I try to save NSBItmapImageRep without alpha channel.
My code is:
NSBitmapImageRep* rep = [[NSBitmapImageRep alloc] initWithCIImage:img];
NSColorSpace *targetColorSpace = [NSColorSpace genericGrayColorSpace];
NSBitmapImageRep *targetImageRep = [rep bitmapImageRepByConvertingToColorSpace:targetColorSpace
renderingIntent:NSColorRenderingIntentPerceptual];
NSData* PNGData = [targetImageRep representationUsingType:NSPNGFileType properties:nil];
[PNGData writeToURL:url atomically:YES];
[rep release];
But It doesn't work. It saves my image with type GrayScaleAlpha.
How to specify using alpha?
Related
Is there a way to save PDF pages to images on OS X by Xcode 5? I have searched on Stackoverflow and found this Xcode save a PDF as Image?
However it is for iOS, not OS X. I want to export PDF pages to images like JPG or PNG etc.
Thank you in advance.
Try this:
NSData *pdfData = [NSData dataWithContentsOfFile:pathToUrPDF];
NSPDFImageRep *pdfImg = [NSPDFImageRep imageRepWithData:pdfData];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSInteger pageCount = [pdfImg pageCount];
for(int i = 0 ; i < pageCount ; i++) {
[pdfImg setCurrentPage:i];
NSImage *temp = [[NSImage alloc] init];
[temp addRepresentation:pdfImg];
NSBitmapImageRep *rep = [NSBitmapImageRep imageRepWithData:[temp TIFFRepresentation]];
NSData *finalData = [rep representationUsingType:NSJPEGFileType properties:nil];
NSString *pageName = [NSString stringWithFormat:#"Page_%ld.jpg", (long)[pdfImg currentPage]];
[fileManager createFileAtPath:[NSString stringWithFormat:#"%#/%#", #"pathWrUWantToSave", pageName] contents:finalData attributes:nil];
}
I have the following code
if (! [url getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:&error]) {
// handle error
}
else if (! [isValidDirectory boolValue]) {
// No error and it’s not a directory; do something with the file
NSString* outP = [url absoluteString];
NSString* extension = [outP substringFromIndex: outP.length-3];
NSString* img = #"png";
if([extension isEqualToString:img]){
NSImage *original = [[NSImage alloc] initWithContentsOfURL: url];
NSSize sizes = NSMakeSize(240, 240);
NSImage *small =original;
[small setSize:sizes];
NSArray* representations = [small representations];
NSInteger* total = [substrings count];
NSData* bitmapData = [NSBitmapImageRep representationOfImageRepsInArray: representations usingType: NSPNGFileType properties:nil];
[bitmapData writeToFile:#"/Users/testuser/downloads/test/test_tn.png" atomically:NO];
}
when I run it it does not resize the image it just gives me a straight copy of the image with the name test_tn.png instead of a smaller image. I'm not sure what I'm doing wrong, this is a mac app also. There is some unused code in there that is for later. Is the problem how I'm passing the NSImage to the NSData after i resize?
edit: ok so i converted the NSData back into an NSImage and it appears the NSData is not getting the sized data but the original data.
edit 2: so this works
ok so this works
if([extension isEqualToString:img]){
NSImage *image = [[NSImage alloc] initWithContentsOfURL: url];
NSData *sourcedata =[image TIFFRepresentation];
NSSize newSize;
newSize.height = 160;
newSize.width = 120;
NSImage *sourceImage =[[NSImage alloc] initWithData: sourcedata];
NSImage *resizedImage = [[NSImage alloc] initWithSize: NSMakeSize(240, 240)];
NSSize originalSize = [sourceImage size];
[resizedImage lockFocus];
[sourceImage drawInRect: NSMakeRect(0, 0, 240, 240) fromRect: NSMakeRect(0, 0, originalSize.width, originalSize.height) operation: NSCompositeSourceOver fraction: 1.0];
[resizedImage unlockFocus];
NSData *resizedData = [resizedImage TIFFRepresentation];
NSData *resizedPreviewData = [resizedImage TIFFRepresentation];
NSBitmapImageRep *resizedCaptureImageBitmapRep = [[NSBitmapImageRep alloc] initWithData:resizedPreviewData];
NSData* saveData = [resizedCaptureImageBitmapRep representationUsingType:NSPNGFileType properties:nil];
[saveData writeToFile:#"/Users/testuser/downloads/test/test_tn.png" atomically:YES];
count++;
}
This works for me. I am using this code to layer images on top of each other, but it should be easily adapted to your purposes:
CGSize destinationSize = smallSize;
UIGraphicsBeginImageContext(original.size);
[Original1 drawInRect:CGRectMake(0, 0, original.size.width, original.size.height)];
[Original2 drawInRect:CGRectMake(0, 0, original.size.width, original.size.height)];
UIImage *returnImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIGraphicsBeginImageContext(destinationSize);
[returnImage drawInRect:CGRectMake(0,0,destinationSize.width,destinationSize.height)];
UIImage *smallImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I get the following error when trying to compress some jpeg data using UIImageJPEGRepresentation(image, 0.5f);
<Error>: Unsupported pixel description - 4 components, 8 bits-per-component, 32 bits-per-pixel
<Error>: CGBitmapContextCreateWithDictionary: failed to create delegate.
<Error>: CGImageDestinationAddImage image could not be converted to destination format.
<Error>: CGImageDestinationFinalize image destination does not have enough images
Here is the code snippet where I download and compress the data...
ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:[NSURL URLWithString:object.largeimage]];
[request startSynchronous];
NSData *imageData = [request responseData];
UIImage *image = [[UIImage alloc] initWithData:imageData];
NSData *compressedImageData = UIImageJPEGRepresentation(image, 0.5f);
//If the data was compressed properly...
if(compressedImageData) [compressedImageData writeToFile:filePath atomically:YES];
//If it wasn't...
else [imageData writeToFile:filePath atomically:YES];
[image release];
if(request.responseStatusCode == 200)
object.fullImageFilename = filePath;
[request release];
[request release];
Thanks in advance for any help :)
Still not sure of the "proper answer", but I managed to find a workaround for anyone who's interested :)
ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:[NSURL URLWithString:object.largeimage]];
[request startSynchronous];
NSData *imageData = [request responseData];
UIImage *image = [[UIImage alloc] initWithData:imageData];
NSData *compressedImageData = UIImageJPEGRepresentation(image, 0.5f);
//If the data was compressed properly...
if(compressedImageData) [compressedImageData writeToFile:filePath atomically:NO];
//If it wasn't...
else
{
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
compressedImageData = UIImageJPEGRepresentation(newImage, 0.5f);
[compressedImageData writeToFile:filePath atomically:NO];
[newImage release];
}
[image release];
if(request.responseStatusCode == 200)
object.fullImageFilename = filePath;
[request release];
I have this code:
NSImage * strImage = [[NSImage alloc]initWithContentsOfFile:ImageFilePath] ;
NSData *imageData = [strImage TIFFRepresentation];
What I require is to convert imageData into JPEG format. I want this to work the same as QImage save() does.
So that you can see how save() works, I will give you a link:
http://doc.qt.nokia.com/4.6/qimage.html#save
Please help me.
From CocoaDev... If you do anything with the NSImage after creating it:
NSData *imageData = [image TIFFRepresentation];
NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData];
NSNumber *compressionFactor = [NSNumber numberWithFloat:0.9];
NSDictionary *imageProps = [NSDictionary dictionaryWithObject:compressionFactor
forKey:NSImageCompressionFactor];
imageData = [imageRep representationUsingType:NSJPEGFileType properties:imageProps];
[imageData writeToFile:filename atomically:YES];
If you don't really do anything else with the NSImage before:
NSArray *representations = [myImage representations];
NSNumber *compressionFactor = [NSNumber numberWithFloat:0.9];
NSDictionary *imageProps = [NSDictionary dictionaryWithObject:compressionFactor
forKey:NSImageCompressionFactor];
NSData *bitmapData = [NSBitmapImageRep representationOfImageRepsInArray:representations
usingType:NSJPEGFileType
properties:imageProps];
[bitmapData writeToFile:filename atomically:YES];
I am receiving images from xml feed they are very large in size how can i compress them before displaying them in table-cell.
my code is
int blogEntryIndex1 = [indexPath indexAtPosition: [indexPath length] -1];
imgstring=[[blogEntries objectAtIndex: blogEntryIndex1] objectForKey: #"image"];
NSURL *url = [NSURL URLWithString:imgstring];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [[UIImage alloc] initWithData:data];
cell.imageView.image=[img autorelease];
please help me if you can.....
I've got this utility method that will scale an image :
- (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize {
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
Use it like this :
int blogEntryIndex1 = [indexPath indexAtPosition: [indexPath length] -1];
imgstring=[[blogEntries objectAtIndex: blogEntryIndex1] objectForKey: #"image"];
NSURL *url = [NSURL URLWithString:imgstring];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img = [self imageWithImage:[UIImage imageWithData:data] scaledToSize:CGSizeMake(20, 20)]; // Scale it to 20x20px
cell.imageView.image=[img autorelease];
NB I can't for the life of me remember where I got it from but it's served me well in the past
Simple to use:-
-(UIImage *)fireYourImageForCompression:(UIImage *)imgComing{
NSData *dataImgBefore = [[NSData alloc] initWithData:UIImageJPEGRepresentation((imgComing), 1.0)];//.1 BEFORE COMPRESSION
int imageSizeBefore = (int)dataImgBefore.length;
NSLog(#"SIZE OF IMAGE: %i ", imageSizeBefore);
NSLog(#"SIZE OF IMAGE in Kb: %i ", imageSizeBefore/1024);
NSData *dataCompressedImage = UIImageJPEGRepresentation(imgComing, .1); //.1 is low quality
int sizeCompressedImage = (int)dataCompressedImage.length;
NSLog(#"SIZE AFTER COMPRESSION OF IMAGE: %i ", sizeCompressedImage);
NSLog(#"SIZE AFTER COMPRESSION OF IMAGE in Kb: %i ", sizeCompressedImage/1024); //AFTER
//now change your image from compressed data
imgComing = [UIImage imageWithData:dataCompressedImage];
return imgComing;}