I have 6 uiimage plates which are placed on the view. Now I am rotating the images 90 degrees on double tap by using the below code:
CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI * 0.5);
plate.transform = transform;
For first double tap it rotates 90 degree but when double tap second time it doesn't rotate.
Am i missing something ? Thanks in advance.
AffineTransform keeps the data of the transformation saved. So if you scale/rotate/move the view, the AffineTransform will keep that info.
In order to rotate 90 degree each time, you will have to get the current value and then modify it, or just keep a variable of your current degree and change the variable.
It's because you are already there, you have already rotated those rads. Try by increwsing the rotation value everytime the user taps the image.
Related
I have an image that i rotate to face the touchLocation of the user, but because the bounding box of the UIImageView gets larger. This is ruining some collision detection.
My only plan is to code a new bounding box system to get each of the 4 points in a bounding box and rotate that myself, then write check collide code for that.
But before i do that, is there an easy way to do this?
My rotate code:
- (void)ObjectPointAtTouch{
//Get the angle
objectAngle = [self findAngleToPoint:Object :touchLocation];
//Convert to radian, +90 for image alignment
double radian = (90 + objectAngle)/(180 / M_PI);
//Transform by radian
Object.transform = CGAffineTransformMakeRotation(radian);
}
I figured it out, as seen in other tutorials they also resize the scale off the bouncing box to fix this problem. CGAffineTransform scale I think it is.
I am rotating main view with 360 degrees, and I have subviews added inside main view, everything works correctly, but with one issue.
What I want to do is when I rotate main view, inner views should not lost their frames/position. Right now, when I rotate main view with infinte repeat count and dynamically if I add subview inside main view, it goes into proper position, but it does not retain its frame.
For example, I am implementing orbit, and for that, I have used entire transparent view as orbit and orbit is rotated from center point to 360 degree infinite times, and User can add many planets as he wants onto orbit, so when planets added on orbit, planets do not retain its frame. Can you suggest any idea?
Thanks in advance.
Well it sounds like you need to add a rotating animation for every subview that you add in your main view. If the main view rotates clockwise your subviews will need to rotate around their center in a counter-clockwise direction.
I guess you're trying to keep the subviews' orientations while rotating.
If I were you, I'd use CAAnimation instead of using a view to rotate.
You may add the animation to every subview, try this:
CAKeyframeAnimation* animation;
animation = [CAKeyframeAnimation animation];
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL,imgview.layer.position.x,imgview.layer.position.y);
int p = [self getblank:tag];
float f = 2.0*M_PI - 2.0*M_PI *p/PHOTONUM;
float h = f + 2.0*M_PI *num/PHOTONUM;
float centery = self.view.center.y;
float centerx = self.view.center.x;
float tmpy = centery + RADIUS*cos(h);
float tmpx = centerx - RADIUS*sin(h);
imgview.center = CGPointMake(tmpx,tmpy);
CGPathAddArc(path,nil,self.view.center.x, self.view.center.y,RADIUS,f+ M_PI/2,f+ M_PI/2 + 2.0*M_PI *num/PHOTONUM,0);
animation.path = path;
CGPathRelease(path);
animation.duration = TIME;
animation.repeatCount = 1;
animation.calculationMode = #"paced";
return animation;
I assume you have a stored variable that represents the rotation of the "world", correct? If not, you should.
Then, for each image you add, also store a variable with it that represents its rotation to the world.
For example, if your world is rotated 180°, and you added a cup (which you want to appear right-side up when the world is upside-down) the cup's "offset" to the world rotation would be -180°.
Then, if the world is at 180° and you rotate your world by adding 90°, then the cup's new rotation value would be cup_rotate_offset + world_rotation, or 180°+270°, which is the same as saying 90°, and the top of the world would be facing left and the cup's top would be facing right.
You have to independently track the offset values for each added object.
I have a custom UIImageView, I can drag it around screen by making a translation with (xDif and yDif is the amount fingers moved):
CGAffineTransform translate = CGAffineTransformMakeTranslation(xDif, yDif);
[self setTransform: CGAffineTransformConcat([self transform], translate)];
Let's say I moved the ImageView for 50px in both x and y directions. I then try to rotate the ImageView (via gesture recognizer) with:
CGAffineTransform transform = CGAffineTransformMakeRotation([recognizer rotation]);
myImageView.transform = transform;
What happens is the ImageView suddenly moves to where the ImageView was originally located (before the translation - not from the moved position + 50px in both directions).
(It seems that no matter how I translate the view, the self.center of the ImageView subclass stays the same - where it was originally laid in IB).
Another problem is, if I rotate the ImageView by 30 deg, and then try to rotate it a bit more, it will again start from the original position (angle = 0) and go from there, why wouldn't it start from the angle 30 deg and not 0.
You are overwriting the earlier transform. To add to the current transform, you should do this –
myImageView.transform = CGAffineTransformRotate(myImageView.transform, recognizer.rotation);
Since you're changing the transform property in a serial order, you should use CGAffineTransformRotate, CGAffineTransformTranslate and CGAffineTransformScale instead so that you add to the original transform and not create a new one.
Me again. I have a simple question. I have an UIImageView like the one shown below.
alt text http://img683.imageshack.us/img683/1999/volumen.png
That UIimageView is supposed to be the knob to control the volume of my iphone project. My question is, how to know the positions of bar on the UIImageView when it is rotated? Because the volume needs to be 0.5 when the little bar on the cercle is vertical.
I got a piece of code which is (in the touchMoved method):
float dx = locationT.x - imgVVolume.center.x;
float dy = locationT.y - imgVVolume.center.y;
CGFloat angleDif = 0.0f;
movedRotationAngle = atan2(dy,dx);
if (beganRotationAngle == 0.0) {
beganRotationAngle = movedRotationAngle;
initialTransform = imgVVolume.transform;
}
else {
angleDif = beganRotationAngle - movedRotationAngle;
CGAffineTransform newTrans = CGAffineTransformRotate(initialTransform, -angleDif);
imgVVolume.transform = newTrans;
}
Help please.
It depends on what input mechanism you want to use to control the rotation.
If the knob is to rotate based on a single finger touch dragging from side to side then you can create a UIPanGestureRecognizer and attach it to the knob UIImageView. The translationInView: method returns a CGPoint which is the amount of X and Y movement from the touch-down point. You can feed that into a formula like the one you post to get an angle of rotation. You'll want to keep track of delta from last position and also check for stop limits (like 0..360) to prevent over-rotation.
OTOH, if you're going to use two finger rotation then you'll want to use a UIRotationGestureRecognizer and look for the rotation value. Just feed that into a CGAffineTransformRotate and set it to the UIImageView transform. That takes care of all of the above for you. Again, you'll want to check for stop limits.
On iPhone, how to implement rotating image around the center point using finger touch ?
Just like wheel, if you put finger on the iPhone screen , then move suddenly, then the image becoming rotating around center point just like the wheel, after a while, it becomes more and more slow , finally stop.
Who can help to give some pieces of codes (Object-C) or some suggest ?
I was working with a "spin the bottle"-app yesterday. On the window I have a ImageView with an bottle that's suppose to response to touches and rotate the way the user swipes his finger. I struggled to get my ImageView to rotate during the touch-events (TouchesBegan, Touchesoved, TouchesEnd). I used this code in TouchesMoved to find out the angle in witch to rotate the image.
public override void TouchesMoved (NSSet touches, UIEvent evt)
{
PointF pt = (touches.AnyObject as UITouch).LocationInView(this);
float x = pt.X - this.Center.X;
float y = pt.Y - this.Center.Y;
double ang = Math.Atan2(x,y);
// yada yada, rotate image using this.Transform
}
THIS IS IMPORTANT! When the ImageView rotates, even the x & y-coordinates changes. So touching the same area all the time would give me different values in the pt and prePt-points. After some thinking, googeling and reading I came up with an simple solution to the problem. The "SuperView"-property of the ImageView.
PointF pt = (touches.AnyObject as UITouch).LocationInView(this.SuperView);
Having that small change in place made it alot easier, no i can use the UITouch-metohs LocationInView and PreviousLocationInView and get the right x & y coordinates. Her is parts of my code.
float deltaAngle;
public override void TouchesMoved (NSSet touches, UIEvent evt)
{
PointF pt = (touches.AnyObject as UITouch).LocationInView(this.Superview);
float x = pt.X - this.Center.X;
float y = pt.Y - this.Center.Y;
float ang = float.Parse(Math.Atan2(dx,dy).ToString());
//do the rotation
if (deltaAngle == 0.0) {
deltaAngle = ang;
}
else
{
float angleDif = deltaAngle - ang;
this.Transform = CGAffineTransform.MakeRotation(angleDif);
}
}
Hope that helped someone from spending hours on how to figure out how to freaking rotate a bottle! :)
I would use the affine transformations - yuou can assign a transformation to any layer or UI element using the transform property.
You can create a rotation transform using CGAffineTransform CGAffineTransformMakeRotation( CGFloat angle) which will return a transformation that rotates an element. The default rotation should be around the centerpoint.
Be aware, the rotation is limited to 360 degrees, so if you want to rotate something more than that (say through 720 degrees) - you have to break the rotation into several sequences.
You may find this SO article useful as well.
The transform property of a view or layer can be used to rotate the image displayed within. As far as the spinning part goes, you just track the location and movement of touches in your view with touchesBegan, touchesMoved, and touchesEnded.
Use the distance and time between the touches updates to calculate a speed, and use that to set a rotational velocity. Once you start the image spinning, update the position periodically (with an NSTimer, maybe), and reduce the rotational velocity by some constant.