[Phpmyadmin-devel] OpenGIS and Flot

[Tyron Madlener]

On Fri, May 20, 2011 at 11:13 AM, Michal Čihař <michal at cihar.com> wrote:
> Hi
>
> Dne Wed, 18 May 2011 18:01:15 +0530
> Madhura Jayaratne <madhura.cj at gmail.com> napsal(a):
>
>> I did it as a test run and it is not finalized. Unfortunately I can't get
>> flot to draw polygons with inner rings and that was a dead end for me. So
>> right now I'm looking into generating all the GIS visualizations with SVG.
>> In particular I am trying to generate them with jQuery-SVG.
>>
>> Well, I agree that flot makes the life very easy for developers and the
>> graphs are rich in quality. However you get less control over the plot. For
>> example with SVG, I can manipulate each elements in the plot, but in flot
>> that ability is limited to few events they have exposed. I'm not sure how
>> this applies in your case, you might not want to manipulate it at all.
>
> Okay, I think we should use as few graphing libraries as possible,
> ideally only one, but I'm not sure if it is possible. So let's summarize
> what every project needs and try to find viable solution.
>
> I think for charts, it would be nice to save them, but that does not
> seem to work with neither flot nor jQuery-SVG.

I just read up that you can do export bitmaps drawn on the <canvas>
Element to pngs and such. Both flot and jQuery-SVG seem to be drawing
on a <canvas>
flot mentions this in the 3rd Question of its FAQ:
http://flot.googlecode.com/svn/trunk/FAQ.txt - but also mentions some
issues with it.
This article has a paragraph 'Exporting & Saving' that reveals some
more details about this technique:
http://html5doctor.com/an-introduction-to-the-canvas-2d-api/

One would need to try out how well such png exports work.
Alternatively, it shouldn't be a problem to offer a print view or pdf
export. Usually the graph image alone without any context is not very
informative anyway.

As for my project, I probably also can use the existing pChart library
aswell if I solve the caching issues that cause the graph not to
update and let the user wait each time until the graph has been
created on the server side.
But if Madhura is going to use a javascript charting library that also
fits my needs I would surely prefer that over pChart.

>
> --
>        Michal Čihař | http://cihar.com | http://blog.cihar.com
>
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