Changes

Summary

Amiga: Improve image display on palette-mapped screens Tidy up guigfx (details)
Amiga: Invert alpha channel on OS3 to work around a bug in guigfx/render (details)
Amiga: Layer hooks should not write to the RastPort This writes direct (details)

Commit bea4ad87dd99d1c2d8adeb65351c2f517fa11b3d by chris Amiga: Improve image display on palette-mapped screens Tidy up guigfx code Use MakePicture() which allows us to scale "for free" Use guigfx always on OS3 On OS4 use the alpha tint function to blend image to the provided bg colour (this appears to use an inverted alpha on OS3)
	frontends/amiga/plotters.c (diff)
	frontends/amiga/theme.c (diff)
	frontends/amiga/gui.c (diff)
	frontends/amiga/bitmap.c (diff)
	frontends/amiga/bitmap.h (diff)
	frontends/amiga/icon.c (diff)
Commit 9e702b94a58d241ad9f65e8dfe56d6bb3c6231cb by chris Amiga: Invert alpha channel on OS3 to work around a bug in guigfx/render Add invert_alpha option as not sure if this bug is in all versions
	frontends/amiga/plotters.c (diff)
	frontends/amiga/bitmap.c (diff)
	frontends/amiga/options.h (diff)
Commit 70c749f7a86c797c768b7c51c40401b0ca05a530 by chris Amiga: Layer hooks should not write to the RastPort This writes direct to the underlying BitMap
	frontends/amiga/plotters.c (diff)