A little rounded black tooltip you can easily point at stuff

gistfile1.txt

/*
 * CPTooltip.j
 * Makes a little black rounded-rect gradient tooltip with some text (can have multiple lines with \n) which points at something.
 * Usage example: 
 * tooltip = [[CPTooltip alloc] initWithText:@"Hello There" atPoint:CPPointMake(100,100)];
 * [self addSubview:tooltip];
 *
 * The above will make a tooltip that says "Hello There" which is pointing at this view's 100x100 point.
 * If the tooltip is too close to its superview's edges, it will adjust itself to maintain readability.
 *
 * Created by Justin Graves
 * Copyright 2009, Infegy, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
@import <AppKit/CPView.j>

@implementation CPTooltip : CPView
{
	CPLabel _text;
	CPPoint _target;
	CPArray _clipPoints;
	var _horizontalPadding;
	var _verticalPadding;
	CPPoint _arrowOffset;
	BOOL _flippedArrow;
}

- (id)initWithText:(CPString)text atPoint:(CPPoint)target
{
	if (self = [super initWithFrame:CGRectMake(0,0,26,26)])
	{
		if(!_text)
		{
			_text = [[CPTextField alloc] initWithFrame:CGRectMakeZero()];
			[_text setFont:[CPFont boldSystemFontOfSize:11.0]];
			[_text setTextColor:[CPColor colorWithCalibratedRed:1.0 green:1.0 blue:1.0 alpha:1.0]];
			[_text setAlignment:CPCenterTextAlignment];
		}
			
		_target = target;
		_arrowOffset = CPPointMakeZero();
		_flippedArrow = NO;
	
		[self setText:text];
		
		[self addSubview:_text];
	}
	
	return self;
}

- (id)init
{
	return [self initWithFrame:CGRectMakeZero()];
}

- (id)initWithFrame:(CGRect)aFrame
{
	return [self initWithText:@"" atPoint:CPPointMakeZero()];
}

- (void)setText:(CPString)text
{
	[self setText:text atPoint:_target];
}

- (void)setText:(CPString)text atPoint:(CPPoint)target
{
	[_text setStringValue:text];
	[_text sizeToFit];
	
	// Make size around the requested point
	var textSize = [_text frame].size;
	
	// Padded height
	_verticalPadding = 2;
	textSize.height += (_verticalPadding * 2);	// 20% padding top/bottom
	
	// Padded width
	_horizontalPadding = 5;
	textSize.width += (_horizontalPadding * 2);	// Add caps at the ends, each half of height
	
	textSize.height += 6;	// Add 6 pixel pointer
	
	var lowerSegment = (textSize.width - 12 - (_horizontalPadding * 2)) / 2;
	
	_clipPoints = Array(_horizontalPadding, _verticalPadding, lowerSegment);
	
	[self setTarget:target withSize:textSize];
	
	var textOrigin;
	if(_flippedArrow)
		textOrigin = CPPointMake(textSize.width/2, ((textSize.height - 6)/2) + 6);
	else
		textOrigin = CPPointMake(textSize.width/2, (textSize.height - 6)/2);
	[_text setCenter:textOrigin];
}

- (void)setTarget:(CPPoint)target withSize:(CPSize)size
{
	var bounds = [self frame];
	var sizesMatch = bounds.size.width == size.width && bounds.size.height == size.height;
	
	if(target.x == _target.x && target.y == _target.y && sizesMatch)
		return;
		
	_target.x = target.x;
	_target.y = target.y;
	
	// Find origin based on target point.
	bounds.origin.y = target.y - size.height;
	bounds.origin.x = target.x - size.width/2;
	
	bounds.size.width = size.width;
	bounds.size.height = size.height;
	
	// Check if the tooltip is too close to the superview's edges
	// If it is, move it around so the text is still clearly visibile
	var oldOffset = CPPointMake(_arrowOffset.x, _arrowOffset.y);
	var wasFlipped = _flippedArrow;
	_arrowOffset.x = 0; _arrowOffset.y = 0;
	_flippedArrow = NO;
	if(_superview)
	{
		// Handle getting pushed to superview's edges
		if(bounds.origin.x + _horizontalPadding < 0)
		{
			bounds.origin.x = -_horizontalPadding;
			_arrowOffset.x = target.x - (bounds.origin.x + (size.width/2));
		}
		else if(bounds.origin.x + size.width - _horizontalPadding > [_superview bounds].size.width)
		{
			bounds.origin.x -= (bounds.origin.x + size.width - _horizontalPadding) - [_superview bounds].size.width;
			_arrowOffset.x = target.x - (bounds.origin.x + (size.width/2));
		}
		
		// Handle moving too high up
		if(bounds.origin.y < 0)
		{
			_flippedArrow = YES;
			bounds.origin.y = target.y;
		}
	}
	
	// If the arrow offset changed and sizes match, we need to redraw and setFrame didn't do it
	// If sizes don't match, setFrame (just below) will redraw for us
	needsDraw = NO;
	if((oldOffset.x != _arrowOffset.x || oldOffset.y != _arrowOffset.y || wasFlipped != _flippedArrow) && sizesMatch)
		needsDraw = YES;
		
	if(needsDraw)
	{
		[self setFrameOrigin:bounds.origin];
		[self setNeedsLayout];
		[self setNeedsDisplay:YES];
	}
	else
		[self setFrame:bounds];
}

- (void)drawRect:(CPRect)aRect
{		
	var context = [[CPGraphicsContext currentContext] graphicsPort];
	
	CGContextBeginPath(context);
	CGContextSaveGState(context);
	
	// Prepare gradient for background
	var locations = new Array(0.0, 1.5/_bounds.size.height, 1.0);
	var components = new Array(	0.9, 0.9, 0.9, 1.0,	// Start (top) color
								0.3, 0.3, 0.3, 0.80,
	  							0.0, 0.0, 0.0, 0.80); // End (bottom) color
	 
	var myGradient = CGGradientCreateWithColorComponents(CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB), components, locations, 3);
	
	var myStartPoint = CPPointMake(0,0);
	var myEndPoint = CPPointMake(0,_bounds.size.height);
	
	// Draw the path for the main body: a rounded rect
	var radius = 6;
	var rect = CPRectMake(_bounds.origin.x, _bounds.origin.y, _bounds.size.width, _bounds.size.height);
	rect.size.height -= 6;
	
	// Draws the rect by setting up scaled four arcs
	CGContextSaveGState(context);
	if(_flippedArrow)
		CGContextTranslateCTM(context, 0, 6);
	CGContextScaleCTM (context, radius, radius);
	fw = CGRectGetWidth (rect) / radius;
	fh = CGRectGetHeight (rect) / radius;
 
	CGContextMoveToPoint(context, fw, fh/2);
	CGContextAddArcToPoint(context, fw, fh, fw/2, fh, 1);
	CGContextAddArcToPoint(context, 0, fh, 0, fh/2, 1);
	CGContextAddArcToPoint(context, 0, 0, fw/2, 0, 1);
	CGContextAddArcToPoint(context, fw, 0, fw, fh/2, 1);
	CGContextClosePath(context);
	CGContextRestoreGState(context);
	
	// Arrow pointing to target
	// If the tooltip is too close to the top of its containing view, the arrow points up as the tooltip is moved down
	if(_flippedArrow)
	{
		CGContextMoveToPoint(context, _clipPoints[0] + _clipPoints[2] + _arrowOffset.x, 6);
		CGContextAddLineToPoint(context, _clipPoints[0] + _clipPoints[2] + 12 + _arrowOffset.x, 6);
		CGContextAddLineToPoint(context, _clipPoints[0] + _clipPoints[2] + 6 + _arrowOffset.x, 0);
	}
	// Otherwise, the arrow points down
	else
	{
		CGContextMoveToPoint(context, _clipPoints[0] + _clipPoints[2] + _arrowOffset.x, rect.size.height);
		CGContextAddLineToPoint(context, _clipPoints[0] + _clipPoints[2] + 12 + _arrowOffset.x, rect.size.height);
		CGContextAddLineToPoint(context, _clipPoints[0] + _clipPoints[2] + 6 + _arrowOffset.x, rect.size.height + 6);
	}
	CGContextClosePath(context);
	
	// Actual gradient fill operation
	CGContextClip(context);
	CGContextDrawLinearGradient(context, myGradient, myStartPoint, myEndPoint, 0);
	
	CGContextRestoreGState(context);
	
	[super drawRect:aRect];
}

@end