将UIImage转换为NSData

| 我在我的应用程序中使用此代码,这将有助于我发送图像。 但是,我有一个带有图像的图像视图。我的文件中没有文件,但图像在我的身边。如何更改以下代码?谁能告诉我如何将
myimage
转换为
NSData
// Attach an image to the email
NSString *path = [[NSBundle mainBundle] pathForResource:@\"rainy\" ofType:@\"jpg\"];
NSData *myData = [NSData dataWithContentsOfFile:path];
[picker addAttachmentData:myData mimeType:@\"image/jpeg\" fileName:@\"rainy\"];
    
已邀请:
        请尝试以下方法之一,具体取决于您的图像格式:   UIImageJPEGRepresentation      以JPEG格式返回指定图像的数据。
NSData * UIImageJPEGRepresentation (
   UIImage *image,
   CGFloat compressionQuality
);
  UIImagePNGRepresentation      以PNG格式返回指定图像的数据
NSData * UIImagePNGRepresentation (
   UIImage *image
);
这里是文档。 编辑: 如果要访问组成UIImage的原始字节,则可以使用以下方法:
CGDataProviderRef provider = CGImageGetDataProvider(image.CGImage);
NSData* data = (id)CFBridgingRelease(CGDataProviderCopyData(provider));
const uint8_t* bytes = [data bytes];
这将为您提供图像RGB像素的低级表示。 (如果不使用ARC,请省略ѭ6位)。     
        
NSData *imageData = UIImagePNGRepresentation(myImage.image);
    
        如果您在UIImageView中有图片,例如\“ myImageView \”,您可以执行以下操作: 使用UIImageJPEGRepresentation()或UIImagePNGRepresentation()转换图像,如下所示:
NSData *data = UIImagePNGRepresentation(myImageView.image);
//or
NSData *data = UIImageJPEGRepresentation(myImageView.image, 0.8);
//The float param (0.8 in this example) is the compression quality 
//expressed as a value from 0.0 to 1.0, where 1.0 represents 
//the least compression (or best quality).
您还可以将此代码放入GCD块中,并在另一个线程中执行,以显示在此过程中的UIActivityIndi​​catorView ...
//*code to show a loading view here*

dispatch_queue_t myQueue = dispatch_queue_create(\"com.my.queue\", DISPATCH_QUEUE_SERIAL);

dispatch_async(myQueue, ^{ 

    NSData *data = UIImagePNGRepresentation(myImageView.image);
    //some code....

    dispatch_async( dispatch_get_main_queue(), ^{
        //*code to hide the loading view here*
    });
});
    
        创建图像的参考。
UIImage *rainyImage = [UIImage imageNamed:@\"rainy.jpg\"];
在图像视图中显示图像... imagedisplay是imageview的引用:
imagedisplay.image = rainyImage;
通过传递
UIImage
参考将其转换为
NSData
并以浮点值提供压缩质量:
NSData *imgData = UIImageJPEGRepresentation(rainyImage, 0.9);
    
        Swift 4中的解决方案
extension UIImage {
    var data : Data? {
      return cgImage?.dataProvider?.data as Data?
    }
}
    
        将if-let块与Data结合使用可防止应用崩溃和代码安全执行,因为函数UIImagePNGRepresentation返回一个可选值。
if let img = UIImage(named: \"TestImage.png\") {
    if let data:Data = UIImagePNGRepresentation(img) {
       // Handle operations with data here...         
    }
}
  注意:数据是Swift 3类。使用Data代替NSData   迅捷3 通用图像操作(如png和jpg均如此):
if let img = UIImage(named: \"TestImage.png\") {  //UIImage(named: \"TestImage.jpg\")
        if let data:Data = UIImagePNGRepresentation(img) {
               handleOperationWithData(data: data)     
        } else if let data:Data = UIImageJPEGRepresentation(img, 1.0) {
               handleOperationWithData(data: data)     
        }
}

*******
func handleOperationWithData(data: Data) {
     // Handle operations with data here...
     if let image = UIImage(data: data) {
        // Use image...
     }
}
通过使用扩展名:
extension UIImage {

    var pngRepresentationData: Data? {
        return UIImagePNGRepresentation(img)
    }

    var jpegRepresentationData: Data? {
        return UIImageJPEGRepresentation(self, 1.0)
    }
}

*******
if let img = UIImage(named: \"TestImage.png\") {  //UIImage(named: \"TestImage.jpg\")
      if let data = img.pngRepresentationData {
              handleOperationWithData(data: data)     
      } else if let data = img.jpegRepresentationData {
              handleOperationWithData(data: data)     
     }
}

*******
func handleOperationWithData(data: Data) {
     // Handle operations with data here...
     if let image = UIImage(data: data) {
        // Use image...
     }
}
    
        
- (void) imageConvert
{
     UIImage *snapshot = self.myImageView.image;
     [self encodeImageToBase64String:snapshot];
}    


call this method for image convert in base 64 
    -(NSString *)encodeImageToBase64String:(UIImage *)image
    {
        return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
    }
    

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