Improved canvas size getter to support high-dpi #9
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jiakuan
commented
Dec 8, 2022
| .get_computed_style(&self.canvas) | ||
| .unwrap().unwrap(); | ||
| let width = style.get_property_value("width").unwrap().replace("px", ""); | ||
| let height = style.get_property_value("height").unwrap().replace("px", ""); |
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Here we can handle it better if the CSS uses a different unit, like pt or rem.
Also, error handlings can be improved.
Please let me know if there is an interest in merging the pull request, then I will improve it further. Otherwise, this code is good enough for my use case at the moment.
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In order to support high-dpi in HTML canvas, we need to scale the canvas size by devicePixelRatio first, and then use CSS style to configure the actual size, please see:
https://www.kirupa.com/canvas/canvas_high_dpi_retina.htm
The Canvas scaling part can be handled outside of this library, but in the
get_sizefunction, we need to get the size from the computed style, not the canvas, which may have been scaled.