本文实例为大家分享了ios生成图片数字字母验证的具体代码，供大家参考，具体内容如下
直接上代码，注释很详细
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#import "captchaview.h"
#define krandomcolor [uicolor colorwithred:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1.0];
//#define krandomcolor [uicolor graycolor];
#define klinecount 6
#define klinewidth 1.0
#define kcharcount 4
#define kfontsize [uifont systemfontofsize:arc4random() % 5 + 15]
@implementation captchaview
@synthesize changestring,changearray;
- (instancetype)initwithframe:(cgrect)frame
{
if (self = [super initwithframe:frame]) {
self.layer.cornerradius = 5.0; //设置layer圆角半径
self.layer.maskstobounds = yes; //隐藏边界
self.backgroundcolor = krandomcolor;
// [uicolor graycolor]
//显示一个随机验证码
[self changecaptcha];
}
return self;
}
#pragma mark 更换验证码,得到更换的验证码的字符串
-(void)changecaptcha
{
//<一>从字符数组中随机抽取相应数量的字符，组成验证码字符串
//数组中存放的是全部可选的字符，可以是字母，也可以是中文
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];
//如果能确定最大需要的容量，使用initwithcapacity:来设置，好处是当元素个数不超过容量时，添加元素不需要重新分配内存
nsmutablestring *getstr = [[nsmutablestring alloc] initwithcapacity:kcharcount];
self.changestring = [[nsmutablestring alloc] initwithcapacity:kcharcount];
//随机从数组中选取需要个数的字符，然后拼接为一个字符串
for(int i = 0; i < kcharcount; i++)
{
nsinteger index = arc4random() % ([self.changearray count] - 1);
getstr = [self.changearray objectatindex:index];
self.changestring = (nsmutablestring *)[self.changestring stringbyappendingstring:getstr];
}
}
#pragma mark 点击view时调用，因为当前类自身就是uiview，点击更换验证码可以直接写到这个方法中，不用再额外添加手势
-(void)touchesbegan:(nsset *)touches withevent:(uievent *)event
{
//点击界面，切换验证码
[self changecaptcha];
//setneedsdisplay调用drawrect方法来实现view的绘制
[self setneedsdisplay];
}
#pragma mark 绘制界面（1.uiview初始化后自动调用； 2.调用setneedsdisplay方法时会自动调用）
- (void)drawrect:(cgrect)rect {
// 重写父类方法，首先要调用父类的方法
[super drawrect:rect];
//设置随机背景颜色
self.backgroundcolor = krandomcolor;
//获得要显示验证码字符串，根据长度，计算每个字符显示的大概位置
nsstring *text = [nsstring stringwithformat:@"%@",self.changestring];
cgsize csize = [@"s" sizewithattributes:@{nsfontattributename:[uifont systemfontofsize:20.0]}];
int width = rect.size.width / text.length - csize.width;
int height = rect.size.height - csize.height;
cgpoint point;
//依次绘制每一个字符,可以设置显示的每个字符的字体大小、颜色、样式等
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 withattributes:@{nsfontattributename:kfontsize}];
}
//调用drawrect：之前，系统会向栈中压入一个cgcontextref，调用uigraphicsgetcurrentcontext()会取栈顶的cgcontextref
cgcontextref context = uigraphicsgetcurrentcontext();
//设置画线宽度
cgcontextsetlinewidth(context, klinewidth);
//绘制干扰的彩色直线
for(int i = 0; i < klinecount; i++)
{
//设置线的随机颜色
uicolor *color = krandomcolor;
cgcontextsetstrokecolorwithcolor(context, [color cgcolor]);
//设置线的起点
px = arc4random() % (int)rect.size.width;
py = arc4random() % (int)rect.size.height;
cgcontextmovetopoint(context, px, py);
//设置线终点
px = arc4random() % (int)rect.size.width;
py = arc4random() % (int)rect.size.height;
cgcontextaddlinetopoint(context, px, py);
//画线
cgcontextstrokepath(context);
}
}
@end
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以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/bobbob32/article/details/77527553