從照片庫中加載圖像

Question

1. 如何從照片庫中加載圖像並將其顯示在imageView？
2. 如何將圖片更改爲黑色和白色？

Answer 1

圖像形式UIImagePickerController轉換爲黑色和白色，你可以使用此代碼：

UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage]; // this image we get from UIImagePickerController 

CGColorSpaceRef colorSapce = CGColorSpaceCreateDeviceGray(); 
CGContextRef context = CGBitmapContextCreate(nil, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width, colorSapce, kCGImageAlphaNone); 
CGContextSetInterpolationQuality(context, kCGInterpolationHigh); 
CGContextSetShouldAntialias(context, NO); 
CGContextDrawImage(context, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), [originalImage CGImage]); 

CGImageRef bwImage = CGBitmapContextCreateImage(context); 
CGContextRelease(context); 
CGColorSpaceRelease(colorSapce); 

UIImage *resultImage = [UIImage imageWithCGImage:bwImage]; // This is result B/W image. 
CGImageRelease(bwImage); 

Answer 2

如果你想從圖片庫中加載圖片，你必須使用UIImagePickerController類。 Refer this Link