I'm making an app in which the user chooses an image, resize it by zooming (in a uiscrollview) and move it in the view. When finished, I would like to save the image like we can see it in the uiscrollview. Do you have any idea ?
Thanks.
Here is the code ......
Here frontGround is a imageview and
testScrool is scroll view
hope this will work for you.
UIGraphicsBeginImageContext(testScrool.frame.size);
CGContextRef currentContext = UIGraphicsGetCurrentContext();
CGRect clippedRect = CGRectMake(0, 0, testScrool.frame.size.width, testScrool.frame.size.height);
CGContextClipToRect(currentContext, clippedRect);
CGRect drawRect = CGRectMake(testScrool.frame.origin.x * -1,
testScrool.frame.origin.y * -1,frontGround.frame.size.width, frontGround.frame.size.height);
CGContextDrawImage(currentContext, drawRect, frontGround.image.CGImage);
UIImage *cropped = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
frontGround.image = cropped;
Related
When you use .imageView.adjustsImageWhenAncestorFocused you get your image scaled, you get it bigger on focus. The image goes beyond it's bounds. That means that you can't see full image - it's coped on all sides.
You have:
You want:
If you want it work from the box, you need to remember to reserve Focused/Safe zone size (from documentation) when you create your image.
In my case I have my images from server and I can't edit them.
What worked for me - it's to redraw image right before setting:
UIImage *oldImage = [UIImage imageNamed:#"example"];
CGFloat width = cell.imageView.frame.size.width;
CGFloat height = cell.imageView.frame.size.height;
CGSize newSize = CGSizeMake(width, height);
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGImageRef imageRef = oldImage.CGImage;
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0);
CGContextRef resizeContext = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(resizeContext, kCGInterpolationHigh);
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, newSize.height);
CGContextConcatCTM(resizeContext, flipVertical);
CGContextDrawImage(resizeContext, newRect, imageRef);
CGImageRef newImageRef = CGBitmapContextCreateImage(resizeContext);
UIImage *newImageResized = [UIImage imageWithCGImage:newImageRef];
CGImageRelease(newImageRef);
UIGraphicsEndImageContext();
dispatch_async(dispatch_get_main_queue(), ^{
cell.imageView.image = newImageResized;
});
It's nor necessary to redraw in this way, but the point is you need to draw your UIImage again in order to have your image displayed properly.
Code from here.
I have an NSTextView inside an NSView (which is being used by a NSPopover, don't know if that is relevant) that I'm trying to resize automatically and programmatically (cf caption).
I have been struggling with a lot of stuff, namely :
Looking at NSLayoutManager and usedRectForTextContainer that give me aberrant size values
(usedRectForTextContainer : {{0, 0}, {0.001, 28}})
Modifying NSScrollView frame, [NSScrollView contentView], [NSScrollView documentView]
Getting rid of AutoLayout
I reached the point where I can resize my scollview and my Popover, but I can't get the actual height of the text inside the NSTextView.
Any kind of help would be appreciated.
-(void)resize
{
//Get clipView and scrollView
NSClipView* clip = [popoverTextView superview];
NSScrollView* scroll = [clip superview];
//First, have an extra long contentSize and ScrollView to test everything else
[popover setContentSize:NSMakeSize([popover contentSize].width, 200)];
[scroll setFrame:(NSRect){
[scroll frame].origin.x,[scroll frame].origin.y,
[scroll frame].size.width,155
}];
NSLayoutManager* layout = [popoverTextView layoutManager];
NSTextContainer* container = [popoverTextView textContainer];
NSRect myRect = [layout usedRectForTextContainer:container]; //Broken
//Now what ?
}
I still have no idea why I can't use [layout usedRectForTextContainer:container], but I managed to get the NSTextView's height by using :
-(void)resize
{
//Get glyph range for boundingRectForGlyphRange:
NSRange range = [[myTextView layoutManager] glyphRangeForTextContainer:container];
//Finally get the height
float textViewHeight = [[myTextView layoutManager] boundingRectForGlyphRange:range
inTextContainer:container].size.height;
}
Here is some functional code that I have tested myself for swift. usedRectForTextContainer is not broken it just is set lazily. To set it i call glyphrangefortextcontainer
I found the answer here: http://stpeterandpaul.ca/tiger/documentation/Cocoa/Conceptual/TextLayout/Tasks/StringHeight.html
let textStorage = NSTextStorage(string: newValue as! String)
let textContainer = NSTextContainer(size: NSSize(width: view!.Text.frame.width, height:CGFloat.max))
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
textContainer.lineFragmentPadding = 0.0
textContainer.lineBreakMode = NSLineBreakMode.ByWordWrapping
textStorage.font = NSFont(name: "Times-Roman", size: 12)
layoutManager.glyphRangeForTextContainer(textContainer)
let rect = layoutManager.usedRectForTextContainer(textContainer)
Swift.print(rect)
The documentation also suggest that is the the case:
Herer is my resize routine...
in the line CGContextDrawImage the app crashes after 2 or 3 calls of the routine.
there is no memory warning or something.
it just chrashes
- (UIImage *)resizedImage:(CGSize)newSize
transform:(CGAffineTransform)transform
drawTransposed:(BOOL)transpose
interpolationQuality:(CGInterpolationQuality)quality {
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGRect transposedRect = CGRectMake(0, 0, newRect.size.height, newRect.size.width);
CGImageRef imageRef = self.CGImage;
// Build a context that's the same dimensions as the new size
CGContextRef bitmap = CGBitmapContextCreate(NULL,
newRect.size.width,
newRect.size.height,
CGImageGetBitsPerComponent(imageRef),
0,
CGImageGetColorSpace(imageRef),
CGImageGetBitmapInfo(imageRef));
// Rotate and/or flip the image if required by its orientation
CGContextConcatCTM(bitmap, transform);
// Set the quality level to use when rescaling
CGContextSetInterpolationQuality(bitmap, quality);
// Draw into the context; this scales the image
////////////AFTER THAT IT CRASHS!!!
CGContextDrawImage(bitmap, transpose ? transposedRect : newRect, imageRef);
// Get the resized image from the context and a UIImage
CGImageRef newImageRef = CGBitmapContextCreateImage(bitmap);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
// Clean up
CGContextRelease(bitmap);
CGImageRelease(newImageRef);
return newImage;
}
someone a hint?
regards, phil
Maybe you should add autorelease pool or #autorelease{} for ARC?
I think, it would help.
I'm developing an iphone application with an UIView that have an image as a background and multiple buttons with image as background. The image is an image of a country and the buttons are the regions/states of that country.
The problem is that the screen is too much little to display all this data, so I want to enable pinch-to-zoom of the UIView which allows user to have a better view of the country.
Inside 'viewDiDLoad' of my UIViewController, I added:
UIPinchGestureRecognizer *twoFingerPinch = [[[UIPinchGestureRecognizer alloc]
initWithTarget:self
action:#selector(twoFingerPinch:)]
autorelease];
[[self view] addGestureRecognizer:twoFingerPinch];
and I added twoFingerPinch method:
- (void)twoFingerPinch:(UIPinchGestureRecognizer *)recognizer {
if (recognizer.scale > minValue){
CGAffineTransform transform = CGAffineTransformMakeScale(recognizer.scale, recognizer.scale);
self.view.transform = transform;
}
}
and it work correctly, the problem is that the UIView becomes bigger but user can't navigate inside.
So I switched my UIView to a UIScrollView and inside 'twoFingerPinch' method I added:
if (recognizer.state == UIGestureRecognizerStateEnded){
float scaleForView = mLastScale;
UIScrollView *tempScrollView=(UIScrollView *)self.view;
int newWidth = self.view.frame.size.width * scaleForView;
int newHeight = self.view.frame.size.height * scaleForView;
tempScrollView.contentSize=CGSizeMake(newWidth,newHeight);
mLastScale = 1.0;
}
but it doesn't work well: the UISrollView becomes much bigger but it's not bigger as the image scaled and also is not centered where pinchToZoom started.
How can i solve this problem?
Thank You
I am trying to draw an image using core graphics such that it has rounded corners and a drop shadow. Here is a snippet of my code:
CGContextSetShadowWithColor(context, CGSizeMake(0, 1), 2, shadowColor);
CGContextAddPath(context, path);
CGContextClip(context);
CGContextDrawImage(context, rect, image);
The problem I am having is that the clipping to create the rounded corners is also clipping the shadow. Since the image may be transparent in areas, I cannot simply draw the rounded rectangle with a shadow under the image. I guess I need to apply the rounded shape to the image first, and then draw the resulting image to the screen and add the shadow. Does anyone know how to do this?
Thanks!
Okay, so assuming that you have a UIView subclass, which has an instance variable, image, which is a UIImage, then you can do your drawRect: function like so...
- (void)drawRect:(CGRect)rect {
[super drawRect:rect];
CGRect _bounds = [self bounds];
CGColorRef aColor;
CGContextRef context = UIGraphicsGetCurrentContext();
// Create a path
CGRect insetRect = CGRectInset(_bounds, kBSImageButtonBorder, kBSImageButtonBorder);
CGRect offsetRect = insetRect; offsetRect.origin = CGPointZero;
UIGraphicsBeginImageContext(insetRect.size);
CGContextRef imgContext = UIGraphicsGetCurrentContext();
CGPathRef clippingPath = [UIBezierPath bezierPathWithRoundedRect:offsetRect cornerRadius:CORNER_RADIUS].CGPath;
CGContextAddPath(imgContext, clippingPath);
CGContextClip(imgContext);
// Draw the image
[image drawInRect:offsetRect];
// Get the image
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// Setup the shadow
aColor = [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.5f].CGColor;
CGContextSetShadowWithColor(context, CGSizeMake(0.0f, 2.0f), 2.0f, aColor);
// Draw the clipped image in the context
[img drawInRect:insetRect];
}
I'm a little new to Quartz programming myself, but that should give you your image, centered in the rectangle, minus a border, with a corner radius, and a 2.f point shadow 2.f points below it. Hope that helps.
Here is a function to round the corners of an image using Daniel Thorpe's answer, in case you came here, like me, just looking for a way to do this.
+ (UIImage *) roundCornersOfImage:(UIImage *)image toRadius:(float)radius {
// create image sized context
UIGraphicsBeginImageContext(image.size);
CGContextRef context = UIGraphicsGetCurrentContext();
// add rounded rect clipping path to context using radius
CGRect imageBounds = CGRectMake(0, 0, image.size.width, image.size.height);
CGPathRef clippingPath = [UIBezierPath bezierPathWithRoundedRect:imageBounds cornerRadius:radius].CGPath;
CGContextAddPath(context, clippingPath);
CGContextClip(context);
// draw the image
[image drawInRect:imageBounds];
// get the image
UIImage *outImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return outImage;
}
You can use an imageView with a layer, the layer has properties for setting shadows and borders, this is how:
self.imageView = [[NSImageView alloc] initWithFrame:NSMakeRect(0,0,60,60)];
self.imageView.image = [NSImage imageNamed:#"yourImageName"];
self.imageView.wantsLayer = YES;
self.imageView.layer.cornerRadius = 10;
//make the shadow and set it
NSShadow* shadow = [[NSShadow alloc] init];
shadow.shadowBlurRadius = 2;
shadow.shadowOffset = NSMakeSize(2, -2);
shadow.shadowColor = [NSColor blackColor];
self.imageView.shadow = shadow;
Hope this helps, this is also much faster to draw then using drawRect overrides