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| |
| import QtQuick 2.12 |
| import QtGraphicalEffects.private 1.12 |
| |
| /*! |
| \qmltype ThresholdMask |
| \inqmlmodule QtGraphicalEffects |
| \since QtGraphicalEffects 1.0 |
| \inherits QtQuick2::Item |
| \ingroup qtgraphicaleffects-mask |
| \brief Masks the source item with another item and applies a threshold |
| value. |
| |
| The masking behavior can be controlled with the \l threshold value for the |
| mask pixels. |
| |
| \table |
| \header |
| \li Source |
| \li MaskSource |
| \li Effect applied |
| \row |
| \li \image Original_bug.png |
| \li \image ThresholdMask_mask.png |
| \li \image ThresholdMask_bug.png |
| \endtable |
| |
| \note This effect is available when running with OpenGL. |
| |
| \section1 Example |
| |
| The following example shows how to apply the effect. |
| \snippet ThresholdMask-example.qml example |
| */ |
| Item { |
| id: rootItem |
| |
| /*! |
| This property defines the source item that is going to be masked. |
| |
| \note It is not supported to let the effect include itself, for |
| instance by setting source to the effect's parent. |
| */ |
| property variant source |
| |
| /*! |
| This property defines the item that is going to be used as the mask. |
| Mask item gets rendered into an intermediate pixel buffer and the alpha |
| values from the result are used to determine the source item's pixels |
| visibility in the display. |
| |
| \table |
| \header |
| \li Original |
| \li Mask |
| \li Effect applied |
| \row |
| \li \image Original_bug.png |
| \li \image ThresholdMask_mask.png |
| \li \image ThresholdMask_bug.png |
| \endtable |
| |
| \note It is not supported to let the effect include itself, for |
| instance by setting maskSource to the effect's parent. |
| */ |
| property variant maskSource |
| |
| /*! |
| This property defines a threshold value for the mask pixels. The mask |
| pixels that have an alpha value below this property are used to |
| completely mask away the corresponding pixels from the source item. The |
| mask pixels that have a higher alpha value are used to alphablend the |
| source item to the display. |
| |
| The value ranges from 0.0 (alpha value 0) to 1.0 (alpha value 255). By |
| default, the property is set to \c 0.0. |
| |
| \table |
| \header |
| \li Output examples with different threshold values |
| \li |
| \li |
| \row |
| \li \image ThresholdMask_threshold1.png |
| \li \image ThresholdMask_threshold2.png |
| \li \image ThresholdMask_threshold3.png |
| \row |
| \li \b { threshold: 0.0 } |
| \li \b { threshold: 0.5 } |
| \li \b { threshold: 0.7 } |
| \row |
| \li \l spread: 0.2 |
| \li \l spread: 0.2 |
| \li \l spread: 0.2 |
| \endtable |
| */ |
| property real threshold: 0.0 |
| |
| /*! |
| This property defines the smoothness of the mask edges near the |
| \l{ThresholdMask::threshold}{threshold} alpha value. Setting spread to |
| 0.0 uses mask normally with the specified threshold. Setting higher |
| spread values softens the transition from the transparent mask pixels |
| towards opaque mask pixels by adding interpolated values between them. |
| |
| The value ranges from 0.0 (sharp mask edge) to 1.0 (smooth mask edge). |
| By default, the property is set to \c 0.0. |
| |
| \table |
| \header |
| \li Output examples with different spread values |
| \li |
| \li |
| \row |
| \li \image ThresholdMask_spread1.png |
| \li \image ThresholdMask_spread2.png |
| \li \image ThresholdMask_spread3.png |
| \row |
| \li \b { spread: 0.0 } |
| \li \b { spread: 0.2 } |
| \li \b { spread: 0.8 } |
| \row |
| \li \l threshold: 0.4 |
| \li \l threshold: 0.4 |
| \li \l threshold: 0.4 |
| \endtable |
| |
| */ |
| property real spread: 0.0 |
| |
| /*! |
| This property allows the effect output pixels to be cached in order to |
| improve the rendering performance. |
| |
| Every time the source or effect properties are changed, the pixels in |
| the cache must be updated. Memory consumption is increased, because an |
| extra buffer of memory is required for storing the effect output. |
| |
| It is recommended to disable the cache when the source or the effect |
| properties are animated. |
| |
| By default, the property is set to \c false. |
| */ |
| property bool cached: false |
| |
| SourceProxy { |
| id: sourceProxy |
| input: rootItem.source |
| } |
| |
| SourceProxy { |
| id: maskSourceProxy |
| input: rootItem.maskSource |
| } |
| |
| ShaderEffectSource { |
| id: cacheItem |
| anchors.fill: parent |
| visible: rootItem.cached |
| smooth: true |
| sourceItem: shaderItem |
| live: true |
| hideSource: visible |
| } |
| |
| ShaderEffect { |
| id: shaderItem |
| property variant source: sourceProxy.output |
| property variant maskSource: maskSourceProxy.output |
| property real threshold: rootItem.threshold |
| property real spread: rootItem.spread |
| |
| anchors.fill: parent |
| |
| fragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/thresholdmask.frag" |
| } |
| } |