[英]convert UIImage to NSData
我在我的應用程序中使用此代碼,這將幫助我發送圖像。
但是,我有一個帶圖像的圖像視圖。 我沒有appbundle文件,但我的身邊有圖像。 如何更改以下代碼? 任何人都可以告訴我如何將myimage
轉換為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"];
請嘗試以下操作之一,具體取決於您的圖像格式:
UIImageJPEGRepresentation
以JPEG格式返回指定圖像的數據。
NSData * UIImageJPEGRepresentation (
UIImage *image,
CGFloat compressionQuality
);
UIImagePNGRepresentation
以PNG格式返回指定圖像的數據
NSData * UIImagePNGRepresentation (
UIImage *image
);
這里的文檔 。
編輯:
如果要訪問構成UIImage的原始字節,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];
這將為您提供圖像RGB像素的低級表示。 (如果不使用ARC,則省略CFBridgingRelease
位)。
NSData *imageData = UIImagePNGRepresentation(myImage.image);
如果你在UIImageView中有一個圖像,例如“myImageView”,你可以執行以下操作:
使用UIImageJPEGRepresentation()或UIImagePNGRepresentation()轉換圖像,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).
您還可以將此代碼放在GCD塊中並在另一個線程中執行,在此過程中顯示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*
});
});
創建圖像的引用....
UIImage *rainyImage = [UIImage imageNamed:@"rainy.jpg"];
在圖像視圖中顯示圖像... imagedisplay是imageview的參考:
imagedisplay.image = rainyImage;
通過傳遞UIImage
引用將其轉換為NSData
,並以浮點值提供壓縮質量:
NSData *imgData = UIImageJPEGRepresentation(rainyImage, 0.9);
Swift 4中的解決方案
extension UIImage {
var data : Data? {
return cgImage?.dataProvider?.data as Data?
}
}
使用if-let阻止數據以防止應用程序崩潰和安全執行代碼,因為函數UIImagePNGRepresentation返回一個可選值。
if let img = UIImage(named: "TestImage.png") {
if let data:Data = UIImagePNGRepresentation(img) {
// Handle operations with data here...
}
}
注意: 數據是Swift 3類。 在Swift 3中使用Data而不是NSData
通用圖像操作(如png和jpg):
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...
}
}
通過使用擴展名:
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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