<h3>引言</h3>
生成二维码的步骤
导入CoreImage框架
通过滤镜CIFilter生成二维码
<h4>生成普通的二维码</h4>
<pre>/** 生成一张普通的二维码 */
+(UIImage )QRcodeToolgeneratedDataString:(NSString )dataString
imageViewWidth:(CGFloat)imageViewWidth;</pre>
创建生成二维码的类方法
<pre>/
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];
}
</pre>
根据CIImage生成指定大小的UIImage
<pre>/** 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];
}
</pre>
生成一张带有logo的二维码
<pre>
/**
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;
}</pre>
生成一张彩色的二维码
<pre>+ (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];
}
</pre>
<h4>图片效果</h4>
readme.png
<h3>Github地址:https://github.com/jwh1650715313/QRcode</h3>
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