My program overrides NSTextView.drawBackground(in:) to draw nested capsules around text in an NSTextView. You can see what I'm talking about in this video:
https://twitter.com/defenestrately/status/1593322315709923335 Each capsule has a CALayer with non-zero shadowRadius and shadowOpacity. That CALayer has one sublayer that fills one or more rounded rectangles to produce the capsule shape. Inside a `drawBackground(in: rect)` call, I find all of the capsules that may intersect `rect` (allowing a large margin for the cast shadows), add them to a master CALayer, and render that master CALayer using the current graphics context: NSGraphicsContext.saveGraphicsState() if let ctx = NSGraphicsContext.current { let cgc = ctx.cgContext master.render(in: cgc) } NSGraphicsContext.restoreGraphicsState() I see a funny graphic artifact appear when the default NSTextView insertion-point caret blinks off: a sliver of shadow disappears when the caret disappears. I have surmised that this may have something to do with the narrow clip path that is set while `drawBackground(in:)` is called to erase the caret. I find that by overriding `setNeedsDisplay(in:flags:)`, I can make the caret-erasure clip path enclose a larger and larger area by calling `super.setNeedsDisplay(in:flags:)` with bigger and bigger rectangles. As the area enclosed enlarges, the region where the shadow may disappear moves further away from the caret. I guess that I can force the whole view to redraw in this way, but that seems inefficient, and it seems like there must be a better way. Is it possible that a CGContext clip path will clip a shadow cast inside the clip path, if the CALayer whose content cast the shadow is fully outside of the clip path? Any ideas why? Dave -- David Young dyo...@pobox.com Urbana, IL (217) 721-9981 _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
