CWGraphicsFoundation.m

/*
//  CWGraphicsFoundation.m
//  Zangetsu
//
//  Created by Colin Wheeler on 12/24/10.
//  Copyright 2010. All rights reserved.
//

Copyright (c) 2011 Colin Wheeler

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#import "CWGraphicsFoundation.h"

/**
 Easy way to return the CGContextRef inside a NSView
 */
inline CGContextRef CWCurrentCGContext()
{
#if !(TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR)
	return (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
#else
	return UIGraphicsGetCurrentContext();
#endif
}

CGRect CWCenteredRect(CGRect smallRect, CGRect largeRect) 
{
	CGRect centeredRect;
	centeredRect.size = smallRect.size;
	centeredRect.origin.x = (largeRect.size.width - smallRect.size.width) * 0.5;
	centeredRect.origin.y = (largeRect.size.height - smallRect.size.height) * 0.5;
	return centeredRect;
}

/**
 Adds a rounded rect path to a CGContextRef
 */
void CWAddRoundedRectToPath(CGContextRef context,
						  CGRect rect,
						  float ovalWidth,
						  float ovalHeight) 
{	
    if (ovalWidth == 0 || ovalHeight == 0) {
        CGContextAddRect(context, rect);
        return;
    }
	
	CWSaveAndRestoreCGContextState(context, ^{
		float fw, fh;
		
		CGContextTranslateCTM (context, CGRectGetMinX(rect),CGRectGetMinY(rect));
		CGContextScaleCTM (context, ovalWidth, ovalHeight);
		
		fw = CGRectGetWidth (rect) / ovalWidth;
		fh = CGRectGetHeight (rect) / ovalHeight;
		
		CGContextMoveToPoint(context, fw, fh/2);
		CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);
		CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);
		CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);
		CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1);
		CGContextClosePath(context);
	});
}

/**
 Saves the CGContext state, executes the block and then restores the context State.
 
 @param ctx a CGContextRef you wish to operate on
 @param block a block containing code you wish to execute between saving & restoring the CGContextRef state
 */
void CWSaveAndRestoreCGContextState(CGContextRef ctx, void(^block)(void)) 
{
	CGContextSaveGState(ctx);
	block();
	CGContextRestoreGState(ctx);
}

/**
 Easy way to Create a CGColorRef
 
 @param r a CGFloat representing the red component of the CGColorRef
 @param g a CGFloat representing the blue component of the CGColorRef
 @param b a CGFloat representing the green component of the CGColorRef
 @param a a CGFloat representing the alpha component of the CGColorRef
 @param cspace the CGColorSpaceRef you want the CGColorRef to be created with. This cannot be NULL, if it is NULL this method returns NULL.
 @return a CGColorRef object created with the components specified in the parameters, you must release this object when done with it
 */
CGColorRef CWCreateCGColor(CGFloat r, CGFloat g, CGFloat b, CGFloat a, CGColorSpaceRef cspace)
{
	if(cspace == NULL) { return NULL; }
	CGFloat components[4];
	components[0] = r; components[1] = g; components[2] = b; components[3] = a;
	CGColorRef colorRef = CGColorCreate(cspace, components);
	return colorRef;
}

CGColorRef CWCGColorLightGray(CGFloat alpha)
{
	const CGFloat kLightGrayValue = CWCGColorFloat(211);
	CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
	CGColorRef color = CWCreateCGColor(kLightGrayValue, kLightGrayValue, kLightGrayValue, alpha, space);
	CGColorSpaceRelease(space);
	return color;
}

CGColorRef CWCGColorGray(CGFloat alpha)
{
	const CGFloat kGrayValue = CWCGColorFloat(190);
	CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
	CGColorRef color = CWCreateCGColor(kGrayValue, kGrayValue, kGrayValue, alpha, space);
	CGColorSpaceRelease(space);
	return color;
}

CGColorRef CWCGColorDarkGray(CGFloat alpha)
{
	const CGFloat kDarkGrayValue = CWCGColorFloat(105);
	CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
	CGColorRef color = CWCreateCGColor(kDarkGrayValue, kDarkGrayValue, kDarkGrayValue, alpha, space);
	CGColorSpaceRelease(space);
	return color;
}

CGColorRef CWCGColorBlue(CGFloat alpha)
{
	CGColorSpaceRef space = CGColorSpaceCreateDeviceRGB();
	CGColorRef color = CWCreateCGColor(0.0, 0.0, 1.0, alpha, space);
	CGColorSpaceRelease(space);
	return color;
}