I want to blend a image, but have a problem that the pixel almost lose half after I blend it. My code is:
UIImageView *baseIgv2 = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 76, 76)];
[self.view addSubview:baseIgv2];
[baseIgv2 setImage:[UIImage imageNamed:#"btn_award_open.png"]];
baseIgv2.center = CGPointMake(300, 300);
UIGraphicsBeginImageContext(baseIgv2.bounds.size);
[baseIgv2.image drawInRect:baseIgv2.bounds];
[baseIgv2.image drawInRect:baseIgv2.bounds blendMode:kCGBlendModeScreen alpha:.8];
[baseIgv2.image drawInRect:baseIgv2.bounds blendMode:kCGBlendModeDestinationIn alpha:.8];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[baseIgv2 setImage:newImage];
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"opacity"];
anim.beginTime = CACurrentMediaTime();
anim.fromValue = #.5;
anim.toValue= #1;
anim.autoreverses = YES;
anim.duration = .5;
anim.repeatDuration = 1000;
anim.repeatCount = 1000;
[baseIgv2.layer addAnimation:anim forKey:nil];
The picture in project contains btn_award_open#2x.png , btn_award_open#2x~ipad.png, btn_award_open~ipad.png
Before I use blend, it just OK,but after I use it, it's no longer retina. Anyone can help?
Although what you are doing is correct, you are using an old UIKit function to create your bitmap context.
To scale your bitmap context for retina screens you should use this function instead:
void UIGraphicsBeginImageContextWithOptions(
CGSize size,
BOOL opaque,
CGFloat scale
);
So you need to replace this line of code:
UIGraphicsBeginImageContext(baseIgv2.bounds.size);
With this:
UIGraphicsBeginImageContextWithOptions(baseIgv2.bounds.size, YES, 0.0);
More info about the function and it's parameters:
https://developer.apple.com/library/ios/documentation/uikit/reference/UIKitFunctionReference/Reference/reference.html
Related
I'm trying to implement image rotation in my code and running a couple of tests. Since I don't know much about the math of how rotation is performed, I just followed some instructions that I'd found on the internet and implemented my code.
I found out that a whole row or column of 1-pixel around the edge is lost everytime I rotate the image. (more than M_PI degree at a time)
This is not obvious when I host the image as a UIImage object, but you can see it when you save the UIImage as a file.
Here's my test code link:
https://github.com/asldkfjwoierjlk/UIImageRotationTest/tree/master
I don't understand that this loss happens. Did I miss something? Or is it something mathematically inevitable?
Here's the rotation method that I implemented if you are interested.
- (UIImage*)rotateImg:(UIImage*)srcImg
{
UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0, srcImg.size.width, srcImg.size.height)];
CGFloat rotationInDegree = ROTATION_DEGREE;
CGAffineTransform t = CGAffineTransformMakeRotation(rotationInDegree);
rotatedViewBox.transform = t;
CGSize rotatedSize = rotatedViewBox.frame.size;
// set opaque option to NO to leave the alpha channel intact.
// Otherwise, there's no point of saving to either png or jpg.
UIGraphicsBeginImageContextWithOptions(rotatedSize, NO, 1.0);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(context, rotatedSize.width / 2.0f, rotatedSize.height / 2.0f);
CGContextRotateCTM(context, rotationInDegree);
[srcImg drawInRect:CGRectMake(-srcImg.size.width / 2.0f, -srcImg.size.height / 2.0f, srcImg.size.width, srcImg.size.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
you can handle the UIImageView as a View. This code works perfectly for me!
CABasicAnimation *rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
NSNumber *currentAngle = [rotatedViewBox.layer.presentationLayer valueForKeyPath:#"transform.rotation"];
rotationAnimation.fromValue = currentAngle;
rotationAnimation.toValue = #(50*M_PI);
rotationAnimation.duration = 50.0f; // this might be too fast
rotationAnimation.repeatCount = HUGE_VALF; // HUGE_VALF is defined in math.h so import it
[rotatedViewBox.layer addAnimation:rotationAnimation forKey:#"rotationAnimationleft"];
Happy coding!
I'm re-introducing myself to iOS programming and am running into a seemingly simple problem. I have been following this example about how to rotate a image according to the user's heading. The crucial part is:
float heading = -1.0f * M_PI * newHeading.magneticHeading / 180.0f;
arrowImage.transform = CGAffineTransformMakeRotation(heading);
The image is indeed rotated but the center doesn't seem to be the anchor point for the rotation. I've been googling but can't figure it out. Could someone point me in the right direction?
Here's a screenshot in case it isn't clear: in the initial state, the label is centered in the circle and the white square is centered in the image:
This code works for my:
UIImage *img = [UIImage imageNamed:#"Image.png"];
UIImageView *imageToMove = [[UIImageView alloc] initWithImage:img];
CATransform3D rotationTransform = CATransform3DMakeRotation(1.0f * M_PI, 0, 0, 1.0);
CABasicAnimation* rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform"];
rotationAnimation.toValue = [NSValue valueWithCATransform3D:rotationTransform];
rotationAnimation.duration = 0.6f;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = FLT_MAX;
[imageToMove.layer addAnimation:rotationAnimation forKey:#"rotationAnimation"];
[self.view addSubview:imageToMove];
Swift port of Greg's code
let rotationTransform: CATransform3D = CATransform3DMakeRotation(.pi, 0, 0, 1.0);
let rotationAnimation = CABasicAnimation(keyPath: "transform");
rotationAnimation.toValue = NSValue(caTransform3D: rotationTransform)
rotationAnimation.duration = 0.6;
rotationAnimation.isCumulative = true;
rotationAnimation.repeatCount = Float.infinity;
progressArc.layer.add(rotationAnimation, forKey:"rotationAnimation")
try this code for your case
var angle=0;
self.btnImage.center=CGPointMake(self.btnImage.center.x, self.btnImage.center.y);
self.btnImage.transform=CGAffineTransformMakeRotation (angle);
angle+=0.15;
keep the above one into method, use the time interval or call the method when ever you want to change the angle of the image.
I have a somewhat unusual problem. In my app, I am shadowing a UIImageView using basic Quartz2d layer shadowing. Here's my code:
imageView.layer.shadowOpacity = 1.0; // Pretty self explanatory
imageView.layer.shadowRadius = 8.0; // My softness
imageView.layer.shadowColor = [UIColor blackColor].CGColor; // Color of the shadow
imageView.layer.shadowOffset = CGSizeMake(0.0, 0.0); // Offset of the shadow
This produces a nice blur behind the image view. However, I am doing some animation with this view, and the constant recalculation of the shadowing during the transitions causes a very choppy transition. What I'd like to be able to do is create a UIImage or .png file out of the image view with the blur and its alpha intact. Here's what I've already tried:
UIGraphicsBeginImageContext(CGSizeMake(320, 396));
[imageView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);
Since I have a shadow which "grows outside" of the image view, I can't just pass his size in the UIGraphicsBeginImageContext function. I set the correct size, but the resulting image doesn't save my alpha, instead it places a white background behind the shadow, which won't work for me because my real background is a wood texture. Also, the view isn't centered in the resulting file.
I'm pretty good with UIKit, but I'm a real noobie with Quartz 2d graphics, so if there's an obvious answer to this, send it anyway. :)
Try setting your UIImageView's backgroundColor to [UIColor clearColor] - this may enable your current solution to work.
imageView.backgroundColor = [UIColor clearColor];
UIGraphicsBeginImageContext(CGSizeMake(320, 396));
[imageView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Source: Converting a CGLayer to a *transparent* UIImage and PNG file in CoreGraphics iphone
I've had this issue before too. My solution was not to do an image, but instead to set the shadow path to just the outline of the view you are animating.
[imageView setContentMode:UIViewContentModeScaleAspectFit];
imageView.layer.masksToBounds = NO;
imageView.layer.shadowOffset = CGSizeMake(5, 5);
imageView.layer.shadowRadius = 200;
imageView.layer.shadowOpacity = 0.5;
CGRect rect = [self rectFromImageView:imageView];
imageView.layer.shadowPath = [UIBezierPath bezierPathWithRect:rect].CGPath;
Which uses the following function which assumes the image is set to content mode aspect fit:
-(CGRect)rectFromImageView:(UIImageView *)iv {
CGRect rect = (CGRect){{0,0},iv.frame.size};
if (iv.image.size.width/iv.frame.size.width > iv.image.size.height/iv.frame.size.height) {
//rect.origin.x == 0
CGFloat sf = iv.frame.size.width/iv.image.size.width;
rect.size.height = sf*iv.image.size.height;
rect.origin.y = floor((iv.frame.size.height - rect.size.height)/2);
} else {
//rect.origin.y == 0;
CGFloat sf = iv.frame.size.height/iv.image.size.height;
rect.size.width = sf*iv.image.size.width;
rect.origin.x = floor((iv.frame.size.width - rect.size.width)/2);
}
return rect;
}
If your image is just set to fill then just using the imageView.bounds should be sufficient
Add shadow path to view like this
[view.layer setShadowPath:[[UIBezierPath bezierPathWithRect:view.bounds] CGPath]]; //add path
view.layer.shadowColor = [[UIColor blackColor] CGColor];
view.layer.shadowOffset = CGSizeMake(x, y);
view.layer.shadowRadius = rad;
view.layer.shadowOpacity = 0.2f;
Please give ideas for how to crop UIImage on oval shape or circle shape. Please share your ideas.
#import <QuartzCore/QuartzCore.h>
CALayer *imageLayer = YourImageview.layer;
[imageLayer setCornerRadius:5];
[imageLayer setBorderWidth:1];
[imageLayer setMasksToBounds:YES];
by increasing radius it will become more round-able.
As long as the image is a square, you can get a perfect circle by taking half the width as the corner radius:
[imageView.layer setCornerRadius:imageView.frame.size.width/2];
You also need to add
[imageView.layer setMasksToBounds:YES];
Swift 4.2
import QuartzCore
var imageLayer: CALayer? = YourImageview.layer
imageLayer?.cornerRadius = 5
imageLayer?.borderWidth = 1
imageLayer?.masksToBounds = true
I started looking into this a couple of weeks back. I tried all the suggestions here, none of which worked well. In the great tradition of RTFM I went and read Apple's documentation on Quartz 2D Programming and came up with this. Please try it out and let me know how you go.
The code could be fairly easily altered to crop to an elipse, or any other shape defined by a path.
Make sure you include Quartz 2D in your project.
#include <math.h>
+ (UIImage*)circularScaleAndCropImage:(UIImage*)image frame:(CGRect)frame {
// This function returns a newImage, based on image, that has been:
// - scaled to fit in (CGRect) rect
// - and cropped within a circle of radius: rectWidth/2
//Create the bitmap graphics context
UIGraphicsBeginImageContextWithOptions(CGSizeMake(frame.size.width, frame.size.height), NO, 0.0);
CGContextRef context = UIGraphicsGetCurrentContext();
//Get the width and heights
CGFloat imageWidth = image.size.width;
CGFloat imageHeight = image.size.height;
CGFloat rectWidth = frame.size.width;
CGFloat rectHeight = frame.size.height;
//Calculate the scale factor
CGFloat scaleFactorX = rectWidth/imageWidth;
CGFloat scaleFactorY = rectHeight/imageHeight;
//Calculate the centre of the circle
CGFloat imageCentreX = rectWidth/2;
CGFloat imageCentreY = rectHeight/2;
// Create and CLIP to a CIRCULAR Path
// (This could be replaced with any closed path if you want a different shaped clip)
CGFloat radius = rectWidth/2;
CGContextBeginPath (context);
CGContextAddArc (context, imageCentreX, imageCentreY, radius, 0, 2*M_PI, 0);
CGContextClosePath (context);
CGContextClip (context);
//Set the SCALE factor for the graphics context
//All future draw calls will be scaled by this factor
CGContextScaleCTM (context, scaleFactorX, scaleFactorY);
// Draw the IMAGE
CGRect myRect = CGRectMake(0, 0, imageWidth, imageHeight);
[image drawInRect:myRect];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
Include the following code in your UIView class replacing "monk2.png" with your own image name.
- (void)drawRect:(CGRect)rect {
UIImage *originalImage = [UIImage imageNamed:[NSString stringWithFormat:#"monk2.png"]];
CGFloat oImageWidth = originalImage.size.width;
CGFloat oImageHeight = originalImage.size.height;
// Draw the original image at the origin
CGRect oRect = CGRectMake(0, 0, oImageWidth, oImageHeight);
[originalImage drawInRect:oRect];
// Set the newRect to half the size of the original image
CGRect newRect = CGRectMake(0, 0, oImageWidth/2, oImageHeight/2);
UIImage *newImage = [self circularScaleAndCropImage:originalImage frame:newRect];
CGFloat nImageWidth = newImage.size.width;
CGFloat nImageHeight = newImage.size.height;
//Draw the scaled and cropped image
CGRect thisRect = CGRectMake(oImageWidth+10, 0, nImageWidth, nImageHeight);
[newImage drawInRect:thisRect];
}
To have imageView in oval shape is not difficult.
You can do the following
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:yourImageView.bounds];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.path = path.CGPath;
yourImageView.layer.mask = maskLayer;
If the rect passed to bezierPathWithOvalInRect is Square the image will be cropped to circle.
Swift Code
let path = UIBezierPath(ovalIn: yourImageView.bounds)
let maskLayer = CAShapeLayer()
maskLayer.path = path.cgPath
yourImageView.layer.mask = maskLayer
To make a RoundShape Image
Step1: in .h file
#property (strong, nonatomic) IBOutlet UIImageView *songImage;
Step2: in .m file
- (void)viewDidLoad
{
self.songImage.layer.cornerRadius = self.songImage.frame.size.width / 2;
self.songImage.clipsToBounds = YES;
//To give the Border and Border color of imageview
self.songImage.layer.borderWidth = 1.0f;
self.songImage.layer.borderColor = [UIColor colorWithRed:249/255.0f green:117/255.0f blue:44/255.0f alpha:1.0f].CGColor;
}
OR For Swift
cell.songImage.layer.cornerRadius = cell.songImage.frame.size.width / 2;
cell.songImage.clipsToBounds = true
//To give the Border and Border color of imageview
cell.songImage.layer.borderWidth = 1.0
cell.songImage.layer.borderColor = UIColor(red: 50.0/255, green: 150.0/255, blue: 65.0/255, alpha: 1.0).CGColor
After a long search I found the correct way to circle the image
Download the Support archive file from URL http://vocaro.com/trevor/blog/2009/10/12/resize-a-uiimage-the-right-way/
#import "UIImage+RoundedCorner.h"
#import "UIImage+Resize.h"
Following lines used to resize the image and convert in to round with radius
UIImage *mask = [UIImage imageNamed:#"mask.jpg"];
mask = [mask resizedImage:CGSizeMake(47, 47) interpolationQuality:kCGInterpolationHigh ];
mask = [mask roundedCornerImage:23.5 borderSize:1];
SWIFT
var vwImage = UIImageView(image: UIImage(named: "Btn_PinIt_Normal.png"))
vwImage.frame = CGRectMake(0, 0, 100, 100)
vwImage.layer.cornerRadius = vwImage.frame.size.width/2
If you only need a perfect circle, changing the shape of the UIImageView could help.
Simply add the QuartzCore framework to your project and add these lines of code somewhere in the lifecycle before the imageView is displayed:
#import <QuartzCore/QuartzCore.h>
.
.
.
//to crop your UIImageView to show only a circle
yourImageView.layer.cornerRadius = yourImageView.frame.size.width/2;
yourImageView.clipsToBounds = YES;
Check out CGImageCreateWithMask. Create a mask of your oval shape, then apply it to the image.
you should refer This ...
// Create the image from a png file
UIImage *image = [UIImage imageNamed:#"prgBinary.jpg"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// Get size of current image
CGSize size = [image size];
// Frame location in view to show original image
[imageView setFrame:CGRectMake(0, 0, size.width, size.height)];
[[self view] addSubview:imageView];
[imageView release];
// Create rectangle that represents a cropped image
// from the middle of the existing image
CGRect rect = CGRectMake(size.width / 4, size.height / 4 ,
(size.width / 2), (size.height / 2)); //oval logic goes here
// Create bitmap image from original image data,
// using rectangle to specify desired crop area
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
// Create and show the new image from bitmap data
imageView = [[UIImageView alloc] initWithImage:img];
[imageView setFrame:CGRectMake(0, 200, (size.width / 2), (size.height / 2))];
[[self view] addSubview:imageView];
[imageView release];
SWIFT 3 answer comes from #Mohammad Sadiq
let path = UIBezierPath.init(ovalIn: workingImgaeView.bounds)
let maskLayer = CAShapeLayer(layer: layer)
maskLayer.path = path.cgPath
workingImgaeView.layer.mask = maskLayer
This should work,
Try pasting below code in viewDidLoad().
self.myImage.layer.cornerRadius = self.myImage.frame.size.width / 2;
self.myImage.clipsToBounds = YES;
What is the best way to move an image along an array of dots?
My recommended approach would be to wrap the UIImage in a UIImageView and use a CAKeyframeAnimation to animate your UIImageView's layer along a path that passes through your three points:
UIImage *image = [UIImage imageNamed:#"image.png"];
imageView = [[UIImageView alloc] initWithImage:image];
[mainView addSubview:imageView];
// Remember to remove the image view and release it when done with it
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
pathAnimation.duration = 1.0f;
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
CGMutablePathRef pointPath = CGPathCreateMutable();
CGPathMoveToPoint(pointPath, NULL, viewOrigin.x, viewOrigin.y);
CGPathAddLineToPoint(pointPath, NULL, point1.x, point1.y);
CGPathAddLineToPoint(pointPath, NULL, point2.x, point2.y);
CGPathAddLineToPoint(pointPath, NULL, point3.x, point3.y);
pathAnimation.path = pointPath;
CGPathRelease(pointPath);
[imageView.layer addAnimation:pathAnimation forKey:#"pathAnimation"];
Note that by default, the position of a layer is at the layer's center. If you'd like to move the layer relative to another reference point, you can set the layer's anchorPoint property to something like (0.0, 0.0) for its upper-left corner (on the iPhone) or (0.0, 1.0) for its lower left.
Also, this won't change the frame of the UIImageView when it's done, so if you refer to that frame later on, you may need to either take that into account or add a delegate method callback for the end of your animation to set it to the proper value.
You can also make your image move along curves, instead of straight lines, by replacing the calls to CGPathAddLineToPoint() with CGPathAddCurveToPoint().
EDIT (5/14/2009): I added the missing pathAnimation.path = pointPath line and changed a mistyped reference to curvedPath to pointPath.
The easiest way is to uses UIView animations
A quick example that assumes you are able to use UIImageView to hold your image and NSArray to hold your point.
UIImage *image = [UIImage imageNamed:#"image.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[someView addSubview:imageView]; // Assume someView exists
NSValue *firstPoint = [NSValue valueWithCGPoint:CGPointMake(0, 0)];
NSValue *secondPoint = [NSValue valueWithCGPoint:CGPointMake(100, 0)];
NSValue *thirdPoint = [NSValue valueWithCGPoint:CGPointMake(100, 100)];
// And so on....
NSArray *points = [NSArray arrayWithObjects:firstPoint, secondPoint, thirdPoint, nil];
for (NSValue *pointValue in points) {
[UIView beginAnimations:#"UIImage Move" context:NULL];
CGPoint point = [pointValue CGPointValue];
CGSize size = imageView.frame.size;
imageView.frame = CGRectMake(point.x, point.y, size.width, size.height);
[UIView commitAnimations];
}