Pixelation problems with PNG8

[zspitzer]

Using PNG8 I am seeing some pixelation issues, mostly black spots and lines which are probably due to sub pixel rendering with AGG

It can been seen on the following page

​http://gis.cecc.com.au/mapguide/mapviewerajax/?WEBLAYOUT=Library%3a%2f%2fvicmap%2fweblayouts%2ftiledBasic.WebLayout&LOCALE=en&USERNAME=Anonymous

Server is running Linux and using a build from subversion post 2.0.1

[tomfukushima]

Snapshot of the site in case the web site is not available when this ticket is investigated

[zspitzer]

Turns out that if a polygon fill is applied as a base layer then this will remove the noise and will also sharpen up the linework.

[jbirch]

Please re-test against 2.1 and let us know if this is still an issue (or close if has been fixed). Will close this ticket if no response by next ticket cleanup cycle.

[lgnemmi]

I have just tested with MG 2.1 and i have the same result on semi-transparent sub-pixels of AGG renderer when there's no background.

[zspitzer]

RFC60 in 2.2 may resolve this issue

[jng]

2.4 fixes this. None of the observed PNG8 images produced by the test suite (and other informal tests) have this pixelation problem.