iOS開發-Quartz2D的基本使用(二)

通過 <iOS開發-Quartz2D的基本使用(一)> 我們能夠利用Quartz2D繪制直線和曲線,并制作了一個簡單的畫板功能 但是真正的開發過程當中這些是遠遠不夠的,那么我們就接著上部分內容更深層次的學習Quartz2D

矩形

//第一種
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(50, 50, 200, 200)];
    [path fill]; // fill就是填充
//第二種
    UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(50, 50, 200, 200)];
    [path stroke]; // stroke是渲染(描邊)
fill

stroke

我們很明顯的看出以上兩種效果是截然不一樣的.

橢圓

橢圓的繪制方式和上面的矩形的繪制方法類似
事例代碼:

    //前兩個參數表示的是需要繪制的圖形在父視圖上的位置
    //后兩個參數表示的是需要繪制的圖形在父視圖上的大小
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 200, 200, 100)];
    [[UIColor purpleColor]set];
    path.lineWidth = 5;
    [path fill];
  
    UIBezierPath *pat = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(50, 50, 200, 100)];
    [[UIColor redColor]set];
    pat.lineWidth = 5;
    [pat stroke];

效果:


橢圓

圓角

-(void)yuanJiao{
    
    //第一個參數是CGRect參數 第二個參數是圓角度
    //[UIBezierPath bezierPathWithRoundedRect:<#(CGRect)#> cornerRadius:<#(CGFloat)#>]
    UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(50, 50, 200, 200) cornerRadius:100];
    [[UIColor greenColor]set];
    path.lineWidth = 5;

    [path stroke];
    
    UIBezierPath *path1 = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(50, 300, 200, 200) cornerRadius:100];
    [[UIColor magentaColor]set];
    path.lineWidth = 5;
    [path1 fill];
}

程序運行結果


圓角

柱狀圖

實例代碼

-(void)zhuZhuangTu{
    
    UIBezierPath *path = [UIBezierPath bezierPath];
    //橫線(橫軸)
    [path moveToPoint:CGPointMake(0, 300)];//起點
    [path addLineToPoint:CGPointMake(300, 300)];//終點
    
    //縱線(縱軸)
    [path moveToPoint:CGPointMake(0, 300)];
    [path addLineToPoint:CGPointMake(0, 0)];
    
    path.lineWidth = 5;
    [[UIColor redColor]set];
    [path stroke];
    
    
    int lines = 0;
    NSArray *dataArray = @[@100,@200,@290,@80,@70,@30,@40,@50];
    for (NSNumber *num in dataArray) {
        
        //柱狀圖的最低點
        CGPoint startPoint = CGPointMake(20 + lines * 300 / dataArray.count, 300);
        
        CGPoint endPoint = CGPointMake(20 + lines * 300 / dataArray.count, 300 - 300 * ([num intValue] / 300.0));
        UIBezierPath *path = [UIBezierPath bezierPath];
        [path moveToPoint:startPoint];
        [path addLineToPoint:endPoint];
        [UIColor greenColor];
        path.lineWidth = 20;
        [path stroke];
        lines++ ;
    }
}
柱狀圖

餅狀圖

-(void)bingZhuangTu{
    NSMutableArray *dataArray = [NSMutableArray array];
    for (int i = 0; i <= 100; i++) {
        [dataArray addObject:@1];//分成100份 這個根據個人情況細分
    }
    CGFloat start = 0;
    CGFloat end = 0;
    
    for (NSNumber *num in dataArray) {
        
        //計算角度
        end = num.floatValue / 100 * M_PI * 2; //總共360度
        
        //參數依次是 圓心 半徑 起始角度 結束角度
        UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:start endAngle:start + end clockwise:YES];
        //關閉路徑
        [path addLineToPoint:CGPointMake(150, 150)];
        [path closePath];
        
        
        [[UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1] set];//隨機色
        [path fill];//設置填充
        start += end;
    }
    
}
餅狀圖

我們在模擬一種等分的效果,把圓分成等比例的四分, 上面代碼也即是等價于下面內容 下面是對上面的一個分解執行

-(void)yuan{
    UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:0 endAngle:M_PI_2 clockwise:YES];
    [path addLineToPoint:CGPointMake(150, 150)];
    [path closePath];
    [path stroke];
    
    UIBezierPath *path2 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:M_PI_2 endAngle:M_PI_2 + M_PI_2 clockwise:YES];
    
    [[UIColor redColor] set];
    [path2 addLineToPoint:CGPointMake(150, 150)];
    
    [path2 closePath];
    
    [path2 stroke];
    
    UIBezierPath *path3 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:M_PI endAngle:M_PI + M_PI_2 clockwise:YES];
    [path3 addLineToPoint:CGPointMake(150, 150)];
    [[UIColor blueColor] set];
    
    [path3 closePath];
    
    [path3 stroke];
    
    UIBezierPath *path4 = [UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 150) radius:100 startAngle:M_PI + M_PI_2 endAngle:0 clockwise:YES];
    
    [path4 addLineToPoint:CGPointMake(150, 150)];
    [[UIColor blackColor] set];
    
    [path4 closePath];
    [path4 stroke];
}

程序運行效果如下:



我們把stroke改為fill就變為了填充的樣式,再次不在演示.

圖片剪切

我們接下來研究一下如何對圖片進行剪切我們在viewDidLoad:方法里

    //擁有一張圖片
    UIImage *image =[UIImage imageNamed:@"2"];
    myImageView *imageView = [[myImageView alloc]initWithImage:image];
    imageView.backgroundColor = [UIColor grayColor];
    CGRect rectFrame = CGRectMake(50, 50, 0, 0);
    rectFrame.size = image.size;
    imageView.frame = rectFrame;
    [self.view addSubview:imageView];
運行以上代碼后的結果

接著我們做一下處理

    //需要剪切的范圍
    UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);
    UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
    [path addClip];
    //剪切
    [image drawAtPoint:CGPointZero];
    
    //獲取剪切好的圖片
    UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    imageView.image= aImage;
再次執行后的結果

這個時候我們可以看到,按照要求我們獲得了一個剪切之后的橢圓圖形.
但是我們有時候可以根據自己實際的需要來進行裁剪 我們接下來做一件事情 需求是什么呢 鼠標在鍵盤上畫一塊區域 我們對圖片進行裁剪 ,獲取這個區域之內的內容.
首先我們自定義一個view視圖

.h
#import <UIKit/UIKit.h>
typedef void(^MyBlock)(UIBezierPath *);
@interface MYView : UIView
@property(nonatomic,copy)MyBlock block;
@end

.m
#import "MYView.h"
@interface MYView ()
@property(nonatomic,strong)NSMutableArray *pathArray;
@end


@implementation MYView

-(NSMutableArray *)pathArray{
    if (!_pathArray) {
        _pathArray=[NSMutableArray array];
    }
    return _pathArray;
}

// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
    for (UIBezierPath *path in self.pathArray) {
        path.lineWidth = 5;
        [path stroke];
    }
}
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:[[touches anyObject] locationInView:self]];
    [self.pathArray addObject:path];
}
-(void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    
    //獲取終點 不止一個終點
    UIBezierPath *path = [self.pathArray lastObject];
    [path addLineToPoint:[[touches anyObject] locationInView:self]];
    //調用drawRect方法
    [self setNeedsDisplay];
}

-(void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    UIBezierPath *path = [_pathArray lastObject];
    [path closePath];
    [self setNeedsDisplay];
    self.block(path);
}

視圖自定義完畢之后 我們回到viewDidLoad:方法里面

- (void)viewDidLoad {
    [super viewDidLoad];
    
    __block UIImage *image = [UIImage imageNamed:@"2"];
    self.imageView = [[UIImageView alloc]initWithImage:image];
    //self.imageView.frame= self.view.frame;
    self.myView = [[MYView alloc]initWithFrame:self.imageView.frame];
    self.myView.backgroundColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0];
    [self.view addSubview:self.imageView];
    [self.view addSubview:self.myView];
    
    
    __weak typeof(self) se = self;
    
    self.myView.block = ^(UIBezierPath *p){
        //剪切
        UIGraphicsBeginImageContextWithOptions(image.size, NO, 0);
        //剪切路徑
        UIBezierPath *path = p;
        [path addClip];//剪切
        
        [image drawAtPoint:CGPointZero];
        
        image = UIGraphicsGetImageFromCurrentImageContext();
        
        //結束上下文
        UIGraphicsEndImageContext();
        
        //給imageView賦值
        se.imageView.image= image;
        
    }; 
}

運行之后我們會看到:



但是當我們用鼠標劃出一個區域的時候 會看到:




由此 我們就獲得了自己想截取的部分~~~~~~
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