原图绘制新图，字符串绘制图片

#import <QuartzCore/QuartzCore.h>

#import <CoreGraphics/CoreGraphics.h>

#import <UIKit/UIKitDefines.h>

#define SCREENWIDTH ([UIScreen mainScreen].bounds.size.width)

#define SCREENHEIGHT ([UIScreen mainScreen].bounds.size.height)

//根据原有图片    绘制一个全屏宽，图等高两侧自定义背景色(红色)的图片

- (UIImage *)shot:(UIImage *)oldImage  backgroundColor:(UIColor *)color{

    CGSize size =CGSizeMake(SCREENWIDTH, oldImage.size.height);

    UIView *backView = [[UIViewalloc] initWithFrame:CGRectMake(0,0, SCREENWIDTH, size.height)];

    backView.backgroundColor = color;

    UIImageView *imageView = [[UIImageViewalloc] initWithImage:oldImage];

    CGFloat imageX = (SCREENWIDTH - oldImage.size.width) * 0.5;

    imageView.frame =CGRectMake(imageX, 0, oldImage.size.width, oldImage.size.height);

    [backView addSubview:imageView];

    UIGraphicsBeginImageContext(backView.bounds.size);

    [backView.layerrenderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

//根据原有图片    绘制一个全屏宽，图等高两侧自定义背景色(白色)的图片

- (UIImage *)snapshotScreenInView:(UIImage *)oldImage backgroundColor:(UIColor *)color{

    CGSize size =CGSizeMake(SCREENWIDTH, oldImage.size.height);

    UIView *backView = [[UIViewalloc] initWithFrame:CGRectMake(0,0, SCREENWIDTH, size.height)];

    backView.backgroundColor = color;

    UIImageView *imageView = [[UIImageViewalloc] initWithImage:oldImage];

    CGFloat imageX = (SCREENWIDTH - oldImage.size.width) * 0.5;

    imageView.frame =CGRectMake(imageX, 0, oldImage.size.width, oldImage.size.height);

    [backView addSubview:imageView];

    UIGraphicsBeginImageContextWithOptions(size,NO, [UIScreenmainScreen].scale);

    CGRect rect = backView.frame;

    [backView drawViewHierarchyInRect:rectafterScreenUpdates:YES];

    UIImage *image =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

//根据一个字符串，绘制一张图片，自定义：位置（居左，中，右），字体间距，大小，颜色，图片背景色

- (UIImage *)getImageWithString:(NSString *)string font:(UIFont *)font textColor:(UIColor *)color size:(CGSize)size {

    UILabel *label = [[UILabelalloc] init];

    label.backgroundColor = [UIColorwhiteColor];

    if (size.width ==MAXFLOAT) {

        //计算宽度

        label.numberOfLines =1;

        label.frame =CGRectMake(0,0, 0, size.height);

    }elseif (size.height ==MAXFLOAT) {

        //计算高度

        label.numberOfLines =0;

        label.frame =CGRectMake(0,0, size.width,0);

    }

    NSMutableAttributedString *attributedText = [[NSMutableAttributedStringalloc] initWithString:string];

    NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyledefaultParagraphStyle] mutableCopy];

    paragraphStyle.lineBreakMode =NSLineBreakByCharWrapping;

    paragraphStyle.alignment =NSTextAlignmentCenter;

    [attributedText addAttributes:@{NSFontAttributeName:font,

                                    NSForegroundColorAttributeName:color,

                                    NSParagraphStyleAttributeName:paragraphStyle,

                                    NSKernAttributeName:@3}range:NSMakeRange(0, string.length)];

    label.attributedText = attributedText;

    [label sizeToFit];

    CGSize realSize = label.frame.size;

    //绘图关键

    UIGraphicsBeginImageContext(realSize);

    [label.layerrenderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}