mapnik-org/mapnik — Issue #662: Allow data values into SVG transform strings to dynamically rotate, scale, offset Symbolizers
Author: artemp
Created: 2011-10-11 08:07:03+00:00
State: open
Labels: Symbolizers

It would be VERY nice to have the possibility to include database fieldnames into the Symbolizer SVG transform string and have the values trickle down to the renderer so as to have data driven 'rotation', 'scaling', 'translation' of all symbolizers including text.
It would enable arrow-pointing, pattern-alignment, text-rotation etc

Even nicer if expressions would be possible like for example:
transform="scale([SIZEX]/10,[SIZEY]/5) translate([POSX1] + [POSX2],[POSY1] + [POSY2]) rotate([ROTATION] + [BASEROT] - 30)"

If these expressions are to complex to implement, just straight [fields] would do as the expression could be implemented in the table SQL query instead.

I have looked into the code in trunk, but it is too 'OO' for me to estimate the complexity of this change. But as it would mean just handing over a number of data values, or an 'svg-string', to the svg handling I hope it is not too complex.

Some other tickets address parts of this 613, 155, 463, 576 and maybe some more.