iOS 字符串截取生成图片

代码如下:

#import@interface UIImage (mask)

/**

*  在一张背景图上绘制文字并且居中

*

*  @param str      要绘制到图片上的文字

*  *

*

*/

+ (UIImage *)createOtherMerchantImage:(NSString *)str  size:(CGSize)size;

@end

#import "UIImage+mask.h

"@implementation UIImage (mask)

+ (UIImage *)createOtherMerchantImage:(NSString *)str  size:(CGSize)size{          NSString * substring = [str substringFromIndex:str.length-2];     

   int texthash = (int)[str hash];   

 texthash=abs(texthash)+1;   

 int lastNum=texthash%10;   

 if (lastNum>=5) {       

 lastNum=lastNum-5;  

  }       

 NSArray* colorArr=@[

[UIColor colorWithRed:237/255.0f green:151/255.0f blue:151/255.0f alpha:1.0],

[UIColor colorWithRed:237/255.0f green:197/255.0f blue:151/255.0f alpha:1.0],

[UIColor colorWithRed:151/255.0f green:198/255.0f blue:237/255.0f alpha:1.0],

[UIColor colorWithRed:145/255.0f green:224/255.0f blue:152/255.0f alpha:1.0],

[UIColor colorWithRed:176/255.0f green:164/255.0f blue:162/255.0f alpha:1.0],

];

NSDictionary * fontAttributes = @{

NSFontAttributeName:[UIFont systemFontOfSize:15],//设置文字的字体

NSForegroundColorAttributeName: [UIColor whiteColor]

};

CGSize textSize = [substring sizeWithAttributes:fontAttributes];

CGPoint drawPoint = CGPointMake((size.width - textSize.width)/2, (size.height - textSize.height)/2);

UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);

CGContextRef context = UIGraphicsGetCurrentContext();

UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, size.width, size.height)];

CGContextSetFillColorWithColor(context, colorArr[lastNum].CGColor);

[path fill];

[substring drawAtPoint:drawPoint withAttributes:fontAttributes];

UIImage *resultImg = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return resultImg;

}

@end