Draw a shape with empty space inside.

[kwinso]

I'm trying to draw a rectangle that has empty space in it for QR code finders (big squares in corners of a qr code). It should look like this:

I'm trying to draw another smaller rectangle inside with transparent color, but it changes nothing.

I need a "hole" to be of transparent color, as the finder will be placed on top of background with variable color (maybe even gradient)

Solutions tried:

• Using a mask. This solution is pretty slow when dealing with sizes larger than 1000 pixels. I need something faster.
• Using a stroke. It works, but I can't really control the form of outer and inner corners of a finder (for example, I can't do rounded outside, and circle inside)

Any suggestions on this problem? Thanks in advance! 🙏

[kwinso]

The solution was to use dc.SetFillRuleEvenOdd(). There's no docs on this, but I assume this will clear filled region if you call Fill on this region.

Note: placeFinderShapes will just place 3 shapes without filling it. Basically, it calls DrawRoundedRectangle under the hood.