Modernize the photosurface demo; update its walkthrough docs

- use Pointer Handlers idiomatically, rather than PinchArea and MouseArea
- give PinchHandler precedence over DragHandler
- use Controls ToolTip (much easier than the ad-hoc one from before)
- use ScrollView rather than ad-hoc scroll decorators
- improve usage of FolderListModel: required props, and stop
  concatenating folder + name
- set an informative window title
- bring the picture(s) being interacted with to the top
- use MomemtumAnimation from qtdeclarative/examples/quick/pointerhandlers
- when the animation ends, grow the canvas rightwards and downwards
  so that no images are lost by being "flung" in those directions
- make main.cpp optional again: handle arguments in QML
- use QtQuick.Dialogs and remove widgets dependency
- stop using context properties
- translate all strings
- fix qmllint warnings
- update the walkthrough docs to explain what we're doing

Task-number: QTBUG-108924
Change-Id: I5b10e314373d31e1b57b1031d481fa2b9b7afe7b
Reviewed-by: Oliver Eftevaag <oliver.eftevaag@qt.io>
(cherry picked from commit 489e346f37fbf31b0034f0e80fcd97e87c2e0304)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/examples/demos/photosurface/resources/MomentumAnimation.qml b/examples/demos/photosurface/resources/MomentumAnimation.qml
new file mode 100644
index 000000000..bd5388fc6
--- /dev/null
+++ b/examples/demos/photosurface/resources/MomentumAnimation.qml
@@ -0,0 +1,34 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+import QtQuick
+
+ParallelAnimation {
+    id: root
+    property Item target: null
+    property int duration: 500
+    property vector2d velocity: Qt.vector2d(0,0)
+
+    function restart(vel) {
+        stop()
+        velocity = vel
+        start()
+    }
+
+    NumberAnimation {
+        id: xAnim
+        target: root.target
+        property: "x"
+        to: target.x + velocity.x / duration * 100
+        duration: root.duration
+        easing.type: Easing.OutQuad
+    }
+    NumberAnimation {
+        id: yAnim
+        target: root.target
+        property: "y"
+        to: target.y + velocity.y / duration * 100
+        duration: root.duration
+        easing.type: Easing.OutQuad
+    }
+}