1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
|
/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\qmltype DropShadow
\inqmlmodule QtGraphicalEffects 1.0
\since QtGraphicalEffects 1.0
\inherits QtQuick2::Item
\ingroup qtgraphicaleffects-drop-shadow
\brief Generates a colorized and blurred shadow image of the
source and places it behind the original, giving the impression that
source item is raised from the background.
By default the effect produces a high quality shadow image, thus the
rendering speed of the shadow might not be the highest possible. The
rendering speed is reduced especially if the shadow edges are heavily
softened.
For use cases that require faster rendering speed and for which the highest
possible visual quality is not necessary, property \l{DropShadow::fast}{fast} can be set to true.
\table
\header
\li Source
\li Effect applied
\row
\li \image Original_butterfly.png
\li \image DropShadow_butterfly.png
\endtable
\section1 Example
The following example shows how to apply the effect.
\snippet snippets/DropShadow-example.qml example
*/
/*!
\qmlproperty variant QtGraphicalEffects1::DropShadow::source
This property defines the source item that is going to be used as the source
for the generated shadow.
*/
/*!
\qmlproperty real QtGraphicalEffects1::DropShadow::radius
Radius defines the softness of the shadow. A larger radius causes the edges
of the shadow to appear more blurry.
Depending on the radius value, value of the \l{DropShadow::samples}{samples} should be set to sufficiently
large to ensure the visual quality.
The value ranges from 0.0 (no blur) to inf. By default, the property is set to
\c 0.0 (no blur).
\table
\header
\li Output examples with different radius values
\li
\li
\row
\li \image DropShadow_radius1.png
\li \image DropShadow_radius2.png
\li \image DropShadow_radius3.png
\row
\li \b { radius: 0 }
\li \b { radius: 6 }
\li \b { radius: 12 }
\row
\li \l samples: 24
\li \l samples: 24
\li \l samples: 24
\row
\li \l color: #000000
\li \l color: #000000
\li \l color: #000000
\row
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\row
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\endtable
*/
/*!
\qmlproperty int QtGraphicalEffects1::DropShadow::samples
This property defines how many samples are taken per pixel when edge softening
blur calculation is done. Larger value produces better quality, but is slower
to render.
Ideally, this value should be twice as large as the highest required radius
value, for example, if the radius is animated between 0.0 and 4.0, samples
should be set to 8.
The value ranges from 0 to 32. By default, the property is set to \c 0.
This property is not intended to be animated. Changing this property may
cause the underlying OpenGL shaders to be recompiled.
When \l{DropShadow::fast}{fast} property is set to true, this property has no effect.
*/
/*!
\qmlproperty real QtGraphicalEffects1::DropShadow::spread
This property defines how large part of the shadow color is strenghtened near
the source edges.
The value ranges from 0.0 to 1.0. By default, the property is set to \c 0.5.
\table
\header
\li Output examples with different spread values
\li
\li
\row
\li \image DropShadow_spread1.png
\li \image DropShadow_spread2.png
\li \image DropShadow_spread3.png
\row
\li \b { spread: 0.0 }
\li \b { spread: 0.5 }
\li \b { spread: 1.0 }
\row
\li \l radius: 8
\li \l radius: 8
\li \l radius: 8
\row
\li \l samples: 16
\li \l samples: 16
\li \l samples: 16
\row
\li \l color: #000000
\li \l color: #000000
\li \l color: #000000
\row
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\row
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\endtable
*/
/*!
\qmlproperty color QtGraphicalEffects1::DropShadow::color
This property defines the RGBA color value which is used for the shadow.
By default, the property is set to \c "black".
\table
\header
\li Output examples with different color values
\li
\li
\row
\li \image DropShadow_color1.png
\li \image DropShadow_color2.png
\li \image DropShadow_color3.png
\row
\li \b { color: #000000 }
\li \b { color: #0000ff }
\li \b { color: #aa000000 }
\row
\li \l radius: 8
\li \l radius: 8
\li \l radius: 8
\row
\li \l samples: 16
\li \l samples: 16
\li \l samples: 16
\row
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\row
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\endtable
*/
/*!
\qmlproperty real QtGraphicalEffects1::DropShadow::horizontalOffset
\qmlproperty real QtGraphicalEffects1::DropShadow::verticalOffset
HorizontalOffset and verticalOffset properties define the offset
for the rendered shadow compared to the DropShadow item position. Often, the
DropShadow item is anchored so that it fills the source element. In this
case, if the HorizontalOffset and verticalOffset properties are set to 0, the
shadow is rendered exactly under the source item. By changing the offset
properties, the shadow can be positioned relatively to the source item.
The values range from -inf to inf. By default, the properties are set to \c 0.
\table
\header
\li Output examples with different horizontalOffset values
\li
\li
\row
\li \image DropShadow_horizontalOffset1.png
\li \image DropShadow_horizontalOffset2.png
\li \image DropShadow_horizontalOffset3.png
\row
\li \b { horizontalOffset: -20 }
\li \b { horizontalOffset: 0 }
\li \b { horizontalOffset: 20 }
\row
\li \l radius: 4
\li \l radius: 4
\li \l radius: 4
\row
\li \l samples: 8
\li \l samples: 8
\li \l samples: 8
\row
\li \l color: #000000
\li \l color: #000000
\li \l color: #000000
\row
\li \l verticalOffset: 0
\li \l verticalOffset: 0
\li \l verticalOffset: 0
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\endtable
*/
/*!
\qmlproperty bool QtGraphicalEffects1::DropShadow::fast
This property selects the blurring algorithm that is used to produce the
softness for the effect. Setting this to true enables fast algorithm,
setting value to false produces higher quality result.
By default, the property is set to \c false.
\table
\header
\li Output examples with different fast values
\li
\li
\row
\li \image DropShadow_fast1.png
\li \image DropShadow_fast2.png
\row
\li \b { fast: false }
\li \b { fast: true }
\row
\li \l radius: 16
\li \l radius: 16
\row
\li \l samples: 24
\li \l samples: 24
\row
\li \l color: #000000
\li \l color: #000000
\row
\li \l horizontalOffset: 0
\li \l horizontalOffset: 0
\row
\li \l verticalOffset: 20
\li \l verticalOffset: 20
\row
\li \l spread: 0
\li \l spread: 0
\endtable
*/
/*!
\qmlproperty bool QtGraphicalEffects1::DropShadow::cached
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.
*/
|
