Status of AGG support?
Stephen Woodbridge
woodbri at SWOODBRIDGE.COM
Fri Jul 6 00:28:03 EDT 2007
Steve Lime wrote:
> For comparison purposes I would use 24-bit png regardless.
>
> My question would be how is the palette being constructed? Ideally
I take a very simple approach to the palette.txt file and that is:
grep -i color mapfile.map > a.txt
#edit a.txt a bunch
sort -u a.txt > palette.txt
wc -l palette.txt
36
so the rest of the colors can be allocated for anti-alias colors.
-Steve W
> you would create a representative image with lot's of linework and
> annotation and then use Gimp, Imagemagick or Photoshop to reduce
> colors to a 8-bit palette and use that. Otherwise the palette force
> option will do a distance computation and the results could get ugly
> (and these images are proof)...
>
> Steve
>
>>>> Paul Spencer <pspencer at DMSOLUTIONS.CA> 07/05/07 9:32 PM >>>
> PHP? Steve, I'm shocked its not a perl page ;)
>
> I have noticed that the text gets 'bolder' when reducing the palette,
> but not like this.
>
> Have you tried without the formatoption for reducing the image? One
> thing that may happen is that the antialiasing colours are getting
> mapped to black because there isn't room in the palette to allocate
> the needed colours. That does seem unlikely, though.
>
> Cheers
>
> Paul
>
> On 5-Jul-07, at 4:56 PM, Stephen Woodbridge wrote:
>
>> Steve,
>>
>> http://imaptools.com/maps/compare-maps2.php?loc=2&ll=41.85
>> +-87.65&address=&city=&state=&zipcode=&country=&asrv=1&amf=%2Fu%
>> 2Fdata%2Fmaps%2Fgoogle-aa2.map&msa=mapserv-4.10&bsrv=1&bmf=%2Fu%
>> 2Fdata%2Fmaps%2Fgoogle-agg.map&msb=mapserv-4.99&submit=Show
>>
>> Here is a side by side comparison.
>>
>> google-aa2 is using "PNG8" google-agg is using "agg/png24"
>>
>> OUTPUTFORMAT NAME "agg/png24" MIMETYPE "image/png; mode=24bit"
>> DRIVER "AGG/PNG" EXTENSION "png" IMAGEMODE "RGB" FORMATOPTION
>> "PALETTE_FORCE=TRUE" FORMATOPTION
>> "PALETTE=/u/data/maps/palette-google-agg.txt" END
>>
>>
>> ONE of the differences is mapserver-4.10 vs mapserv-4.99 and the
>> fact that 4.99 has broken support for:
>>
>> OUTPUTFORMAT NAME PNG8 DRIVER "GD/PNG" EXTENSION "png" MIMETYPE
>> "image/png" IMAGEMODE RGBA TRANSPARENT OFF FORMATOPTION
>> "QUANTIZE_FORCE=ON" FORMATOPTION "QUANTIZE_DITHER=OFF" FORMATOPTION
>> "QUANTIZE_COLORS=256" END
>>
>> as none of the roads render.
>>
>> -Steve
>>
>>
>> Steve Lime wrote:
>>> Would be nice to have a non-tiled, side-by-side browser to do the
>>> comparison with... ;-) It doesn't look to me like identical
>>> mapfiles. For example, I'm looking at Chicago and there look to
>>> be some differences in scale settings. For example, the shape of
>>> Lake Michigan changes dramatically, see:
>>> http://maps.dnr.state.mn.us/~stlime/chicago_gd.gif
>>> http://maps.dnr.state.mn.us/~stlime/chicago_agg.gif I'll wait on
>>> other comments until that can be confirmed. Steve
>>>>>> On 7/4/2007 at 10:47 AM, in message <468BC11E.
>>>>>> 2050101 at swoodbridge.com>, Stephen
>>> Woodbridge <woodbri at SWOODBRIDGE.COM> wrote:
>>>> Hi Zak,
>>>>
>>>> Thank you and the others for all the responses. I got it
>>>> working this morning:
>>>>
>>>> http://imaptools.com/agg-test.html I have a few questions and
>>>> observations:
>>>>
>>>> The OL app above has two base layers. Both use the same
>>>> mapfile, except one supports AGG and is using 5.0 and the other
>>>> is using 4.10.
>>>>
>>>> 1) Notice the white lines in the water boarding some of the
>>>> polygons. What is causing that? How do you get rid of these?
>>>>
>>>> 2) If you switch between 4.10 and 5.0 AGG base layers notice
>>>> that the road widths change. What is causing this? I assume
>>>> this is the same issue as the polygons above.
>>>>
>>>> 3) If you zoom in to 15K scale of closer so street names are
>>>> displayed the text looks really bad on text ALIGN FOLLOW
>>>> labels. And the text is much bolder and blacker than the 4.10
>>>> example.
>>>>
>>>> more below ...
>>>>
>>>> Zak James wrote:
>>>>> Steve,
>>>>>
>>>>> In our testing, the AGG renderer is about 10% faster than GD
>>>>> over a variety of conditions. One caveat is that the
>>>>> sub-pixel positioning of vertices (which greatly improves the
>>>>> appearance of features) can cause far longer rendering times
>>>>> if suitable overview data aren't available for a given scale.
>>>>> We discussed but did not implement strategies for mitigating
>>>>> this problem.
>>>> I think that discussion should get added to the RFC. If I
>>>> wanted to provide my own overview data what are we talking
>>>> about. Just having generalized data? Any rule of thumb on when
>>>> you need to provide this?
>>>>
>>>>> Another issue is that the antialiasing tends to cause larger
>>>>> image file sizes.
>>>> There really is not much that you can do about this. It will
>>>> impact on bandwidth and tile repository sizes.
>>>>
>>>> -Steve
>>>>
>>>>> zak
>>>>>
>>>>> On 7/3/07, Stephen Woodbridge <woodbri at swoodbridge.com>
>>>>> wrote:
>>>>>> Paul, Steve,
>>>>>>
>>>>>> A few questions:
>>>>>>
>>>>>> 1) could one of you do a short post on what if anything
>>>>>> needs to be done to use AGG other than install the libs and
>>>>>> select some ./ configure options.
>>>>>>
>>>>>> 2) Any sense on how this compares speed wise to the GD
>>>>>> implementation.
>>>>>>
>>>>>> 3) is what is in the trunk all that 5.0 will see or is
>>>>>> there some additional work that is planed to be
>>>>>> implemented.
>>>>>>
>>>>>> I would like to give it a try.
>>>>>>
>>>>>> -Steve W
>>>>>>
>>>>>> Paul Spencer wrote:
>>>>>>> The other thing that I am very keen to have is text
>>>>>>> rendered/ placed using AGG. Not sure if it will be done
>>>>>>> for 5.0 though.
>>>>>>>
>>>>>>> Cheers
>>>>>>>
>>>>>>> Paul
>>>>>>>
>>>>>>> On 3-Jul-07, at 1:25 PM, Steve Lime wrote:
>>>>>>>
>>>>>>>> Hi Tom: AGG support is in the codebase for 5.0. I still
>>>>>>>> owe an RFC to explain what was done although the
>>>>>>>> addition of AGG doesn't affect any other portions of
>>>>>>>> MapServer. It's a big user feature though. I recently
>>>>>>>> got a big time sink off my plate and will work that up
>>>>>>>> ASAP.
>>>>>>>>
>>>>>>>> The support is relatively complete. The guys from DM
>>>>>>>> Solutions can probably comment further as they've been
>>>>>>>> using it the most. The AGG vs. GD images DM has
>>>>>>>> supplied are very nice. The quality difference is
>>>>>>>> noticeable with roads in
>>>>>> particular.
>>>>>>>> The only missing capability that I am aware of has to
>>>>>>>> do with PIXMAP symbols that contain an alpha channel.
>>>>>>>> There is a fundamental difference in how AGG and GD
>>>>>>>> handle alpha blending (GD is flat out backwards). We
>>>>>>>> use GD to manage the pixel buffer that AGG is rendering
>>>>>>>> into so that becomes a problem. I'll go into options in
>>>>>>>> the RFC.
>>>>>>>>
>>>>>>>> Anyway, other than that the support seems to be working
>>>>>>>> nicely is worth trying.
>>>>>>>>
>>>>>>>> Steve
>>>>>>>>
>>>>>>>>>>> On 7/1/2007 at 10:08 PM, in message
>>>>>>>> <7b5b710d0707012008i59c41e8bq8e0ef4d8022f40f8 at mail.gmail.com>,
>>>>>>>> T om
>>>>>> Beard
>>>>>>>> <tom at PROJECTX.CO.NZ> wrote:
>>>>>>>>> Hi there,
>>>>>>>>>
>>>>>>>>> This is my first time posting here, and I hope this
>>>>>>>>> is the right forum to ask this question.
>>>>>>>>>
>>>>>>>>> I was wondering what the status of AGG support was
>>>>>>>>> for the 5.0 release. On searching the archives, the
>>>>>>>>> most recent reference I could find was
>>>>>> the
>>>>>>>>> minutes from the May 22 IRC meeting that said that
>>>>>>>>> there would be
>>>>>> an RFC
>>>>>>>>> freeze on June 15, and that an RFC for AGG was
>>>>>>>>> "forthcoming". Did AGG support make it into that
>>>>>>>>> freeze? Is it listed somewhere online?
>>>>>>>>>
>>>>>>>>> I'd also be interested to know if there is a version
>>>>>>>>> currently in Subversion that includes AGG sub-pixel
>>>>>>>>> rendering and that works well enough to have a go at
>>>>>>>>> compiling on Windows.
>>>>>>>>>
>>>>>>>>> Regards, Tom Beard
>>>>>>> +----------------------------------------------------------------
>>>>>>> -+ |Paul Spencer pspencer at dmsolutions.ca |
>>>>>>> +----------------------------------------------------------------
>>>>>>> -+ |Chief Technology Officer
>>>>>>> | |DM Solutions Group Inc http://
>>>>>>> www.dmsolutions.ca/ |
>>>>>>> +----------------------------------------------------------------
>>>>>>> -+
>
> +-----------------------------------------------------------------+
> |Paul Spencer pspencer at dmsolutions.ca |
> +-----------------------------------------------------------------+
> |Chief Technology Officer |
> |DM Solutions Group Inc http://www.dmsolutions.ca/ |
> +-----------------------------------------------------------------+
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