MBSliderButton.m

/*
 Created on 28/02/2009
 Copyright 2009 Max Howell <max@methylblue.com>
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define KNOB_WIDTH 38
#define HEIGHT 26
#define WIDTH 89
#define KNOB_MIN_X 0
#define KNOB_MAX_X (WIDTH-KNOB_WIDTH)

@interface MBKnobAnimation : NSAnimation
{
  int start, range;
  id delegate;
}
@end
@implementation MBKnobAnimation
-(id)initWithStart:(int)begin end:(int)end
{
  [super init];
  start = begin;
  range = end - begin;
  return self;
}
-(void)setCurrentProgress:(NSAnimationProgress)progress
{
  int x = start+progress*range;
  [super setCurrentProgress:progress];
  [delegate performSelector:@selector(setPosition:) withObject:[NSNumber numberWithInteger:x]];
}
-(void)setDelegate:(id)d
{
  delegate = d;
}
@end


#import "MBSliderButton.h"

@implementation MBSliderButton

-(void)awakeFromNib
{
  surround = [[NSImage alloc] initByReferencingFile:[[prefpane bundle] pathForResource:@"button_surround" ofType:@"png"]];
  knob = [[NSImage alloc] initByReferencingFile:[[prefpane bundle] pathForResource:@"button_knob" ofType:@"png"]];
  
  state = false;
}

-(void)drawRect:(NSRect)rect
{      
  NSColor* darkColor = [NSColor colorWithDeviceRed:0.33 green:0.33 blue:0.33 alpha:1.0];
  NSColor* lightColor = [NSColor colorWithDeviceRed:0.66 green:0.66 blue:0.66 alpha:1.0];    
  NSColor* darkGray = [NSColor colorWithDeviceRed:0.5 green:0.5 blue:0.5 alpha:1.0];
  NSColor* lightGray = [NSColor colorWithDeviceRed:0.7 green:0.7 blue:0.7 alpha:1.0];    
  
  NSGradient* green_gradient = [[NSGradient alloc] initWithStartingColor:darkColor endingColor:lightColor];
  NSGradient* gray_gradient = [[NSGradient alloc] initWithStartingColor:darkGray endingColor:lightGray];
  
  [green_gradient drawInRect:NSMakeRect(0, location.y, location.x+10, HEIGHT) angle:270];   
  
  int x = location.x+KNOB_WIDTH-2;
  [gray_gradient drawInRect:NSMakeRect(x, location.y, WIDTH-x, HEIGHT) angle:270];
    
  NSPoint pt;
  [surround drawAtPoint:NSMakePoint(0,0) fromRect:NSZeroRect 
              operation:NSCompositeSourceOver
               fraction:1.0];    
  pt = location;
  pt.x -= 2;
  [knob drawAtPoint:pt fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
}

-(BOOL)isOpaque
{
  return YES;
}

-(NSInteger)state
{
  return state ? NSOnState : NSOffState;
}

-(void)animateTo:(int)x
{
  MBKnobAnimation* a = [[MBKnobAnimation alloc] initWithStart:location.x end:x];
  [a setDelegate:self];
  if (location.x == 0 || location.x == KNOB_MAX_X){
    [a setDuration:0.20];
    [a setAnimationCurve:NSAnimationEaseInOut];
  }else{
    [a setDuration:0.35 * ((fabs(location.x-x))/KNOB_MAX_X)];
    [a setAnimationCurve:NSAnimationLinear];
  }
  
  [a setAnimationBlockingMode:NSAnimationBlocking];
  [a startAnimation];
  [a release];
}

-(void)setPosition:(NSNumber*)x
{
  location.x = [x intValue];
  [self display];
}

-(void)setState:(NSInteger)newstate
{
  [self setState:newstate animate:true];
}

-(void)setState:(NSInteger)newstate animate:(bool)animate
{
  if(newstate == [self state])
    return;
  
  int x = newstate == NSOnState ? KNOB_MAX_X : 0;
  
  //TODO animate if  we are visible and otherwise don't
  if(animate)
    [self animateTo:x];
  else
    [self setNeedsDisplay:YES];
  
  state = newstate == NSOnState ? true : false;
  location.x = x;
}

-(void)offsetLocationByX:(float)x
{
  location.x = location.x + x;
  
  if (location.x < KNOB_MIN_X) location.x = KNOB_MIN_X;
  if (location.x > KNOB_MAX_X) location.x = KNOB_MAX_X;
  
  [self setNeedsDisplay:YES];
}

-(void)mouseDown:(NSEvent *)event
{
  BOOL loop = YES;
  
  // convert the initial click location into the view coords
  NSPoint clickLocation = [self convertPoint:[event locationInWindow] fromView:nil];
  
  // did the click occur in the draggable item?
  if (NSPointInRect(clickLocation, [self bounds])) {
    
    NSPoint newDragLocation;
    
    // the tight event loop pattern doesn't require the use
    // of any instance variables, so we'll use a local
    // variable localLastDragLocation instead.
    NSPoint localLastDragLocation;
    
    // save the starting location as the first relative point
    localLastDragLocation=clickLocation;
    
    while (loop) {
      // get the next event that is a mouse-up or mouse-dragged event
      NSEvent *localEvent;
      localEvent= [[self window] nextEventMatchingMask:NSLeftMouseUpMask | NSLeftMouseDraggedMask];
      
      
      switch ([localEvent type]) {
        case NSLeftMouseDragged:
          
          // convert the new drag location into the view coords
          newDragLocation = [self convertPoint:[localEvent locationInWindow]
                                      fromView:nil];
          
          
          // offset the item and update the display
          [self offsetLocationByX:(newDragLocation.x-localLastDragLocation.x)];
          
          // update the relative drag location;
          localLastDragLocation = newDragLocation;
          
          // support automatic scrolling during a drag
          // by calling NSView's autoscroll: method
          [self autoscroll:localEvent];
          
          break;
        case NSLeftMouseUp:
          // mouse up has been detected, 
          // we can exit the loop
          loop = NO;
          
          if (memcmp(&clickLocation, &localLastDragLocation, sizeof(NSPoint)) == 0)
            [self animateTo:state ? 0 : KNOB_MAX_X];
          else if (location.x > 0 && location.x < KNOB_MAX_X)
            [self animateTo:state ? KNOB_MAX_X : 0];
          
          //TODO if let go of it halfway then slide to non destructive side
          
          if(location.x == 0 && state || location.x == KNOB_MAX_X && !state){
            state = !state;
            // wanted to use self.action and self.target but both are null
            // even though I set them up in IB! :(
            [prefpane performSelector:@selector(startStopDaemon:) withObject:self];
          }
          
          // the rectangle has moved, we need to reset our cursor
          // rectangle
          [[self window] invalidateCursorRectsForView:self];
          
          break;
        default:
          // Ignore any other kind of event. 
          break;
      }
    }
  };
  return;
}

-(BOOL)acceptsFirstResponder
{
  return YES;
}

-(IBAction)moveLeft:(id)sender
{
  [self offsetLocationByX:-10.0];
  [[self window] invalidateCursorRectsForView:self];
}

-(IBAction)moveRight:(id)sender
{
  [self offsetLocationByX:10.0];
  [[self window] invalidateCursorRectsForView:self];
}

@end