Problems with transparent color in Index8 color format.

Description:

This article describes the usage of transparency on Index8 targets and gives some hints what you can do in case of missing transparent colors or even in case of wrong color display.

Solution:

In general you should avoid semi-transparent colors and the opacity feature in Index 8 format, because you need a lot of transparent colors with many different alpha values to get a good result. As you know the Index8 color format is a low quality format which makes it difficult to get a high quality display.

Nevertheless in case of a bad image quality you can do some things to improve the display result.

1.) The CLUT file is in a readable text format. So first check whether the required colors are available in the CLUT.

2.) If the colors are represented in the CLUT, but the display is still wrong, ensure that you have set the correct CLUT file in the brick of the used profile (see attribute "Clut" in the profile bricks of your EmWi project).

3.) The next countermeasure is to improve the used CLUT. This can either be done, by a manual editing of the used CLUT file (see attribute "Clut" in your profile) or with the latest feature level EmWi offers an automatic CLUT generation. Please have a look in the HowTo document HT-010-GenPalette.pdf for a guided tour for manual and automatic CLUT generation.

See also:

HowTo document [HT-010-GenPalette.pdf]

FAQ article [Jaggy character display]

Keywords:

CLUT, Index8, display, missing, bad, quality, transparency, transparent, color format