ios 将 UIImage 转换为 NSData
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convert UIImage to NSData
提问by Christina
I am using this code in my app which will help me to send a image.
我在我的应用程序中使用此代码，它将帮助我发送图像。
However, I have an image view with an image. I have no file in appbundle but have the image in my side. How can I change the below code ? Can anyone tell me how can I convert myimageto NSData?
但是，我有一个带有图像的图像视图。我在 appbundle 中没有文件，但在我身边有图像。如何更改以下代码？谁能告诉我如何转换myimage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"];
回答by sergio
Try one of the following, depending on your image format:
根据您的图像格式，尝试以下操作之一：
UIImageJPEGRepresentation
Returns the data for the specified image in JPEG format.
UIImageJPEG 表示
以 JPEG 格式返回指定图像的数据。
NSData * UIImageJPEGRepresentation (
UIImage *image,
CGFloat compressionQuality
);
UIImagePNGRepresentation
Returns the data for the specified image in PNG format
UIImagePNG 表示
以PNG格式返回指定图像的数据
NSData * UIImagePNGRepresentation (
UIImage *image
);
EDIT:
编辑：
if you want to access the raw bytes that make up the UIImage, you could use this approach:
如果要访问构成 UIImage 的原始字节，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];
This will give you the low-level representation of the image RGB pixels.
(Omit the CFBridgingReleasebit if you are not using ARC).
这将为您提供图像 RGB 像素的低级表示。（CFBridgingRelease如果您不使用 ARC，请省略该位）。
回答by Radix
NSData *imageData = UIImagePNGRepresentation(myImage.image);
回答by FormigaNinja
If you have an image inside a UIImageView , e.g. "myImageView", you can do the following:
如果您在 UIImageView 中有图像，例如“myImageView”，您可以执行以下操作：
Convert your image using UIImageJPEGRepresentation() or UIImagePNGRepresentation() like this:
使用 UIImageJPEGRepresentation() 或 UIImagePNGRepresentation() 转换您的图像，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).
You can also put this code inside a GCD block and execute in another thread, showing an UIActivityIndicatorView during the process ...
您也可以将此代码放在 GCD 块中并在另一个线程中执行，在此过程中显示 UIActivityIndicatorView ...
//*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*
});
});
回答by Jemythehigh
Create the reference of image....
创建图像的参考....
UIImage *rainyImage = [UIImage imageNamed:@"rainy.jpg"];
displaying image in image view... imagedisplayis reference of imageview:
在图像视图中显示图像... imagedisplay是 imageview 的参考：
imagedisplay.image = rainyImage;
convert it into NSDataby passing UIImagereference and provide compression quality in float values:
NSData通过传递UIImage引用将其转换为浮点值并提供压缩质量：
NSData *imgData = UIImageJPEGRepresentation(rainyImage, 0.9);
回答by Charlton Provatas
Solution in Swift 4
Swift 4 中的解决方案
extension UIImage {
var data : Data? {
return cgImage?.dataProvider?.data as Data?
}
}
回答by Krunal
Use if-let block with Data to prevent app crash & safe execution of code, as function UIImagePNGRepresentation returns an optional value.
使用带有数据的 if-let 块来防止应用程序崩溃和安全执行代码，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...
}
}
Note: Datais Swift 3 class. Use Data instead of NSData with Swift 3
注意：数据是 Swift 3 类。在 Swift 3 中使用 Data 而不是 NSData
Generic image operations (like png & jpg both):
通用图像操作（如 png 和 jpg 两者）：
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...
}
}
By using extension:
通过使用扩展：
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...
}
}
回答by Jayesh Mardiya
- (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];
}
