Currently I have an image inside of a frame in my view.
I would like to get an absolute position of the image.
By using image.frame.origin.x I get a position relative to the frame where image is.
e.g if the frame is at the bottom I should get a large number x and y. But I receive 0 and 0 as image is right next to top and left border of the frame.
Try:
CGRect absolutePosition = [image convertRect:self.view.bounds toView:nil];
This will give you the position in the window. If you want it referenced to another view, change nil to that view.
Related
In the image we need to find the frame for inner square wrt to windows. Normat cgRect : to method is giving wrong answer.
A much better method than my previous answer, and will handle subviews regardless of ratio / centering.
You can get the "innerView" frame like this:
innerView.frame = outerView.convert(innerView.frame, to: view)
I have a problem. I'm working on making a game. As part of my game I need images to be rotated and then moved in the direction of the rotated angle inside a game loop (using an NSTimer). In essence I'm trying to create the effect of launching a projectile. The code works fine when moving in perpendicular directions such as 0, 90, 180, 270, and 360 degrees, but any other angle and the image starts to glitch out. The object on the screen maintains its correct bounds and contents, but the actual displayed image disappears. Does anybody know what the problem is or someway I could get around it? If needed, I can make and post a video of my problem so you can see what I'm talking about.
Here is a sample of the code I'm using. The "background" variable is just a UIImageView:
angle = 60;
background.transform = CGAffineTransformRotate(object.transform, angle*M_PI/180); //converts degrees to radians and rotates the image
background.frame = CGRectMake( background.frame.origin.x + cos(angle*m_PI/180)*32; background.frame.origin.y -sin(angle*M_PI/180)*32, background.frame.size.width, background.frame.size.height); //moves the image in the direction of the angle
For starters, there is a semicolon after the x origin in your CGRect instead of a comma. Was that just a typo?
The UIView documentation for frame states:
Warning: If the transform property is not the identity transform, the
value of this property is undefined and therefore should be ignored.
Changes to this property can be animated. However, if the transform
property contains a non-identity transform, the value of the frame
property is undefined and should not be modified. In that case, you
can reposition the view using the center property and adjust the size
using the bounds property instead.
So there you have it, you should not be trying to change the frame when setting a custom transform. You are only trying to adjust the position of the view anyway so just modify your code to adjust center instead of the origin coordinates.
To change the size, you can use the bounds.
CGRect bounds = myView.bounds;
bounds.size.width = whatever;
bounds.size.height = whatever;
myView.bounds = bounds;
I need to resize an UImageView dynamically
for that I need to find the UImageview's absolute rect on screen, x,y is what i need actually.
because my ImageView is inside another view, if i query the ImageView frame, i get x,y of it to be 0,0
how do I find the absolute rect on screen ?
try using
CGRect targetFrame = [self.view convertRect:imageView.frame fromView:imageView];
I have an draggable UIImageView that at some point changes to another UIImageView frame. Problem is I need to make the transformation using the same clicked point in the first UIImageView. I simply do this:
_firstImageView.frameSize = _secondImageView.frameSize;
But the frame changes from the _firstImageView origin. I need to do the transformation from the point I clicked inside the _firstImageView:
CGPoint clickedPoint = [sender locationInView:self.view];
I had tried the layer.anchorPoint but that makes the imageView disappear, don't know why (I did first a conversionPoint from self.view to the _firstImageView reference system)
EDIT e.g for better explanation of problem:
I have a uiimage1 frame with height of 100. And another with 50.
If I click in the point (y=90) of uiimage1 and start dragging, there's an test intersection that I make and if intersects it changes that UIImage1 to the frame of UIImage2. But since the click was on y=90 and UIImage2 only has max y-height of 50, it changes the frame size by the UIImage1 origin. I continue dragging with the click point outside the new frame (that is only y-height=50 and point click is y=90). My question is: Can I change the frame not by its origins but by that point clicked position?
Thanks in advance
+(CGRect)getUpdatedFrame:(CGRect)frame byChangingCenterTo:(CGPoint)newCenter
{
float width = frame.size.width;
float height = frame.size.height;
return CGRectMake(newCenter.x-width/2, newCenter.y-height/2, width, height);
}
+(CGPoint)centerForRect:(CGRect)rect
{
return CGPointMake( rect.origin.x+rect.size.width/2 , rect.origin.y+rect.size.height/2 );
}
I have a round image that I want to "squish" vertically so that it looks more like a horizontal line, then expand it back to the original shape. I thought this would work by setting the layer's anchor point to the center and then animating the frame via UIViewAnimation with the height of the frame = 1.
[self.imageToSquish.layer setAnchorPoint:CGPointMake(0.5, 0.5)];
CGRect newFrame = CGRectMake(self.imageToSquish.frame.origin.x, self.imageToSquish.frame.origin.y, self.imageToSquish.frame.size.width, 1 );
[UIView animateWithDuration:3
animations:^{self.imageToSquish.frame = newFrame;}
completion:nil];
But the image shrinks toward the top instead of around the center.
You’re giving it a frame that has its origin—at the top left—in the same position as it started. You probably want to do something more like this, adding half the image’s height:
CGRect newFrame = CGRectMake(self.imageToSquish.frame.origin.x, self.imageToSquish.frame.origin.y + self.imageToSquish.frame.size.height / 2, self.imageToSquish.frame.size.width, 1);
Alternatively—and more efficiently—you could set the image view’s transform property to, say, CGAffineTransformMakeScale(1, 0.01) instead of messing with its frame. That’ll be centered on the middle of the image, and you can easily undo it by setting the transform to CGAffineTransformIdentity.