I can use the following code to create image from UIView.
However the same code won't capture the text of UILabel.(it captures label's background color though)
How can I create image of UILabel with text?
CGSize size = view.bounds.size;
CGContextRef context = CreateARGBBitmapContext(size);
CGContextTranslateCTM(context, 0, size.height);
CGContextScaleCTM(context, 1.0, -1.0);
[view.layer renderInContext: context];
CGImageRef imageRef = CGBitmapContextCreateImage(context);
UIImage* img = [UIImage imageWithCGImage: imageRef];
CGImageRelease(imageRef);
CGContextRelease(context);
In the viewcontroller, select the label and on the right side, you should be able to set an image to the label.
Also, you might be having a problem with layers... [self addChild: label z:0 tag:1];
Just in case you don't know, z:0 means the layer. So something with z:-1 would be below a picture with z:0. You could just set the text ontop of the label
Related
I would like to change the color of an image that I have placed as a button in my navBar. The code I am using to create the image/button is:
UIImage *btnGoImage = [UIImage imageNamed:#"settings_cog.png"];
UIButton *btnGoPre = [UIButton buttonWithType:UIButtonTypeCustom];
btnGoPre.bounds = CGRectMake( 0, 0, 30, 30 );
[btnGoPre setImage:btnGoImage forState:UIControlStateNormal];
[btnGoPre addTarget:self action:#selector(loginAction)
forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *btnGo = [[UIBarButtonItem alloc] initWithCustomView:btnGoPre];
If I wanted to change the image to red (it is currently gray). How would I do this? Thanks!
this is the method that will help to change the color of your image you need to pass the image and color as your input variables and it will return the output image
-(UIImage *)imageNamed:(NSString *)name withColor:(UIColor *)color
{
// load the image
UIImage *img = [UIImage imageNamed:name];
// begin a new image context, to draw our colored image onto
UIGraphicsBeginImageContext(img.size);
// get a reference to that context we created
CGContextRef context = UIGraphicsGetCurrentContext();
// set the fill color
[color setFill];
// translate/flip the graphics context (for transforming from CG* coords to UI* coords
CGContextTranslateCTM(context, 0, img.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// set the blend mode to color burn, and the original image
CGContextSetBlendMode(context, kCGBlendModeColorBurn);
CGRect rect = CGRectMake(0, 0, img.size.width, img.size.height);
CGContextDrawImage(context, rect, img.CGImage);
// set a mask that matches the shape of the image, then draw (color burn) a colored rectangle
CGContextClipToMask(context, rect, img.CGImage);
CGContextAddRect(context, rect);
CGContextDrawPath(context,kCGPathFill);
// generate a new UIImage from the graphics context we drew onto
UIImage *coloredImg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//return the color-burned image
return coloredImg;
}
and here is the example how you can call this method
yourImageView.image = [self imageNamed:#"yourImageName" withColor:[UIColor orangeColor]];
Try a UIBarButtonItem class tintColor property.
I am working on creating an image gallery which has thumbnails in different sizes. I want to convert these rectangle thumbnails to square size so that all of them could appear similar in size. I dont mind cropping it from extended portion but I am not sure how to do it. can anyone please help me?
Thanks
Pankaj
You need to use the image in rect method passing in the image and the required bounds...
CGImageRef imageRef = CGImageCreateWithImageInRect([anImage CGImage], requiredBounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
I have added this to a UIImage category (UIImage+Resize) in the following post, you can download the source code as well - Categories example
Well if you use an UIImageView to display your images (wich I am more than sure that you do) you can set it's contentMode property to UIViewContentModeScaleAspectFill. This should 'crop' your image to the boundaries of your UIImageView. In case your image will go out of the boundaries of the UIImageView make sure clipsToBounds is also set to YES.
Let me know if that helps.
I'm using the next method. The input are the UIImage to scale and the size of the UIImageView's frame where the UIImage is. It works when the frame's height and width are equal.
One important thing: I keep the image's ratio. I don't expand the image to cover the full square. If you want to do it you have to change the 'drawInRect' line for [self drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)]; and remove the if-else.
- (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
CGFloat scaleRatio;
if (image.size.width > image.size.height) {
scaleRatio = image.size.height/image.size.width;
}else{
scaleRatio = image.size.width/image.size.height;
}
CGAffineTransform scaleTransform = CGAffineTransformMakeScale(scaleRatio, scaleRatio);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextConcatCTM(context, scaleTransform);
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0);
if (image.size.width > image.size.height) {
[image drawInRect:CGRectMake(0, (newSize.height/2)-(newSize.height*scaleRatio/2), newSize.width, newSize.height*scaleRatio)];
}else{
[image drawInRect:CGRectMake((newSize.width/2)-(newSize.width*scaleRatio/2), 0, newSize.width*scaleRatio, newSize.height)];
}
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
I want to know, how can I erase a custom rect (with, for example, an UIView in IB or something else) of an UIImageView in order to display an other UIImageView positioned underneath.
I didn't manage to do it using some response in the forum...
This will clear a rect in an image:
- (UIImage *)clearRect:(CGRect)rect inImage:(UIImage *)image {
if (UIGraphicsBeginImageContextWithOptions != NULL)
UIGraphicsBeginImageContextWithOptions([image size], NO, 0.0);
else
UIGraphicsBeginImageContext([image size]);
CGContextRef context = UIGraphicsGetCurrentContext();
[image drawInRect:CGRectMake(0.0, 0.0, [image size].width, [image size].height)];
CGContextClearRect(context, rect);
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}
Just load your image and clear the rects before assigning it to the image view:
UIImage *image = [UIImage imageNamed:#"Image.png"];
UIImage *maskedImage = [self clearRect:CGRectMake(10.0, 10.0, 50.0, 50.0) inImage:image];
[imageView setImage:maskedImage];
probably not the best solution but you can do the other way and take the 4 parts around the rect separately and combine them afterwards without the inner rect. You would repeat this as long as you have rect's to crop out.
You cannot clear the UIImageView itself because this just draws the UIImage. So you have erase the rect in the UIImage. Create a bitmap context, draw the image into it. Erase the part you want to "see through" with CGContextClearRect. When create a new new image from the bitmap context.
I have an image formed by a number of sublayers on a UIView, and then it takes a screenshot as so:
UIGraphicsBeginImageContext(object.bounds.size);
[object.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenShot = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Then it puts it onto a button:
[objectButton setImage:screenShot forState:UIControlStateNormal];
But the image displays at it's own size, so if the button isn't the same size as the image then i have a problem of it not making the image bigger or smaller.
How can i get it to change the size of the image to the size of the button?
Try this category -
.h file -
#interface UIImage (UIImageAdditions)
- (UIImage*)scaleToSize:(CGSize)size;
#end
.m file -
#implementation UIImage (UIImageAdditions)
- (UIImage*)scaleToSize:(CGSize)size {
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, 0.0, size.height);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, size.width, size.height), self.CGImage);
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return scaledImage;
}
#end
you can call it like this -
[imageObject scaleToSize:CGSizeMake(weight, height)];
Hope it help!
Try Like this,
[objectButton setBackgroundImage:screenShot forState:UIControlStateNormal];
You can change the contentMode on the UIButton to scale to fit. This will adjust the size of the image to not be larger than the bounds of the button. Also set the image as the background Image of the button instead of the image.
objectButton.contentMode = UIViewContentModeScaleAspectFit;
[objectButton setBackgroundImage:image forStage:UIControlStateNormal];
I need to darken a UIImageView when it gets touched, almost exactly like icons on the springboard (home screen).
Should I be added UIView with a 0.5 alpha and black background. This seems clumsy. Should I be using Layers or something (CALayers).
I would let a UIImageView handle the actual drawing of the image, but toggle the image to one that's been darkened in advance. Here's some code I've used to generate darkened images with alpha maintained:
+ (UIImage *)darkenImage:(UIImage *)image toLevel:(CGFloat)level
{
// Create a temporary view to act as a darkening layer
CGRect frame = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
UIView *tempView = [[UIView alloc] initWithFrame:frame];
tempView.backgroundColor = [UIColor blackColor];
tempView.alpha = level;
// Draw the image into a new graphics context
UIGraphicsBeginImageContext(frame.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[image drawInRect:frame];
// Flip the context vertically so we can draw the dark layer via a mask that
// aligns with the image's alpha pixels (Quartz uses flipped coordinates)
CGContextTranslateCTM(context, 0, frame.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextClipToMask(context, frame, image.CGImage);
[tempView.layer renderInContext:context];
// Produce a new image from this context
CGImageRef imageRef = CGBitmapContextCreateImage(context);
UIImage *toReturn = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
UIGraphicsEndImageContext();
[tempView release];
return toReturn;
}
How about subclassing UIView and adding a UIImage ivar (called image)? Then you could override -drawRect: something like this, provided you had a boolean ivar called pressed that was set while touched.
- (void)drawRect:(CGRect)rect
{
[image drawAtPoint:(CGPointMake(0.0, 0.0))];
// if pressed, fill rect with dark translucent color
if (pressed)
{
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
CGContextSetRGBFillColor(ctx, 0.5, 0.5, 0.5, 0.5);
CGContextFillRect(ctx, rect);
CGContextRestoreGState(ctx);
}
}
You would want to experiment with RGBA values above. And, of course, non-rectangular shapes would require a bit more work - like a CGMutablePathRef.
UIImageView can have multiple images; you could have two versions of the image and switch to the darker one when needed.