[新手学IOS]第八天:使用Quartz绘图

于 2013-11-27 21:30:49 发布
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分类专栏： iOS学习 新手学IOS
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/ministarler/article/details/16993185
本文介绍了一种在iOS应用中使用的绘图技术——Quartz绘图，并通过具体实例展示了如何利用Quartz绘制不同形状，包括直线、矩形、椭圆等。此外，还介绍了如何在触摸事件中更新绘图内容，以及如何在视图中随机生成颜色。

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1.我们学习了很多的UI和知识点,但是并非多姿多彩的,现在我们就如何在view上绘图学习两种方法,一种是Quartz绘图,这种绘图方式比较简单.但是还有一种更加强大的接口OpenGL,但是代码的实现也相对是比较麻烦的.

今天就来学习Quartz绘图吧.

首先,我们来定义几个常量.

//
//  BIDCOstants.h
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#ifndef _______Quartz___BIDCOstants_h
#define _______Quartz___BIDCOstants_h

typedef enum {
    kLineShape = 0,
    kRectShape,
    kEllipseShape,
    KImageShape

}ShapeType;

typedef enum {
    kRedColorTab = 0,
    kBlueColorTab ,
    kYellowColorTab,
    kGreenColorTab,
    kRandomColorTab
}colorTabIndex;


#define degreesToRadian(x) (M_PI *(x)/180.0)


#endif

2)下面就owner下面的view添加如下控制类. 

//
//  BIDQuartzFun.h
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "BIDCOstants.h"
@interface BIDQuartzFun : UIView


@property (nonatomic)CGPoint firstTouch;
@property (nonatomic)CGPoint lastTouch;

@property (nonatomic,strong)UIColor *currentColor;
@property (nonatomic)ShapeType shapeType;

@property (nonatomic,strong)UIImage *drawImage;
@property (nonatomic)BOOL useRandomColor;

@property CGRect reDrawRect;


-(CGRect)currentRect;


@end

1.m文件 

//
//  BIDQuartzFun.m
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import "BIDQuartzFun.h"
#import "UIColor+BIDRandom.h"

@implementation BIDQuartzFun

@synthesize firstTouch,lastTouch,currentColor,drawImage,useRandomColor,shapeType;


@synthesize reDrawRect;

-(CGRect)currentRect
{
    return  CGRectMake(firstTouch.x, firstTouch.y, lastTouch.x-firstTouch.x, lastTouch.y - firstTouch.y);
}

-(id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super initWithCoder:aDecoder]) {
        currentColor = [UIColor redColor];
        useRandomColor = NO;
        self.drawImage = [UIImage imageNamed:@"screen.png"];
    }
    
    return self;

}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    if (useRandomColor) {
        self.currentColor = [UIColor randomColor];
    }
    
    UITouch *touch = [touches anyObject];
    firstTouch = [touch locationInView:self];
    lastTouch = [touch locationInView:self];
    
    [self setNeedsDisplay];

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    lastTouch = [touch locationInView:self];
    if (shapeType == KImageShape) {
        CGFloat horizontalOffset = drawImage.size.width/2;
        CGFloat verticalOffset = drawImage.size.height/2;
        reDrawRect = CGRectUnion(reDrawRect, CGRectMake(lastTouch.x -horizontalOffset, lastTouch.y - verticalOffset, drawImage.size.width, drawImage.size.height));
    }
    else
        reDrawRect = CGRectUnion(reDrawRect, self.currentRect);
    
    reDrawRect = CGRectInset(reDrawRect, -2.0, -2.0);
    [self setNeedsDisplayInRect:reDrawRect];
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    UITouch *touch = [touches anyObject];
    lastTouch = [touch locationInView:self];
    
    if (shapeType == KImageShape) {
        CGFloat horizontalOffset = drawImage.size.width/2;
        CGFloat verticalOffset = drawImage.size.height/2;
        reDrawRect = CGRectUnion(reDrawRect, CGRectMake(lastTouch.x -horizontalOffset, lastTouch.y - verticalOffset, drawImage.size.width, drawImage.size.height));
    }
      reDrawRect = CGRectUnion(reDrawRect, self.currentRect);
    
    
    [self setNeedsDisplayInRect:reDrawRect];

}



// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
    CGContextRef context = UIGraphicsGetCurrentContext();
    //检索对当前上下文的引用,以便知道要绘图的位置
    
    CGContextSetLineWidth(context, 2.0f);
    
    CGContextSetStrokeColorWithColor(context, currentColor.CGColor);
    //椭圆和矩形
    
    CGContextSetFillColorWithColor(context, currentColor.CGColor);
    
  //  CGRect currentRect = CGRectMake(firstTouch.x, firstTouch.y, lastTouch.x-firstTouch.x, lastTouch.y - firstTouch.y);
    
    
    
    
    switch (shapeType) {
        case kLineShape:
            CGContextMoveToPoint(context, firstTouch.x, firstTouch.y);
            CGContextAddLineToPoint(context, lastTouch.x, lastTouch.y);
            CGContextStrokePath(context);
            break;
        case kRectShape:
            CGContextAddRect(context, self.currentRect);
            CGContextDrawPath(context, kCGPathFillStroke);
            break;
        case kEllipseShape:
            CGContextAddEllipseInRect(context, self.currentRect);
            CGContextDrawPath(context, kCGPathFillStroke);
            
            break;
        case KImageShape:
        {
            CGFloat horizontalOffset = drawImage.size.width/2;
            CGFloat verticalOffset = drawImage.size.height/2;
            CGPoint drawPoint = CGPointMake(lastTouch.x - horizontalOffset, lastTouch.y - verticalOffset);
            
            [drawImage drawAtPoint:drawPoint];
            
            break;
        }
        default:
            break;
    }
    
    
}















@end


3)下面就UIColor添加一个 随机方法

//
//  UIColor+BIDRandom.h
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIColor (BIDRandom)

+(UIColor *)randomColor;

@end

.m文件 

//
//  UIColor+BIDRandom.m
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import "UIColor+BIDRandom.h"

@implementation UIColor (BIDRandom)

+(UIColor *)randomColor
{
    static BOOL seeded = NO;
    
    if (!seeded) {
        seeded = YES;
        srandom(time(NULL));
    }
    
    CGFloat red = (CGFloat)random()/(CGFloat)RAND_MAX;
    CGFloat blue = (CGFloat)random()/(CGFloat)RAND_MAX;
    CGFloat green = (CGFloat)random()/(CGFloat)RAND_MAX;
    
    return [UIColor colorWithRed:red green:green blue:blue alpha:1.0f];
}

@end




3.然后我们定义自己的viewCOntroller 也就是app运行时的记载文件 

//
//  BIDViewController.h
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface BIDViewController : UIViewController

@property (weak, nonatomic) IBOutlet UISegmentedControl *colorControl;

- (IBAction)changeColor:(id)sender;

- (IBAction)changeShape:(id)sender;


@end

.m文件 

//
//  BIDViewController.m
//  第十六章:使用Quartz绘图
//
//  Created by lichan on 13-11-27.
//  Copyright (c) 2013年 com.lichan. All rights reserved.
//

#import "BIDViewController.h"
#import "BIDQuartzFun.h"

@interface BIDViewController ()

@end

@implementation BIDViewController
@synthesize colorControl;

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (IBAction)changeColor:(id)sender {
    
    UISegmentedControl *control = sender;
    NSInteger index= [control selectedSegmentIndex];
    
    BIDQuartzFun *quartzView = (BIDQuartzFun *)self.view;
    
    switch (index) {
        case kRedColorTab:
            quartzView.currentColor = [UIColor redColor];
            quartzView.useRandomColor = NO;
            break;
        case kYellowColorTab:
            quartzView.currentColor = [UIColor yellowColor];
            quartzView.useRandomColor = NO;
            break;
        case kBlueColorTab:
            quartzView.currentColor = [UIColor blueColor];
            quartzView.useRandomColor = NO;
            break;
        case kGreenColorTab:
            quartzView.currentColor = [UIColor greenColor];
            quartzView.useRandomColor = NO;
            break;
        case kRandomColorTab:
            quartzView.useRandomColor = YES;
            break;
            
        default:
            break;

       }
}

- (IBAction)changeShape:(id)sender {
    
    UISegmentedControl *control = sender;
    
    [(BIDQuartzFun *)self.view setShapeType:[control selectedSegmentIndex]];
    
    if ([control selectedSegmentIndex] == KImageShape) {
        colorControl.hidden =YES;
    }
    else
        colorControl.hidden = NO;
}

@end



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