Detection of wires at any angle
Is there any way to detect scrolling in the iPhone from any angle? UISwipeGestureRecognizer
seems to have only 4 directions.
If I put it like this:
\ \ \ X
I want it to give me something like 60 degrees, and not just down like UISwipeGestureRecognizer
.
How can i do this?
You can use UIPanGestureRecognizer
. When you discover the state of Ended, you can get speed. The speed is divided into components x and y. You can use the x and y components to calculate the slope of m.
m = Δy / Δx
The angle of the line, Σ, determined by the slope, m relative to the x axis, is determined as follows:
Σ = arctan (m)
Sort of:
- (void)didPan:(UIPanGestureRecognizer*)recognizer { switch (recognizer.state) { case UIGestureRecognizerStateBegan: ... break; case UIGestureRecognizerStateEnded: CGPoint velocity = [recognizer velocityInView:[recognizer.view superview]]; // If needed: CGFloat slope = velocity.y / velocity.x; CGFloat angle = atan2f(velocity.y, velocity.x); ... break; } }
You can simply determine the start and stop of the touch and calculate the angle with two points.
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ //global CGPoint. //this should be it GLOBAL coordinates, not just relative to the view startPoint=[[touches anyObject] locationInView:self.superview.superview]; } -(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{ //global CGPoint endPoint=[[touches anyObject] locationInView:self.superview.superview]; }
To calculate the angle between them, you can use something like this:
static inline CGFloat angleBetweenLinesInRadians(CGPoint line1Start, CGPoint line1End, CGPoint line2Start, CGPoint line2End) { CGFloat a = line1End.x - line1Start.x; CGFloat b = line1End.y - line1Start.y; CGFloat c = line2End.x - line2Start.x; CGFloat d = line2End.y - line2Start.y; CGFloat line1Slope = (line1End.y - line1Start.y) / (line1End.x - line1Start.x); CGFloat line2Slope = (line2End.y - line2Start.y) / (line2End.x - line2Start.x); CGFloat degs = acosf(((a*c) + (b*d)) / ((sqrt(a*a + b*b)) * (sqrt(c*c + d*d)))); return (line2Slope > line1Slope) ? degs : -degs; } //This code came from someone else and I don't remember who to give credit to.
So, to find the angle of the horizontal line, you can do something like this
CGFloat angle=angleBetweenLinesInRadians(startPoint, endPoint, startPoint, CGPointMake(startPoint.x + 10, startPoint.y));
That would be such an angle
________ \ this angle \ \ x
Hope this helps
CHANGE the best way
What you can do is subclass UIGestureRecognizer
#import <UIKit/UIGestureRecognizerSubclass.h>
Then you implement these methods
- (void)reset; - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event;
Each of them is used to define and set the state property for gestures.
Here is a complete example: http://developer.apple.com/library/ios/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizers/GestureRecognizers.html