core-foundation-rs/core-graphics/src/path.rs

// Copyright 2017 The Servo Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

pub use crate::sys::CGPathRef as SysCGPathRef;

use crate::geometry::{CGAffineTransform, CGPoint, CGRect};
use core::ffi::c_void;
use core_foundation::base::{CFRelease, CFRetain, CFTypeID};
use foreign_types::{foreign_type, ForeignType};
use std::fmt::{self, Debug, Formatter};
use std::marker::PhantomData;
use std::ops::Deref;
use std::ptr;
use std::slice;

foreign_type! {
    #[doc(hidden)]
    pub unsafe type CGPath {
        type CType = crate::sys::CGPath;
        fn drop = |p| CFRelease(p as *mut _);
        fn clone = |p| CFRetain(p as *const _) as *mut _;
    }
}

impl CGPath {
    pub fn from_rect(rect: CGRect, transform: Option<&CGAffineTransform>) -> CGPath {
        unsafe {
            let transform = match transform {
                None => ptr::null(),
                Some(transform) => transform as *const CGAffineTransform,
            };
            CGPath::from_ptr(CGPathCreateWithRect(rect, transform))
        }
    }

    pub fn type_id() -> CFTypeID {
        unsafe { CGPathGetTypeID() }
    }

    pub fn apply<'a, F>(&'a self, mut closure: &'a F)
    where
        F: FnMut(CGPathElementRef<'a>),
    {
        unsafe {
            CGPathApply(
                self.as_ptr(),
                &mut closure as *mut _ as *mut c_void,
                do_apply::<F>,
            );
        }

        unsafe extern "C" fn do_apply<'a, F>(info: *mut c_void, element: *const CGPathElement)
        where
            F: FnMut(CGPathElementRef<'a>),
        {
            let closure = info as *mut *mut F;
            (**closure)(CGPathElementRef::new(element))
        }
    }
}

#[repr(i32)]
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum CGPathElementType {
    MoveToPoint = 0,
    AddLineToPoint = 1,
    AddQuadCurveToPoint = 2,
    AddCurveToPoint = 3,
    CloseSubpath = 4,
}

pub struct CGPathElementRef<'a> {
    element: *const CGPathElement,
    phantom: PhantomData<&'a CGPathElement>,
}

impl CGPathElementRef<'_> {
    fn new<'b>(element: *const CGPathElement) -> CGPathElementRef<'b> {
        CGPathElementRef {
            element,
            phantom: PhantomData,
        }
    }
}

impl Deref for CGPathElementRef<'_> {
    type Target = CGPathElement;
    fn deref(&self) -> &CGPathElement {
        unsafe { &*self.element }
    }
}

#[repr(C)]
pub struct CGPathElement {
    pub element_type: CGPathElementType,
    points: *mut CGPoint,
}

impl Debug for CGPathElement {
    fn fmt(&self, formatter: &mut Formatter) -> Result<(), fmt::Error> {
        write!(formatter, "{:?}: {:?}", self.element_type, self.points())
    }
}

impl CGPathElement {
    pub fn points(&self) -> &[CGPoint] {
        unsafe {
            match self.element_type {
                CGPathElementType::CloseSubpath => &[],
                CGPathElementType::MoveToPoint | CGPathElementType::AddLineToPoint => {
                    slice::from_raw_parts(self.points, 1)
                }
                CGPathElementType::AddQuadCurveToPoint => slice::from_raw_parts(self.points, 2),
                CGPathElementType::AddCurveToPoint => slice::from_raw_parts(self.points, 3),
            }
        }
    }
}

type CGPathApplierFunction = unsafe extern "C" fn(info: *mut c_void, element: *const CGPathElement);

#[cfg_attr(feature = "link", link(name = "CoreGraphics", kind = "framework"))]
extern "C" {
    fn CGPathCreateWithRect(
        rect: CGRect,
        transform: *const CGAffineTransform,
    ) -> crate::sys::CGPathRef;
    fn CGPathApply(path: crate::sys::CGPathRef, info: *mut c_void, function: CGPathApplierFunction);
    fn CGPathGetTypeID() -> CFTypeID;
}