Fuzzy brushes and antialiased lines
dmorissette at DMSOLUTIONS.CA
Fri Dec 16 15:06:26 EST 2005
As promised in the 4.8.0-beta3 release announcement a few minutes ago,
here is a bit more info about the fuzzy brushes and antialiased lines
support that was just added.
First, here are Steve's test mapfile and results:
I also copied below from the first message in the "Fuzzy brushes..."
mapserver-dev thread that describes how to use the new feature.
-------- Original Message --------
Subject: [UMN_MAPSERVER-DEV] Fuzzy brushes...
Date: Wed, 14 Dec 2005 00:05:18 -0600
From: Steve Lime <steve.lime at DNR.STATE.MN.US>
Reply-To: Steve Lime <steve.lime at DNR.STATE.MN.US>
To: MAPSERVER-DEV at LISTS.UMN.EDU
In case anyone would like to test I have hooked up the fuzzy brush
generator in mapgd.c for the most trivial line drawing case (no symbol
defined). To use:
1) define a 24-bit output format, IMAGETYPE 'png24' works nicely
2) define a simple style definition for a line layer (or polygon
outline) like so:
COLOR 255 0 0
3) set TRANSPARENCY ALPHA to enable alpha blending
- brushes need to be odd sized. That requirement is enforced in the
brush builder which detects even sized requests and rounds up. Symbol
scaling should work just fine.
- you'll notice that the line "fades" in at the start which is due to
the transparent nature of the brush. Adjusting the default "hardness"
may minimize that.
That should do it. I will enable for circles layers and other instances
where it makes sense (circle symbols, simple symbols with dash
patterns and so on) ASAP. I also will enable image cache use in the most
simple case which may help performance a bit.
Note, I hope to do away with 3) (there is a bug filed) but can't yet
because of a problem in the image merging code in mapgd.c (not mine old
code for a change).
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