I have a photo that is 15360x5079 pixels. I want to load it into Marzipano, to make a panorama, but it requires that the file be in 1:2 aspect ratio. So the final height needs to be 7680 pixels.
The thing I'm trying to figure out is how to stretch only part of the image to fill the height. The reason I need to do this is that the 7680 pixels represent 180 degrees of vertical angle and if I stretch the entire image, the horizon line in the photo get's shifted up.
So basically, how can I stretch the top ~1000 pixels of the image to get to the desired height?