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Diffstat (limited to 'src/gui/image/qpixmapfilter.cpp')
| -rw-r--r-- | src/gui/image/qpixmapfilter.cpp | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/src/gui/image/qpixmapfilter.cpp b/src/gui/image/qpixmapfilter.cpp index cd80b10..aad2f16 100644 --- a/src/gui/image/qpixmapfilter.cpp +++ b/src/gui/image/qpixmapfilter.cpp @@ -93,6 +93,9 @@ public: \value DropShadowFilter A filter that is used to add a drop shadow to an image. See QPixmapDropShadowFilter for more information. + \value BlurFilter A filter that is used to blur an image using + a simple blur radius. See QPixmapBlurFilter + for more information. \value UserFilter The first filter type that can be used for application-specific purposes. @@ -475,6 +478,227 @@ void QPixmapConvolutionFilter::draw(QPainter *painter, const QPointF &p, const Q } } +/*! + \class QPixmapBlurFilter + \since 4.6 + \ingroup multimedia + + \brief The QPixmapBlurFilter class provides blur filtering + for pixmaps. + + QPixmapBlurFilter implements a blur pixmap filter, + which is applied when \l{QPixmapFilter::}{draw()} is called. + + The filter lets you specialize the radius of the blur as well + as the quality. + + By default, the blur effect is produced by applying an exponential + filter generated from the specified blurRadius(). Paint engines + may override this with a custom blur that is faster on the + underlying hardware. + + \sa {Pixmap Filters Example}, QPixmapConvolutionFilter, QPixmapDropShadowFilter + + \internal +*/ + +class QPixmapBlurFilterPrivate : public QPixmapFilterPrivate +{ +public: + QPixmapBlurFilterPrivate() : radius(5), quality(Qt::FastTransformation) {} + + int radius; + Qt::TransformationMode quality; +}; + + +/*! + Constructs a pixmap blur filter. + + \internal +*/ +QPixmapBlurFilter::QPixmapBlurFilter(QObject *parent) + : QPixmapFilter(*new QPixmapBlurFilterPrivate, BlurFilter, parent) +{ +} + +/*! + Destructor of pixmap blur filter. + + \internal +*/ +QPixmapBlurFilter::~QPixmapBlurFilter() +{ +} + +/*! + Sets the radius of the blur filter. Higher radius produces increased blurriness. + + \internal +*/ +void QPixmapBlurFilter::setRadius(int radius) +{ + Q_D(QPixmapBlurFilter); + d->radius = radius; +} + +/*! + Gets the radius of the blur filter. + + \internal +*/ +int QPixmapBlurFilter::radius() const +{ + Q_D(const QPixmapBlurFilter); + return d->radius; +} + +/*! + Setting the quality to FastTransformation causes the implementation + to trade off visual quality to blur the image faster. Setting the + quality to SmoothTransformation causes the implementation to improve + visual quality at the expense of speed. The implementation is free + to ignore this value if it only has a single blur algorithm. + + \internal +*/ +void QPixmapBlurFilter::setQuality(Qt::TransformationMode quality) +{ + Q_D(QPixmapBlurFilter); + d->quality = quality; +} + +/*! + Gets the quality of the blur filter. + + \internal +*/ +Qt::TransformationMode QPixmapBlurFilter::quality() const +{ + Q_D(const QPixmapBlurFilter); + return d->quality; +} + +/*! + \reimp + + \internal +*/ +QRectF QPixmapBlurFilter::boundingRectFor(const QRectF &rect) const +{ + Q_D(const QPixmapBlurFilter); + const qreal delta = d->radius * 2; + return rect.adjusted(-delta, -delta, delta, delta); +} + +// Blur the image according to the blur radius +// Based on exponential blur algorithm by Jani Huhtanen +// (maximum radius is set to 16) +static QImage blurred(const QImage& image, const QRect& rect, int radius) +{ + int tab[] = { 14, 10, 8, 6, 5, 5, 4, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2 }; + int alpha = (radius < 1) ? 16 : (radius > 17) ? 1 : tab[radius-1]; + + QImage result = image.convertToFormat(QImage::Format_ARGB32_Premultiplied); + int r1 = rect.top(); + int r2 = rect.bottom(); + int c1 = rect.left(); + int c2 = rect.right(); + + int bpl = result.bytesPerLine(); + int rgba[4]; + unsigned char* p; + + for (int col = c1; col <= c2; col++) { + p = result.scanLine(r1) + col * 4; + for (int i = 0; i < 4; i++) + rgba[i] = p[i] << 4; + + p += bpl; + for (int j = r1; j < r2; j++, p += bpl) + for (int i = 0; i < 4; i++) + p[i] = (rgba[i] += ((p[i] << 4) - rgba[i]) * alpha / 16) >> 4; + } + + for (int row = r1; row <= r2; row++) { + p = result.scanLine(row) + c1 * 4; + for (int i = 0; i < 4; i++) + rgba[i] = p[i] << 4; + + p += 4; + for (int j = c1; j < c2; j++, p += 4) + for (int i = 0; i < 4; i++) + p[i] = (rgba[i] += ((p[i] << 4) - rgba[i]) * alpha / 16) >> 4; + } + + for (int col = c1; col <= c2; col++) { + p = result.scanLine(r2) + col * 4; + for (int i = 0; i < 4; i++) + rgba[i] = p[i] << 4; + + p -= bpl; + for (int j = r1; j < r2; j++, p -= bpl) + for (int i = 0; i < 4; i++) + p[i] = (rgba[i] += ((p[i] << 4) - rgba[i]) * alpha / 16) >> 4; + } + + for (int row = r1; row <= r2; row++) { + p = result.scanLine(row) + c2 * 4; + for (int i = 0; i < 4; i++) + rgba[i] = p[i] << 4; + + p -= 4; + for (int j = c1; j < c2; j++, p -= 4) + for (int i = 0; i < 4; i++) + p[i] = (rgba[i] += ((p[i] << 4) - rgba[i]) * alpha / 16) >> 4; + } + + return result; +} + +/*! + \reimp + + \internal +*/ +void QPixmapBlurFilter::draw(QPainter *painter, const QPointF &p, const QPixmap &src, const QRectF &srcRect) const +{ + Q_D(const QPixmapBlurFilter); + if (!painter->isActive()) + return; + + if (d->radius == 0) { + painter->drawPixmap(srcRect.translated(p), src, srcRect); + return; + } + + QPixmapFilter *filter = painter->paintEngine() && painter->paintEngine()->isExtended() ? + static_cast<QPaintEngineEx *>(painter->paintEngine())->createPixmapFilter(type()) : 0; + QPixmapBlurFilter *blurFilter = static_cast<QPixmapBlurFilter*>(filter); + if (blurFilter) { + blurFilter->setRadius(d->radius); + blurFilter->setQuality(d->quality); + blurFilter->draw(painter, p, src, srcRect); + delete blurFilter; + return; + } + + QImage srcImage; + QImage destImage; + + if (srcRect.isNull()) { + srcImage = src.toImage(); + destImage = blurred(srcImage, srcImage.rect(), d->radius); + } else { + QRect rect = srcRect.toAlignedRect().intersected(src.rect()); + + srcImage = src.copy(rect).toImage(); + destImage = blurred(srcImage, srcImage.rect(), d->radius); + } + + painter->drawImage(p, destImage); +} + // grayscales the image to dest (could be same). If rect isn't defined // destination image size is used to determine the dimension of grayscaling // process. @@ -837,4 +1061,5 @@ void QPixmapDropShadowFilter::draw(QPainter *p, // Draw the actual pixmap... p->drawPixmap(pos, px, src); } + QT_END_NAMESPACE |