1/**************************************************************************** 2** 3** Copyright (C) 2016 The Qt Company Ltd. 4** Contact: https://www.qt.io/licensing/ 5** 6** This file is part of the Qt Graphical Effects module. 7** 8** $QT_BEGIN_LICENSE:BSD$ 9** Commercial License Usage 10** Licensees holding valid commercial Qt licenses may use this file in 11** accordance with the commercial license agreement provided with the 12** Software or, alternatively, in accordance with the terms contained in 13** a written agreement between you and The Qt Company. For licensing terms 14** and conditions see https://www.qt.io/terms-conditions. For further 15** information use the contact form at https://www.qt.io/contact-us. 16** 17** BSD License Usage 18** Alternatively, you may use this file under the terms of the BSD license 19** as follows: 20** 21** "Redistribution and use in source and binary forms, with or without 22** modification, are permitted provided that the following conditions are 23** met: 24** * Redistributions of source code must retain the above copyright 25** notice, this list of conditions and the following disclaimer. 26** * Redistributions in binary form must reproduce the above copyright 27** notice, this list of conditions and the following disclaimer in 28** the documentation and/or other materials provided with the 29** distribution. 30** * Neither the name of The Qt Company Ltd nor the names of its 31** contributors may be used to endorse or promote products derived 32** from this software without specific prior written permission. 33** 34** 35** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 36** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 37** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 38** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 39** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 40** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 41** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 42** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 43** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 44** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 45** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." 46** 47** $QT_END_LICENSE$ 48** 49****************************************************************************/ 50 51import QtQuick 2.0 52import "private" 53 54/*! 55 \qmltype DropShadow 56 \inqmlmodule QtGraphicalEffects 1.0 57 \since QtGraphicalEffects 1.0 58 \inherits QtQuick2::Item 59 \ingroup qtgraphicaleffects-drop-shadow 60 \brief Generates a colorized and blurred shadow image of the 61 source and places it behind the original, giving the impression that 62 source item is raised from the background. 63 64 By default the effect produces a high quality shadow image, thus the 65 rendering speed of the shadow might not be the highest possible. The 66 rendering speed is reduced especially if the shadow edges are heavily 67 softened. 68 69 For use cases that require faster rendering speed and for which the highest 70 possible visual quality is not necessary, property 71 \l{DropShadow::fast}{fast} can be set to true. 72 73 \table 74 \header 75 \li Source 76 \li Effect applied 77 \row 78 \li \image Original_butterfly.png 79 \li \image DropShadow_butterfly.png 80 \endtable 81 82 \section1 Example 83 84 The following example shows how to apply the effect. 85 \snippet DropShadow-example.qml example 86 87*/ 88Item { 89 id: rootItem 90 91 /*! 92 This property defines the source item that is going to be used as the 93 source for the generated shadow. 94 95 \note It is not supported to let the effect include itself, for 96 instance by setting source to the effect's parent. 97 */ 98 property variant source 99 100 /*! 101 Radius defines the softness of the shadow. A larger radius causes the 102 edges of the shadow to appear more blurry. 103 104 Depending on the radius value, value of the 105 \l{DropShadow::samples}{samples} should be set to sufficiently large to 106 ensure the visual quality. 107 108 The value ranges from 0.0 (no blur) to inf. By default, the property is 109 set to \c 0.0 (no blur). 110 111 \table 112 \header 113 \li Output examples with different radius values 114 \li 115 \li 116 \row 117 \li \image DropShadow_radius1.png 118 \li \image DropShadow_radius2.png 119 \li \image DropShadow_radius3.png 120 \row 121 \li \b { radius: 0 } 122 \li \b { radius: 6 } 123 \li \b { radius: 12 } 124 \row 125 \li \l samples: 24 126 \li \l samples: 24 127 \li \l samples: 24 128 \row 129 \li \l color: #000000 130 \li \l color: #000000 131 \li \l color: #000000 132 \row 133 \li \l horizontalOffset: 0 134 \li \l horizontalOffset: 0 135 \li \l horizontalOffset: 0 136 \row 137 \li \l verticalOffset: 20 138 \li \l verticalOffset: 20 139 \li \l verticalOffset: 20 140 \row 141 \li \l spread: 0 142 \li \l spread: 0 143 \li \l spread: 0 144 \endtable 145 146 */ 147 property real radius: 0.0 148 149 /*! 150 This property defines how many samples are taken per pixel when edge 151 softening blur calculation is done. Larger value produces better 152 quality, but is slower to render. 153 154 Ideally, this value should be twice as large as the highest required 155 radius value, for example, if the radius is animated between 0.0 and 156 4.0, samples should be set to 8. 157 158 The value ranges from 0 to 32. By default, the property is set to \c 0. 159 160 This property is not intended to be animated. Changing this property may 161 cause the underlying OpenGL shaders to be recompiled. 162 163 When \l{DropShadow::fast}{fast} property is set to true, this property 164 has no effect. 165 166 */ 167 property int samples: 0 168 169 /*! 170 This property defines the RGBA color value which is used for the shadow. 171 172 By default, the property is set to \c "black". 173 174 \table 175 \header 176 \li Output examples with different color values 177 \li 178 \li 179 \row 180 \li \image DropShadow_color1.png 181 \li \image DropShadow_color2.png 182 \li \image DropShadow_color3.png 183 \row 184 \li \b { color: #000000 } 185 \li \b { color: #0000ff } 186 \li \b { color: #aa000000 } 187 \row 188 \li \l radius: 8 189 \li \l radius: 8 190 \li \l radius: 8 191 \row 192 \li \l samples: 16 193 \li \l samples: 16 194 \li \l samples: 16 195 \row 196 \li \l horizontalOffset: 0 197 \li \l horizontalOffset: 0 198 \li \l horizontalOffset: 0 199 \row 200 \li \l verticalOffset: 20 201 \li \l verticalOffset: 20 202 \li \l verticalOffset: 20 203 \row 204 \li \l spread: 0 205 \li \l spread: 0 206 \li \l spread: 0 207 \endtable 208 209 */ 210 property color color: "black" 211 212 /*! 213 \qmlproperty real QtGraphicalEffects1::DropShadow::horizontalOffset 214 \qmlproperty real QtGraphicalEffects1::DropShadow::verticalOffset 215 216 HorizontalOffset and verticalOffset properties define the offset for the 217 rendered shadow compared to the DropShadow item position. Often, the 218 DropShadow item is anchored so that it fills the source element. In this 219 case, if the HorizontalOffset and verticalOffset properties are set to 220 0, the shadow is rendered exactly under the source item. By changing the 221 offset properties, the shadow can be positioned relatively to the source 222 item. 223 224 The values range from -inf to inf. By default, the properties are set to 225 \c 0. 226 227 \table 228 \header 229 \li Output examples with different horizontalOffset values 230 \li 231 \li 232 \row 233 \li \image DropShadow_horizontalOffset1.png 234 \li \image DropShadow_horizontalOffset2.png 235 \li \image DropShadow_horizontalOffset3.png 236 \row 237 \li \b { horizontalOffset: -20 } 238 \li \b { horizontalOffset: 0 } 239 \li \b { horizontalOffset: 20 } 240 \row 241 \li \l radius: 4 242 \li \l radius: 4 243 \li \l radius: 4 244 \row 245 \li \l samples: 8 246 \li \l samples: 8 247 \li \l samples: 8 248 \row 249 \li \l color: #000000 250 \li \l color: #000000 251 \li \l color: #000000 252 \row 253 \li \l verticalOffset: 0 254 \li \l verticalOffset: 0 255 \li \l verticalOffset: 0 256 \row 257 \li \l spread: 0 258 \li \l spread: 0 259 \li \l spread: 0 260 \endtable 261 262 */ 263 property real horizontalOffset: 0.0 264 property real verticalOffset: 0.0 265 266 /*! 267 This property defines how large part of the shadow color is strenghtened 268 near the source edges. 269 270 The value ranges from 0.0 to 1.0. By default, the property is set to \c 271 0.5. 272 273 \table 274 \header 275 \li Output examples with different spread values 276 \li 277 \li 278 \row 279 \li \image DropShadow_spread1.png 280 \li \image DropShadow_spread2.png 281 \li \image DropShadow_spread3.png 282 \row 283 \li \b { spread: 0.0 } 284 \li \b { spread: 0.5 } 285 \li \b { spread: 1.0 } 286 \row 287 \li \l radius: 8 288 \li \l radius: 8 289 \li \l radius: 8 290 \row 291 \li \l samples: 16 292 \li \l samples: 16 293 \li \l samples: 16 294 \row 295 \li \l color: #000000 296 \li \l color: #000000 297 \li \l color: #000000 298 \row 299 \li \l horizontalOffset: 0 300 \li \l horizontalOffset: 0 301 \li \l horizontalOffset: 0 302 \row 303 \li \l verticalOffset: 20 304 \li \l verticalOffset: 20 305 \li \l verticalOffset: 20 306 \endtable 307 308 */ 309 property real spread: 0.0 310 311 /*! 312 This property selects the blurring algorithm that is used to produce the 313 softness for the effect. Setting this to true enables fast algorithm, 314 setting value to false produces higher quality result. 315 316 By default, the property is set to \c false. 317 318 \table 319 \header 320 \li Output examples with different fast values 321 \li 322 \li 323 \row 324 \li \image DropShadow_fast1.png 325 \li \image DropShadow_fast2.png 326 \row 327 \li \b { fast: false } 328 \li \b { fast: true } 329 \row 330 \li \l radius: 16 331 \li \l radius: 16 332 \row 333 \li \l samples: 24 334 \li \l samples: 24 335 \row 336 \li \l color: #000000 337 \li \l color: #000000 338 \row 339 \li \l horizontalOffset: 0 340 \li \l horizontalOffset: 0 341 \row 342 \li \l verticalOffset: 20 343 \li \l verticalOffset: 20 344 \row 345 \li \l spread: 0 346 \li \l spread: 0 347 \endtable 348 349 */ 350 property bool fast: false 351 352 /*! 353 This property allows the effect output pixels to be cached in order to 354 improve the rendering performance. Every time the source or effect 355 properties are changed, the pixels in the cache must be updated. Memory 356 consumption is increased, because an extra buffer of memory is required 357 for storing the effect output. 358 359 It is recommended to disable the cache when the source or the effect 360 properties are animated. 361 362 By default, the property is set to \c false. 363 364 */ 365 property bool cached: false 366 367 property bool transparentBorder: false 368 369 Loader { 370 x: rootItem.horizontalOffset 371 y: rootItem.verticalOffset 372 width: parent.width 373 height: parent.height 374 sourceComponent: rootItem.fast ? fastGlow : gaussianGlow 375 } 376 377 Component { 378 id: gaussianGlow 379 GaussianGlow { 380 anchors.fill: parent 381 source: sourceProxy.output 382 radius: rootItem.radius 383 maximumRadius: rootItem.samples * 0.5 384 color: rootItem.color 385 cached: rootItem.cached 386 spread: rootItem.spread 387 transparentBorder: rootItem.transparentBorder 388 } 389 } 390 391 Component { 392 id: fastGlow 393 FastGlow { 394 anchors.fill: parent 395 source: sourceProxy.output 396 blur: Math.pow(rootItem.radius / 64.0, 0.4) 397 color: rootItem.color 398 cached: rootItem.cached 399 spread: rootItem.spread 400 transparentBorder: rootItem.transparentBorder 401 } 402 } 403 404 SourceProxy { 405 id: sourceProxy 406 input: rootItem.source 407 sourceRect: rootItem.transparentBorder ? Qt.rect(-1, -1, parent.width + 2.0, parent.height + 2.0) : Qt.rect(0, 0, 0, 0) 408 } 409 ShaderEffect { 410 anchors.fill: parent 411 property variant source: sourceProxy.output 412 } 413} 414
