Rotate a circle based on UITouch

Ok.
I'm racking my brain on this one.
Onscreen I have an object (UIImageView) that I want to be able to rotate with my finger. Basically touch it and move my finger around and have it rotate on it's center to follow my finger.
Rotating the image is no big deal, I give it the radial that I want it to rotate on(0-360) and it aligns itself nicely.
CGAffineTransform imgObjectRot = CGAffineTransformMakeRotation(radians(90));
[imgObject setTransform:imgObjectRot];
static inline float radians (double degrees) {
return degrees * M_PI/180;
My problem is when I incorporate the touch. I can't figure out a way of finding the angle from the center of the image to the touch location.
Should be a simple formula based on x1,y1 and x2,y2. In fact I found some examples but the math is pretty complicated - and the iPhone doesn't seem to have the built in math functions like ATAN.
Anyhow, there must be some easier / built in way that I'm missing.
I don't know if it makes sense to find the degrees between the two locations or if I can "attach" the touch location to the image object and follow it with some built in commands.
Any ideas?

I'm a n00b have a knob as well, and have no problem with a simple CGAffineTransformMakeRotation(RotationInRadians) being called after a swipe gesture.
I image you are using the ATAN function and the distance between touch down and touch up hortizontally to "scale" the rotation of the knob. I haven't gotten there yet...
My issue is this: I have a processRightSwipe rotation (CGAffineTransformMakeRotation) with positive radians, and a processLeftSwipe with negative radians.
I animate the rotation, but when the animation is completed and I swipe the other direction, instead of returning to the original knob position, it treats the "zero angle" as the position and rotates to an undesired position in the opposite direction. Not sure how to get the knob (representing 'volume' levels in a game) to 'increase' or 'decrease' by the desired 36 degrees 'notches' with each swipe. (Later I will attempt to use the ATAN function to 'spin' the dial based off the distance the swipe covers. Right?)
I guess what I need is a rotation property to "reset" after the animation (Rotate, then zero out the angle?).
Or is there something my non-engineer self is missing?

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Hey there, your code has a few issues.
1st: to use props like "offset" and "width", you can't use Edge symbols, you have to use the raw object- I use jQery for this.
2nd: you need to set the mouse position vars (sym.x, sym.y), in the mousemove function.
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www.timjaramillo.com/code/edge/rotateSymbolToMouse
source:
www.timjaramillo.com/code/edge/_source/rotateSymbolToMouse.zip
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So I see normally for the rotation it's based on X, Y, and Z, by choosing one of them.. I also saw somewhere where you can specify the angle for the cam, but that's about it.. I want to be able to manipulate a 3d object at any angle :)

For that you need to rotate the camera rather than the object.
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http://stackoverflow.com/questions/14182704/javafx-2-animation-scale-node-depending-pathtransition-duration/14182917#14182917
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Rotating Item: Need help with perspective (skewing)

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import javax.swing.*;
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import java.awt.*;
import java.util.*;
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                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
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                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
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                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
                             {1,2,2,2,2,2,2,2,2,2,3,2,2,2,1},
                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
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                             {1,2,2,2,2,2,2,2,2,2,2,2,2,2,1},
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import java.awt.Graphics2D;
import java.awt.Image;
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          if (map.blocked(nx - size, ny + size))
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     public void paint(Graphics2D g) {
          int xp = (int) (map.TILE_SIZE * x);
          int yp = (int) (map.TILE_SIZE * y);
          // rotate the sprite based on the current angle and then
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          g.rotate(ang, xp, yp);
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          g.rotate(-ang, xp, yp);
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rotate() should always be accompanied with appropriate translate().
See:
http://java.sun.com/docs/books/tutorial/2d/TOC.html
http://www.adtmag.com/java/articleold.aspx?id=1241
http://www.apl.jhu.edu/~hall/java/Java2D-Tutorial.html
And, never mix AWT components with Swing ones.
Use JPanel instead of Canvas.
Use also standard drawing/painting technique shown above URSs.

How to rotate photographs? I've tried everything

Hi!
I am a fairly new user of mac, and after months I still don't know how/when/why do photographs rotate. I am very confused.
This is the thing:
Some of my vertical photographs appear upright in the Finder. But some appear sideways, for no apparent reason. Some of the ones that appear sideways in the Finder, appear upright when I open them in the Viewer, in Photoshop and in iPhoto. But are sideways if I upload them to a blog or to a website.
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Now once I have managed to get a photo to appear upright in the Viewer/Photoshop/iPhoto (but still not on the Finder), if I open it in Photoshop and simply save (without doing absolutely anything else), it will automatically rotate and appear upright in the Finder, and anywhere i may post it in the net. This is the only method that has worked for me so far, but it is very time consuming when you want to rotate fifty pictures everyday.
Now I don't know why each vertical photograph acts differently (I would like to), but my guess is that when photographs appear upright in the Finder, the file has been correctly rotated. So I have been trying to rotate them directly from the Finder (right click- automator- rotate photo- ok) but that doesn't work, nothing happens.
Can anyone explain to me how this whole thing works and if there's a logic to it? And if there is a faster way to rotate than to open in photoshop and save?
For reference, I upload the photographs from a Sony Cybershot 12.1 camera by opening it like a harddrive and drag-drop. I do not use iPhoto. Could it have something to do with the way I take the photos from the camera- vertical up or down...?
Thank you so much. It's driving me crazy.
D.d.

HI there Violet, In my camera I have the settings saved to not rotate in camera. Does your camera have that capability? Some do some do not. As far as understanding the rotation.This is based on how you turn your camera when you take the shot. Vertical or Horizontal. That is how it will be displayed in the finder or anywhere else for that matter.
I change rotation right within the I Photo window, it is quicker and easier than opening photoshop to change your aspect ratio. Any edits I make aside from rotating, I do in Photoshop. In I Photo preferences, I have photoshop set as the external editor, this way all changes you make will be depicted within I Photo. You need some type of organizational tool to keep track of your photos, that is what I Photo does so well. Its your database. Ileen
Message was edited by: Ileen Cuccaro

Rotate a circle based on UITouch

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