/**************************************************************************** ** ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). ** Contact: http://www.qt-project.org/legal ** ** This file is part of the Qt Graphical Effects module. ** ** $QT_BEGIN_LICENSE:BSD$ ** You may use this file under the terms of the BSD license as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names ** of its contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/ import QtQuick 2.0 import "private" /*! \qmltype ZoomBlur \inqmlmodule QtGraphicalEffects 1.0 \since QtGraphicalEffects 1.0 \inherits QtQuick2::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{QtGraphicalEffects1::DirectionalBlur}{DirectionalBlur} and \l{QtGraphicalEffects1::RadialBlur}{RadialBlur}. \table \header \li Source \li Effect applied \row \li \image Original_bug.png \li \image ZoomBlur_bug.png \endtable \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 QtGraphicalEffects1::ZoomBlur::horizontalOffset \qmlproperty real QtGraphicalEffects1::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: " varying highp vec2 qt_TexCoord0; uniform highp float qt_Opacity; uniform lowp sampler2D source; uniform highp float len; uniform highp float weight; uniform highp float samples; uniform highp vec2 center; uniform highp vec2 expand; uniform highp vec2 delta; void main(void) { mediump vec2 texCoord = qt_TexCoord0; mediump vec2 centerCoord = center; PLACEHOLDER_EXPAND_STEPS highp vec2 dir = vec2(centerCoord.x - texCoord.s, centerCoord.y - texCoord.t); dir /= max(1.0, length(dir) * 2.0); highp vec2 shift = delta * len * dir * 2.0 / max(1.0, samples - 1.0); gl_FragColor = vec4(0.0); PLACEHOLDER_UNROLLED_LOOP gl_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 = "gl_FragColor += texture2D(source, texCoord);\n" if (rootItem.samples > 1) { unrolledLoop = "" for (var i = 0; i < rootItem.samples; i++) unrolledLoop += "gl_FragColor += texture2D(source, texCoord); texCoord += shift;\n" } shader = shader.replace("PLACEHOLDER_EXPAND_STEPS", expandSteps) fragmentShader = shader.replace("PLACEHOLDER_UNROLLED_LOOP", unrolledLoop) } onFragmentShaderChanged: sourceChanged() onSamplesChanged: buildFragmentShader() onTransparentBorderChanged: buildFragmentShader() Component.onCompleted: buildFragmentShader() } }