Give the eraser a width

[lovasoa]

Currently, the eraser is just one pixel wide. It means that you have to be very precise when trying to erase a small shape, like a single point. We could make the eraser larger, so that you can just click less that X pixels away from a shape to erase it.

[adrian1001]

For long pencil strokes deleting the entire object is usually a bit too much. Boils down to what is already mentioned in the eraser.js //TODO: add the ability to erase only some points in a line.

Thoughts:

• Add function to boolean-subtract a shape from the drawing (there must be many libraries, e.g. https://github.com/w8r/GreinerHormann, or https://sourceforge.net/p/jsclipper/wiki/Home%206/)
• Add rectangle-eraser: click to mark corner of rectangle, drag to diagonal corner, upon release clip the drawing against rectangle
• Add a pen-like eraser:
  • option1: At every position, clip drawing against a circle-like polygon around cursor position
  • option2 (optimized): Tool draws a white shape to give user feedback; upon release, the shape is used to clip the drawing

Potential issues:

• performance: clipping a large drawing might require good algorithms (partitioning)
• cutting a line into segments will not look nice for thick lines because the end points have no information about at what angle the line was cut. (Draw line as polygon?)

[lovasoa]

Yes, these are good ideas. But all of them require a significant refactoring of the existing code. There is currently no spacial index of the shapes.