画板使用

Painting.h

#import <UIKit/UIKit.h>

//CONSTANTS:

#define kRubberWidth              20
#define kBrushLineAlpha           1.0
#define kPaintViewBackGroudImg    @"背景.png"

@interface Painting : UIView {
	UIImageView *drawImage;
	int mouseMoved;
	BOOL mouseSwiped;
	BOOL isRubber;
	CGPoint lastPoint;
	CGFloat kBrushRGBColorRed;
	CGFloat kBrushRGBColorGreen;
	CGFloat  kBrushRGBColorBlue;
	CGFloat  kBrushLineWidth;

}
@property(nonatomic, readwrite) BOOL isRubber;
@property(nonatomic, readwrite) CGFloat  kBrushLineWidth;
- (void)clear;
- (void)save;
//- (void)changRGBColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue;
- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue;
@end

Painting.m

#import "Painting.h"
#import <QuartzCore/QuartzCore.h>

@implementation Painting
@synthesize isRubber;
@synthesize kBrushLineWidth;

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
	   
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
	drawImage = [[UIImageView alloc] initWithImage:[UIImage imageNamed:kPaintViewBackGroudImg]];
	drawImage.frame = self.frame;
	[self addSubview:backGroudImage];
	[self addSubview:drawImage];
	mouseMoved = 0;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
	mouseSwiped = NO;
	UITouch *touch = [touches anyObject];
	
	//双击清空
	//if ([touch tapCount] == 2) {
	//	[self clear];
	//}
	lastPoint = [touch locationInView:self];
	//lastPoint.y -= 20;
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
	mouseSwiped = YES;
	UITouch *touch = [touches anyObject];        
	CGPoint currentPoint = [touch locationInView:self];
	//currentPoint.y -= 20; // only for 'kCGLineCapRound'
	UIGraphicsBeginImageContext(self.frame.size);
	//Albert Renshaw - Apps4Life
	[drawImage.image drawInRect:CGRectMake(0, 0, drawImage.frame.size.width, drawImage.frame.size.height)]; //originally self.frame.size.width, self.frame.size.height)];

	CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); //kCGLineCapSquare, kCGLineCapButt, kCGLineCapRound
	CGContextSetLineWidth(UIGraphicsGetCurrentContext(), kBrushLineWidth); // for size 线条宽度
	CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), kBrushRGBColorRed, kBrushRGBColorGreen, kBrushRGBColorBlue, kBrushLineAlpha); //values for R, G, B, and Alpha
	

	//CGContextSetLineJoin(UIGraphicsGetCurrentContext() , kCGLineJoinRound );
	if (isRubber) {
		CGContextSetLineWidth(UIGraphicsGetCurrentContext(), kRubberWidth); // for size 线条宽度
		CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeClear);//混合模式
//		CGContextClearRect(UIGraphicsGetCurrentContext(),CGRectMake(currentPoint.x - kRubberWidth/2, currentPoint.y - kRubberWidth/2,kRubberWidth,kRubberWidth));
	}
//	else {
//		CGContextBeginPath(UIGraphicsGetCurrentContext());
//		CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
//		CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
//	}
	CGContextBeginPath(UIGraphicsGetCurrentContext());
	CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
	CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
	

	CGContextStrokePath(UIGraphicsGetCurrentContext());
	drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	
	lastPoint = currentPoint;
	mouseMoved++;
	
	if (mouseMoved == 10) {
		mouseMoved = 0;
	}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
	//UITouch *touch = [touches anyObject];
	//双击清空
	//if ([touch tapCount] == 2) {
	//	[self clear];
	//}
	if(!mouseSwiped) {
		
		UIGraphicsBeginImageContext(self.frame.size);
		[drawImage.image drawInRect:CGRectMake(0, 0, drawImage.frame.size.width, drawImage.frame.size.height)]; //originally self.frame.size.width, self.frame.size.height)];
		CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); //kCGLineCapSquare, kCGLineCapButt, kCGLineCapRound
		CGContextSetLineWidth(UIGraphicsGetCurrentContext(), kBrushLineWidth); 
		CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), kBrushRGBColorRed, kBrushRGBColorGreen, kBrushRGBColorBlue, kBrushLineAlpha);
		//CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
		if (isRubber) {
			CGContextClearRect(UIGraphicsGetCurrentContext(),CGRectMake(lastPoint.x - kRubberWidth/2, lastPoint.y - kRubberWidth/2,kRubberWidth,kRubberWidth));
		}else {
			CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
			CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
		}
		
		CGContextStrokePath(UIGraphicsGetCurrentContext());
		CGContextFlush(UIGraphicsGetCurrentContext());
		drawImage.image = UIGraphicsGetImageFromCurrentImageContext();
		UIGraphicsEndImageContext();
	}
}



- (void) clear{
    [drawImage setImage:[UIImage imageNamed:kPaintViewBackGroudImg]];
}

- (void)save{
	UIGraphicsBeginImageContext(self.bounds.size);
    [self.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
	//UIImage *viewImage = [UIImage imageNamed:@"pink2.png"]; 
	UIGraphicsEndImageContext();
	if (viewImage != nil) {
		
		UIImageWriteToSavedPhotosAlbum(viewImage, self, nil, nil);
		UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存完毕"
														message:@"保存到图片浏览目录中" 
													   delegate:nil
											  cancelButtonTitle:@"关闭"
											  otherButtonTitles:nil];
		[alert show];
		[alert release];
	}
	
}

- (void)setBrushColorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue
{
	kBrushRGBColorRed = red;
	kBrushRGBColorGreen = green;
	kBrushRGBColorBlue = blue;
}

- (void)dealloc {
    [super dealloc];
}
@end