Qt Reference Documentation

- Qt 4.8
- ALL VERSIONS

- A
- A
- A
- Print

# videowidgetsurface.cpp Example File

multimedia/videowidget/videowidgetsurface.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2015 The Qt Company Ltd.
     ** Contact: http://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** 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 The Qt Company Ltd 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."
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include "videowidgetsurface.h"

     #include <QtMultimedia>

     VideoWidgetSurface::VideoWidgetSurface(QWidget *widget, QObject *parent)
         : QAbstractVideoSurface(parent)
         , widget(widget)
         , imageFormat(QImage::Format_Invalid)
     {
     }

     QList<QVideoFrame::PixelFormat> VideoWidgetSurface::supportedPixelFormats(
             QAbstractVideoBuffer::HandleType handleType) const
     {
         if (handleType == QAbstractVideoBuffer::NoHandle) {
             return QList<QVideoFrame::PixelFormat>()
                     << QVideoFrame::Format_RGB32
                     << QVideoFrame::Format_ARGB32
                     << QVideoFrame::Format_ARGB32_Premultiplied
                     << QVideoFrame::Format_RGB565
                     << QVideoFrame::Format_RGB555;
         } else {
             return QList<QVideoFrame::PixelFormat>();
         }
     }

     bool VideoWidgetSurface::isFormatSupported(
             const QVideoSurfaceFormat &format, QVideoSurfaceFormat *similar) const
     {
         Q_UNUSED(similar);

         const QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(format.pixelFormat());
         const QSize size = format.frameSize();

         return imageFormat != QImage::Format_Invalid
                 && !size.isEmpty()
                 && format.handleType() == QAbstractVideoBuffer::NoHandle;
     }

     bool VideoWidgetSurface::start(const QVideoSurfaceFormat &format)
     {
         const QImage::Format imageFormat = QVideoFrame::imageFormatFromPixelFormat(format.pixelFormat());
         const QSize size = format.frameSize();

         if (imageFormat != QImage::Format_Invalid && !size.isEmpty()) {
             this->imageFormat = imageFormat;
             imageSize = size;
             sourceRect = format.viewport();

             QAbstractVideoSurface::start(format);

             widget->updateGeometry();
             updateVideoRect();

             return true;
         } else {
             return false;
         }
     }

     void VideoWidgetSurface::stop()
     {
         currentFrame = QVideoFrame();
         targetRect = QRect();

         QAbstractVideoSurface::stop();

         widget->update();
     }

     bool VideoWidgetSurface::present(const QVideoFrame &frame)
     {
         if (surfaceFormat().pixelFormat() != frame.pixelFormat()
                 || surfaceFormat().frameSize() != frame.size()) {
             setError(IncorrectFormatError);
             stop();

             return false;
         } else {
             currentFrame = frame;

             widget->repaint(targetRect);

             return true;
         }
     }

     void VideoWidgetSurface::updateVideoRect()
     {
         QSize size = surfaceFormat().sizeHint();
         size.scale(widget->size().boundedTo(size), Qt::KeepAspectRatio);

         targetRect = QRect(QPoint(0, 0), size);
         targetRect.moveCenter(widget->rect().center());
     }

     void VideoWidgetSurface::paint(QPainter *painter)
     {
         if (currentFrame.map(QAbstractVideoBuffer::ReadOnly)) {
             const QTransform oldTransform = painter->transform();

             if (surfaceFormat().scanLineDirection() == QVideoSurfaceFormat::BottomToTop) {
                painter->scale(1, -1);
                painter->translate(0, -widget->height());
             }

             QImage image(
                     currentFrame.bits(),
                     currentFrame.width(),
                     currentFrame.height(),
                     currentFrame.bytesPerLine(),
                     imageFormat);

             painter->drawImage(targetRect, image, sourceRect);

             painter->setTransform(oldTransform);

             currentFrame.unmap();
         }
     }