-[UIImage _imageByUnpremultiplying]: 无法识别的选择器发送到实例

Question

我正在使用CI过滤器并遇到奇怪的错误，如何通过查看日志知道我缺少什么？

CIFilter *filter = [CIFilter filterWithName:@"CIFalseColor"];        
    [filter setValue:image forKey:@"inputImage"];
    CIColor *myBlue = [CIColor colorWithRed:0.0 green:0.0 blue:0.6 alpha:0.5];
    [filter setValue:myBlue forKey:@"inputColor0"];
    CIImage *filteredImageData = [filter valueForKey:@"outputImage"];
    UIImage *newImage = [UIImage imageWithCIImage:filteredImageData];
     _imageView.image=newImage;



2014-02-22 16:04:12.002 colorMaker[1574:70b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIImage _imageByUnpremultiplying]: unrecognized selector sent to instance 0x8b7aca0'

libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb) 

- DreamWatcher

---

看起来可能是一个UIKit的bug。 - Woodstock

Answer 1

如果您将作为"inputImage"设置的对象是UIImage，则会发生此异常。根据文档，inputImage对象必须是CIImage。

首先尝试从UIImage中获取CIImage。

[filter setValue:image.CIImage forKey:@"inputImage"];
                       ^^^^^^^

- Matthias Bauch

Answer 2

在Matthia的帮助下，终于成功解决了问题。正确的代码是...

CIFilter *filter = [CIFilter filterWithName:@"CIFalseColor"];        
CIImage *  beginImage = [CIImage imageWithCGImage:image.CGImage];
// set value must be of ciimage not uiimage
[filter setValue:beginImage forKey:@"inputImage"];
CIColor *myBlue = [CIColor colorWithRed:0.0 green:0.0 blue:0.6 alpha:0.5];
[filter setValue:myBlue forKey:@"inputColor0"];
CIImage *filteredImageData = [filter valueForKey:@"outputImage"];
UIImage *newImage = [UIImage imageWithCIImage:filteredImageData];
_imageView.image=newImage;

- DreamWatcher