I'm trying to animate a sprite using only CoreAnimation. It's working so far except I can't figure out how to flip the sprite sheet.
Right now, I have a walking animation, but I want the sprite to face the direction it's walking (because it looks kind of silly walking backwards).
I guess I could add the reversed images on the sprite sheet, but I would rather avoid that because it could make it really big when I decide to add more.
Right now, my sprite is extending CALayer and I've set its contents to the CGImageRef which is the sprite sheet:
self.contents = (id) image;
To flip it I tried:
UIImage *tmp = [UIImage imageWithCGImage:image scale:1.0 orientation:UIImageOrientationUpMirrored];
CGImageRef flippedImage = tmp.CGImage;
self.contents = (id) flippedImage;
..and that's not working.
I found other solutions which involve animating, but I don't want to animate the flip. I just want it to happen instantly.
Is there a simple way to do this?
If there's a way to flip the whole CALayer, I'd like to know that too. =]
Thanks!
Rather than flipping your image, you could try applying a transform to your layer object.
Something like:
self.transform = CATransform3DMakeScale(-1, 1, 1);
This may be better for performance too; if the sprite needs to walk in the opposite direction, you can just set your transform back to CATransform3DIdentity rather than allocing a new image and rotating it.
Related
I'm working on an app in which i have to detect left eye, right eye, and mouth position.
I have an imageView on my self.view and imageView contains a face image, now I want to get both eyes and mouth coordinates. I have seen 2-3 sample codes for this but all are approximately same in all codes we have to invert my view for matching the coordinates which I don't want because my view have some other controls. And one more thing they all are using
UIImageView *imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:#"image.png"]];
but my imageView has frame and i cant init it with image. When I do so I found faceFeature's eyes and mouth coordinates wrong.
I had started my code from this sample code but in this also view is being invert its Y coordinate.
Can any one help me how can i detect the face eyes and mouth position on UIImageView's image without invert my self.view.
Please let me know if my question is not clear enough.
The trick here is to transform the returned points and bounds from CIDetector to your coordinates, instead of flipping your own view. CIImage has origin at the bottom left which you will need to transform to the top left
int height = CVPixelBufferGetHeight(pixelBuffer);
CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
transform = CGAffineTransformTranslate(transform, 0, -1 * height);
/* Do your face detection */
CGRect faceRect = CGRectApplyAffineTransform(feature.bounds, transform);
CGPoint mouthPoint = CGPointApplyAffineTransform(feature.mouthPosition, transform);
// Same for eyes, etc
For your second question about UIImageView, you just have to do
imageview.image = yourImage
After you have initialized your imageview
Worked it out! - edited the class to have a faceContainer which contains all of the face objects (the mouth and eyes), then this container is rotated and thats all. Obviously this is very crude, but it does work. Here is a link, http://www.jonathanlking.com/download/AppDelegate.m. Then replace the app delegate from the sample code with it.
-- OLD POST --
Have a look at this Apple Documentation, and slide 42 onwards from this apple talk. Also you should probably watch the talk as it has a demo of what you are trying to achieve, it's called "Using Core Image on iOS & Mac OS X" and is here.
I'm implementing a basic speedometer using an image and rotating it. However, when I set the initial rotation (at something like 240 degrees, converted to radians) It rotates the image and makes it much smaller than it otherwise would be. Some values make the image disappear entirely. (like M_PI_4)
the slider goes from 0-360 for testing.
the following code is called on viewDidLoad, and when the slider value is changed.
-(void) updatePointer
{
double progress = testSlider.value;
progress += pointerStart
CGAffineTransform rotate = CGAffineTransformMakeRotation((progress*M_PI)/180);
[pointerImageView setTransform:rotate];
}
EDIT: Probably important to note that once it gets set the first time, the scale remains the same. So, if I were to set pointerStart to 240, it would shrink, but moving the slider wouldn't change the scale (and it would rotate it as you'd suspect) Replacing "progress" with 240 in the transformation does the same thing. (shrinks it.)
I was able to resolve the issue for anybody who stumbles across this question. Apparently the image is not fully loaded/measured when viewDidLoad is called, so the matrix transforms that cgAffineTransform does actually altered the size of the image. Moving the update code to viewDidAppear fixed the problem.
Take the transform state of the view which you want to rotate and then apply the rotation transform to it.
CGAffineTransform trans = pointerImageView.transform;
pointerImageView.transform = CGAffineTransformRotate(trans, 240);
hi all upto now i know making rectangle with the CGrectmake and this rect(frame) i am using as imageview frame like UIImageView *someImage=[[uiimageview alloc]initwithframe:someRect]; now i can add an image with the frame of someRect. my problem here is when the coordinates like
(rectangleFirstx-coordinate,tectangleFirstY-cordinate)=(10,10)
(rectangleLastx-cordinate,rectangleLasty-cordinate)=(17,7) this, how can i give frame to the uiimageview....This is like a inclined rectangle..can any one suggest me how to apply frame through the ios library for these type of coordinates..Thanks in advance..
Your example isn't very clear because a rectangle with opposite corners at (10,10) and (10,7) can be in any one of a myriad of different orientations, including one perfectly aligned along the x and y axis.
What you can certainly do is create a UIImageView of the desired size and location and then rotate it by using one of many techniques, including animation methods.
[UIImageView animateWithDuration:0.1 animations:^
{
your_UIImageView_here.transform = CGAffineTransformMakeRotation((M_PI/180.0) * degrees);
}];
You can hide the UIImageView until the rotation is done and then show it.
If your question is about how to use the coordinates you provided to arrive at an angle I'd suggest that more data is needed because it is impossible to pick one of the billions of possible rectangles with corners at those two points without more information. Once you have more data then it is pretty basic trigonometry to figure out the angle to feed into the rotation.
I have a UIView container that has two UIImageViews inside it, one partially obscuring the other (they're being composed like this to allow for occasional animation of one "layer" or another.
Sometimes I want to make this container 50% alpha, so what the users sees fades. Here's the problem: setting my container view to 50% alpha makes all my subviews inherit this as well, and now you can see through the first subview into the second, which in my application has a weird X-Ray effect that I'm not looking for.
What I'm after, of course, is for what the user currently sees to become 50% transparent-- the equivalent of flattening the visible view into one bitmap, and then making that 50% alpha.
What are my best bets for accomplishing this? Ideally would like to avoid actually, dynamically flattening the views if I can help it, but best practices on that welcome as well. Am I missing something obvious? Since most views have subviews and would run into this issue, I feel like there's some obvious solution here.
Thanks!
EDIT: Thanks for the thoughts folks. I'm just moving one image around on top of another image, which it only partially obscures. And this pair of images has to move together sometimes, as well. And sometimes I want to fade the whole thing out, wherever it is, and whatever the state of the image pair is at the moment. Later, I want to bring it back and continue animating it.
Taking a snapshot of the container, either by rendering its layer (?) or by doing some other offscreen compositing on the fly before alpha'ing out the whole thing, is definitely possible, and I know there are a couple ways to do it. But what if the animation should continue to happen while the whole thing's at 50% alpha, for example?
It sounds like there's no obvious solution to what I'm trying to do, which seems odd to me, but thank you all for the input.
Recently I had this same problem, where I needed to animate layers of content with a global transparency. Since my animation was quite complex, I discovered that flattening the UIView hierarchy made for a choppy animation.
The solution I found was using CALayers instead of UIViews, and setting the .shouldRasterize property to YES in the container layer, so that any sublayers would be flattened automatically prior to applying the opacity.
Here's what a UIView could look like:
#import <QuartzCore/QuartzCore.h> //< Needed to use CALayers
...
#interface MyView : UIView{
CALayer *layer1;
CALayer *layer2;
CALayer *compositingLayer; //< Layer where compositing happens.
}
...
- (void)initialization
{
UIImage *im1 = [UIImage imageNamed:#"image1.png"];
UIImage *im2 = [UIImage imageNamed:#"image2.png"];
/***** Setup the layers *****/
layer1 = [CALayer layer];
layer1.contents = im1.CGImage;
layer1.bounds = CGRectMake(0, 0, im1.size.width, im1.size.height);
layer1.position = CGPointMake(100, 100);
layer2 = [CALayer layer];
layer2.contents = im2.CGImage;
layer2.bounds = CGRectMake(0, 0, im2.size.width, im2.size.height);
layer2.position = CGPointMake(300, 300);
compositingLayer = [CALayer layer];
compositingLayer.shouldRasterize = YES; //< Here we turn this into a compositing layer.
compositingLayer.frame = self.bounds;
/***** Create the layer three *****/
[compositingLayer addSublayer:layer1]; //< Add first, so it's in back.
[compositingLayer addSublayer:layer2]; //< Add second, so it's in front.
// Don't mess with the UIView's layer, it's picky; just add sublayers to it.
[self.layer addSublayer:compositingLayer];
}
- (IBAction)animate:(id)sender
{
/* Since we're using CALayers, we can use implicit animation
* to move and change the opacity.
* Layer2 is over Layer1, the compositing is partially transparent.
*/
layer1.position = CGPointMake(200, 200);
layer2.position = CGPointMake(200, 200);
compositingLayer.opacity = 0.5;
}
I think that flattening the UIView into a UIImageView is your best bet if you have your heart set on providing this feature. Also, I don't think that flattening the image is going to be as complicated as you might think. Take a look at the answer provided in this question.
Set the bottom UIImageView to have .hidden = YES, then set .hidden = NO when you setup a cross-fade animation between the top and bottom UIImageViews.
When you need to fade the whole thing, you can either set .alpha = 0.5 on the container view or the top image view - it shouldn't matter. It may be computationally more efficient to set .alpha = 0.5 on the image view itself, but I don't know enough about the graphics pipeline on the iPhone to be sure about that.
The only downside to this approach is that you can't do a cross-fade when your top image is set to 50% opacity.
A way to do this would be to add the ImageViews to the UIWindow (the container would be a fake one)
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.