Test which verifies the basic facilities of feComposite.
This test uses the following elements: <path>, <filter> <feImage> <feComposite>.
The test case shows six pairs of overlapping triangles depicting the six different feComposite operators. The first row shows compositing when both triangles have opacity=1. The second row shows compositing when both triangles have opacity=.5. The six columns illustrate the six types of compositing operations.
Run the test. No interaction required.
The rendered picture should match the reference image exactly, except for possible variations in the labelling text (per CSS2 rules).