I am trying capture UIIMage with UIGraphicsBeginImageContext(); but my code capture the whole screen then save it into photo library ...
UIGraphicsBeginImageContext(self.view.frame.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
UIImageWriteToSavedPhotosAlbum(screenshot, nil, nil, nil);
UIGraphicsEndImageContext();
I just want capture my UIImageView things on it ! ...
any suggest ?
Found it ! :
UIGraphicsBeginImageContext(image.bounds.size);
[image.layer
renderInContext:UIGraphicsGetCurrentContext()];
Related
I'm creating many colour variations of an image using Core Graphics. I need to create about 320 in total but gradually, the memory usage of the app keeps increasing until it crashes. From Instruments, I see that more CGImage objects are being created and stay alive. I want to release them because I store the images to the cache directory in PNG format.
I have searched through all other solutions I could find without success. Any help is appreciated. Thanks.
Here's the main part:
+(UIImage *)tintedImageFromImage:(UIImage *)sourceImage colour:(UIColor *)color intensity:(float)intensity {
if (UIGraphicsBeginImageContextWithOptions != NULL) {
UIGraphicsBeginImageContextWithOptions(sourceImage.size, NO, 0.0);
} else {
UIGraphicsBeginImageContext(sourceImage.size);
}
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect rect = CGRectMake(0, 0, sourceImage.size.width, sourceImage.size.height);
// draw alpha-mask
CGContextSetBlendMode(context, kCGBlendModeNormal);
CGContextDrawImage(context, rect, sourceImage.CGImage);
// draw tint color, preserving alpha values of original image
CGContextSetBlendMode(context, kCGBlendModeSourceIn);
[color setFill];
CGContextFillRect(context, rect);
//Set the original greyscale template as the overlay of the new image
sourceImage = [self verticallyFlipImage:sourceImage];
[sourceImage drawInRect:CGRectMake(0,0, sourceImage.size.width,sourceImage.size.height) blendMode:kCGBlendModeMultiply alpha:intensity];
UIImage *colouredImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
colouredImage = [self verticallyFlipImage:colouredImage];
return colouredImage;
}
this is used to flip the image:
+(UIImage *)verticallyFlipImage:(UIImage *)originalImage {
UIImageView *tempImageView = [[UIImageView alloc] initWithImage:originalImage];
UIGraphicsBeginImageContext(tempImageView.frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, tempImageView.frame.size.height);
CGContextConcatCTM(context, flipVertical);
[tempImageView.layer renderInContext:context];
UIImage *flippedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return flippedImage;
}
Add to verticallyFlipImage the line tempImageView.image = nil; in order to make the image view release the image. This solves the problem.
I must be doing something wrong, but I could use some advice on the following:
I am trying to capture a partial screen on both iPad and iPad retina.
I can get the portrait views ok, but I cannot get the right side of a landscape view to be in bounds.
This is the code I'm using (I did not have this problem before UIGetScreenImage() was made contraband)..
CGRect screenRect = [[UIScreen mainScreen] bounds];
UIGraphicsBeginImageContext(screenRect.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
[[UIColor blackColor] set];
CGContextFillRect(ctx, screenRect);
[self.view.layer renderInContext:ctx];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect([img CGImage], CGRectMake (0, 100, self.view.bounds.size.width, (self.view.bounds.size.height - 200)));
UIImage *img2Save = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
// Request to save the image to camera roll
UIImageWriteToSavedPhotosAlbum(img2Save, self, nil, nil);
These are the two images I get for portrait, and landscape:
If you are using your window as your frame, it will always show up in portrait mode. You can set screenRect to a full-screen view, which should work in both portrait and landscape mode.
This line of code has no effect. It does not change orientation of the image. What am I doing wrong?
// image is of type UIImage
UIImage * newImage = [UIImage imageWithCGImage:[image CGImage] scale:image.scale orientation:UIImageOrientationLeft];
Refer to the definition of this method below, make sure your CGImage is of a CGImageRef class.
imageWithCGImage:[image CGImage]
+(UIImage *)imageWithCGImage:(CGImageRef)imageRef scale:(CGFloat)scale orientation:(UIImageOrientation)orientation
Following three lines are some initializations before you call the method.
CIContext * context = [CIContext contextWithOptions:nil]; //your choice
CIImage * OriginalImage = [CIImage imageWithContentsOfURL:fileNameAndPath]; //your own choice of source image file.
CGImageRef CGImage = [context createCGImage:OriginalImage fromRect:(CGRect)];
UIImage *newImage = [UIImage imageWithCGImage:CGImage scale:1.0 orientation:UIImageOrientationLeft]
Hope this helps.
In the drawrect function of a UIView I use CGContext to draw some shapes. This Works fine, I can see my shapes.
Now I'm trying to save what has been drawn on the view as a png on disk. I've read various docs / articles but nothing gets saved. Im testing on the simulator for ios 4.3.
Edit 1
I changed my code and uncommented the context part. I can save the png but it is blank.
- (void)drawRect:(CGRect)rect
{
CGContextRef ctx= UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(ctx, 0, 0, 0, .5);
CGContextBeginPath(ctx);
CGContextAddPath(ctx, mutatablepath);
//CGContextStrokePath(ctx);
CGContextFillPath(ctx);
CFRelease(mutatablepath);
NSString *path0;
NSArray *paths0=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
path0=[[paths0 objectAtIndex:0]stringByAppendingPathComponent:#"images"];
NSError *error;
if (![[NSFileManager defaultManager]fileExistsAtPath:path0]) {
if(![[NSFileManager defaultManager]createDirectoryAtPath:path0 withIntermediateDirectories:NO attributes:nil error:&error])
{
NSLog(#"Create directory error %#",error);
}
}
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *imagedata=UIImagePNGRepresentation(image);
NSString *namepath=[NSString stringWithFormat:#"%#.png",#"test"];
NSString *path;
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
path=[[paths objectAtIndex:0]stringByAppendingPathComponent:#"images"];
NSString *savepath=[NSString stringWithFormat:#"%#/%#",path,namepath ];
// NSError
NSLog(#"%#",savepath);
[imagedata writeToFile:savepath atomically:YES];
}
You can do so by taking the image saving code out of your drawRect method, since the renderInContext method implicitly calls drawRect as necessary:
UIView *myView = [[MyViewClass alloc] initWithFrame:CGRectMake(/*...*/)];
UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Source: http://pastie.org/244916
I'm working on an Acne app in which I have to choose image from UIImagePicker and after adding subViews to it I want to save it in camera roll.
Problem: If I add UIImageView as a subView to the superView, the pickerImage does not save with subView.
And if I add that UIImage as subView to the Picker Image, I am unable to move the added UIImage Views.
I am using the following code for saving images:
-(IBAction)savePhoto
{
NSParameterAssert(imgToDisplayFromPicker.image);
UIImageWriteToSavedPhotosAlbum(imgToDisplayFromPicker.image, nil, nil, nil);
}
Finally Found the Solution :
CGRect contextRect = CGRectMake(6, 6, 302, 230);
UIGraphicsBeginImageContext(contextRect.size);
[self.view.layer renderInContext : UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], contextRect);
UIImage * newImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:viewImage.imageOrientation];
UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);