Fix Qt screenhot crash (#889)

Author: m-seker

include/utils/ImageData.h

@@ -136,7 +136,9 @@ class ImageData : public QSharedData
 
 	void toRgb(ImageData<ColorRgb>& image)
 	{
-		image.resize(_width, _height);
+		if (image.width() != _width || image.height() != _height)
+			image.resize(_width, _height);
+
 		const unsigned imageSize = _width * _height;
 
 		for (unsigned idx = 0; idx < imageSize; idx++)

libsrc/grabber/qt/QtGrabber.cpp

@@ -101,6 +101,7 @@ int QtGrabber::grabFrame(Image<ColorRgb> & image)
 	QPixmap originalPixmap = _screen->grabWindow(0, _src_x, _src_y, _src_x_max, _src_y_max);
 	QPixmap resizedPixmap = originalPixmap.scaled(_width,_height);
 	QImage imageFrame = resizedPixmap.toImage().convertToFormat( QImage::Format_RGB888);
+	image.resize(imageFrame.width(), imageFrame.height());
 
 	for (int y=0; y<imageFrame.height(); ++y)
 		for (int x=0; x<imageFrame.width(); ++x)

libsrc/utils/ImageResampler.cpp

@@ -60,7 +60,9 @@ void ImageResampler::processImage(const uint8_t * data, int width, int height, i
 	// calculate the output size
 	int outputWidth = (width - _cropLeft - cropRight - (_horizontalDecimation >> 1) + _horizontalDecimation - 1) / _horizontalDecimation;
 	int outputHeight = (height - _cropTop - cropBottom - (_verticalDecimation >> 1) + _verticalDecimation - 1) / _verticalDecimation;
-	outputImage.resize(outputWidth, outputHeight);
+
+	if (outputImage.width() != outputWidth || outputImage.height() != outputHeight)
+		outputImage.resize(outputWidth, outputHeight);
 
 	for (int yDest = 0, ySource = _cropTop + (_verticalDecimation >> 1); yDest < outputHeight; ySource += _verticalDecimation, ++yDest)
 	{