Left sidebar drop positioning accuracy

[peteward]

Describe the bug

When dragging in new schema from the left-hand sidebar they are not positioned correctly and the positioning inaccuracy increases the further away from the top-left corner

To Reproduce

• build v4 branch
• Drag a schema from the left side bar
• Drop onto the canvas

Expected behavior

The schema should be positioned exactly where it is dropped.

Your Environment

- pdfme version: v4 branch

Your Error Log

-

Additional context

The fix should consider:

• zooming
• multi-page PDFs
• bordered pdfs
• window size relative to pdf (zoomed in and unable to see full canvas)
• different schema types
• placing the editor in an area with both top and left sidebars outside of the canvas
• a combination of the above

[peteward]

Initial notes:

• getBoundingClientRect() returns values relative to the viewport (the entire page), whereas other values are relative to the canvas. In the playground case we have headers at the top of the page which will therefore be included in getBoundingClientRect() and must be negated.
• Similarly, although not in the playground it's possible that the designer is embedded somewhere with additional left sidebars which must be compensated for.
• Dragging fields when zoomed will start (visually) from a negative offset, this might also need to be considered.