Move currentFrame and frameCount properties up to QQuickImageBase

AnimatedImage already had these properties, but some typically non-animated
image formats such as PDF, TIFF and ICO can also support multiple pages.
In either case, the currentFrame property can be used to select a specific
frame or page.  However an AnimatedImage uses a QMovie to do that, whereas
a plain Image uses QQuickPixmap.  So the accessors need to be virtual in
order to have these different implementations.

[ChangeLog][QtQuick][Image] Image and BorderImage now have currentFrame
and frameCount properties which can be used to step through the frames of
multi-page image formats such as TIFF, WEBP and ICO.

Task-number: QTBUG-77506
Change-Id: Id4d95a99a26a862957e44b1bd8ffe06d7eababef
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

5 files changed, 170 insertions, 0 deletions

diff --git a/examples/quick/imageelements/content/multi.ico b/examples/quick/imageelements/content/multi.ico
new file mode 100644
index 0000000000..b748ceaa29
--- /dev/null
+++ b/examples/quick/imageelements/content/multi.ico
diff --git a/examples/quick/imageelements/framestepping.qml b/examples/quick/imageelements/framestepping.qml
new file mode 100644
index 0000000000..f5bad46e7b
--- /dev/null
+++ b/examples/quick/imageelements/framestepping.qml
@@ -0,0 +1,82 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples 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 2.14
+
+Rectangle {
+    width: 480
+    height: 320
+    Image {
+        id: img
+        anchors.centerIn: parent
+        cache: true
+        source: "content/multi.ico"
+
+        Shortcut {
+            sequence: StandardKey.MoveToNextPage
+            enabled: img.currentFrame < img.frameCount - 1
+            onActivated: img.currentFrame++
+        }
+        Shortcut {
+            sequence: StandardKey.MoveToPreviousPage
+            enabled: img.currentFrame > 0
+            onActivated: img.currentFrame--
+        }
+    }
+
+    Text {
+        anchors.horizontalCenter: parent.horizontalCenter
+        anchors.bottom: parent.bottom
+        anchors.margins: 6
+        horizontalAlignment: Text.AlignHCenter
+        text: "frame " + (img.currentFrame + 1) + " of " + img.frameCount +
+              "\nPress PgUp/PgDn to switch frames"
+    }
+}
diff --git a/examples/quick/imageelements/imageelements.qml b/examples/quick/imageelements/imageelements.qml
index dfb4d24ea6..91f2e034f7 100644
--- a/examples/quick/imageelements/imageelements.qml
+++ b/examples/quick/imageelements/imageelements.qml
@@ -64,6 +64,8 @@ Item {
             addExample("AnimatedImage", "An image which plays animated formats", Qt.resolvedUrl("animatedimage.qml"));
             addExample("AnimatedSprite", "A simple sprite-based animation", Qt.resolvedUrl("animatedsprite.qml"));
             addExample("SpriteSequence", "A sprite-based animation with complex transitions", Qt.resolvedUrl("spritesequence.qml"));
+            addExample("FrameStepping", "A multi-frame non-animated image", Qt.resolvedUrl("framestepping.qml"));
+            addExample("MultiBorderImage", "A multi-frame image with scaled borders", Qt.resolvedUrl("multiframeborderimage.qml"));
         }
     }
 }
diff --git a/examples/quick/imageelements/imageelements.qrc b/examples/quick/imageelements/imageelements.qrc
index 2488fb083b..cedef2204c 100644
--- a/examples/quick/imageelements/imageelements.qrc
+++ b/examples/quick/imageelements/imageelements.qrc
@@ -8,6 +8,7 @@
         <file>content/colors-stretch.sci</file>
         <file>content/colors.png</file>
         <file>content/ImageCell.qml</file>
+        <file>content/multi.ico</file>
         <file>content/MyBorderImage.qml</file>
         <file>content/qt-logo.png</file>
         <file>content/shadow.png</file>
@@ -18,6 +19,8 @@
         <file>animatedimage.qml</file>
         <file>animatedsprite.qml</file>
         <file>borderimage.qml</file>
+        <file>framestepping.qml</file>
+        <file>multiframeborderimage.qml</file>
         <file>image.qml</file>
         <file>shadows.qml</file>
         <file>spritesequence.qml</file>
diff --git a/examples/quick/imageelements/multiframeborderimage.qml b/examples/quick/imageelements/multiframeborderimage.qml
new file mode 100644
index 0000000000..0805ea4243
--- /dev/null
+++ b/examples/quick/imageelements/multiframeborderimage.qml
@@ -0,0 +1,83 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples 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 2.14
+
+Rectangle {
+    width: 480
+    height: 320
+    BorderImage {
+        id: img
+        anchors.fill: parent
+        anchors.margins: 6
+        cache: true
+        source: "content/multi.ico"
+        border { left: 19; top: 19; right: 19; bottom: 19 }
+        horizontalTileMode: BorderImage.Stretch
+
+        Shortcut {
+            sequence: StandardKey.MoveToNextPage
+            enabled: img.currentFrame < img.frameCount - 1
+            onActivated: img.currentFrame++
+        }
+        Shortcut {
+            sequence: StandardKey.MoveToPreviousPage
+            enabled: img.currentFrame > 0
+            onActivated: img.currentFrame--
+        }
+    }
+
+    Text {
+        anchors.centerIn: parent
+        horizontalAlignment: Text.AlignHCenter
+        text: "frame " + (img.currentFrame + 1) + " of " + img.frameCount +
+              "\nPress PgUp/PgDn to switch frames"
+    }
+}