html canvas, javascript

Useful links for html canvas functions and questions

Mask layer effect:

• https://stackoverflow.com/questions/66887415/multiple-masked-images-on-top-of-each-other-using-html-canvas
• https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/globalCompositeOperation

Undo and redo drawing

• https://codepen.io/abidibo/pen/kdRZjV

Check points and mouse path boundaries

• CanvasRenderingContext2D/isPointInStroke

When your mouse coordinate and canvas drawing coordinate does not match

• https://stackoverflow.com/questions/39784153/mouse-pointer-coordinates-and-canvas-coordinates-not-matching

Save canvas, toDataUrl into image source

• so that you can draw the generated image or uploaded image source into canvas 2d context with drawImage() function
• https://stackoverflow.com/questions/4773966/drawing-an-image-from-a-data-url-to-a-canvas