The viewport function defines the rectangular area of the canvas
that will be used for drawing operations.
It is used to clip the rendering output to the boundaries of the rectangle.
Apps can use this function to set the drawing region within the canvas.
When the ThorVG canvas is partially inside the screen area such as during scrolling
it could help enhance rendering performance.
New Experimental API:
- Result Canvas::viewport(int32_t x, int32_t y, int32_t w, int32_t h) noexcept;
Issue: https://github.com/thorvg/thorvg/issues/2274
enhance decoding efficiency by determining the desired canvas format
during image loading. This allows loaders to preemptively decode
the image in the specified format, to not convert the format again.
