用CIFilter生成QRCode二维码图片

用CIFilter生成QRCode二维码图片



CIFilter不仅仅可以用来做滤镜,它还可以用来生成二维码.

CIFilterEffect.h + CIFilterEffect.m

//
//  CIFilterEffect.h
//  CIFilter
//
//  Created by YouXianMing on 14-5-9.
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import <Foundation/Foundation.h>

/*

CILinearToSRGBToneCurve
CIPhotoEffectChrome
CIPhotoEffectFade
CIPhotoEffectInstant
CIPhotoEffectMono
CIPhotoEffectNoir
CIPhotoEffectProcess
CIPhotoEffectTonal
CIPhotoEffectTransfer
CISRGBToneCurveToLinear
CIVignetteEffect

*/

@interface CIFilterEffect : NSObject

@property (nonatomic, strong, readonly) UIImage *filterImage;
- (instancetype)initWithImage:(UIImage *)image filterName:(NSString *)name;

@property (nonatomic, strong, readonly) UIImage *QRCodeImage;
- (instancetype)initWithQRCodeString:(NSString *)string width:(CGFloat)width;

@end

//
//  CIFilterEffect.m
//  CIFilter
//
//  Created by YouXianMing on 14-5-9.
//  Copyright (c) 2014年 Y.X. All rights reserved.
//

#import "CIFilterEffect.h"

@interface CIFilterEffect ()

@property (nonatomic, strong, readwrite) UIImage *filterImage;
@property (nonatomic, strong, readwrite) UIImage *QRCodeImage;

@end

@implementation CIFilterEffect

- (instancetype)initWithImage:(UIImage *)image filterName:(NSString *)name
{
self = [super init];
if (self)
{
// 将UIImage转换成CIImage
CIImage *ciImage = [[CIImage alloc] initWithImage:image];

// 创建滤镜
CIFilter *filter = [CIFilter filterWithName:name
keysAndValues:kCIInputImageKey, ciImage, nil];
[filter setDefaults];

// 获取绘制上下文
CIContext *context = [CIContext contextWithOptions:nil];

// 渲染并输出CIImage
CIImage *outputImage = [filter outputImage];

// 创建CGImage句柄
CGImageRef cgImage = [context createCGImage:outputImage
fromRect:[outputImage extent]];

_filterImage = [UIImage imageWithCGImage:cgImage];

// 释放CGImage句柄
CGImageRelease(cgImage);
}
return self;
}

- (instancetype)initWithQRCodeString:(NSString *)string width:(CGFloat)width
{
self = [super init];
if (self)
{
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

[filter setDefaults];

NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];

[filter setValue:data
forKey:@"inputMessage"];

CIImage *outputImage = [filter outputImage];

CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgImage = [context createCGImage:outputImage
fromRect:[outputImage extent]];

UIImage *image = [UIImage imageWithCGImage:cgImage
scale:0.1
orientation:UIImageOrientationUp];

// 不失真的放大
UIImage *resized = [self resizeImage:image
withQuality:kCGInterpolationNone
rate:5.0];

// 缩放到固定的宽度(高度与宽度一致)
_QRCodeImage = [self scaleWithFixedWidth:width image:resized];

CGImageRelease(cgImage);
}
return self;
}

- (UIImage *)scaleWithFixedWidth:(CGFloat)width image:(UIImage *)image
{
float newHeight = image.size.height * (width / image.size.width);
CGSize size = CGSizeMake(width, newHeight);
UIGraphicsBeginImageContextWithOptions(size, NO, 0);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextTranslateCTM(context, 0.0, size.height);
CGContextScaleCTM(context, 1.0, -1.0);

CGContextSetBlendMode(context, kCGBlendModeCopy);
CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, size.width, size.height), image.CGImage);

UIImage *imageOut = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return imageOut;
}

- (UIImage *)resizeImage:(UIImage *)image
withQuality:(CGInterpolationQuality)quality
rate:(CGFloat)rate
{
UIImage *resized = nil;
CGFloat width = image.size.width * rate;
CGFloat height = image.size.height * rate;

UIGraphicsBeginImageContext(CGSizeMake(width, height));
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, quality);
[image drawInRect:CGRectMake(0, 0, width, height)];
resized = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return resized;
}

@end

看看以下使用情况,一行代码搞定!



以下几个二维码,闲得无聊可以扫一扫......