brushed masks follow expanded canvas to new x/y origins

[zero01101]

Describe the bug after expanding the canvas upwards or to the left, any brushed masks use the new "0px origin" instead of where they're actually drawn

To Reproduce

• start a new canvas or use one you're already painting on
• press the leftward expand canvas button and expand it by 128 px
• draw a new brushed mask on the image and engage it with txt/img2img
• observe that it's too far left
• realize that this probably happens on the y-axis too and you're bad at troubleshooting properly
• expand the canvas 128px up
• notice that nothing in the example images got changed at all after doing that

Expected behavior the modified result should be where the mask is drawn instead of being offset by the new x-axis "zero point"

Screenshots --after expanding vertically--

Desktop (please complete the following information):

• OS: win10x64
• Browser: firefox
• Version 108.0.1x64

[seijihariki]

On it

[seijihariki]

Strangely, this was a case of overcorrection rather than a lack of corrections.

I previously modified masking to work with a less magical version of the black magic, but after making the mask as magical as it is now, those corrections were moving things to the other side.

Simple commit incoming.

[zero01101]

lmao i was literally going to look into this later and oh gee you fixed it in 5 minutes of noticing

enormous thanks as always :D

[zero01101]

I previously modified masking to work with a less magical version of the black magic, but after making the mask as magical

i just wanted to say i love this so so much