summaryrefslogtreecommitdiffstats
path: root/src/declarative/graphicsitems/qdeclarativerectangle.cpp
blob: 1ffd3bdc2582cff04f53b198b98706d9b9485b2f (plain)
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
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtDeclarative module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "private/qdeclarativerectangle_p.h"
#include "private/qdeclarativerectangle_p_p.h"

#include <QPainter>
#include <QStringBuilder>
#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

/*!
    \internal
    \class QDeclarativePen
    \brief The QDeclarativePen class provides a pen used for drawing rectangle borders on a QDeclarativeView.

    By default, the pen is invalid and nothing is drawn. You must either set a color (then the default
    width is 1) or a width (then the default color is black).

    A width of 1 indicates is a single-pixel line on the border of the item being painted.

    Example:
    \qml
    Rectangle { border.width: 2; border.color: "red" ... }
    \endqml
*/

void QDeclarativePen::setColor(const QColor &c)
{
    _color = c;
    _valid = _color.alpha() ? true : false;
    emit penChanged();
}

void QDeclarativePen::setWidth(int w)
{
    if (_width == w && _valid)
        return;

    _width = w;
    _valid = (_width < 1) ? false : true;
    emit penChanged();
}


/*!
    \qmlclass GradientStop QDeclarativeGradientStop
    \ingroup qml-basic-visual-elements
    \since 4.7
    \brief The GradientStop item defines the color at a position in a Gradient.

    \sa Gradient
*/

/*!
    \qmlproperty real GradientStop::position
    \qmlproperty color GradientStop::color

    The position and color properties describe the color used at a given
    position in a gradient, as represented by a gradient stop.

    The default position is 0.0; the default color is black.

    \sa Gradient
*/

void QDeclarativeGradientStop::updateGradient()
{
    if (QDeclarativeGradient *grad = qobject_cast<QDeclarativeGradient*>(parent()))
        grad->doUpdate();
}

/*!
    \qmlclass Gradient QDeclarativeGradient
    \ingroup qml-basic-visual-elements
    \since 4.7
    \brief The Gradient item defines a gradient fill.

    A gradient is defined by two or more colors, which will be blended seamlessly.

    The colors are specified as a set of GradientStop child items, each of
    which defines a position on the gradient from 0.0 to 1.0 and a color.
    The position of each GradientStop is defined by setting its
    \l{GradientStop::}{position} property; its color is defined using its
    \l{GradientStop::}{color} property.

    A gradient without any gradient stops is rendered as a solid white fill.

    Note that this item is not a visual representation of a gradient. To display a
    gradient, use a visual element (like \l Rectangle) which supports the use
    of gradients.

    \section1 Example Usage

    \beginfloatright
    \inlineimage qml-gradient.png
    \endfloat

    The following example declares a \l Rectangle item with a gradient starting
    with red, blending to yellow at one third of the height of the rectangle,
    and ending with green:

    \snippet doc/src/snippets/declarative/gradient.qml code

    \clearfloat
    \section1 Performance and Limitations

    Calculating gradients can be computationally expensive compared to the use
    of solid color fills or images. Consider using gradients for static items
    in a user interface.

    In Qt 4.7, only vertical, linear gradients can be applied to items. If you
    need to apply different orientations of gradients, a combination of rotation
    and clipping will need to be applied to the relevant items. This can
    introduce additional performance requirements for your application.

    The use of animations involving gradient stops may not give the desired
    result. An alternative way to animate gradients is to use pre-generated
    images or SVG drawings containing gradients.

    \sa GradientStop
*/

/*!
    \qmlproperty list<GradientStop> Gradient::stops
    This property holds the gradient stops describing the gradient.

    By default, this property contains an empty list.

    To set the gradient stops, define them as children of the Gradient element.
*/

const QGradient *QDeclarativeGradient::gradient() const
{
    if (!m_gradient && !m_stops.isEmpty()) {
        m_gradient = new QLinearGradient(0,0,0,1.0);
        for (int i = 0; i < m_stops.count(); ++i) {
            const QDeclarativeGradientStop *stop = m_stops.at(i);
            m_gradient->setCoordinateMode(QGradient::ObjectBoundingMode);
            m_gradient->setColorAt(stop->position(), stop->color());
        }
    }

    return m_gradient;
}

void QDeclarativeGradient::doUpdate()
{
    delete m_gradient;
    m_gradient = 0;
    emit updated();
}


/*!
    \qmlclass Rectangle QDeclarativeRectangle
    \ingroup qml-basic-visual-elements
    \since 4.7
    \brief The Rectangle item provides a filled rectangle with an optional border.
    \inherits Item

    Rectangle items are used to fill areas with solid color or gradients, and are
    often used to hold other items.

    \section1 Appearance

    Each Rectangle item is painted using either a solid fill color, specified using
    the \l color property, or a gradient, defined using a Gradient element and set
    using the \l gradient property. If both a color and a gradient are specified,
    the gradient is used.

    You can add an optional border to a rectangle with its own color and thickness
    by settting the \l border.color and \l border.width properties.

    You can also create rounded rectangles using the \l radius property. Since this
    introduces curved edges to the corners of a rectangle, it may be appropriate to
    set the \l smooth property to improve its appearance.

    \section1 Example Usage

    \beginfloatright
    \inlineimage declarative-rect.png
    \endfloat

    The following example shows the effects of some of the common properties on a
    Rectangle item, which in this case is used to create a square:

    \snippet doc/src/snippets/declarative/rectangle/rectangle.qml document

    \clearfloat
    \section1 Performance

    Using the \l smooth property improves the appearance of a rounded rectangle at
    the cost of rendering performance. You should consider unsetting this property
    for rectangles in motion, and only set it when they are stationary.

    \sa Image
*/

int QDeclarativeRectanglePrivate::doUpdateSlotIdx = -1;

QDeclarativeRectangle::QDeclarativeRectangle(QDeclarativeItem *parent)
  : QDeclarativeItem(*(new QDeclarativeRectanglePrivate), parent)
{
}

void QDeclarativeRectangle::doUpdate()
{
    Q_D(QDeclarativeRectangle);
    d->rectImage = QPixmap();
    const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
    d->setPaintMargin((pw+1)/2);
    update();
}

/*!
    \qmlproperty int Rectangle::border.width
    \qmlproperty color Rectangle::border.color

    The width and color used to draw the border of the rectangle.

    A width of 1 creates a thin line. For no line, use a width of 0 or a transparent color.

    If \c border.width is an odd number, the rectangle is painted at a half-pixel offset to retain
    border smoothness. Also, the border is rendered evenly on either side of the
    rectangle's boundaries, and the spare pixel is rendered to the right and below the
    rectangle (as documented for QRect rendering). This can cause unintended effects if
    \c border.width is 1 and the rectangle is \l{Item::clip}{clipped} by a parent item:

    \beginfloatright
    \inlineimage rect-border-width.png
    \endfloat

    \snippet doc/src/snippets/declarative/rectangle/rect-border-width.qml 0

    \clearfloat
    Here, the innermost rectangle's border is clipped on the bottom and right edges by its
    parent. To avoid this, the border width can be set to two instead of one.
*/
QDeclarativePen *QDeclarativeRectangle::border()
{
    Q_D(QDeclarativeRectangle);
    return d->getPen();
}

/*!
    \qmlproperty Gradient Rectangle::gradient

    The gradient to use to fill the rectangle.

    This property allows for the construction of simple vertical gradients.
    Other gradients may by formed by adding rotation to the rectangle.

    \beginfloatleft
    \inlineimage declarative-rect_gradient.png
    \endfloat

    \snippet doc/src/snippets/declarative/rectangle/rectangle-gradient.qml rectangles
    \clearfloat

    If both a gradient and a color are specified, the gradient will be used.

    \sa Gradient, color
*/
QDeclarativeGradient *QDeclarativeRectangle::gradient() const
{
    Q_D(const QDeclarativeRectangle);
    return d->gradient;
}

void QDeclarativeRectangle::setGradient(QDeclarativeGradient *gradient)
{
    Q_D(QDeclarativeRectangle);
    if (d->gradient == gradient)
        return;
    static int updatedSignalIdx = -1;
    if (updatedSignalIdx < 0)
        updatedSignalIdx = QDeclarativeGradient::staticMetaObject.indexOfSignal("updated()");
    if (d->doUpdateSlotIdx < 0)
        d->doUpdateSlotIdx = QDeclarativeRectangle::staticMetaObject.indexOfSlot("doUpdate()");
    if (d->gradient)
        QMetaObject::disconnect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
    d->gradient = gradient;
    if (d->gradient)
        QMetaObject::connect(d->gradient, updatedSignalIdx, this, d->doUpdateSlotIdx);
    update();
}


/*!
    \qmlproperty real Rectangle::radius
    This property holds the corner radius used to draw a rounded rectangle.

    If radius is non-zero, the rectangle will be painted as a rounded rectangle, otherwise it will be
    painted as a normal rectangle. The same radius is used by all 4 corners; there is currently
    no way to specify different radii for different corners.
*/
qreal QDeclarativeRectangle::radius() const
{
    Q_D(const QDeclarativeRectangle);
    return d->radius;
}

void QDeclarativeRectangle::setRadius(qreal radius)
{
    Q_D(QDeclarativeRectangle);
    if (d->radius == radius)
        return;

    d->radius = radius;
    d->rectImage = QPixmap();
    update();
    emit radiusChanged();
}

/*!
    \qmlproperty color Rectangle::color
    This property holds the color used to fill the rectangle.

    The default color is white.

    \beginfloatright
    \inlineimage rect-color.png
    \endfloat

    The following example shows rectangles with colors specified
    using hexadecimal and named color notation:

    \snippet doc/src/snippets/declarative/rectangle/rectangle-colors.qml rectangles

    \clearfloat
    If both a gradient and a color are specified, the gradient will be used.

    \sa gradient
*/
QColor QDeclarativeRectangle::color() const
{
    Q_D(const QDeclarativeRectangle);
    return d->color;
}

void QDeclarativeRectangle::setColor(const QColor &c)
{
    Q_D(QDeclarativeRectangle);
    if (d->color == c)
        return;

    d->color = c;
    d->rectImage = QPixmap();
    update();
    emit colorChanged();
}

void QDeclarativeRectangle::generateRoundedRect()
{
    Q_D(QDeclarativeRectangle);
    if (d->rectImage.isNull()) {
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
        const int radius = qCeil(d->radius);    //ensure odd numbered width/height so we get 1-pixel center

        QString key = QLatin1String("q_") % QString::number(pw) % d->color.name() % QString::number(d->color.alpha(), 16) % QLatin1Char('_') % QString::number(radius);
        if (d->pen && d->pen->isValid())
            key += d->pen->color().name() % QString::number(d->pen->color().alpha(), 16);

        if (!QPixmapCache::find(key, &d->rectImage)) {
            d->rectImage = QPixmap(radius*2 + 3 + pw*2, radius*2 + 3 + pw*2);
            d->rectImage.fill(Qt::transparent);
            QPainter p(&(d->rectImage));
            p.setRenderHint(QPainter::Antialiasing);
            if (d->pen && d->pen->isValid()) {
                QPen pn(QColor(d->pen->color()), d->pen->width());
                p.setPen(pn);
            } else {
                p.setPen(Qt::NoPen);
            }
            p.setBrush(d->color);
            if (pw%2)
                p.drawRoundedRect(QRectF(qreal(pw)/2+1, qreal(pw)/2+1, d->rectImage.width()-(pw+1), d->rectImage.height()-(pw+1)), d->radius, d->radius);
            else
                p.drawRoundedRect(QRectF(qreal(pw)/2, qreal(pw)/2, d->rectImage.width()-pw, d->rectImage.height()-pw), d->radius, d->radius);
            QPixmapCache::insert(key, d->rectImage);
        }
    }
}

void QDeclarativeRectangle::generateBorderedRect()
{
    Q_D(QDeclarativeRectangle);
    if (d->rectImage.isNull()) {
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;

        QString key = QLatin1String("q_") % QString::number(pw) % d->color.name() % QString::number(d->color.alpha(), 16);
        if (d->pen && d->pen->isValid())
            key += d->pen->color().name() % QString::number(d->pen->color().alpha(), 16);

        if (!QPixmapCache::find(key, &d->rectImage)) {
            // Adding 5 here makes qDrawBorderPixmap() paint correctly with smooth: true
            // See QTBUG-7999 and QTBUG-10765 for more details.
            d->rectImage = QPixmap(pw*2 + 5, pw*2 + 5);
            d->rectImage.fill(Qt::transparent);
            QPainter p(&(d->rectImage));
            p.setRenderHint(QPainter::Antialiasing);
            if (d->pen && d->pen->isValid()) {
                QPen pn(QColor(d->pen->color()), d->pen->width());
                pn.setJoinStyle(Qt::MiterJoin);
                p.setPen(pn);
            } else {
                p.setPen(Qt::NoPen);
            }
            p.setBrush(d->color);
            if (pw%2)
                p.drawRect(QRectF(qreal(pw)/2+1, qreal(pw)/2+1, d->rectImage.width()-(pw+1), d->rectImage.height()-(pw+1)));
            else
                p.drawRect(QRectF(qreal(pw)/2, qreal(pw)/2, d->rectImage.width()-pw, d->rectImage.height()-pw));
            QPixmapCache::insert(key, d->rectImage);
        }
    }
}

void QDeclarativeRectangle::paint(QPainter *p, const QStyleOptionGraphicsItem *, QWidget *)
{
    Q_D(QDeclarativeRectangle);
    if (d->radius > 0 || (d->pen && d->pen->isValid())
        || (d->gradient && d->gradient->gradient()) ) {
        drawRect(*p);
    }
    else {
        bool oldAA = p->testRenderHint(QPainter::Antialiasing);
        if (d->smooth)
            p->setRenderHints(QPainter::Antialiasing, true);
        p->fillRect(QRectF(0, 0, width(), height()), d->color);
        if (d->smooth)
            p->setRenderHint(QPainter::Antialiasing, oldAA);
    }
}

void QDeclarativeRectangle::drawRect(QPainter &p)
{
    Q_D(QDeclarativeRectangle);
    if ((d->gradient && d->gradient->gradient())
        || d->radius > width()/2 || d->radius > height()/2) {
        // XXX This path is still slower than the image path
        // Image path won't work for gradients or invalid radius though
        bool oldAA = p.testRenderHint(QPainter::Antialiasing);
        if (d->smooth)
            p.setRenderHint(QPainter::Antialiasing);
        if (d->pen && d->pen->isValid()) {
            QPen pn(QColor(d->pen->color()), d->pen->width());
            pn.setJoinStyle(Qt::MiterJoin);
            p.setPen(pn);
        } else {
            p.setPen(Qt::NoPen);
        }
        if (d->gradient && d->gradient->gradient())
            p.setBrush(*d->gradient->gradient());
        else
            p.setBrush(d->color);
        const int pw = d->pen && d->pen->isValid() ? d->pen->width() : 0;
        QRectF rect;
        if (pw%2)
            rect = QRectF(0.5, 0.5, width()-1, height()-1);
        else
            rect = QRectF(0, 0, width(), height());
        qreal radius = d->radius;
        if (radius > width()/2 || radius > height()/2)
            radius = qMin(width()/2, height()/2);
        if (radius > 0.)
            p.drawRoundedRect(rect, radius, radius);
        else
            p.drawRect(rect);
        if (d->smooth)
            p.setRenderHint(QPainter::Antialiasing, oldAA);
    } else {
        bool oldAA = p.testRenderHint(QPainter::Antialiasing);
        bool oldSmooth = p.testRenderHint(QPainter::SmoothPixmapTransform);
        if (d->smooth)
            p.setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform, d->smooth);

        const int pw = d->pen && d->pen->isValid() ? (d->pen->width()+1)/2*2 : 0;

        if (d->radius > 0)
            generateRoundedRect();
        else
            generateBorderedRect();

        int xOffset = (d->rectImage.width()-1)/2;
        int yOffset = (d->rectImage.height()-1)/2;
        Q_ASSERT(d->rectImage.width() == 2*xOffset + 1);
        Q_ASSERT(d->rectImage.height() == 2*yOffset + 1);

        QMargins margins(xOffset, yOffset, xOffset, yOffset);
        QTileRules rules(Qt::StretchTile, Qt::StretchTile);
        //NOTE: even though our item may have qreal-based width and height, qDrawBorderPixmap only supports QRects
        qDrawBorderPixmap(&p, QRect(-pw/2, -pw/2, width()+pw, height()+pw), margins, d->rectImage, d->rectImage.rect(), margins, rules);

        if (d->smooth) {
            p.setRenderHint(QPainter::Antialiasing, oldAA);
            p.setRenderHint(QPainter::SmoothPixmapTransform, oldSmooth);
        }
    }
}

/*!
    \qmlproperty bool Rectangle::smooth

    Set this property if you want the item to be smoothly scaled or
    transformed.  Smooth filtering gives better visual quality, but is slower.  If
    the item is displayed at its natural size, this property has no visual or
    performance effect.

    \note Generally scaling artifacts are only visible if the item is stationary on
    the screen.  A common pattern when animating an item is to disable smooth
    filtering at the beginning of the animation and reenable it at the conclusion.

    \image rect-smooth.png
    On this image, smooth is turned off on the top half and on on the bottom half.
*/

QRectF QDeclarativeRectangle::boundingRect() const
{
    Q_D(const QDeclarativeRectangle);
    return QRectF(-d->paintmargin, -d->paintmargin, d->width()+d->paintmargin*2, d->height()+d->paintmargin*2);
}

QT_END_NAMESPACE