I am creating a "cartoonizer" application, which takes an image as an input and modifies it so as to format it in comics style.
At the moment, the original image is stored in a UIImageView, and I access to it by doing:
imageView.image
I was wondering whether it is possible to position an object on the image imageView.image (like a balloon) and then store the image with the object on it, like if it was originally part of the image content.
Thank you in advance.
You can do it like this, assuming you have correct opacity in the top image.
Like you said you get your image from imageView.image:
From here: blend two uiimages based on alpha/transparency of top image
UIImage *bottomImage = [UIImage imageNamed:#"bottom.png"];
UIImage *image = [UIImage imageNamed:#"top.png"];
CGSize newSize = CGSizeMake(width, height);
UIGraphicsBeginImageContext( newSize );
// Use existing opacity as is
[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
// Apply supplied opacity
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.8];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
More compositing techniques here: http://mobile.tutsplus.com/tutorials/iphone/ios-sdk-advanced-uiimage-techniques/
Related
In my app, the user is able to put stickers on top of a photo. When they go to save their creation, I do a screen grab and store it in a UIImage:
UIGraphicsBeginImageContextWithOptions(self.mainView.bounds.size, NO, [UIScreen mainScreen].scale);
[self.mainView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultImage = [UIGraphicsGetImageFromCurrentImageContext() retain];
UIGraphicsEndImageContext();
(where self.mainView has a subview UIImageView which holds the photo, and another subview UIView which holds the stickers).
I am wondering, is it possible to do a screen shot in this manner, and maintain the resolution of the aforementioned photo?
The following will 'flatten' two UIImages into one while maintaining the resolution of the original image(s):
CGSize photoSize = photoImage.size;
UIGraphicsBeginImageContextWithOptions(photoSize, NO, 0.0);
CGRect photoRect = CGRectMake(0, 0, photoSize.width, photoSize.height);
// Add the original photo into the context
[photoImage drawInRect:photoRect];
// Add the sticker image with its upper left corner set to where the user placed it
[stickerImage drawAtPoint:stickerView.frame.origin];
// Get the resulting 'flattened' image
UIImage *flattenedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
The above assumes photoImage and stickerImage are both instances of UIImage and stickerView is a UIView with containing the stickerImage and thus will be able to use the stickerView frame to determine its origin.
If you have multiple stickers, just iterate through the collection.
If you are looking to save an image of your current view then this might help you.
UIGraphicsBeginImageContext(self.scrollView.contentSize);
[self.scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect(finalImage.CGImage,
CGRectMake(scrollView.contentOffset.x, scrollView.contentOffset.y,
scrollView.frame.size.width, scrollView.frame.size.height));
UIImage *screenImage = [UIImage imageWithCGImage:imageRef scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp];
CGImageRelease(imageRef);
I am using imagview with size of 320X320 to display large image (350 X 783).
While placing the large image into the imageview, the image looks squeezed, compressed something not like the quality one.
My question is, how can I make the large image into small with as good quality as the original image ?
You can set your image view a proper content mode, like that
imageView.contentMode = UIViewContentModeScaleAspectFit
-(UIImage*)scaleToSize:(CGSize)size {
// Create a bitmap graphics context
// This will also set it as the current context
UIGraphicsBeginImageContext(size);
// Draw the scaled image in the current context
[self drawInRect:CGRectMake(0, 0, size.width, size.height)];
// Create a new image from current context
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
// Pop the current context from the stack
UIGraphicsEndImageContext();
// Return our new scaled image
return scaledImage;
}
You can do like this,
UIImage* sourceImage = "yourImage";
CGSize newSize=CGSizeMake(80,80);
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
yourImageView.image=newImage;
I want to get the following result with two images.
Please help me.
To combine two images on an image view try this
UIImage *bottomImage = [UIImage imageNamed:#"bottom.png"]; //background image
UIImage *image = [UIImage imageNamed:#"top.png"]; //foreground image
CGSize newSize = CGSizeMake(width, height);
UIGraphicsBeginImageContext( newSize );
// Use existing opacity as is
[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
// Apply supplied opacity if applicable
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.8];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Add newImage to UIImageView
After #Sumanth's code for combine two images you need to mask final image like how-to-mask-an-image link
I have made a program for image effects but when I try to add the effects like photoshop using the code below the image is not allocated any memory and therefore the resulting image is not shown.
UIImage *bottomImage = originalImage;
UIImage *upperImage = originalImage;
UIGraphicsBeginImageContextWithOptions(sizeR, YES, imageBeforeEffect.scale);
[bottomImage drawInRect:CGRectMake(0.0, 0.0, sizeR.width, sizeR.height)];
[upperImage drawInRect:CGRectMake(0.0, 0.0, sizeR.width, sizeR.height) blendMode:kCGBlendModeDarken alpha:1.0];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Check if your sizeR has got any frame... put a break - point and check it. If there is no frame then the UIGraphicsBeginImageContextWithOptions will not work.
I'm subclassing UIImageView to create a tile-based application. Essentially, I am taking a single image file and breaking it up into pieces, and then assigning the pieces to my tiles (UIImageViews), so that they can be manipulated independently.
What's the best way to grab a portion of an image and use that to draw a UIImageView? I thought about overriding drawRect and using CGAffineTransform, but it seems like there ought to be a simpler way to do this, perhaps by specifying a CGRect to the UIImage that is passed to the UIImageView, but I don't see an API for this.
Here we go:
UIImage* img = [UIImage imageNamed:#"myImage.jpg"];
CGRect imgFrame = CGRectMake(x, y, tileWidth, tileHeight);
CGImageRef imageRef = CGImageCreateWithImageInRect([img CGImage], imgFrame);
UIImage* subImage = [UIImage imageWithCGImage: imageRef];
CGImageRelease(imageRef);