLContext::OpenGLModuleType QPlatformIntegration::openGLModuleType()
 }
 #endif
 
+/*!
+    \since 5.5
+
+    Platform integration function for setting the application icon.
+
+    \sa QGuiApplication::setWindowIcon()
+*/
+void QPlatformIntegration::setApplicationIcon(const QIcon &icon) const
+{
+    Q_UNUSED(icon);
+}
+
 QT_END_NAMESPACE

src/gui/kernel/qplatformintegration.h

@@ -90,7 +90,8 @@ public:
         WindowManagement,
         SyncState,
         RasterGLSurface,
-        AllGLFunctionsQueryable
+        AllGLFunctionsQueryable,
+        ApplicationIcon
     };
 
     virtual ~QPlatformIntegration() { }
@@ -169,7 +170,7 @@ public:
 #ifndef QT_NO_OPENGL
     virtual QOpenGLContext::OpenGLModuleType openGLModuleType();
 #endif
-
+    virtual void setApplicationIcon(const QIcon &icon) const;
 protected:
     void screenAdded(QPlatformScreen *screen, bool isPrimary = false);
     void destroyScreen(QPlatformScreen *screen);

src/plugins/platforms/cocoa/qcocoaintegration.h

@@ -138,6 +138,8 @@ public:
     QCocoaWindow *popPopupWindow();
     QCocoaWindow *activePopupWindow() const;
     QList<QCocoaWindow *> *popupWindowStack();
+
+    void setApplicationIcon(const QIcon &icon) const;
 private:
     static QCocoaIntegration *mInstance;
 

src/plugins/platforms/cocoa/qcocoaintegration.mm

@@ -420,6 +420,7 @@ bool QCocoaIntegration::hasCapability(QPlatformIntegration::Capability cap) cons
     case ForeignWindows:
     case RasterGLSurface:
     case ApplicationState:
+    case ApplicationIcon:
         return true;
     default:
         return QPlatformIntegration::hasCapability(cap);
@@ -569,4 +570,16 @@ QList<QCocoaWindow *> *QCocoaIntegration::popupWindowStack()
     return &m_popupWindowStack;
 }
 
+void QCocoaIntegration::setApplicationIcon(const QIcon &icon) const
+{
+    NSImage *image = nil;
+    if (!icon.isNull()) {
+        NSSize size = [[[NSApplication sharedApplication] dockTile] size];
+        QPixmap pixmap = icon.pixmap(size.width, size.height);
+        image = static_cast<NSImage *>(qt_mac_create_nsimage(pixmap));
+    }
+    [[NSApplication sharedApplication] setApplicationIconImage:image];
+    [image release];
+}
+
 QT_END_NAMESPACE

tests/manual/cocoa/appicon/README

@@ -0,0 +1,3 @@
+Test for checking that the dock icon is changed when
+QGuiApplication::setWindowIcon() is called. Clicking the
+buttong should change the entry in the dock to a red icon.

tests/manual/cocoa/appicon/appicon.pro

@@ -0,0 +1,4 @@
+QT += widgets
+TEMPLATE = app
+TARGET = appicon
+SOURCES += main.cpp

tests/manual/cocoa/appicon/main.cpp

@@ -0,0 +1,68 @@
+/****************************************************************************
+ **
+ ** Copyright (C) 2015 The Qt Company Ltd.
+ ** Contact: http://www.qt.io/licensing/
+ **
+ ** This file is part of the test suite of the Qt Toolkit.
+ **
+ ** $QT_BEGIN_LICENSE:LGPL21$
+ ** 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 http://www.qt.io/terms-conditions. For further
+ ** information use the contact form at http://www.qt.io/contact-us.
+ **
+ ** GNU Lesser General Public License Usage
+ ** Alternatively, this file may be used under the terms of the GNU Lesser
+ ** General Public License version 2.1 or version 3 as published by the Free
+ ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+ ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+ ** following information to ensure the GNU Lesser General Public License
+ ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+ ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+ **
+ ** As a special exception, The Qt Company gives you certain additional
+ ** rights. These rights are described in The Qt Company LGPL Exception
+ ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+#include <QApplication>
+#include <QPushButton>
+#include <QVBoxLayout>
+
+class TopWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    TopWidget(QWidget *parent = 0) : QWidget(parent)
+    {
+        QVBoxLayout *layout = new QVBoxLayout;
+        QPushButton *button = new QPushButton("Change app icon");
+        connect(button, SIGNAL(clicked()), this, SLOT(changeIcon()));
+        layout->addWidget(button);
+        setLayout(layout);
+    }
+public slots:
+    void changeIcon()
+    {
+        QPixmap pix(32, 32);
+        pix.fill(Qt::red);
+        QIcon i(pix);
+        qApp->setWindowIcon(i);
+    }
+};
+
+#include "main.moc"
+
+int main(int argc, char **argv)
+{
+    QApplication a(argc, argv);
+    TopWidget w;
+    w.show();
+    return a.exec();
+}