二维码的生成
+ (UIImage *)qrImageForString:(NSString *)string imageSize:(CGFloat)Imagesize logoImageSize:(CGFloat)waterImagesize{
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[filter setDefaults];
NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
[filter setValue:data forKey:@"inputMessage"];//通过kvo方式给一个字符串,生成二维码
[filter setValue:@"H" forKey:@"inputCorrectionLevel"];//设置二维码的纠错水平,越高纠错水平越高,可以污损的范围越大
CIImage *outPutImage = [filter outputImage];//拿到二维码图片
return [[self alloc] createNonInterpolatedUIImageFormCIImage:outPutImage withSize:Imagesize waterImageSize:waterImagesize];
}
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size waterImageSize:(CGFloat)waterImagesize{
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;
//创建一个DeviceGray颜色空间
CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
//CGBitmapContextCreate(void * _Nullable data, size_t width, size_t height, size_t bitsPerComponent, size_t bytesPerRow, CGColorSpaceRef _Nullable space, uint32_t bitmapInfo)
//width:图片宽度像素
//height:图片高度像素
//bitsPerComponent:每个颜色的比特值,例如在rgba-32模式下为8
//bitmapInfo:指定的位图应该包含一个alpha通道。
CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
CIContext *context = [CI