- Qt 5.15
- Qt Quick Demo - Tweet Search
- Qt 5.15.12 Reference Documentation

# Qt Quick Demo - Tweet Search

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     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;
             }"

         }
     }