Inherits Operation.
Converts a set of 2D grid layers to a QImage. The image is created within the given region. If the region bounds are the same the region is automatically calulated from the spatial ranges of all grid layers. The number of pixels in the image is calculated using the given pixel resolution. The range maximum and minimum determine the bounds on the colour scheme. If these are equal, the range is automatically calculated. Above or below this range a transparent pixel is used, unless the 'Draw values' options are set. In this case a pixel colour of the bounding value is used. The scale factor sets the scaling applied to the output image. The opacity value sets the alpha value of the output image. If smooth scaling is used the scaled output image uses bilinear filtering. The colour scheme option selects from a range of colour schemes.
