Port to VectorBoolean

[behdad]

We should port this module to use VectorBoolean instead of Clipper.

https://bitbucket.org/andyfinnell/vectorboolean
http://losingfight.com/blog/category/graphics/

Main obstacle is that it's a Objective-C library. We should port to C++ (or ask Andy to do; I'm contacting him separately), but might be worth trying it out first. I managed to get it compiled on Linux using:

clang++ -fblocks *.m  -I /usr/include/GNUstep -I /usr/lib/gcc/x86_64-nux-gnu/4.8/include/objc -lobjc -lgnustep-base -lgnustep-gui -lBlocksRuntime

I had issues with blocks_runtime.h missing from my system, which I hacked around. The app doesn't run for me, but I imagine the operations work. It should be even easier to get it running on OS X. It's probably a weekend's work to hook this up to booleanOperations for someone comfortable with Objective-C, or a week for someone who isn't.

[adrientetar]

Skia does have vector boolean ops: https://www.youtube.com/watch?v=OmfliNQsk88

Maybe we can use it or extract the relevant code? cc @khaledhosny

[typemytype]

Boths seems promissing... but python bindings are really necessary in any case...

[behdad]

So we need someone who's comfortable with C++ and Objective-C to make a bridge.

[anthrotype]

or Swift... https://github.com/lrtitze/Swift-VectorBoolean

[behdad]

The Objective-C version at least I can compile on Linux using clang / gcc.

[anthrotype]

yes, sure. I just mentioned the swift version because it seems more recent, has a few tests, and the code may be easier to read than Objective-C.

EDIT: at least for me... 😄

[adrientetar]

Behdad, do you dislike the Skia option?

It's battle-tested with fuzzing etc. probably the most robust vector boolean code out there. One has to extract the relevant source files from "core" and "pathops" subfolders and work from there.

[behdad]

I definitely don't like pulling all of Skia. I have not watched that video yet. Will do. I think extracting it would be much more work than porting the other project. I'll watch the video today; I'm also taking a look at the Swift version to see if I can just port it straight.

[behdad]

In general I'm skeptical of Skia getting this right. A lot of Skia vector code I've checked was just not there...

[adrientetar]

I think extracting it would be much more work than porting the other project.

I looked at it briefly and it seems relatively self-contained... mostly the vector ops depend on primitive types like SkRect/SkMatrix etc. and other ground stuff like SkArenaAlloc/SkBuffer.

A lot of Skia vector code I've checked was just not there...

idk, but in the video he says he first wrote boolean ops for QuickDraw GX in the 80s. I would think he has it right if he's been working on it for 30 years...

[behdad]

idk, but in the video he says he first wrote boolean ops for QuickDraw GX in the 80s. I would think he has it right if he's been working on it for 30 years...

Sure. I'll watch the video.

[behdad]

Yeah, I like the video.

[khaledhosny]

Why this is needed/wanted?