Rainbow Painter

From Norbyte:

Aimed at professionals and amateurs alike, Rainbow Painter 3 comes with lots of exciting features and technologies. It supports 32-bit float/channel HDR, which permits adjustments to be made back and forth without losing quality. There is also a revolutionary new pattern editing mode, which puts the old technique of using a so called "Offset Filter" to achieve seamless tiles to shame. When switching on the repeat function in Rainbow Painter (horizontally, vertically or both), not only will the image be displayed repeatedly, but all effects support this mode and brush strokes will continue over the edges when drawing.

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