SCGraph.m

//
//  SCGraph.m
//  Alarm-Clock
//
//  Created by Robert Palmer on 31.01.10.
//  Copyright 2010 Robert. All rights reserved.
//

#import "SCGraph.h"
#import "SC2DScale.h"

@interface SCGraph ()

- (BOOL)isValidPoint: (NSPoint) point;
- (void)removePastPoints;

@end


@implementation SCGraph

@synthesize scaler;
@synthesize dirty;

- (id) init {
	self = [super init];
	if (self != nil) {
		points = [[NSMutableArray alloc] init]; 
		dirty = NO;
	}
	
	return self;
}

- (void) dealloc {
	[scaler release];
	[points release];
	
	[super dealloc];
}

- (void)addPoint: (NSPoint)point {
	[points addObject:[NSValue valueWithPoint: point]];
	self.dirty = YES;
}

- (void)draw: (CGContextRef) context {
	if ([points count] == 0) {
		return;
	}
	
	[self removePastPoints];
	
	CGContextSetRGBStrokeColor(context, 0, 0, 0, 1);

	CGContextBeginPath(context);
	NSPoint point = [[points objectAtIndex:0] pointValue];
	point = [scaler scaleValue:point];
	CGContextMoveToPoint(context, point.x, point.y);

	for (int i = 1; i < [points count]; i++) {
		NSPoint point = [[points objectAtIndex:i] pointValue];
		
		if ([self isValidPoint: point]) {
			point = [scaler scaleValue:point];
			CGContextAddLineToPoint(context, point.x, point.y);			
		}
	}
	
	CGContextStrokePath(context);
	self.dirty = NO;
}
	
- (float)width {
	return [[points lastObject] pointValue].x; 
}

#pragma mark -
#pragma mark Private Methods

- (BOOL)isValidPoint: (NSPoint) point {
	if (point.x < scaler.fromRect.origin.x) {
		return NO;
	}
	
	return YES;
}

- (void)removePastPoints 
{
	if ([points count] < 3) {
		return;
	}
	
	for (int i = 1; i < [points count]; i++) {
		if (![self isValidPoint: [[points objectAtIndex:i] pointValue]]) {
			[points removeObjectAtIndex:0];
		} else {
			return;
		}
	}
}





@end