I want to transform/rotate an UIImage in circular motion without changing the angle of the image. Following diagram explains the requirement.
How this can be done using UIView transform property. Thanks in advance.
Sounds to me like you only need to use the UIView frame property. However, because you are taking a non-linear path between your source and destination you will likely have to dabble with CoreAnimation.
Check out CAKeyFrameAnimation to animate a property through an arbitrary key path.
Good Luck!
My book provides sample code for animating an image along a path:
http://www.apeth.com/iOSBook/ch17.html#FIGnancyBell
CGMutablePathRef path = CGPathCreateMutable();
// ... define the path using CGPath... functions ...
CAKeyframeAnimation* anim1 = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim1.path = path;
Related
I am trying to use a UIBezier path for drawing a line using user touch. I have the physics body and bezier working separately although I need to merge them together. Is there a way to implement drawRect or an equivalent within SpriteKit? Thanks in advance!
Nope. DrawRect or other custom drawing methods are not (currently) supported by Sprite Kit. Use SKShapeNode to draw the path.
SKShapeNode* shape = [SKShapeNode node];
CGMutablePathRef path = CGPathCreateMutable();
// create your path here ...
shape.path = path;
[self addChild:shape];
I have a layer that will move from point A to point B on a UIBezierPath.
I have found a lot of samples those are refers to CAAnimation and UIBezierPath.
But I need to move my layer only from specified point to another on bezier path.
Any suggestions would be appreciated.
Thanks
Hope this will be helpful.
UIBezierPath *trackPath = [UIBezierPath bezierPath];
.
.
.
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim.path = trackPath.CGPath;
anim.repeatCount = 1;
anim.duration = 2.0;
[layerToAnimate addAnimation:anim forKey:#"pathGuide"];
If your bezier path is a circle or even a half circle, you could just skip the path and instead add the point to a larger square layer. Set the point to be a fixed distance from the center of that larger square layer. Then you can just rotate the larger layer on the z axis around the center whatever number of degrees you need it to move. Seems it would simplify things a bit, though I'm not sure exactly what else you need it to do.
i'd been looking to do something like this and fount this tutorial, it shows how to follow a specific path. It works with a car (a CALayer) and a UIBezierpath as the race track and is solved in this order:
Defining the path the car should follow (in this case your BezierPath)
Drawing the black line that defines the track; (N/A)
Drawing the white dashed center-line of the track; (N/A)
Creating the layer defining the car; (your Layer)
Animating the car along the path. (What your asked!)
You can check the reference Post here:
http://nachbaur.com/2011/01/07/core-animation-part-4/
Also you can download the source code here:
http://cdn5.nachbaur.com/wp-content/uploads/2011/01/CALayerAnimTest.zip?25881d
hope this helps!
regards,
Jorge.
I have a UIImageView that contains an image of a circle. I would like to be able to remove a portion of the image (while maintaining the transparency) to create the effect of a slice missing as shown below. My ultimate goal is to create something like the ITunes app, where as you play a song preview, the circle slowly fills in, in a clockwise direction.
If you don't need the image of the circle for anything other than the progress display, you could skip the UIImageView and just use CoreGraphics to draw the progress indicator. The basic steps would be:
Create a path - CGContextBeginPath
Add an arc using CGContextAddArc
Fill the path using CGContextFillPath
Close the path - CGContextClosePath
Repeat this for each progress step, changing the endpoint of your arc each time.
I've implemented a similar filling-up circle with the following code:
(the delegate provides a value between 0 and 1)
- (void)drawRect:(CGRect)rect
{
CGFloat endAngle=([self.delegate giveCompletion]+0.75)*2*M_PI;
UIBezierPath *path=[UIBezierPath bezierPathWithArcCenter:self.center radius:self.bounds.size.width/(3) startAngle:0.75*2*M_PI endAngle:endAngle clockwise:YES];
[path addLineToPoint:self.center];
[path addLineToPoint:CGPointMake(self.center.x, self.center.y+self.bounds.size.width/(3)) ];
[path addClip];
[[UIColor blueColor]setFill];
UIRectFill(self.bounds);
}
I haven't figured out how to dynamically make it fill up yet, though I guess that this would depend heavily on the specific context where it is being used. Hope it is of any help! Cheers.
I would like to animate a radial gradient to shrink and grow the inner radius, as if it were pulsing.
Right now I'm rendering the gradient with CGGradient, but I'm not sure how to animate it. I've seen this topic
Can you animate gradients using Quartz in an iPhone?
Which explains how animate a linear gradient with CAGradientLayer, but it doesn't seem like this will draw a radial gradient.
Is there an easy way to animate a CGGradient, or some way to create a radial gradient CAGradientLayer?
Any thoughts are appreciated.
If only Core Image was on the phone, this would be trivial. An animatable filter is what you need. ;-)
The CAGradientLayer does allow for animating its properties, however, it currently only supports linear gradients.
The only thing I can think of if you're wanting to animate using Core Animation is to animate the transform of the view into which you're drawing your gradient.
You can animate any view's transform pretty simply. Just draw your gradient in the view as you're probably already doing and then animate the transform using scaling. Using explicit animation, it would be something like:
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"transform"];
[anim setFromValue:[NSValue valueWithCATransform3D:CATransform3DIdentity]];
// Scale x and y up
[anim setToValue:[NSValue valueWithCATransform3D:
CATransform3DMakeScale (1.0f, 1.0f,0.0f)]];
[anim setAutoreverses:YES];
[anim setRepeatCount:HUGE_VALF];
[[gradientView layer] addAnimation:anim];
Unfortunately this would look like expanding and contracting more than pulsing, I think (though I haven't tried it).
I think if you want a true pulsing with your gradient at this point, you probably have to do the animation manually using your own timer. Just re-draw periodically changing your inner radius value as you go. Ugh. I'm not absolutely sure that's the only way, but I have yet to see a compelling pulse animation on the phone with a gradient as you're wanting.
There is one other idea I would like to try at some point. Core Animation now allows animating arbitrary properties/values. You could theoretically set up an animation using some arbitrary keypath that you name (say innerRadius, for example) and override the -drawLayerInContext delegate method. Then you could grab the current value from the presentationLayer while it's in mid-flight and re-draw your gradient there instead. This is just theoretical as I haven't tried it, but it seems like it might be worth looking into.
Best regards.
I want Stretch a image. For that i use sprite. I want stretch sprite & this stretching is may be Circular or curve animation. I don't understand what methode used for that. Can anyone help me?
Since you tagged your question with cocos2d I guess you'll be using that. It's really basic to strech an image
Sprite *mySprite = [Sprite spriteWithFile:#"mysprite.png"];
mySprite.position = ccp(100, 100);
mySprite.scale = 2.0;
[self addChild:mySprite];
If you want to animate it you can use the cocos2d actions or just create your own animation. The example below does a linear animation to 3x original sprite size in 1 second:
id action1 = [ScaleTo actionWithDuration:1.0 scale:3.0];
[mySprite runAction: action1];
For manipulating views and images in general in ways such as streching you can read up on transforms provided by the sdk, you can learn about 2D transforms here http://developer.apple.com/iphone/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_affine/dq_affine.html and you can extend that further to 3D by manipulating the layers transforms instead of the views transforms. Youll be able to do things such as scaling and rotating and you can define your own transforms as well. This example project http://developer.apple.com/iphone/library/samplecode/MoveMe/ is a good reference to get started with transforms and animating them.