// Copyright (C) 2022 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only // Qt-Security score:significant reason:default import QtQuick import Qt5Compat.GraphicalEffects.private /*! \qmltype ZoomBlur \inqmlmodule Qt5Compat.GraphicalEffects \since Qt5Compat.GraphicalEffects 1.0 \inherits QtQuick::Item \ingroup qtgraphicaleffects-motion-blur \brief Applies directional blur effect towards source items center point. Effect creates perceived impression that the source item appears to be moving towards the center point in Z-direction or that the camera appears to be zooming rapidly. Other available motion blur effects are \l{Qt5Compat.GraphicalEffects::DirectionalBlur}{DirectionalBlur} and \l{Qt5Compat.GraphicalEffects::RadialBlur}{RadialBlur}. \table \header \li Source \li Effect applied \row \li \image Original_bug.png \li \image ZoomBlur_bug.png \endtable \note This effect is available when running with OpenGL. \section1 Example The following example shows how to apply the effect. \snippet ZoomBlur-example.qml example */ Item { id: rootItem /*! This property defines the source item that is going to be blurred. \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 maximum perceived amount of movement for each pixel. The amount is smaller near the center and reaches the specified value at the edges. The quality of the blur depends on \l{ZoomBlur::samples}{samples} property. If length value is large, more samples are needed to keep the visual quality at high level. The value ranges from 0.0 to inf. By default the property is set to \c 0.0 (no blur). \table \header \li Output examples with different length values \li \li \row \li \image ZoomBlur_length1.png \li \image ZoomBlur_length2.png \li \image ZoomBlur_length3.png \row \li \b { length: 0.0 } \li \b { length: 32.0 } \li \b { length: 48.0 } \row \li \l samples: 24 \li \l samples: 24 \li \l samples: 24 \row \li \l horizontalOffset: 0 \li \l horizontalOffset: 0 \li \l horizontalOffset: 0 \row \li \l verticalOffset: 0 \li \l verticalOffset: 0 \li \l verticalOffset: 0 \endtable */ property real length: 0.0 /*! This property defines how many samples are taken per pixel when blur calculation is done. Larger value produces better quality, but is slower to render. This property is not intended to be animated. Changing this property may cause the underlying OpenGL shaders to be recompiled. Allowed values are between 0 and inf (practical maximum depends on GPU). By default the property is set to \c 0 (no samples). */ property int samples: 0 /*! \qmlproperty real QtGraphicalEffects::ZoomBlur::horizontalOffset \qmlproperty real QtGraphicalEffects::ZoomBlur::verticalOffset These properties define an offset in pixels for the blur direction center point. The values range from -inf to inf. By default these properties are set to \c 0. \table \header \li Output examples with different horizontalOffset values \li \li \row \li \image ZoomBlur_horizontalOffset1.png \li \image ZoomBlur_horizontalOffset2.png \li \image ZoomBlur_horizontalOffset3.png \row \li \b { horizontalOffset: 100.0 } \li \b { horizontalOffset: 0.0 } \li \b { horizontalOffset: -100.0 } \row \li \l samples: 24 \li \l samples: 24 \li \l samples: 24 \row \li \l length: 32 \li \l length: 32 \li \l length: 32 \row \li \l verticalOffset: 0 \li \l verticalOffset: 0 \li \l verticalOffset: 0 \endtable */ property real horizontalOffset: 0.0 property real verticalOffset: 0.0 /*! This property defines the blur behavior near the edges of the item, where the pixel blurring is affected by the pixels outside the source edges. If the property is set to \c true, the pixels outside the source are interpreted to be transparent, which is similar to OpenGL clamp-to-border extension. The blur is expanded slightly outside the effect item area. If the property is set to \c false, the pixels outside the source are interpreted to contain the same color as the pixels at the edge of the item, which is similar to OpenGL clamp-to-edge behavior. The blur does not expand outside the effect item area. By default, the property is set to \c false. */ property bool transparentBorder: false /*! 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 sourceRect: rootItem.transparentBorder ? Qt.rect(-1, -1, parent.width + 2.0, parent.height + 2.0) : Qt.rect(0, 0, 0, 0) } ShaderEffectSource { id: cacheItem anchors.fill: shaderItem visible: rootItem.cached smooth: true sourceItem: shaderItem live: true hideSource: visible } ShaderEffect { id: shaderItem property variant source: sourceProxy.output property variant center: Qt.point(0.5 + rootItem.horizontalOffset / width, 0.5 + rootItem.verticalOffset / height) property real len: rootItem.length property bool transparentBorder: rootItem.transparentBorder property real samples: rootItem.samples property real weight: 1.0 / Math.max(1.0, rootItem.samples) property variant expandPixels: transparentBorder ? Qt.size(rootItem.samples, rootItem.samples) : Qt.size(0,0) property variant expand: transparentBorder ? Qt.size(expandPixels.width / width, expandPixels.height / height) : Qt.size(0,0) property variant delta: Qt.size(1.0 / rootItem.width, 1.0 / rootItem.height) x: transparentBorder ? -expandPixels.width - 1 : 0 y: transparentBorder ? -expandPixels.height - 1 : 0 width: transparentBorder ? parent.width + 2.0 * expandPixels.width + 2 : parent.width height: transparentBorder ? parent.height + 2.0 * expandPixels.height + 2 : parent.height property string fragmentShaderSkeleton: "#version 440 layout(location = 0) in vec2 qt_TexCoord0; layout(location = 0) out vec4 fragColor; layout(std140, binding = 0) uniform buf { mat4 qt_Matrix; float qt_Opacity; float len; float weight; float samples; vec2 center; vec2 expand; vec2 delta; }; layout(binding = 1) uniform sampler2D source; void main() { vec2 texCoord = qt_TexCoord0; vec2 centerCoord = center; PLACEHOLDER_EXPAND_STEPS vec2 dir = vec2(centerCoord.x - texCoord.s, centerCoord.y - texCoord.t); dir /= max(1.0, length(dir) * 2.0); vec2 shift = delta * len * dir * 2.0 / max(1.0, samples - 1.0); fragColor = vec4(0.0); PLACEHOLDER_UNROLLED_LOOP fragColor *= weight * qt_Opacity; } " function buildFragmentShader() { var shader = fragmentShaderSkeleton var expandSteps = "" if (transparentBorder) { expandSteps += "centerCoord = (centerCoord - expand) / (1.0 - 2.0 * expand);" expandSteps += "texCoord = (texCoord - expand) / (1.0 - 2.0 * expand);" } var unrolledLoop = "fragColor += texture(source, texCoord);\n" if (rootItem.samples > 1) { unrolledLoop = "" for (var i = 0; i < rootItem.samples; i++) unrolledLoop += "fragColor += texture(source, texCoord); texCoord += shift;\n" } shader = shader.replace("PLACEHOLDER_EXPAND_STEPS", expandSteps) fragmentShader = ShaderBuilder.buildFragmentShader(shader.replace("PLACEHOLDER_UNROLLED_LOOP", unrolledLoop)) } onFragmentShaderChanged: sourceChanged() onSamplesChanged: buildFragmentShader() onTransparentBorderChanged: buildFragmentShader() Component.onCompleted: buildFragmentShader() } }