I'm rendering UIImage in the - drawRect: and placing it in the passed in CGRect by calling drawInRect: rect on the UIImage. It automatically resizes and stretches itself, which I don't want. How can I keep it the original size?
UIImage* left = [UIImage imageNamed: #"Map_info_bubble_left"];
UIImage* center = [UIImage imageNamed: #"Map_info_bubble_center"];
UIImage* right = [UIImage imageNamed: #"Map_info_bubble_right"];
UIImage* leftCapStretched = [left resizableImageWithCapInsets: UIEdgeInsetsMake(0, 20, 0, 0)];
UIImage* rightCapStretched = [right resizableImageWithCapInsets: UIEdgeInsetsMake(0, 0, 0, 15)];
CGFloat fullWidth = leftCapStretched.size.width + center.size.width + rightCapStretched.size.width;
UIGraphicsBeginImageContextWithOptions(CGSizeMake(fullWidth, center.size.height), NO, 0);
[leftCapStretched drawAtPoint: CGPointMake(0, 0)];
[center drawAtPoint: CGPointMake(leftCapStretched.size.width, 0)];
[rightCapStretched drawAtPoint: CGPointMake(left.size.width + center.size.width, 0)];
UIImage* callout = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[callout drawInRect: rect];
Essentially what is happening is the center image should remain the original size while the caps stretch, but the center is stretching and the caps don't stretch enough. I noticed that if I multiply fullWidth by 2, it shrinks the center closer to what it should be.
EDIT: More simply asked after reading the documentation a bit more, is there a way to prevent the UIImage from scaling to fit the rect when drawInRect: is called?
This can be done simply by passing the images size property to drawInRect:
e.x:
[myImage drawInRect:CGRectMake(someOriginX, someOriginY, myImage.size.width, myImage.size.height)];
Related
In objective-c, I make a circle shape programmatically by following codes:
+(UIImage *)makeRoundedImage:(CGSize) size backgroundColor:(UIColor *) backgroundColor cornerRadius:(int) cornerRadius
{
UIImage* bgImage = [self imageWithColor:backgroundColor andSize:size];;
CALayer *imageLayer = [CALayer layer];
imageLayer.frame = CGRectMake(0, 0, size.width, size.height);
imageLayer.contents = (id) bgImage.CGImage;
imageLayer.masksToBounds = YES;
imageLayer.cornerRadius = cornerRadius;
UIGraphicsBeginImageContext(bgImage.size);
[imageLayer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *roundedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return roundedImage;
}
The imageWithColor method is as following:
+(UIImage *)imageWithColor:(UIColor *)color andSize:(CGSize)size
{
//quick fix, or pop up CG invalid context 0x0 bug
if(size.width == 0) size.width = 1;
if(size.height == 0) size.height = 1;
//---quick fix
UIImage *img = nil;
CGRect rect = CGRectMake(0, 0, size.width, size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context,
color.CGColor);
CGContextFillRect(context, rect);
img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
Then I used it to create a pure color circle shape image, but what I found is the circle image is not perfect rounded. As an example, please see following code:
CGSize size = CGSizeMake(diameter, diameter);
int r = ceil((float)diameter/2.0);
UIImage *imageNormal = [self makeRoundedImage:size backgroundColor:backgroundColor cornerRadius:r];
[slider setThumbImage:imageNormal forState:UIControlStateNormal];
First I created a circle image, then I set the image as the thumb to a UISlider. But what shown is as the picture shown below:
You can see the circle is not an exact circle. I'm thinking probably it caused by the screen resolution issue? Because if I use an image resource for the thumb, I need add #2x. Anybody know the reason? Thanx in advance.
updated on 8th Aug 2015.
Further to this question and the answer from #Noah Witherspoon, I found the blurry edge issue has been solved. But still, the circle looks like being cut. I used the code as following:
CGRect rect = CGRectMake(0.0f, 0.0f, radius*2.0f, radius*2.0f);
UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, color.CGColor);
CGContextFillEllipseInRect(context, rect);
UIImage* image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
And the circle looks like:
You can see the edge has been cut.
I changed the code as following:
CGRect rect = CGRectMake(0.0f, 0.0f, radius*2.0f+4, radius*2.0f+4);
CGRect rectmin = CGRectMake(2.0f, 2.0f, radius*2, radius*2);
UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, color.CGColor);
CGContextFillEllipseInRect(context, rectmin);
UIImage* image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
You can see the circle looks better(The top edge and the bottom edge):
I made the fill rect size smaller, and the edge looks better, but I don't think it's a nice solution. Still, does anybody know why this happen?
From your screenshot it looks like you do actually have a circular image, but its scale is wrong—it’s not Retina—so it looks blurry and not-circular. The key thing is that instead of using UIGraphicsBeginImageContext which defaults to a scale of 1.0 (as compared to your screen, which is at a scale of 2.0 or 3.0), you should be using UIGraphicsBeginImageContextWithOptions. Also, you don’t need to make a layer or a view to draw a circle in an image context.
+ (UIImage *)makeCircleImageWithDiameter:(CGFloat)diameter color:(UIColor *)color {
UIGraphicsBeginImageContextWithOptions(CGSizeMake(diameter, diameter), NO, 0 /* scale (0 means “use the current screen’s scale”) */);
[color setFill];
CGContextFillEllipseInRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, diameter, diameter));
UIImage *image = UIGraphicsGetImageFromCurrentContext();
UIGraphicsEndImageContext();
return image;
}
If you want to get a circle every time try this:
- (UIImage *)makeCircularImage:(CGSize)size backgroundColor:(UIColor *)backgroundColor {
CGSize squareSize = CGSizeMake((size.width > size.height) ? size.width : size.height,
(size.width > size.height) ? size.width : size.height);
UIView *circleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, squareSize.width, squareSize.height)];
circleView.layer.cornerRadius = circleView.frame.size.height * 0.5f;
circleView.backgroundColor = backgroundColor;
circleView.opaque = NO;
UIGraphicsBeginImageContextWithOptions(circleView.bounds.size, circleView.opaque, 0.0);
[circleView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
Hi i want to covert my UIView to UIImage in particular frame size kindly help me.
I have 'UITableView` which is added as subview of 'UIScrollView' for horizontal scroll, my table view frame size is (0, 0, 12000, 768).
I want to convert the current visible are of my UITableView as UIImage after scrolling.
Example:
if i scrolled my table view horizontally some distance means that current visible are is (150,0,1200,768) that means full device screen.
if i use the following code:
UIGraphicsBeginImageContext(self.frame.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *backgroundImage = UIGraphicsGetImageFromCurrentImageContext();
its capturing always the frame size of (0, 0, 1200, 768) only.
so, how can i set the origin of image capturing.
Kindly help me out.... Thanks in advance....
- (UIImage *)rasterizedImageInView:(UIView *)view atRect:(CGRect)rect {
UIGraphicsBeginImageContextWithOptions(rect.size, view.opaque, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, -rect.origin.x, -rect.origin.y);
[view.layer renderInContext:context];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
This will allow you to capture a UIImage from a particular region within a UIView as defined by a CGRect.
CGRect rect = [self.view bounds];
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Try this.
UIView *viewprint=[[UIView alloc] initWithFrame:CGRectMake(0, 0, width, height)];
viewprint.backgroundColor=[UIColor whiteColor];
tableView.frame = CGRectMake(0, 0, width, height);
[viewprint addSubview:tableView];
UIGraphicsBeginImageContext(viewprint.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[view.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
How can i show only a portion of the original image in a UIImageView
This question may be very familiar and old, But the reason for asking again is,i could not find a workable idea with the help of those answers
Many said set image.contentMode = UIViewContentModeCenter; (but not working)
I need almost a rectangle containing the center of the original image,How do I get this ?
I do make this working,when i am displaying a static image to my app and setting Content mode of UIImageVie as Aspect Fill.
But this is not workable in the case when i am displaying an image from url and using NSData
Adding my code and the images
NSString *weburl = #"http://topnews.in/files/Sachin-Tendulkar_15.jpg";
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 50, 108, 86)];
NSURL *url = [NSURL URLWithString:weburl];
NSData *data = [NSData dataWithContentsOfURL:url];
imageView.image = [UIImage imageWithData:data];
[self.view addSubview:imageView];
If you added the UIImageView form XIB, you can find a "mode" property there and then you can see and set different modes from there (from Interface builder). Or by programatically, you can set different modes by
imageView.contentMode = UIViewContentModeCenter;
imageView.clipsToBounds = YES;
Try this:
self.imageView.layer.contentsRect = CGRectMake(0.25, 0.25, 0.5, 0.5);
self.imageView will display middle part of image. You can calculate itself the required values of CGRect
For this kind of output, you need to crop the image according to your requirement.
Cropping code as below which can be used.
-(UIImage *) CropImageFromTop:(UIImage *)image
{
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(0, 12, image.size.width, image.size.height - 12));
UIImage *cropimage = [[[UIImage alloc] initWithCGImage:imageRef] autorelease];
CGImageRelease(imageRef);
return cropimage;
}
you try to scale image and then add image in UiImageView and set center that image then it is in center. code of scale image is
-(UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize{
UIGraphicsBeginImageContext(newSize);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
then you set the center of that image and add in the image view i hope this is work
I want to crop an image which is on the UIImageview into any shape
You set the clipping path and voila:
// Load image thumbnail
NSString *imageName = [self.picArray objectAtIndex:indexPath.row];
UIImage *image = [UIImage imageNamed:imageName];
CGSize imageSize = image.size;
CGRect imageRect = CGRectMake(0, 0, imageSize.width, imageSize.height);
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);
// Create the clipping path and add it
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:imageRect cornerRadius:5.0f];
[path addClip];
[image drawInRect:imageRect];
UIImage *roundedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
This code loads an image and creates a path by rounding the rectangle, the result is that the final image has been clipped, i.e. rounded corners. RoundedImage is the result.
You can use a CGImageMask.
A sample exists in the class QuartzMaskingView of Apple's QuartzDemo.
I am getting into a dilemma. I am trying to show the middle of an image. I use the the mageWithImage:CovertToSize function to scale the image. The problem is that the image is being stretched height wise. So the question is, what is the correct method to scale an image to 320 pixels wide and show the middle of the photo or close to it?
UIImage *image = [[UIImage alloc] initWithData:imageData];
Scale *scale = [[Scale alloc] init];
float newHeight = (image.size.height * 2) / image.size.width * 320.0f;
image = [scale2 imageWithImage:image CovertToSize:CGRectMake(0, -(newHeight / 2), 320.0f, newHeight)];
CGImageRef imageRef;
if (newHeight > 125) {
imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(0, 0, 320, 125));
}else{
imageRef = CGImageCreateWithImageInRect([image CGImage], CGRectMake(0, 0, 320, newHeight));
}
NSData *imgData = UIImageJPEGRepresentation([UIImage imageWithCGImage:imageRef], 1.0);
UIImage *cimg = [UIImage imageWithData:imgData];
If your not aware of how layers work, http://www.ruttencutter.com/?p=90
If you are, I suggest you have a frame of an image as a layer with the selected area in the middle cut out so that, under that layer, you can put the image there so that you'll only see that selected area.