Add memory limits

[RazrFalcon]

Add an ability to limit memory usage somehow. Or at least limit maximum Pixmaps size.

[ducan-ne]

@RazrFalcon I'm wondering if there is any way to calculate the memory needed for an SVG file? Maybe a workaround until this implemented, eg showing a error this file is not supported

[LaurenzV]

I think in most cases you can just check what the size of the SVG is. If the SVG contains filters, things might be a bit trickier.

[RazrFalcon]

You can try to guess it, but it would be tricky. resvg constantly allocates image buffers, some are small, some are big: "layers", filters buffers, masks, patters, etc. Depends of the SVG.

You basically have to reimplement/duplicate resvg rendering logic, but without actual rendering.

The "easier" solution would be to track each image buffer allocation and check if we haven't reached the limit.
But it would mean that rendering can "fail" now.

[thekingofcity]

Or is it possible to render the image part by part? Maybe cut into smaller tiles?

[RazrFalcon]

Not really possible with SVG.