一键生成微信二维码

引言

生成二维码的步骤
导入CoreImage框架
通过滤镜CIFilter生成二维码

生成普通的二维码

/** 生成一张普通的二维码 */
 +(UIImage )QRcodeToolgeneratedDataString:(NSString )dataString
 imageViewWidth:(CGFloat)imageViewWidth;

创建生成二维码的类方法

/
 生成一个普通的二维码
 
 
@param dataString 传入要生成二维码的数据
 @param imageViewWidth 图片的宽度
 
 
*/
 +(UIImage *)QRcodeToolgeneratedDataString:(NSString *)dataString
 imageViewWidth:(CGFloat)imageViewWidth
 {
 //通过滤镜CIFilter生成二维码
 
 
//1.创建过滤器
CIFilter  *filter=[CIFilter filterWithName:@"CIQRCodeGenerator"];

// 2.恢复默认
[filter setDefaults];

// 3.给过滤器添加数据
NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];


// 4.通过KVO设置滤镜inputMessage数据
[filter setValue:data forKeyPath:@"inputMessage"];
// 4.获取输出的二维码
CIImage *outputImage = [filter outputImage];
 
 
return [QRcodeTool createNonInterpolatedUIImageFormCIImage:outputImage withSize:imageViewWidth];
 
 
}
 

根据CIImage生成指定大小的UIImage

/** 根据CIImage生成指定大小的UIImage */
 
 
 
  
 
(UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(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];
 
 
 
 
 
}
 

生成一张带有logo的二维码

 /**
 生成一张带有logo的二维码
 
 
@param dataString 传入要生成二维码的数据
 @param logoimageName 图片名字
 @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）
 
 
*/
 +(UIImage *)QRcodeToolgeneratedLogoDataString:(NSString *)dataString
 logoimageName:(NSString *)logoimageName
 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 = dataString;
// 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 = logoimageName;
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;
 
 
}

生成一张彩色的二维码

+ (UIImage *)QRcodeToolgeneratedDataString:(NSString *)data backgroundColor:(CIColor *)backgroundColor 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:backgroundColor forKey:@"inputColor0"];
[color_filter setValue:mainColor forKey:@"inputColor1"];

// 7、设置输出
CIImage *colorImage = [color_filter outputImage];

return [UIImage imageWithCIImage:colorImage];
 
 
}
 

图片效果

readme.png

Github地址:https://github.com/jwh1650715313/QRcode