Qt 5.6 | Qt Multimedia | QML Video Shader Effects Example | EffectMagnify.qml Example File

Qt 5.6.3 Reference Documentation

# EffectMagnify.qml Example File

multimedia/video/qmlvideofx/qml/qmlvideofx/EffectMagnify.qml

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      import QtQuick 2.1
      import QtQuick.Window 2.1

      Effect {
          id: root
          divider: false
          parameters: ListModel {
              ListElement {
                  name: "Radius"
                  value: 0.5
              }
              ListElement {
                  name: "Diffraction"
                  value: 0.5
              }
              onDataChanged: updateParameters()
          }

          function updateParameters()
          {
              radius   = parameters.get(0).value * 100;
              diffractionIndex = parameters.get(1).value;
          }

          property real posX: -1
          property real posY: -1
          property real pixDens: Screen.pixelDensity

          QtObject {
              id: d
              property real oldTargetWidth: root.targetWidth
              property real oldTargetHeight: root.targetHeight
          }

          // Transform slider values, and bind result to shader uniforms
          property real radius: 0.5 * 100
          property real diffractionIndex: 0.5

          onTargetWidthChanged: {
              if (posX == -1)
                  posX = targetWidth / 2
              else if (d.oldTargetWidth != 0)
                  posX *= (targetWidth / d.oldTargetWidth)
              d.oldTargetWidth = targetWidth
          }

          onTargetHeightChanged: {
              if (posY == -1)
                  posY = targetHeight / 2
              else if (d.oldTargetHeight != 0)
                  posY *= (targetHeight / d.oldTargetHeight)
              d.oldTargetHeight = targetHeight
          }

          fragmentShaderFilename: "magnify.fsh"

          MouseArea {
              anchors.fill: parent
              onPositionChanged: { root.posX = mouse.x; root.posY = root.targetHeight - mouse.y }
          }
      }