Auto merge of #250 - mehcode:feature/cgcontext, r=jrmuizel

Allow most CGContext methods to be usable from a immutable reference and expose several more methods

If this is too much to submit at once, please tell me. This is what I've got left to send in and I'm unsure where to break it up more.

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core-graphics/src/context.rs

@@ -9,9 +9,11 @@
 
 use base::CGFloat;
 use color_space::CGColorSpace;
-use core_foundation::base::{CFRelease, CFRetain, CFTypeID};
+use core_foundation::base::{ToVoid, CFRelease, CFRetain, CFTypeID};
 use font::{CGFont, CGGlyph};
 use geometry::CGPoint;
+use color::CGColor;
+use path::CGPathRef;
 use libc::{c_int, size_t};
 use std::os::raw::c_void;
 
@@ -20,7 +22,7 @@ use std::ptr;
 use std::slice;
 use geometry::{CGAffineTransform, CGRect};
 use image::CGImage;
-use foreign_types::ForeignType;
+use foreign_types::{ForeignType, ForeignTypeRef};
 
 #[repr(C)]
 pub enum CGTextDrawingMode {
@@ -77,7 +79,9 @@ impl CGContext {
                     (self.height() * self.bytes_per_row()) as usize)
         }
     }
+}
 
+impl CGContextRef {
     pub fn flush(&self) {
         unsafe {
             CGContextFlush(self.as_ptr())
@@ -102,6 +106,12 @@ impl CGContext {
         }
     }
 
+    pub fn set_fill_color(&self, color: &CGColor) {
+        unsafe {
+            CGContextSetFillColorWithColor(self.as_ptr(), color.to_void());
+        }
+    }
+
     pub fn set_rgb_fill_color(&self, red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) {
         unsafe {
             CGContextSetRGBFillColor(self.as_ptr(), red, green, blue, alpha)
@@ -174,6 +184,24 @@ impl CGContext {
         }
     }
 
+    pub fn add_path(&self, path: &CGPathRef) {
+        unsafe {
+            CGContextAddPath(self.as_ptr(), path.as_ptr());
+        }
+    }
+
+    pub fn close_path(&self) {
+        unsafe {
+            CGContextClosePath(self.as_ptr());
+        }
+    }
+
+    pub fn fill_path(&self) {
+        unsafe {
+            CGContextFillPath(self.as_ptr());
+        }
+    }
+
     pub fn fill_rect(&self, rect: CGRect) {
         unsafe {
             CGContextFillRect(self.as_ptr(), rect)
@@ -222,6 +250,30 @@ impl CGContext {
                                            count)
         }
     }
+
+    pub fn save(&self) {
+        unsafe {
+            CGContextSaveGState(self.as_ptr());
+        }
+    }
+
+    pub fn restore(&self) {
+        unsafe {
+            CGContextRestoreGState(self.as_ptr());
+        }
+    }
+
+    pub fn translate(&self, tx: CGFloat, ty: CGFloat) {
+        unsafe {
+            CGContextTranslateCTM(self.as_ptr(), tx, ty);
+        }
+    }
+
+    pub fn scale(&self, sx: CGFloat, sy: CGFloat) {
+        unsafe {
+            CGContextScaleCTM(self.as_ptr(), sx, sy);
+        }
+    }
 }
 
 #[test]
@@ -279,6 +331,10 @@ extern {
     fn CGContextSetShouldSubpixelPositionFonts(c: ::sys::CGContextRef,
                                                shouldSubpixelPositionFonts: bool);
     fn CGContextSetTextDrawingMode(c: ::sys::CGContextRef, mode: CGTextDrawingMode);
+    fn CGContextSetFillColorWithColor(c: ::sys::CGContextRef, color: *const c_void);
+    fn CGContextAddPath(c: ::sys::CGContextRef, path: ::sys::CGPathRef);
+    fn CGContextClosePath(c: ::sys::CGContextRef);
+    fn CGContextFillPath(c: ::sys::CGContextRef);
     fn CGContextSetRGBFillColor(context: ::sys::CGContextRef,
                                 red: CGFloat,
                                 green: CGFloat,
@@ -295,5 +351,10 @@ extern {
                                       glyphs: *const CGGlyph,
                                       positions: *const CGPoint,
                                       count: size_t);
+
+    fn CGContextSaveGState(c: ::sys::CGContextRef);
+    fn CGContextRestoreGState(c: ::sys::CGContextRef);
+    fn CGContextTranslateCTM(c: ::sys::CGContextRef, tx: CGFloat, ty: CGFloat);
+    fn CGContextScaleCTM(c: ::sys::CGContextRef, sx: CGFloat, sy: CGFloat);
 }