[Bug]: Text globalCompositeOperation

[ShaMan123]

Text globalCompositeOperation that isn't source-over must render in isolation.
Without context isolation, since it renders letter by letter and the nature of letters that they don't overlap globalCompositeOperation will render nothing since each letter will render and clear the canvas.
We need to fix that by changing shouldCache

https://jsfiddle.net/ex9zo8mp/

toggle textbox.shouldCache = () => true/false

[ShaMan123]

Original:

https://jsfiddle.net/8cneqdmx/

globalCompositeOperation
sorry，Your revision did not achieve my purpose！

1.Only the text part of the picture needs to be shown, the rest of the picture is transparent

2.The text should be centered

3.I have tried to use pattern to achieve, but it is not easy to center

That's what it should look like

Originally posted by @carior in #7708 (comment)

[ShaMan123]

This part of the scope of #7874