#59 CropWindow doesn't work when left or bottom > 0

[Matthias Baas]

The CropWindow call only works when the minimum
values for x and y are 0. Whenever one of them is >0 a
black image is rendered.
Here is an example RIB of a sphere where only the lower
right quarter should be rendered:

PixelSamples 1 1
Format 320 240 1
CropWindow 0.5 1.0 0.5 1.0
Display "out.tif" "framebuffer" "rgb"
Projection "perspective" "fov" [30.0]
Translate 0 0 5
WorldBegin
Sphere 1 -1 1 360
WorldEnd

When rendered with Pixie 1.5.2 (on WinXP) only a black
image is rendered.

Also, the cropped images always have full resolution
whereas I'd expect the image to have the cropped
resolution.

- Matthias -