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UIImage: Resize, then Crop
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I have app in which i capture the image it works fine but i want to reduce the size of the image i searched from net i found some code which is here
This is my code working fine when image captured
NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
UIImage *pickedImage = [info objectForKey:UIImagePickerControllerOriginalImage];
NSData *imageData = UIImagePNGRepresentation(pickedImage);
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
I want to reduce the size of picked image i got the following code but i am did not getting it use like it use newSize but where it is using the original image to compress
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
what you can do is....
NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
UIImage *pickedImage = [info objectForKey:UIImagePickerControllerOriginalImage];
CGSize sizeCropped = CGSizeMake(602, 450);//you can adjust any size here...
pickedImage = [yourclassname imageWithImage:pickedImage scaledToSize:sizeCropped];//call below function...
+ (UIImage*)imageWithImage:(UIImage*)image
scaledToSize:(CGSize)newSize;
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
let me know it is working or not!!!!
Happy coding!!!!!
+(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize;
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
you can call this function where you want the compressed image using these lines of code.
CGSize firstSize = CGSizeMake(210.0,210.0);
UIImage *compImage=[mainclass imageWithImage:image scaledToSize:firstSize];
if you want to save that new Image with new size then after your code add that image in library with bellow line..
UIImageWriteToSavedPhotosAlbum(UIImage *image, id completionTarget, SEL completionSelector, void *contextInfo);
EX:
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);
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the image is not compressed Im using the following code
UIImage *image = [UIImage imageNamed:#"1.png"];
CGSize newSize = CGSizeMake(100.0f, 100.0f);
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
_backgroundImageView.image = newImage;
If you want to compress the image
UIImage *img = [UIImage imageNamed:#"yourimagename"];
NSData *postData = UIImageJPEGRepresentation(img, 1.0);
NSInteger imgSizeBytes = [postData length];
double imgSizeKBytes = ceil((double)imgSizeBytes / 1024);
NSString *strBytes;
if(imgSizeKBytes > 1024) {
double imgSizeMBytes = (double)imgSizeKBytes / 1024;
strBytes = [NSString stringWithFormat:#"%.1f MB", imgSizeMBytes];
}
else {
strBytes = [NSString stringWithFormat:#"%d KB", (int)imgSizeKBytes];
}
imageView.image = [UIImage imageWithData:postData scale:0.1];
You can compress with your required image size by using below code
NSData *postData = UIImageJPEGRepresentation(img, (double)(100-75)/100);
Above I have given 75.If you want to give your size,give there.
Due to some reasons, I need to transform an image from UIImage to CIImage(for processing) and to UIImage back again. I do it by UIImage-CGImage-CIImage-UIImage.Ignoring the irrelevant code, the code is showing behind.
UIImage *originalPic = [[UIImage alloc]init];//get this from UIImagePickerController
CIImage *originalCIPic = [[CIImage alloc]init];
originalCIPic = [CIImage imageWithCGImage:originalPic.CGImage];
UIImage *finalResultUIImage = [UIImage imageWithCIImage:originalCIPic];
//then I put the image on an Image View(contentMode has been set)
self.viewOfImage.contentMode = UIViewContentModeScaleAspectFit;
self.viewOfImage.image=finalResultUIImage;
//I used NSLog to check the size, but they are the same.(before transforming and after)
NSLog(#"this is the final UIImage,size is %# ",NSStringFromCGSize(finalResultUIImage.size));
But the image showing on the screen is stretched.
What's wrong with me? Or Is there any alternative choice for me?
Thank you very much andI am so sorry I have not enough reputation to post picture.
:)
Try this:
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"abcd" ofType:#"png"];
CIImage *ciImage = [CIImage imageWithContentsOfURL:[NSURL fileURLWithPath:filePath]];
UIImage *imageByCIImage = [UIImage imageWithCIImage:ciImage scale:1.0f orientation:UIImageOrientationUp];
UIGraphicsBeginImageContext(imageByCIImage.size);
[imageByCIImage drawInRect:CGRectMake(0,0,imageByCIImage.size.width,imageByCIImage.size.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
self.imageview.image = newImage;
UIGraphicsEndImageContext();
i'm trying to figure out this problem but failed after doing every thing i found on OS or google. Problem is that when i convert UIImage to NSData using UIImageJPEGRepresentation or UIImagePNGRepresentation it increases the memory size to 30Mb (believe me or not).
Here is my code
myImage= image;
LoginSinglton*loginObj = [LoginSinglton sharedInstance];
NSError *error;
NSData *pngData = UIImageJPEGRepresentation(image, scaleValue); //scaleVale is 1.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory
self.imageCurrentDateAndTime =[self getTimeAndDate];
self.filePathAndDirectory = [documentsPath stringByAppendingPathComponent:#"Photos Dir"];
NSLog(#"Documents path %#",self.filePathAndDirectory);
if (![[NSFileManager defaultManager] createDirectoryAtPath:self.filePathAndDirectory
withIntermediateDirectories:NO
attributes:nil
error:&error])
{
NSLog(#"Create directory error: %#", error);
}
self.imageName= [NSString stringWithFormat:#"photo-%#-%#.jpg",loginObj.userWebID,self.imageCurrentDateAndTime];
NSString *filePath = [self.filePathAndDirectory stringByAppendingPathComponent:self.imageName];
[pngData writeToFile:filePath atomically:YES]; //Write the file
[self writeImageThumbnailToFolder:image];
[self writeImageHomeViewThumbnailToFolder:image];
I have tried following solution as well
UIImageJPEGRepresentation - memory release issue
1- Used #autoreleasepool
2- done pngData = nil;
but still facing that memory issue.
EDIT I think i'm not able to convey my problem. It's ok if UIImageJPEGRepresentation taking huge memory,but memory should back to it's earlier position after saving that image. Hope this will help you in detail.
Use a scaleValue of less than 1. Even 0.9 will massively reduce the memory footprint with minimal quality loss.
Try this:
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
If not got solution for your expectation, no need to worry try this too:
UIImage *small = [UIImage imageWithCGImage:original.CGImage scale:0.25 orientation:original.imageOrientation];
Get sample app form here for editing image or scale:
http://mattgemmell.com/2010/07/05/mgimageutilities/
To resize using minimum memory try Using CoreGraphics
SO answer by #Mina Nabil, see full answer for more details
#import <ImageIO/ImageIO.h>
-(UIImage*) resizedImageToRect:(CGRect) thumbRect {
CGImageRef imageRef = [inImage CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;
// Build a bitmap context that's the size of the thumbRect
CGContextRef bitmap = CGBitmapContextCreate(
NULL,
thumbRect.size.width, // width
thumbRect.size.height, // height
CGImageGetBitsPerComponent(imageRef), // really needs to always be 8
4 * thumbRect.size.width, // rowbytes
CGImageGetColorSpace(imageRef),
alphaInfo
);
// Draw into the context, this scales the image
CGContextDrawImage(bitmap, thumbRect, imageRef);
// Get an image from the context and a UIImage
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage* result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap); // ok if NULL
CGImageRelease(ref);
return result;
}
I'm trying to resize an image on a background thread and the app always crashes after a few low memory warnings. How can I rewrite the code below to fix this?
float max = 1024*1024;
NSData *pngData = UIImagePNGRepresentation(setImage);
while ([pngData length] > max) {
pngData = nil;
CGSize newSize = CGSizeMake(setImage.size.width*.9, setImage.size.height *.9);
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSLog(#"scale: %f", (1024.0*1024.0)/((float)[pngData length]));
pngData = UIImagePNGRepresentation(image);
}
NSLog(#"image length: %i",[pngData length]);
[pngData writeToFile:imageLocation atomically:YES];
I have already tried doing this by calculating the scale and replace the .9 in the code with a scale value
float scale = (max)/((float)[pngData length]);
CGSize newSize = CGSizeMake(setImage.size.width*scale, setImage.size.height *scale);
This made the image too small.
The end goal is to take an image from the camera and save it to disk. I originally had to resize the image because I was getting a "Low Memory warning" when loading the image.
Your code causes an infinite loop and creates images until you run out of memory. Try something like this to fix the infinite loop:
float max = 1024*1024;
NSData *pngData = UIImagePNGRepresentation(setImage);
CGSize newSize = setImage.size;
while ([pngData length] > max) {
newSize = CGSizeMake(newSize.width * 0.9, newSize.height * 0.9);
UIGraphicsBeginImageContext(newSize);
[setImage drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSLog(#"scale: %f", (1024.0*1024.0)/((float)[pngData length]));
pngData = UIImagePNGRepresentation(image);
image = nil;
}
NSLog(#"image length: %i",[pngData length]);
[pngData writeToFile:imageLocation atomically:YES];
Is there any reason why you need to do this by hand? If you use a UIImageView and set the image either with initWithImage: or with the image property and then change UIImageView's frame the image will resize accordingly
I'm currently uploading an image to a server using Imgur on iOS with the following code:
NSData* imageData = UIImagePNGRepresentation(image);
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString* fullPathToFile = [[paths objectAtIndex:0] stringByAppendingPathComponent:#"SBTempImage.png"];
[imageData writeToFile:fullPathToFile atomically:NO];
[uploadRequest setFile:fullPathToFile forKey:#"image"];
The code works fine when run in the simulator and uploading a file from the simulator's photo library because I'm on a fast ethernet connection. However, the same code times out on the iPhone when selecting an image taken with the iPhone. So, I tried it by saving a small image from the web and attempting to upload that, which worked.
This leads me to believe the large images taken by the iPhone are timing out over the somewhat slow 3G network. Is there any way to compress/resize the image from the iPhone before sending it?
This snippet will resize the image:
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
The variable newSize is a CGSize and can be defined like so:
CGSize newSize = CGSizeMake(100.0f, 100.0f);
A self-contained solution:
- (UIImage *)compressForUpload:(UIImage *)original scale:(CGFloat)scale
{
// Calculate new size given scale factor.
CGSize originalSize = original.size;
CGSize newSize = CGSizeMake(originalSize.width * scale, originalSize.height * scale);
// Scale the original image to match the new size.
UIGraphicsBeginImageContext(newSize);
[original drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *compressedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return compressedImage;
}
Thanks to #Tuan Nguyen.
To complement #Tuan Nguyen, this is maybe the fastest and most elegant way to do that.
To link to John Muchow's post at iphonedevelopertips.com , adding a category to a UIImage is a very very handy way to scale in a very fast fashion.
Just calling
UIImage *_image = [[[UIImage alloc] initWithData:SOME_NSDATA] scaleToSize:CGSizeMake(640.0,480.0)];
returns you a 640x480 representation image of your NSDATA ( that could be an online image ) without any more line of code.
Matt Gemmell's MGImageUtilities are very nice, resizing efficiently and with some effort-reducing methods.
In this code 0.5 means 50% ...
UIImage *original = image;
UIImage *compressedImage = UIImageJPEGRepresentation(original, 0.5f);
use this simple method NSData *data = UIImageJPEGRepresentation(chosenImage, 0.2f);
Swift implementation of Zorayr's function (with a bit of a change to include height or width constraints by actual units not scale):
class func compressForUpload(original:UIImage, withHeightLimit heightLimit:CGFloat, andWidthLimit widthLimit:CGFloat)->UIImage{
let originalSize = original.size
var newSize = originalSize
if originalSize.width > widthLimit && originalSize.width > originalSize.height {
newSize.width = widthLimit
newSize.height = originalSize.height*(widthLimit/originalSize.width)
}else if originalSize.height > heightLimit && originalSize.height > originalSize.width {
newSize.height = heightLimit
newSize.width = originalSize.width*(heightLimit/originalSize.height)
}
// Scale the original image to match the new size.
UIGraphicsBeginImageContext(newSize)
original.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
let compressedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return compressedImage
}
#import <ImageIO/ImageIO.h>
#import <MobileCoreServices/MobileCoreServices.h>
+ (UIImage *)resizeImage:(UIImage *)image toResolution:(int)resolution {
NSData *imageData = UIImagePNGRepresentation(image);
CGImageSourceRef src = CGImageSourceCreateWithData((__bridge CFDataRef)imageData, NULL);
CFDictionaryRef options = (__bridge CFDictionaryRef) #{
(id) kCGImageSourceCreateThumbnailWithTransform : #YES,
(id) kCGImageSourceCreateThumbnailFromImageAlways : #YES,
(id) kCGImageSourceThumbnailMaxPixelSize : #(resolution)
};
CGImageRef thumbnail = CGImageSourceCreateThumbnailAtIndex(src, 0, options);
CFRelease(src);
UIImage *img = [[UIImage alloc]initWithCGImage:thumbnail];
return img;
}
Swift 2.0 version of Jagandeep Singh method but need to convert data to image because NSData? is not converted UIImage automatically.
let orginalImage:UIImage = image
let compressedData = UIImageJPEGRepresentation(orginalImage, 0.5)
let compressedImage = UIImage(data: compressedData!)
NsData *data=UiImageJPEGRepresentation(Img.image,0.2f);
UIImage *image = [UIImage imageNamed:#"image.png"];
NSData *imgData1 = UIImageJPEGRepresentation(image, 1);
NSLog(#"Original --- Size of Image(bytes):%d",[imgData1 length]);
NSData *imgData2 = UIImageJPEGRepresentation(image, 0.5);
NSLog(#"After --- Size of Image(bytes):%d",[imgData2 length]);
image = [UIImage imageWithData:imgData2];
imgTest.image = image;
try to convert JPG by scaling factor. Here I am using 0.5
In my case:
Original --- Size of Image(bytes): 85KB & After --- Size of Image(bytes): 23KB
-(UIImage *) resizeImage:(UIImage *)orginalImage resizeSize:(CGSize)size
{
CGFloat actualHeight = orginalImage.size.height;
CGFloat actualWidth = orginalImage.size.width;
// if(actualWidth <= size.width && actualHeight<=size.height)
// {
// return orginalImage;
// }
float oldRatio = actualWidth/actualHeight;
float newRatio = size.width/size.height;
if(oldRatio < newRatio)
{
oldRatio = size.height/actualHeight;
actualWidth = oldRatio * actualWidth;
actualHeight = size.height;
}
else
{
oldRatio = size.width/actualWidth;
actualHeight = oldRatio * actualHeight;
actualWidth = size.width;
}
CGRect rect = CGRectMake(0.0,0.0,actualWidth,actualHeight);
UIGraphicsBeginImageContext(rect.size);
[orginalImage drawInRect:rect];
orginalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return orginalImage;
}
This is the method calling
UIImage *compimage=[appdel resizeImage:imagemain resizeSize:CGSizeMake(40,40)];
it returns image this image u can display any where...........
You should be able to make a smaller image by doing something like
UIImage *small = [UIImage imageWithCGImage:original.CGImage scale:0.25 orientation:original.imageOrientation];
(for a quarter-size image) then convert the smaller image to a PNG or whatever format you need.