为CIImage添加类目
#import <CoreImage/CoreImage.h>
#import <UIKit/UIKit.h>
@interface CIImage (Extension)
/**
* 根据CIImage生成指定大小的UIImage
*
* @param size 图片宽度
*/
- (UIImage *)createNonInterpolatedWithSize:(CGFloat)size;
@end
#import "CIImage+Extension.h"
@implementation CIImage (Extension)
/**
* 根据CIImage生成指定大小的UIImage
*
* @param size 图片宽度
*/
- (UIImage *)createNonInterpolatedWithSize:(CGFloat)size
{
CGRect extent = CGRectIntegral(self.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:self 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
使用
// 引入库名和类目
#import <CoreImage/CoreImage.h>
#import "CIImage+Extension.h"
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
// 1.创建滤镜对象
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 2.恢复默认设置
[filter setDefaults];
// 3.设置数据
NSString *info = @"http://www.baidu.com";
NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
[filter setValue:infoData forKeyPath:@"inputMessage"];
// 4.生成二维码
CIImage *outputImage = [filter outputImage];
self.imageView.image = [outputImage createNonInterpolatedWithSize:200];
}
