TASImage::CopyArea() limits destination index and crops picture when copying into bigger image

When copying from a smaller to a bigger TASImage with CopyArea(), idx2, index in destination array is clamped to smallImage->GetWidth() * smallImage->GetHeight() (line 5057 in TASImage.cxx) even though destination picture is bigger. As a result, bigger image contains only a cropped portion of the smaller one.

MWE:

#include <TASImage.h>

void CopyAreaMWE() {
   TASImage *smallImage = new TASImage("small.png");
   TASImage* bigImage = new TASImage(2 * smallImage->GetWidth(), 2 * smallImage->GetHeight());
   smallImage->CopyArea(bigImage, 0, 0, smallImage->GetWidth(), smallImage->GetHeight(), 0, 0);
   bigImage->WriteImage("big.png");
}