void VideoPreviewer::paintEvent(QPaintEvent* event) {
Q_UNUSED(event);
QPainter painter(this);
// Copy the image so the lock isn't held while actually drawing the image.
// This is fast because QImage is reference counted.
QImage img;
QSize source_size;
{
SharedLock lock(&m_shared_data);
img = lock->m_image;
source_size = lock->m_source_size;
}
if(!img.isNull()) {
// draw the image
// Scaling is only used if the widget was resized after the image was captured, which is unlikely
// except when the video is paused. That's good because the quality after Qt's scaling is horrible.
QSize out_size = CalculateScaledSize(source_size, QSize(width() - 2, height() - 2));
QPoint out_pos((width() - out_size.width()) / 2, (height() - out_size.height()) / 2);
QRect out_rect(out_pos, out_size);
painter.drawImage(out_rect, img);
// draw the border
painter.setPen(Qt::black);
painter.setBrush(Qt::NoBrush);
painter.drawRect(out_rect.adjusted(-1, -1, 0, 0));
}
}
void VideoPreviewer::paintEvent(QPaintEvent* event) {
Q_UNUSED(event);
QPainter painter(this);
// copy the image data so the lock isn't held while actually drawing the image
std::shared_ptr<TempBuffer<uint8_t> > image_buffer;
int image_stride;
QSize image_size, source_size;
{
SharedLock lock(&m_shared_data);
image_buffer = lock->m_image_buffer; // shared pointer copy is cheap
image_stride = lock->m_image_stride;
image_size = lock->m_image_size;
source_size = lock->m_source_size;
}
if(image_buffer != NULL) {
// create image (data is not copied)
QImage img(image_buffer->GetData(), image_size.width(), image_size.height(), image_stride, QImage::Format_RGB32);
// draw the image
// Scaling is only used if the widget was resized after the image was captured, which is unlikely
// except when the video is paused. That's good because the quality after Qt's scaling is horrible.
QSize out_size = CalculateScaledSize(source_size, QSize(width() - 2, height() - 2));
QPoint out_pos((width() - out_size.width()) / 2, (height() - out_size.height()) / 2);
QRect out_rect(out_pos, out_size);
painter.drawImage(out_rect, img);
// draw the border
painter.setPen(Qt::black);
painter.setBrush(Qt::NoBrush);
painter.drawRect(out_rect.adjusted(-1, -1, 0, 0));
}
}
