- Qt 5.3
- Qt Quick
- Qt Quick Demo - Tweet Search
- FlipBar.qml Example File
- Qt 5.3.2 Reference Documentation

# FlipBar.qml Example File

demos/tweetsearch/content/FlipBar.qml

    /****************************************************************************
    **
    ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** 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 Digia Plc and its Subsidiary(-ies) 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 2.0

    Item {
        id: container
        property int animDuration: 300
        property Item front: Item {}
        property Item back: Item {}
        property real factor: 0.1 // amount the edges fold in for the 3D effect
        property alias delta: effect.delta
        property Item cur: frontShown ? front : back
        property Item noncur: frontShown ? back : front

        function swap() {
            var tmp = front;
            front = back;
            back = tmp;
            resync();
        }

        width: cur.width
        height: cur.height
        onFrontChanged: resync();
        onBackChanged: resync();

        function resync() {//TODO: Are the items ever actually visible?
            back.parent = container;
            front.parent = container;
            frontShown ? back.visible = false : front.visible = false;
        }

        property bool frontShown: true

        onFrontShownChanged: {
            back.visible = !frontShown
            front.visible = frontShown
        }

        function flipUp(start) {
            effect.visible = true;
            effect.sourceA = effect.source1
            effect.sourceB = effect.source2
            if (start == undefined)
                start = 1.0;
            deltaAnim.from = start;
            deltaAnim.to = 0.0
            dAnim.start();
            frontShown = false;
        }

        function flipDown(start) {
            effect.visible = true;
            effect.sourceA = effect.source1
            effect.sourceB = effect.source2
            if (start == undefined)
                start = 0.0;
            deltaAnim.from = start;
            deltaAnim.to = 1.0
            dAnim.start();
            frontShown = true;
        }

        ShaderEffect {
            id: effect
            width: cur.width
            height: cur.height
            property real factor: container.factor * width
            property real delta: 1.0

            mesh: GridMesh { resolution: Qt.size(8,2) }

            SequentialAnimation on delta {
                id: dAnim
                running: false
                NumberAnimation {
                id: deltaAnim
                duration: animDuration//expose anim
                }
            }

            property variant sourceA: source1
            property variant sourceB: source1
            property variant source1: ShaderEffectSource {
                sourceItem: front
                hideSource: effect.visible
            }

            property variant source2: ShaderEffectSource {
                sourceItem: back
                hideSource: effect.visible
            }

            fragmentShader: "
                uniform lowp float qt_Opacity;
                uniform sampler2D sourceA;
                uniform sampler2D sourceB;
                uniform highp float delta;
                varying highp vec2 qt_TexCoord0;
                void main() {
                    highp vec4 tex = vec4(qt_TexCoord0.x, qt_TexCoord0.y * 2.0, qt_TexCoord0.x, (qt_TexCoord0.y-0.5) * 2.0);
                    highp float shade = clamp(delta*2.0, 0.5, 1.0);
                    highp vec4 col;
                    if (qt_TexCoord0.y < 0.5) {
                        col = texture2D(sourceA, tex.xy) * (shade);
                    } else {
                        col = texture2D(sourceB, tex.zw) * (1.5 - shade);
                        col.w = 1.0;
                    }
                    gl_FragColor = col * qt_Opacity;
                }
            "
            property real h: height
            vertexShader: "
            uniform highp float delta;
            uniform highp float factor;
            uniform highp float h;
            uniform highp mat4 qt_Matrix;
            attribute highp vec4 qt_Vertex;
            attribute highp vec2 qt_MultiTexCoord0;
            varying highp vec2 qt_TexCoord0;
            void main() {
                highp vec4 pos = qt_Vertex;
                if (qt_MultiTexCoord0.y == 0.0)
                    pos.x += factor * (1. - delta) * (qt_MultiTexCoord0.x * -2.0 + 1.0);
                else if (qt_MultiTexCoord0.y == 1.0)
                    pos.x += factor * (delta) * (qt_MultiTexCoord0.x * -2.0 + 1.0);
                else
                    pos.y = delta * h;
                gl_Position = qt_Matrix * pos;
                qt_TexCoord0 = qt_MultiTexCoord0;
            }"

        }
    }