[OpenLayers-Users] PNG, IE and change opacity...

[Olivier Bedel]

Dear list,

I am facing a problem with png transparency rendering with I.E. (7 and
8) that does not appear with firefox. My OL map is composed of several
OL mapserver layers. Each OL mapserver layer refers itself to several
mapfile layers with differents transparency values. The selected mapserver
output format is PNG RGB with alpha transparency. This enabled to have
an OL mapserver layer with colors being partially transparent.

When loading maps, the rendering is the same on both browsers (I.E. and
Firefox). However, the problem appears when i tried to change the
opacity (using the setOpacity layer method)
of an OL mapserver layer in I.E. Rendering of colors changes drastically
compared to firefox rendering. With an opacity of 0.8, colors appear
darkener than the colors from the original image in I.E.

I tried with other image output formats, but png alpha is the only one
that enables me to have transparent colors in OL layers.
Does anyone have faced a similar problem with a successfull answer ?

Best regards,

Olivier.