Status of AGG support?

[Steve Lime]

Typically the glphys are rendered to a bitmap of some sort with alpha transparency enabled
so that character level caching can be done. That's the way I had assumed AGG was working
and it's the blending that may be at issue here.

We can look though...

Steve

>>> On 7/4/2007 at 2:57 PM, in message
<FF385261-462E-407F-9A98-62E44A034CC0 at DMSOLUTIONS.CA>, Paul Spencer
<pspencer at DMSOLUTIONS.CA> wrote:
> Steve,
> 
> I'm not sure I follow why this is a problem for using AGG to render  
> text into the existing GD buffer?  How is rendering glyphs different  
> from the existing strokes and fills that are used to do lines and  
> polygons using AGG?
> 
> My understanding is that AGG reads the glyph vector geometries  
> directly using FreeType and rasterizes the text using its own  
> routines rather than the FreeType rasterizer.  Also, it is my  
> understanding that 'halo' text can be achieved relatively easily by  
> rendering the stroke in the outline colour, possibly with some  
> interesting effects to make the halo larger etc.
> 
> Also, AGG uses sub-pixel placement, which would make the labels in  
> FOLLOW mode substantially better (by fixing the jitter effect in  
> nearly straight lines).
> 
> I think that this, and potentially nicer halos, would make a  
> substantial improvement to overall text quality.
> 
> Paul
> 
> On 4-Jul-07, at 10:20 AM, Steve Lime wrote:
> 
>> I don't think that will be ready for 5.0 because of the blending  
>> issue I
>> mentioned. GD development is active again and one of the planned
>> additions is a true RGBA buffer that AGG could render into with  
>> correct
>> blending support (and we wouldn't have to re-write any of the raster
>> support). Otherwise we have to use an AGG managed buffer, which
>> may be doable but not in time for 5.0.
>>
>> Steve
>>
>>>>> Paul Spencer <pspencer at DMSOLUTIONS.CA> 07/03/07 2:01 PM >>>
>> 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>, Tom
>>> 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/ |
> +-----------------------------------------------------------------+