i have CGImageRef object (var quartzImage). How convert this object to format PNG data for web:
"data:image/png;base64,"+ base64 data image
my code:
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer, 0);
void *baseAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGImageRef quartzImage = CGBitmapContextCreateImage(context);
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
NSLog(#"%#",quartzImage);
}
If you already have a CGImageRef (with name quartzImage in your code) then you do not need to create an NSImage. Create a NSBitmapImageRep directly. And you should in no case use the lockFocus method. This is good for images that shall be depicted to the screen. And therefore lockFocus usually creates images with a resolution of 72 dpi and 144 dpi for Retina screens. Or do you want to create images for the web with the properties of your screen? Try this:
NSBitmapImageRep *bitmapRep = [[NSBitmapImageRep alloc] initWithCGImage:quartzImage];
NSData *repData = [bitmapRep representationUsingType:NSPNGFileType] properties:nil];
NSString *base64String = [repData base64EncodedStringWithOptions:0];
This base64… method is not available before OS X 10.9. In that case you should use base64Encoding
NSImage *image = [NSImage imageWithCGImage:imageRef];
[image lockFocus];
NSBitmapImageRep *bitmapRep = [[NSBitmapImageRep alloc] initWithFocusedViewRect:NSMakeRect(0, 0, image.size.width, image.size.height)];
[image unlockFocus];
NSData *imageData = [bitmapRep representationUsingType:NSPNGFileType properties:nil];;
NSString *base64String = [imageData base64EncodedStringWithOptions:0];
Related
I have a custom class Frame that gets image data from multiple sources. The class can generate an UIImage. The problem is when a generated UIImage is drawn on the screen, it crashes with EXC_BAD_ACCESS.
Callstack is empty, it ends at start->main->UIApplicationMain.
I think it has something to do with CGImageCreate and that the pointer isn't retained somehow. But I have a hard time figuring out why. The XCode debugger shows the UIImage exists right before it's added as a subview through UIImageView, but after it just crashes. I've also tried to draw it directly to a custom UIView with drawRect, but it crashes with EXC_BAD_ACCESS at drawRect.
Any thoughts would be greatly appreciated!
Here's the code:
UIImage *image = [UIImage imageNamed:#"test.png"];
// To NSData
CGImageRef imageRef = image.CGImage;
CFDataRef dataRef = CGDataProviderCopyData(CGImageGetDataProvider(imageRef));
const unsigned char *pixels = CFDataGetBytePtr(dataRef);
const signed long length = CFDataGetLength(dataRef);
NSData *data = [NSData dataWithBytes:pixels length:length];
CGFloat width = CGImageGetWidth(imageRef);
CGFloat height = CGImageGetHeight(imageRef);
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
// NSData to UIImage
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGDataProviderRef dataProviderRef =
CGDataProviderCreateWithData(NULL, data.bytes, data.length, NULL);
CGImageRef imageRef2 =
CGImageCreate(width, height, 8, 32, 4 * width, colorSpaceRef, bitmapInfo,
dataProviderRef, NULL, NO, kCGRenderingIntentDefault);
UIImage *image2 = [UIImage imageWithCGImage:imageRef2];
CGColorSpaceRelease(colorSpaceRef);
CGDataProviderRelease(dataProviderRef);
CGImageRelease(imageRef);
//Show UIImage
UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.view.frame];
imageView.image = image2;
//Breakpoint here shows that `image2` is equal to `image`
[self.view addSubview:imageView];
//EXC_BAD_ACCESS
I am trying to send an image through sockets to a server, but the image doesn't appear well on the server side.
I am using this code, what can be the problem? I am sending text to the server and it works, but the image appears unformatted.
UIImage *imageResized=[self resizeImage:editedImage newSize:CGSizeMake(64,32)];
NSData *imageData = UIImageJPEGRepresentation(imageResized, 1.0f);
NSString *encodedString = [imageData base64EncodedStringWithOptions:nil];
NSString *finalStr= [NSString stringWithFormat:#"image:%#",encodedString];
NSData* data = [finalStr dataUsingEncoding:NSASCIIStringEncoding];
[tcpsocket initNetworkCommunication:[tcpSocket linkWebserviceInet1] porta:[tcpSocket linkWebport]];
[tcpsocket sendNSData:data];
- (UIImage *)resizeImage:(UIImage*)image newSize:(CGSize)newSize {
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGImageRef imageRef = image.CGImage;
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
// Set the quality level to use when rescaling
CGContextSetInterpolationQuality(context, kCGInterpolationHigh);
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, newSize.height);
CGContextConcatCTM(context, flipVertical);
// Draw into the context; this scales the image
CGContextDrawImage(context, newRect, imageRef);
// Get the resized image from the context and a UIImage
CGImageRef newImageRef = CGBitmapContextCreateImage(context);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
CGImageRelease(newImageRef);
UIGraphicsEndImageContext();
return newImage;
}
I create NSBitmapImageRep witch I fill with glReadPixels information. It looks like this:
NSBitmapImageRep *imageRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:width pixelsHigh:height bitsPerSample:8 samplesPerPixel:3 hasAlpha:NO isPlanar:NO colorSpaceName:NSDeviceRGBColorSpace bytesPerRow:3 * width bitsPerPixel:0];
glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, [imageRep bitmapData]);
and later turn it to NSData and write to file. But I get flipped upside down image. How can I fix it?
Draw into a flipped NSImage. This will draw the upsidedown image to the correct orientation. You then get the tiff representation of the NSImage which you can change to other image types using another NSBitmapImageRep with imageRepWithData:. Use the new image representation to make a new NSData object using representationUsingType:properties: and save the new NSData object to file.
NSRect rect = self.bounds;
NSSize size = rect.size;
GLsizei width = (GLsizei)size.width;
GLsizei height = (GLsizei)size.height;
NSBitmapImageRep* imgRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:width pixelsHigh:height bitsPerSample:8 samplesPerPixel:3 hasAlpha:NO isPlanar:NO colorSpaceName:NSDeviceRGBColorSpace bytesPerRow:width*3 bitsPerPixel:0];
glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, [imgRep bitmapData]);
#ifdef __MAC_10_8
NSImage* image = [NSImage imageWithSize:size flipped:YES drawingHandler:^(NSRect dstRect){
return [imgRep drawInRect:dstRect];
}];
#else
NSImage* image = [[NSImage alloc] initWithSize:size];
[image lockFocusFlipped:YES];
[imgRep drawInRect:rect];
[image unlockFocus];
#endif
NSData* tiff = [image TIFFRepresentation];
bytesPerRow should be (width*3+3)&~3
I have an NSImageView which I get an image for from an NSOpenPanel. That works great.
Now, how can I take that NSImage, half its size and save it as the same format in the same directory as the original as well?
If you can help at all with anything I'd appreciate it, thanks.
Check the ImageCrop sample project from Matt Gemmell:
http://mattgemmell.com/source/
Nice example how to resize / crop images.
Finally you can use something like this to save the result (dirty sample):
// Write to TIF
[[resultImg TIFFRepresentation] writeToFile:#"/Users/Anne/Desktop/Result.tif" atomically:YES];
// Write to JPG
NSData *imageData = [resultImg TIFFRepresentation];
NSBitmapImageRep *imageRep = [NSBitmapImageRep imageRepWithData:imageData];
NSDictionary *imageProps = [NSDictionary dictionaryWithObject:[NSNumber numberWithFloat:0.9] forKey:NSImageCompressionFactor];
imageData = [imageRep representationUsingType:NSJPEGFileType properties:imageProps];
[imageData writeToFile:#"/Users/Anne/Desktop/Result.jpg" atomically:NO];
Since NSImage objects are immutable you will have to:
Create a Core Graphics context the size of the new image.
Draw the NSImage into the CGContext. It should automatically scale it for you.
Create an NSImage from that context
Write out the new NSImage
Don't forget to release any temporary objects you allocated.
There are definitely other options, but this is the first one that came to mind.
+(NSImage*) resize:(NSImage*)aImage scale:(CGFloat)aScale
{
NSImageView* kView = [[NSImageView alloc] initWithFrame:NSMakeRect(0, 0, aImage.size.width * aScale, aImage.size.height* aScale)];
[kView setImageScaling:NSImageScaleProportionallyUpOrDown];
[kView setImage:aImage];
NSRect kRect = kView.frame;
NSBitmapImageRep* kRep = [kView bitmapImageRepForCachingDisplayInRect:kRect];
[kView cacheDisplayInRect:kRect toBitmapImageRep:kRep];
NSData* kData = [kRep representationUsingType:NSJPEGFileType properties:nil];
return [[NSImage alloc] initWithData:kData];
}
Here is a specific implementation
-(NSImage*)resizeImage:(NSImage*)input by:(CGFloat)factor
{
NSSize size = NSZeroSize;
size.width = input.size.width*factor;
size.height = input.size.height*factor;
NSImage *ret = [[NSImage alloc] initWithSize:size];
[ret lockFocus];
NSAffineTransform *transform = [NSAffineTransform transform];
[transform scaleBy:factor];
[transform concat];
[input drawAtPoint:NSZeroPoint fromRect:NSZeroRect operation:NSCompositeCopy fraction:1.0];
[ret unlockFocus];
return [ret autorelease];
}
Keep in mind that this is pixel based, with HiDPI the scaling must be taken into account, it is simple to obtain :
-(CGFloat)pixelScaling
{
NSRect pixelBounds = [self convertRectToBacking:self.bounds];
return pixelBounds.size.width/self.bounds.size.width;
}
Apple has source code for downscaling and saving images found here
http://developer.apple.com/library/mac/#samplecode/Reducer/Introduction/Intro.html
Here is some code that makes a more extensive use of Core Graphics than other answers. It's made according to hints in Mark Thalman's answer to this question.
This code downscales an NSImage based on a target image width. It's somewhat nasty, but still useful as an extra sample for documenting how to draw an NSImage in a CGContext, and how to write contents of CGBitmapContext and CGImage into a file.
You may want to add extra error checking. I didn't need it for my use case.
- (void)generateThumbnailForImage:(NSImage*)image atPath:(NSString*)newFilePath forWidth:(int)width
{
CGSize size = CGSizeMake(width, image.size.height * (float)width / (float)image.size.width);
CGColorSpaceRef rgbColorspace = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGImageAlphaPremultipliedLast;
CGContextRef context = CGBitmapContextCreate(NULL, size.width, size.height, 8, size.width * 4, rgbColorspace, bitmapInfo);
NSGraphicsContext * graphicsContext = [NSGraphicsContext graphicsContextWithGraphicsPort:context flipped:NO];
[NSGraphicsContext setCurrentContext:graphicsContext];
[image drawInRect:NSMakeRect(0, 0, size.width, size.height) fromRect:NSMakeRect(0, 0, image.size.width, image.size.height) operation:NSCompositeCopy fraction:1.0];
CGImageRef outImage = CGBitmapContextCreateImage(context);
CFURLRef outURL = (CFURLRef)[NSURL fileURLWithPath:newFilePath];
CGImageDestinationRef outDestination = CGImageDestinationCreateWithURL(outURL, kUTTypeJPEG, 1, NULL);
CGImageDestinationAddImage(outDestination, outImage, NULL);
if(!CGImageDestinationFinalize(outDestination))
{
NSLog(#"Failed to write image to %#", newFilePath);
}
CFRelease(outDestination);
CGImageRelease(outImage);
CGContextRelease(context);
CGColorSpaceRelease(rgbColorspace);
}
To resize image
- (NSImage *)scaleImage:(NSImage *)anImage newSize:(NSSize)newSize
{
NSImage *sourceImage = anImage;
if ([sourceImage isValid])
{
if (anImage.size.width == newSize.width && anImage.size.height == newSize.height && newSize.width <= 0 && newSize.height <= 0) {
return anImage;
}
NSRect oldRect = NSMakeRect(0.0, 0.0, anImage.size.width, anImage.size.height);
NSRect newRect = NSMakeRect(0,0,newSize.width,newSize.height);
NSImage *newImage = [[NSImage alloc] initWithSize:newSize];
[newImage lockFocus];
[sourceImage drawInRect:newRect fromRect:oldRect operation:NSCompositeCopy fraction:1.0];
[newImage unlockFocus];
return newImage;
}
}
I'm trying to save a multiple masked image to disk.
The code below explains How I do it. The maskImagewithStroke masks 2 times a picture : first time to provide an irregular stroke to a texture then I'm remasking it with a bigger mask to get a stroke from it. It's the bast way I found to get an irregular stroke around my texture.
Now, for the sake of the iPhone and its performance, I'd like to generate all masked textures and save them to disk. I'll use thos files in another app to load premasked textures. the masking process is perfect on screen but when saving file i'm have a black image with the irregular stroke BUT without texture in it ... How may I change that ?
I'm calling the method masImageWihStrokandSaveToFile to launch the maskin + saving process..
-(void)masImageWihStrokandSaveToFile:(UIImage *)image withMask:(UIImage *)maskImage imageIndex:(NSInteger)i{
//mask image with stroke
//[self maskImageWithStroke:image withMask:maskImage];
//save masked image to disk
// Create paths to output images
NSString *pngPath = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:#"Documents/Test_%d.png",i]];
NSString *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Test.jpg"];
// Write a UIImage to JPEG with minimum compression (best quality)
// The value 'image' must be a UIImage object
// The value '1.0' represents image compression quality as value from 0.0 to 1.0
[UIImageJPEGRepresentation([self maskImageWithStroke:image withMask:maskImage], 1.0) writeToFile:jpgPath atomically:YES];
// Write image to PNG
[UIImagePNGRepresentation([self maskImageWithStroke:image withMask:maskImage]) writeToFile:pngPath atomically:YES];
// Let's check to see if files were successfully written...
// Create file manager
NSError *error;
NSFileManager *fileMgr = [NSFileManager defaultManager];
// Point to Document directory
NSString *documentsDirectory = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents"];
// Write out the contents of home directory to console
NSLog(#"Documents directory: %#", [fileMgr contentsOfDirectoryAtPath:documentsDirectory error:&error]);
}
- (UIImage *) maskImageWithStroke:(UIImage *)image withMask:(UIImage *)maskImage{
UIImage* maskedImage = [self maskImage:image withMask:maskImage];
//****** Add a Stroke - Begin *******//
//grow the actual mask
UIImage* biggerMaskImage = [maskImage scaleToSize:CGSizeMake(310,310)];
//now add a stroke to the image.
//UIImage *bottomImage = [UIImage imageNamed:#"bottom.png"];
//UIImage *image = [UIImage imageNamed:#"top.png"];
CGSize newSize = CGSizeMake(310, 310);
UIGraphicsBeginImageContext( newSize );
// Use existing opacity as is
//[biggerMaskImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
//[biggerMaskImage drawInRect:CGRectMake(0,0,410,410)];
[maskImage drawInRect:CGRectMake(0,0,310,310)];
// Apply supplied opacity
//[retImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.8];
[maskedImage drawInRect:CGRectMake(0,0,300,300) blendMode:kCGBlendModeNormal alpha:1];
UIImage *maskedStrokedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//****** Add a Stroke - End *******//
//****** Remask - Begin ******//
maskedStrokedImage = [self maskImage:maskedStrokedImage withMask:biggerMaskImage];
//****** Remask - End ******//
return maskedStrokedImage;
}
/*************Mask Images ***************/
CGImageRef CopyImageAndAddAlphaChannel(CGImageRef sourceImage) {
CGImageRef retVal = NULL;
size_t width = CGImageGetWidth(sourceImage);
size_t height = CGImageGetHeight(sourceImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef offscreenContext = CGBitmapContextCreate(NULL, width, height,
8, 0, colorSpace, kCGImageAlphaPremultipliedFirst);
if (offscreenContext != NULL) {
CGContextDrawImage(offscreenContext, CGRectMake(0, 0, width, height), sourceImage);
retVal = CGBitmapContextCreateImage(offscreenContext);
CGContextRelease(offscreenContext);
}
CGColorSpaceRelease(colorSpace);
return retVal;
}
// masker method
- (UIImage*)maskImage:(UIImage *)image withMask:(UIImage *)maskImage {
CGImageRef maskRef = maskImage.CGImage;
CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
CGImageGetHeight(maskRef),
CGImageGetBitsPerComponent(maskRef),
CGImageGetBitsPerPixel(maskRef),
CGImageGetBytesPerRow(maskRef),
CGImageGetDataProvider(maskRef), NULL, false);
CGImageRef sourceImage = [image CGImage];
CGImageRef imageWithAlpha = sourceImage;
//add alpha channel for images that don't have one (ie GIF, JPEG, etc...)
//this however has a computational cost
if (CGImageGetAlphaInfo(sourceImage) == kCGImageAlphaNone) {
imageWithAlpha = CopyImageAndAddAlphaChannel(sourceImage);
}
CGImageRef masked = CGImageCreateWithMask(imageWithAlpha, mask);
CGImageRelease(mask);
//release imageWithAlpha if it was created by CopyImageAndAddAlphaChannel
if (sourceImage != imageWithAlpha) {
CGImageRelease(imageWithAlpha);
}
UIImage* retImage = [UIImage imageWithCGImage:masked];
//UIImage* retImage = [UIImage imageWithCGImage:maskedTransparent];
CGImageRelease(masked);
return retImage;
}