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iOS从绘图开始：DrawRect&CoreText

作者：佚名 IOS开发编辑：admin 更新时间：2022-07-23

- (void)drawRect:(CGRect)rect {
    // Drawing code
    
    //Quartz 2D绘画环境,一张画布
    CGContextRef context = UIGraphicsGetCurrentContext();

    //边框圆  背景圆
    CGContextSetRGBStrokeColor(context,1,1,0,1.0);//画笔线的颜色
    CGContextSetLineWidth(context, 2.0);//线的宽度
    //void CGContextAddArc(CGContextRef c,CGFloat x, CGFloat y,CGFloat radius,CGFloat startAngle,CGFloat endAngle, int clockwise)1弧度＝180°/π （≈57.3°） 度＝弧度×180°/π 360°＝360×π/180 ＝2π 弧度
    // x,y为圆点坐标，radius半径，startAngle为开始的弧度，endAngle为 结束的弧度，clockwise 0为顺时针，1为逆时针。
    CGContextAddArc(context, 120, 120, 100, 0, 2*M_PI, 0); //添加一个圆
    CGContextDrawPath(context, kCGPathStroke); //绘制路径
    
    //所占比例圆弧
    CGContextSetRGBStrokeColor(context,1,0,0,1.0);//画笔线的颜色
    CGContextSetLineWidth(context, 3.0);//线的宽度
    CGContextAddArc(context, 120, 120, 100, -90 * M_PI/180, (endRadius-90) * M_PI/180, 0); //添加一个圆
    CGContextDrawPath(context, kCGPathStroke); //绘制路径
    
    
    //绘制字符串
    if ([[UIDevice currentDevice] systemVersion].floatValue >= 7.0) {
        
        NSMutableAttributedString *mabstring = [[NSMutableAttributedString alloc]initWithString:drawText];
        [mabstring beginEditing];
        
        //对同一段字体进行多属性设置
        NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithObject:(id)[UIColor redColor].CGColor forKey:(id)kCTForegroundColorAttributeName];//红色字体
        //设置字体属性
        CTFontRef font = CTFontCreateWithName(CFSTR("Georgia"), 14, NULL);
        [attributes setObject:(id)(__bridge id)font forKey:(id)kCTFontAttributeName];//下划线
        [mabstring endEditing];//结束编辑
        [mabstring addAttributes:attributes range:NSMakeRange(0, mabstring.length)];
        
        //开始绘制
        CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)mabstring);
        CGMutablePathRef Path = CGPathCreateMutable();
        CGPathAddRect(Path, NULL ,CGRectMake(100 , -100 ,self.bounds.size.width-10 , self.bounds.size.height-10));
        CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), Path, NULL);
        
        //压栈，压入图形状态栈中.
        CGContextSetTextMatrix(context , CGAffineTransformIdentity);
        //保存现在得上下文图形状态。
        CGContextSaveGState(context);
        //x，y轴方向移动
        CGContextTranslateCTM(context , 0 ,self.bounds.size.height);
        //缩放x，y轴方向缩放，代码中坐标系转换是沿x轴翻转180度
        CGContextScaleCTM(context, 1.0 ,-1.0);
        CTFrameDraw(frame,context);//开始绘制大小
        CGPathRelease(Path);//开始绘制路径
        CFRelease(framesetter);
    }else {
        
        //表示开始绘制路径
        CGContextBeginPath(context);
        //设置文字大小
        CGContextSelectFont(context, "Helvetica", 20, kCGEncodingMacRoman);
        CGContextSetTextDrawingMode(context, kCGTextFill);
        // 设置文本颜色字符为白色
        CGContextSetRGBFillColor(context, 1.0, 0.0, 1.0, 1.0); //白色
        CGContextSetTextMatrix(context, CGAffineTransformMakeScale(1.0, -1.0));
        //绘制文字
        CGContextShowTextAtPoint(context,20, 100, [@"characterAttribute" cStringUsingEncoding:[NSString defaultCStringEncoding]],
                                 @"characterAttribute".length);
        CGContextStrokePath(context);
        //表示结束绘制路径
        CGContextClosePath(context);
    }
    
    /////////////////////一些字体属性设置////////////////////////
    //        [mabstring addAttribute:(id)kCTFontAttributeName value:(__bridge id)font range:NSMakeRange(0, 4)];
    //        [attributes setObject:(id)[NSNumber numberWithInt:kCTUnderlineStyleDouble] forKey:(id)kCTUnderlineStyleAttributeName];//下划线
    //        [mabstring addAttributes:attributes range:NSMakeRange(0, 4)];//设置属性的文字范围
    
    //设置斜体字
    //        CTFontRef font = CTFontCreateWithName((CFStringRef)[UIFont italicSystemFontOfSize:20].fontName, 14, NULL);
    //        [mabstring addAttribute:(id)kCTFontAttributeName value:(__bridge id)(font) range:NSMakeRange(0, 4)];
}

上面的代码，是在UIView上绘制一个圆形比例图和文字。

下面是CoreText在Label上的使用。

 1 UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(60, 2, sectionHeader.bounds.size.width-60-15-10, 56)];
 2 titleLabel.font = [UIFont systemFontOfSize:17.0f];
 3 [sectionHeader addSubview:titleLabel];
 4 NSString *titleStr = [NSString stringWithFormat:@"你还有%ld未通过", courseCount];
 5 NSInteger courseCount = [obligatoryCourseArray count];
 6 
 7  // 设置标签文字
 8  NSMutableAttributedString *attrituteString = [[NSMutableAttributedString alloc] initWithString:titleStr];
 9 // 设置标签文字的属性
10 [attrituteString setAttributes:@{NSForegroundColorAttributeName : [UIColor redColor],   NSFontAttributeName : [UIFont systemFontOfSize:25]} range:NSMakeRange(3, [NSString stringWithFormat:@"%ld", courseCount].length)];
11 // 显示在Label上
12  titleLabel.attributedText = attrituteString;

当然Label上绘制的Text的属性可以用上面的在UIView上绘制中的方法。

再来看一个UIImageView的：

 1  {
 2         
 3         UIImageView *obligatoryImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 30, tableView.bounds.size.width, ([UIScreen mainScreen].bounds.size.height-20-44)/3-30*2)];
 4         [cell addSubview:obligatoryImageView];
 5         obligatoryImageView.backgroundColor = [UIColor whiteColor];
 6         UIGraphicsBeginImageContext(obligatoryImageView.bounds.size);
 7         [obligatoryImageView.image drawInRect:CGRectMake(0, 0, obligatoryImageView.bounds.size.width, obligatoryImageView.bounds.size.height)];
 8         CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCaPRound);  //边缘样式
 9         CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 0.2);  //线宽
10         CGContextSetAllowsAntialiasing(UIGraphicsGetCurrentContext(), YES);
11         CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(),153/255.0,153/255.0,153/255.0,1.0);  //颜色
12         CGContextBeginPath(UIGraphicsGetCurrentContext());
13         CGContextMoveToPoint(UIGraphicsGetCurrentContext(), 35, 5);  //起点坐标
14         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, 5);//终点坐标
15         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, (obligatoryImageView.bounds.size.height-5));
16         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, (obligatoryImageView.bounds.size.height-5));
17         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, 5);
18         
19         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, (obligatoryImageView.bounds.size.height-5)/5+5);
20         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, (obligatoryImageView.bounds.size.height-5)/5+5);
21         
22         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, (obligatoryImageView.bounds.size.height-5)/5*2+5);
23         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, (obligatoryImageView.bounds.size.height-10)/5*2+5);
24         
25         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, (obligatoryImageView.bounds.size.height-10)/5*3+5);
26         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, (obligatoryImageView.bounds.size.height-10)/5*3+5);
27         
28         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), self.view.bounds.size.width-35, (obligatoryImageView.bounds.size.height-10)/5*4+5);
29         CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), 35, (obligatoryImageView.bounds.size.height-10)/5*4+5);
30         
31         CGContextStrokePath(UIGraphicsGetCurrentContext());
32         obligatoryImageView.image=UIGraphicsGetImageFromCurrentImageContext();
33         UIGraphicsEndImageContext();
34         
35         NSArray *obligatoryArray = [courseArray objectAtIndex:indexPath.row];
36         
37         UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, tableView.bounds.size.width, 30)];
38         titleLabel.textColor = [UIColor murpTextLowColor];
39         titleLabel.textAlignment = NSTextAlignmentCenter;
40         titleLabel.font = [UIFont systemFontOfSize:15.0f];
41         titleLabel.text = [[obligatoryArray objectAtIndex:0] objectForKey:@"Extend2"];
42         [cell addSubview:titleLabel];
43         
44         for (int i = 0; i <= 5; i ++) {
45             
46             UILabel *left1 = [[UILabel alloc] initWithFrame:CGRectMake(0, 30+(obligatoryImageView.bounds.size.height-10)/5*i, 35, 10)];
47             left1.textColor = [UIColor murpTextLowColor];
48             left1.textAlignment = NSTextAlignmentRight;
49             left1.font = [UIFont systemFontOfSize:12.0f];
50             left1.text = [NSString stringWithFormat:@"%d%%", 100-20*i];
51             [cell addSubview:left1];
52             
53             if (i < obligatoryArray.count-1) {
54                 
55                 UILabel *down = [[UILabel alloc] initWithFrame:CGRectMake(35+(tableView.bounds.size.width-35*2)/5*i, ([UIScreen mainScreen].bounds.size.height-20-44)/3-30, (tableView.bounds.size.width-35*2)/5, 30)];
56                 down.textColor = [UIColor murpTextLowColor];
57                 down.textAlignment = NSTextAlignmentCenter;
58                 down.font = [UIFont systemFontOfSize:12.0f];
59                 [cell addSubview:down];
60                 down.text = [NSString stringWithFormat:@"%@分",[[obligatoryArray objectAtIndex:i+1] objectForKey:@"Extend1"]];
61                 
62                 CGFloat heights = [[[obligatoryArray objectAtIndex:i+1] objectForKey:@"Extend3"] floatValue]/100.0*(obligatoryImageView.bounds.size.height-5*2);
63                 UIImageView *heightImageView = [[UIImageView alloc] initWithFrame:CGRectMake(35+(tableView.bounds.size.width-35*2)/5*i+5, (([UIScreen mainScreen].bounds.size.height-20-44)/3-30-5)-heights, (tableView.bounds.size.width-35*2)/5-10, heights)];
64                 heightImageView.backgroundColor = [UIColor murpThemeGreenColor];
65                 [cell addSubview:heightImageView];
66                 
67                 UILabel *heightsLabel = [[UILabel alloc] initWithFrame:CGRectMake(35+(tableView.bounds.size.width-35*2)/5*i+5, (([UIScreen mainScreen].bounds.size.height-20-44)/3-30-5)-heights-20, (tableView.bounds.size.width-35*2)/5-10, 20)];
68                 heightsLabel.textColor = [UIColor murpTextLowColor];
69                 heightsLabel.textAlignment = NSTextAlignmentCenter;
70                 heightsLabel.font = [UIFont systemFontOfSize:10.0f];
71                 [cell addSubview:heightsLabel];
72                 heightsLabel.text = [[obligatoryArray objectAtIndex:i+1] objectForKey:@"Extend2"];
73             }
74         }
75     }

其实我也不知道想说什么，哟嘿，最后看个效果吧：

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iOS从绘图开始：DrawRect&CoreText

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