iOS 生成二维码

.h

#import <UIKit/UIKit.h>

@interface UIImage (Utils)

/**
 颜色转图片
 
 @param color 颜色
 @return 图片
 */
+ (UIImage *)imageWithColor:(UIColor *)color;


/**
 颜色转图片（指定尺寸）
 
 @param color 颜色
 @param size 尺寸
 @return 图片
 */
+ (UIImage *)imageWithColor:(UIColor *)color size:(CGSize)size;


/**
 生成一张普通的二维码
 
 @param data 需要生成二维码的数据
 @param imageWidth 图片的宽度
 @return 二维码
 */
+ (UIImage *)createNormalQrWithData:(NSString *)data imageWidth:(CGFloat)imageWidth;


/**
 生成一张带有logo的二维码
 
 @param data 需要生成二维码的数据
 @param logoImage logo的图片名称
 @param logoScale logo相对于父视图的缩放比（取值范围：0-1，0，代表不显示，1，代表与父视图大小相同
 @return 带logo二维码
 */
+ (UIImage *)createLogoQrWithData:(NSString *)data logoImage:(NSString *)logoImage logoScale:(CGFloat)logoScale;


/**
 生成一张彩色的二维码
 
 @param data 需要生成二维码的数据
 @param bgColor 背景色
 @param mainColor 主颜色
 @return 彩色二维码
 */
+ (UIImage *)createColorQrWithData:(NSString *)data bgColor:(CIColor *)bgColor mainColor:(CIColor *)mainColor;


/**
 根据CIImage生成指定大小的UIImage
 
 @param image 二维码图片
 @param size 二维码尺寸
 @return 生成的UIImage
 */
+ (UIImage *)createUIImageFromCIImage:(CIImage *)image size:(CGFloat)size;

@end

.m

#import "UIImage+Utils.h"

@implementation UIImage (Utils)

+ (UIImage *)imageWithColor:(UIColor *)color{
    return [self imageWithColor:color size:CGSizeMake(1, 1)];
}

+ (UIImage *)imageWithColor:(UIColor *)color size:(CGSize)size {
    if (!color || size.width <= 0 || size.height <= 0) return nil;
    CGRect rect = CGRectMake(0.f, 0.f, size.width, size.height);
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, color.CGColor);
    CGContextFillRect(context, rect);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

+ (UIImage *)createNormalQrWithData:(NSString *)data imageWidth:(CGFloat)imageWidth{
    
    // 1、创建滤镜对象
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    
    // 恢复滤镜的默认属性
    [filter setDefaults];
    
    // 2、设置数据
    NSString *info = data;
    // 将字符串转换成
    NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
    
    // 通过KVC设置滤镜inputMessage数据
    [filter setValue:infoData forKeyPath:@"inputMessage"];
    
    // 3、获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    
    return [self createUIImageFromCIImage:outputImage size:imageWidth];
}



+ (UIImage *)createLogoQrWithData:(NSString *)data logoImage:(NSString *)logoImage logoScale:(CGFloat)logoScale{
    
    // 1、创建滤镜对象
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    
    // 恢复滤镜的默认属性
    [filter setDefaults];
    
    // 2、设置数据
    NSString *string_data = data;
    // 将字符串转换成 NSdata (虽然二维码本质上是字符串, 但是这里需要转换, 不转换就崩溃)
    NSData *qrImageData = [string_data dataUsingEncoding:NSUTF8StringEncoding];
    
    // 设置过滤器的输入值, KVC赋值
    [filter setValue:qrImageData forKey:@"inputMessage"];
    
    // 3、获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    
    // 图片小于(27,27),我们需要放大
    outputImage = [outputImage imageByApplyingTransform:CGAffineTransformMakeScale(20, 20)];
    
    // 4、将CIImage类型转成UIImage类型
    UIImage *start_image = [UIImage imageWithCIImage:outputImage];
    
    
    // - - - - - - - - - - - - - - - - 添加中间小图标 - - - - - - - - - - - - - -
    // 5、开启绘图, 获取图形上下文 (上下文的大小, 就是二维码的大小)
    UIGraphicsBeginImageContext(start_image.size);
    
    // 把二维码图片画上去 (这里是以图形上下文, 左上角为(0,0)点
    [start_image drawInRect:CGRectMake(0, 0, start_image.size.width, start_image.size.height)];
    
    // 再把小图片画上去
    NSString *icon_imageName = logoImage;
    UIImage *icon_image = [UIImage imageNamed:icon_imageName];
    CGFloat icon_imageW = start_image.size.width * logoScale;
    CGFloat icon_imageH = start_image.size.height * logoScale;
    CGFloat icon_imageX = (start_image.size.width - icon_imageW) * 0.5;
    CGFloat icon_imageY = (start_image.size.height - icon_imageH) * 0.5;
    
    [icon_image drawInRect:CGRectMake(icon_imageX, icon_imageY, icon_imageW, icon_imageH)];
    
    // 6、获取当前画得的这张图片
    UIImage *final_image = UIGraphicsGetImageFromCurrentImageContext();
    
    // 7、关闭图形上下文
    UIGraphicsEndImageContext();
    
    return final_image;
}

+ (UIImage *)createColorQrWithData:(NSString *)data bgColor:(CIColor *)bgColor mainColor:(CIColor *)mainColor{
    
    // 1、创建滤镜对象
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    
    // 恢复滤镜的默认属性
    [filter setDefaults];
    
    // 2、设置数据
    NSString *string_data = data;
    // 将字符串转换成 NSdata (虽然二维码本质上是字符串, 但是这里需要转换, 不转换就崩溃)
    NSData *qrImageData = [string_data dataUsingEncoding:NSUTF8StringEncoding];
    
    // 设置过滤器的输入值, KVC赋值
    [filter setValue:qrImageData forKey:@"inputMessage"];
    
    // 3、获得滤镜输出的图像
    CIImage *outputImage = [filter outputImage];
    
    // 图片小于(27,27),我们需要放大
    outputImage = [outputImage imageByApplyingTransform:CGAffineTransformMakeScale(9, 9)];
    
    
    // 4、创建彩色过滤器(彩色的用的不多)
    CIFilter * color_filter = [CIFilter filterWithName:@"CIFalseColor"];
    
    // 设置默认值
    [color_filter setDefaults];
    
    // 5、KVC 给私有属性赋值
    [color_filter setValue:outputImage forKey:@"inputImage"];
    
    // 6、需要使用 CIColor
    [color_filter setValue:bgColor forKey:@"inputColor0"];
    [color_filter setValue:mainColor forKey:@"inputColor1"];
    
    // 7、设置输出
    CIImage *colorImage = [color_filter outputImage];
    
    return [UIImage imageWithCIImage:colorImage];
}

+ (UIImage *)createUIImageFromCIImage:(CIImage *)image size:(CGFloat)size{
    
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    
    // 1.创建bitmap;
    size_t width = CGRectGetWidth(extent) * scale;
    size_t height = CGRectGetHeight(extent) * scale;
    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
    CGContextScaleCTM(bitmapRef, scale, scale);
    CGContextDrawImage(bitmapRef, extent, bitmapImage);
    
    // 2.保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}

@end

用法：

UIImageView *icon = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];

icon.image = [UIImage createLogoQrWithData:@"xxx.url" logoImage:@"logo" logoScale:0.2];