Qt Reference Documentation

# GrayscaleEffect.qml Example File

declarative/shadereffects/qml/shadereffects/GrayscaleEffect.qml

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     import QtQuick 1.0
     import Qt.labs.shaders 1.0

     ShaderEffectItem {
         id: effect
         property real ratio: 1.0
         property variant source: 0

         fragmentShader:
             "
             varying highp vec2 qt_TexCoord0;
             uniform sampler2D source;
             uniform highp float ratio;
             void main(void)
             {
                 lowp vec4 textureColor = texture2D(source, qt_TexCoord0.st);
                 lowp float gray = dot(textureColor, vec4(0.299, 0.587, 0.114, 0.0));
                 gl_FragColor = vec4(gray * ratio + textureColor.r * (1.0 - ratio), gray * ratio + textureColor.g * (1.0 - ratio), gray * ratio + textureColor.b * (1.0 - ratio), textureColor.a);
             }
             "
     }