Gaps/bugs in enable.savage implementation

Kiva/Renderer Tasks
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* Line Dashing. [not sure if this is being parsed...]
* gradients
* blending
* Font lookup isn't very good. It seems to fail a lot.
* Correct handling of viewBox and x,y,width,height of , et al.
* Relative units (em, ex, %)
* Markers and symbols

Parsing/Document
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* Strike-through and underline. [do we or does the font handle this?]
* Text alignment/anchoring handled [ this will likely require more parsing]
* Add lines from svg to the compiled path in one call using lines instead of line_to.
* Line dash styles.

App
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* Adding kiva.agg and kiva.quartz versions in same UI to get timing and quality comparisons.
* Test using Image comparisons
* Cleaning up code so that both wx and kiva backends can use the same Document code.

Architecture
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* Sepearation of rendering from document. - I *think* the Document should just build a tree that represents the SVG scene. We then write renderers (wx, kiva, whatever) that walk the tree and render it appropriately. This should simplify the separation of the code and improve the modularity of the various pieces.

* It would be interesting if the SVG backend to *kiva* actually used this same Document as its internal representation before writing out to text.

Kiva Bugs
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* Mac requires ints for string styles and weights on fonts. I think it should take strings like 'bold', 'italic', etc.

Questions
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* Should text color be the stroke or fill color? Note that the svg library is using fill color and Kiva uses stroke color.