/Users/awniemel/Notepad-SVN/svn/trunk/CatNiP/CatNiP/UIScrollBar.m

Go to the documentation of this file.

#import "UIScrollBar.h"

@implementation UIScrollBar

@synthesize delegate;

- (void)setDirection:(float)value
{
    // Remakes the rotation matrix according to the new value and combines
    // it with the normal transformation matrix.
    rotate = CGAffineTransformMakeRotation(value);
    super.transform = CGAffineTransformConcat(rotate, transform);
}

- (float)direction
{
    // Extracts the angle from the rotation matrix.
    return atan2(rotate.b,rotate.a);
}

- (void)setTransform:(CGAffineTransform)value
{
    transform = value;
    super.transform = CGAffineTransformConcat(rotate, transform);
}

- (CGAffineTransform)transform
{
    return transform;
}

- (id)init
{
    [self addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(thumbWasRelocated:)]];
    [self addTarget:self action:@selector(thumbDidMove:event:) forControlEvents:UIControlEventValueChanged];
    return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    if((self = [super initWithCoder:aDecoder]))
        return [self init];
    else
        return nil;
}

- (id)initWithFrame:(CGRect)frame
{
    if((self = [super initWithFrame:frame]))
        return [self init];
    else
        return nil;
}

- (void)thumbWasRelocated:(UIGestureRecognizer *)gestureRecognizer
{
    CGPoint newOffset = delegate.contentOffset;
    
    // Transformations do not affect internal coordinates (used here), so we
    // can safely calculate the new value from the ratio between the x
    // coordinate of the touch and the "width" of the scroll bar.
    float newValue = [gestureRecognizer locationInView:self].x / self.bounds.size.width;
    
    // Calculate the new offset based on whether the scroll bar is horizontal or
    // vertical.
    if((int)(self.direction * 180 / M_PI) % 180 == 0)
        newOffset.x = ABS(cos(self.direction)) * newValue * (delegate.contentSize.width - delegate.bounds.size.width);
    else
        newOffset.y = ABS(sin(self.direction)) * newValue * (delegate.contentSize.height - delegate.bounds.size.height);
    
    // This also calls scrollViewDidScroll automatically, so there's no need to
    // set the new value by hand.
    [delegate setContentOffset:newOffset animated:YES];
}

- (void)thumbDidMove:(id)sender event:(id)event
{
    CGPoint newOffset = delegate.contentOffset;
    float newValue = ((UISlider *)sender).value;
    
    // Calculate the new offset based on whether the scroll bar is horizontal or
    // vertical.
    if((int)(self.direction * 180 / M_PI) % 180 == 0)
        newOffset.x = ABS(cos(self.direction)) * newValue * (delegate.contentSize.width - delegate.bounds.size.width);
    else
        newOffset.y = ABS(sin(self.direction)) * newValue * (delegate.contentSize.height - delegate.bounds.size.height);
    
    // Don't animate this, the method gets called all the time.
    [delegate setContentOffset:newOffset animated:NO];
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // Calculate the new value based on whether the scroll bar is horizontal or
    // vertical.
    if((int)(self.direction * 180 / M_PI) % 180 == 0)
        [self setValue:ABS(cos(self.direction)) * scrollView.contentOffset.x / (scrollView.contentSize.width - scrollView.bounds.size.width) animated:NO];
    else
        [self setValue:ABS(sin(self.direction)) * scrollView.contentOffset.y / (scrollView.contentSize.height - scrollView.bounds.size.height) animated:NO];
}

@end