iOS 生成图片验证码绘制实例代码

 _pooCodeView = [[PooCodeView alloc] initWithFrame:CGRectMake(50, 100, 82, 32)]; UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapClick:)]; [_pooCodeView addGestureRecognizer:tap];[self.view addSubview:_pooCodeView];#import <UIKit/UIKit.h>@interface PooCodeView : UIView@property (nonatomic, retain) NSArray *changeArray;@property (nonatomic, retain) NSMutableString *changeString;@property (nonatomic, retain) UILabel *codeLabel;-(void)changeCode;@end#import "PooCodeView.h"@implementation PooCodeView@synthesize changeArray = _changeArray;@synthesize changeString = _changeString;@synthesize codeLabel = _codeLabel;- (id)initWithFrame:(CGRect)frame{  self = [super initWithFrame:frame];  if (self) {    // Initialization code//    self.layer.cornerRadius = 5.0;//    self.layer.masksToBounds = YES;    float red = arc4random() % 100 / 100.0;    float green = arc4random() % 100 / 100.0;    float blue = arc4random() % 100 / 100.0;    UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:0.2];    self.backgroundColor = color;    [self change];  }  return self;} //-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event//{//  [self change];//  [self setNeedsDisplay];//}-(void)changeCode{[self change];[self setNeedsDisplay];} - (void)change {   self.changeArray = [[NSArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];  NSMutableString *getStr = [[NSMutableString alloc] initWithCapacity:5];  self.changeString = [[NSMutableString alloc] initWithCapacity:6];  for(NSInteger i = 0; i < 4; i++)  {    NSInteger index = arc4random() % ([self.changeArray count] - 1);    getStr = [self.changeArray objectAtIndex:index];    self.changeString = (NSMutableString *)[self.changeString stringByAppendingString:getStr];  }  } - (void)drawRect:(CGRect)rect {[super drawRect:rect];  float red = arc4random() % 100 / 100.0;  float green = arc4random() % 100 / 100.0;  float blue = arc4random() % 100 / 100.0;  UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:0.5];  [self setBackgroundColor:color];  NSString *text = [NSString stringWithFormat:@"%@",self.changeString];  CGSize cSize = [@"S" sizeWithFont:[UIFont systemFontOfSize:20]];  int width = rect.size.width / text.length - cSize.width;  int height = rect.size.height - cSize.height;  CGPoint point;  float pX, pY;  for (int i = 0; i < text.length; i++)  {    pX = arc4random() % width + rect.size.width / text.length * i;    pY = arc4random() % height;    point = CGPointMake(pX, pY);    unichar c = [text characterAtIndex:i];    NSString *textC = [NSString stringWithFormat:@"%C", c];    [textC drawAtPoint:point withFont:[UIFont systemFontOfSize:20]];  }  CGContextRef context = UIGraphicsGetCurrentContext();  CGContextSetLineWidth(context, 1.0);  for(int cout = 0; cout < 10; cout++)  {    red = arc4random() % 100 / 100.0;    green = arc4random() % 100 / 100.0;    blue = arc4random() % 100 / 100.0;    color = [UIColor colorWithRed:red green:green blue:blue alpha:0.2];    CGContextSetStrokeColorWithColor(context, [color CGColor]);    pX = arc4random() % (int)rect.size.width;    pY = arc4random() % (int)rect.size.height;    CGContextMoveToPoint(context, pX, pY);    pX = arc4random() % (int)rect.size.width;    pY = arc4random() % (int)rect.size.height;    CGContextAddLineToPoint(context, pX, pY);    CGContextStrokePath(context);  }}@end