SVGResource constructor has absolute size options

[tobyspark]

Description of change

SVG assets are resolution independent. At present, there is no way to precisely set the resolution they rasterise at during initialisation. Subsequent resizing will scale this fixed resolution asset – leading to blurriness etc.

While a scale multiplier is provided as a constructor option to alter the fixed render size, this cannot be used to set an exact size as the SVG size is unknown before instantiation. This PR provides alternative constructor options to set size directly.

Pre-Merge Checklist

• Tests and/or benchmarks are included
• Documentation is changed or added
• Lint process passed (npm run lint)
• Tests passed (npm run test)

[tobyspark]

Fixes underlying need of #5754

[ivanpopelyshev]

Need our SVG specialist here :) @JetLua yo!

I think there might be something wrong with that round , give me some time to think about it.

In general, your idea looks good.

[tobyspark]

The round was already in the code. If I were coding this from scratch, it would have been a ceil, as the canvas should contain whatever is drawn without clipping?

[ivanpopelyshev]

Yes, but that also means that we need to use scale, not just width/height because we adjust aspect ratio slightly. Also just ceil isnt that good, Need eps too, like here: https://github.com/pixijs/pixi.js/blob/dev/packages/math/src/shapes/Rectangle.js#L216

Also something needs to be done about resolution. How do we pass it to BaseTexture? Do we pass it to baseTexture only, not to resource?

I can approve current version, but if you have time to think about round. resolution and ceil - that'll be even better! I can look at it in weekend too.

[ivanpopelyshev]

OK, I approve, I know what kind of tests to do about rounding, and its better to be handled in separate PR.

[tobyspark]

On resolution – I did wonder about that. As a general design pattern, could passing in an optional rendering destination allow the particular from method to act appropriately? Here it could be to set the rasterisation to e.g. retina, but perhaps there are other optimisations. Though that sounds increasingly like a separate PR.

[JetLua]

Need our SVG specialist here :) @JetLua yo!

Ah，thanks.

[bigtimebuddy]

One small change, could you just make a small documentation change to this: http://pixijs.download/dev/docs/PIXI.resources.html#.autoDetectResource

Notice that width and height say BufferResource. Would be good to mention the overrides for SVG width/height.

[codecov-io]

Codecov Report

Merging #5776 into dev will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              dev    #5776      +/-   ##
==========================================
+ Coverage   70.55%   70.57%   +0.01%     
==========================================
  Files         205      205              
  Lines       10389    10396       +7     
==========================================
+ Hits         7330     7337       +7     
  Misses       3059     3059

Impacted Files	Coverage Δ
.../core/src/textures/resources/autoDetectResource.js	100% <ø> (ø)	⬆️
...ackages/core/src/textures/resources/SVGResource.js	90.47% <100%> (+1.19%)	⬆️

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[tobyspark]

@bigtimebuddy Good oversight. I've pushed two commits to address your points. As part of the documentation commit, I also changed the language from 'render' to 'rasterize'. More precise, and I'd say helpful to separate out from 'render' as in the ongoing rendering of the scene.

[bigtimebuddy]

Nice thanks for making those fixes.