I loaded a jpg into a UIImageView. The image is oversized to the iPhone screen. How can I resize it to a specific CGRect frame?
UIImageView *uivSplash = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"iPhone-Splash.jpg"]];
[self.view addSubview:uivSplash];
A UIImageView is just a UIView, so you can change its frame property.
uivSplash.frame = CGRectMake(0, 0, width, height);
You'll want a method like the following:
CGFloat newWidth = whateverYourDesiredWidth; // someView.size.width for example
CGFloat newHeight = whateverYourDesiredHeight; // someView.size.height for example
CGSize newSize = CGSizeMake(newWidth, newHeight);
UIGraphicsBeginImageContext(newSize);
[yourLargeImage drawInRect:CGRectMake(0, 0, newWidth, newHeight)];
UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
So this is getting your desired width and height (maybe the screen size, maybe hard-coded size, maybe a size based on a UIView) and re-drawing the image in a context that is that size.
~Good Luck
EDIT: it occurs to me I may have misunderstood your desire, so I'll also point out (as others have said) that UIImageView has properties for its image that let you fit it to size, scale to fill, retain aspect ratio, etc.
Related
Ok, so I have a UIImageView inside UIScrollView. I dynamically load an image into UIImageView and then manually resize it. So far so good. But then, if I touch UIScroll scroll view (containing resized elements) everything is resized back to the original size. Just in case, here's the code that resizes the image:
/**
* Proportionally resize and position doodle
*/
- (void)resizeDoodle:(CGFloat)height {
self.doodleImageView.frame = CGRectMake(0, 0, self.view.bounds.size.width, height);
[self.scrollView setContentSize:self.doodleImageView.frame.size];
}
self.Imageview.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
And This line keep image to fit
self.Imageview.contentMode = UIViewContentModeScaleAspectFit;
Write above code for restrict your issue.
Another way:
Use following method for specific hight and width (That you want) with image
+ (UIImage*)resizeImage:(UIImage*)image withWidth:(int)width withHeight:(int)height
{
CGSize newSize = CGSizeMake(width, height);
float widthRatio = newSize.width/image.size.width;
float heightRatio = newSize.height/image.size.height;
if(widthRatio > heightRatio)
{
newSize=CGSizeMake(image.size.width*heightRatio,image.size.height*heightRatio);
}
else
{
newSize=CGSizeMake(image.size.width*widthRatio,image.size.height*widthRatio);
}
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
This method return NewImage, with specific size that you specify :)
This code may be helpful for you:)
I have one UIImageView which is in scale to fill mode. Now i want to crop the image in imageview. I have one rectangle on this imageview which user can move and change the size. After particular size is selected i want to crop the image using this frame. But since my mode of uiimageview is scale to fill this messes the cropping rectangle and different part is cropped. Has any one faced this problem. How to crop properly ?
Your options are to calculate, or use this walkaround:
-(UIImage *)imageFromImageView:(UIImageView *)view withCropRect:(CGRect)cropRect
{
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * largeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage CGImage], cropRect);
UIImage* img = UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return img;
}
I've got a large display area that can be panned and zoomed to view different objects. The problem that I'm running into is that the quality of the PNG images UIButton becomes somewhat degraded if I'm zoomed out (however it is back to normal when I zoom back in to 100%). It almost looks as if the image becomes oversharpened. Is this something that I'm going to have to live with, or is there a way to get rid of this grainy edge effect? The aspect ratio of the images are always 1:1, by the way.
I was able to solve this by using the answer found here in my scrollViewDidEndZooming method. Here is my code:
Resize function
- (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;
}
ScrollView Method
(Widget is a UIViewController subclass which contains a button and a "widgetImage" which stores the full resolution of the image that the button should display)
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale
{
for(Widget *theWidget in widgets){
UIImage *newScaledImage = [self resizeImage:theWidget.widgetImage newSize:CGSizeMake(theWidget.view.frame.size.width * scale, theWidget.view.frame.size.height * scale)];
[theWidget.widgetButton setImage:newScaledImage forState:UIControlStateNormal];
// theWidget.widgetButton.currentImage = newScaledImage;
}
}
I want to create an image of fixed size e.g. 612 by 612. I am using an image picker to select photos from my iphone. So in order to ensure that all the photos fit to the 612 by 612 size without distortion, I am using the following method to re-scale the photo so that they conform to the size of 612 by 612. However as a result, blank spaces might be created in the final image. (see example below)
I am using the following code to scale my image (of fixed size 612 by 612)
//Scale the image to fit to imageview
UIImage *image = [self scaleImage:img toRectSize:CGRectMake(0, 0, 612, 612)];
//Method to scale image
- (UIImage *)scaleImage:(UIImage *)img toRectSize:(CGRect)screenRect
{
UIGraphicsBeginImageContext(screenRect.size);
float hfactor = img.size.width / screenRect.size.width;
float vfactor = img.size.height / screenRect.size.height;
float factor = MAX(hfactor, vfactor);
float newWidth = img.size.width / factor;
float newHeight = img.size.height / factor;
float leftOffset = (screenRect.size.width - newWidth) / 2;
float topOffset = (screenRect.size.height - newHeight) / 2;
CGRect newRect = CGRectMake(leftOffset, topOffset, newWidth, newHeight);
[img drawInRect:newRect blendMode:kCGBlendModePlusDarker alpha:1];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
As mentioned, as the image is sometimes not a full square, I get a result like what you see below:
How can I feel up the white spaces in the image with black color?
One way is to set the backgroundColor of UIImageView to blackColor.
Another way is to fill the rect with blackColor while you scale the image.
- (UIImage *)scaleImage:(UIImage *)img toRectSize:(CGRect)screenRect {
...
CGRect newRect = CGRectMake(leftOffset, topOffset, newWidth, newHeight);
// Fill the original rect with black color
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor blackColor] CGColor]);
CGContextFillRect(context, screenRect);
[img drawInRect:newRect blendMode:kCGBlendModeNormal alpha:1];
...
}
Note that the blendMode in drawInRect:blendMode:alpha: method is set to kCGBlendModeNormal. If you set some other blend modes you will get undesired results. For example, if you set the blend mode to kCGBlendModePlusDarker and fill the rect with blackColor then the entire image will become black.
Set the background color on your UIImageView to black and you'll get what you want
How do UIImageView autoresize according to UIImage's size?
imageView.image = image2;
Now, the size of image2 is (Width = 123.0; height = 123.0); and the size of imageView is (Width = 18;height=18);
My problem is, could imageView autoresize to (123.0,123.0) ? I have all type of the property UIViewContentMode, but imageView didn't change its size.
You can subclass UIImageView (say, AutoresizedImageView) and override -setImage: method in it:
- (void)setImage:(UIImage*)image{
[super setImage:image];
self.bounds = CGRectMake(0, 0, image.size.width, image.size.height);
}
Haven't tried it myself but I think it should work fine
you can alter imageView.frame=CGRectMake(position.x,position.y,size.x,size.y);