Webcolor.m

/**
 * Appcelerator Titanium Mobile
 * Copyright (c) 2009-2010 by Appcelerator, Inc. All Rights Reserved.
 * Licensed under the terms of the Apache Public License
 * Please see the LICENSE included with this distribution for details.
 */

#import "Webcolor.h"
#import "TiBase.h"
#import "TiUtils.h"

NSString * const IOS_COLOR_SCROLLVIEW_TEXTURED_BACKGROUND = @"scrollview_textured";
NSString * const IOS_COLOR_VIEW_FLIPSIDE_BACKGROUND = @"view_flipside";
NSString * const IOS_COLOR_GROUP_TABLEVIEW_BACKGROUND = @"group_tableview";

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_5_0
NSString * const IOS_COLOR_UNDER_PAGE_BACKGROUND = @"under_page";
#endif

UIColor * checkmarkColor = nil;
NSMutableDictionary * colorLookup = nil;

BOOL isASCIIHexDigit(unichar c) { return (c >= '0' && c <= '9') || ((c | 0x20) >= 'a' && (c | 0x20) <= 'f'); }
int toASCIIHexValue(unichar c) {return (c & 0xF) + (c < 'A' ? 0 : 9); }

@implementation Webcolor

+(UIColor*)checkmarkColor
{
	if(checkmarkColor==nil)
	{
		checkmarkColor = RGBACOLOR(55.0,79.0,130.0,1);
	}
	return checkmarkColor;
}

+(UIColor*)webColorNamed:(NSString*)colorName
{
	if (![colorName isKindOfClass:[NSString class]])
	{
		return nil;
	}
	colorName = [colorName stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
	if (colorLookup == nil)
	{
		UIColor * white = [UIColor whiteColor];
		UIColor * black = [UIColor blackColor];
		colorLookup = [[NSMutableDictionary alloc] initWithObjectsAndKeys:
					   black,@"black",
					   [UIColor grayColor],@"gray",
					   [UIColor darkGrayColor],@"darkgray",
					   [UIColor lightGrayColor],@"lightgray",
					   white,@"white",
					   [UIColor redColor],@"red",
					   [UIColor greenColor],@"green",
					   [UIColor blueColor],@"blue",
					   [UIColor cyanColor],@"cyan",
					   [UIColor yellowColor],@"yellow",
					   [UIColor magentaColor],@"magenta",
					   [UIColor orangeColor],@"orange",
					   [UIColor purpleColor],@"purple",
					   [UIColor brownColor],@"brown",
					   [UIColor clearColor],@"transparent",
					   [UIColor groupTableViewBackgroundColor],@"stripped",
					   [UIColor groupTableViewBackgroundColor],IOS_COLOR_GROUP_TABLEVIEW_BACKGROUND,
					   [UIColor scrollViewTexturedBackgroundColor],IOS_COLOR_SCROLLVIEW_TEXTURED_BACKGROUND,
					   [UIColor viewFlipsideBackgroundColor],IOS_COLOR_VIEW_FLIPSIDE_BACKGROUND,
                       
					   // these are also defined by the W3C HTML spec so we support them
					   [Webcolor colorForHex:@"0ff"],@"aqua",
					   [Webcolor colorForHex:@"f0f"],@"fuchsia",
					   [Webcolor colorForHex:@"0f0"],@"lime",
					   [Webcolor colorForHex:@"800"],@"maroon",
					   [Webcolor colorForHex:@"FFC0CB"],@"pink",
					   [Webcolor colorForHex:@"000080"],@"navy",
					   [Webcolor colorForHex:@"c0c0c0"],@"silver",
					   [Webcolor colorForHex:@"808000"],@"olive",
					   [Webcolor colorForHex:@"008080"],@"teal",
					   
					   white,@"fff",
					   white,@"ffff",
					   white,@"ffffff",
					   white,@"ffffffff",
					   black,@"000",
					   black,@"f000",
					   black,@"000000",
					   black,@"ff000000",
					   nil];
	}
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_5_0
	if ([TiUtils isIOS5OrGreater])
	{
		[colorLookup setObject:[UIColor underPageBackgroundColor] forKey:IOS_COLOR_UNDER_PAGE_BACKGROUND];
	}
#endif
	if ([colorName hasPrefix:@"#"]) 
	{
		colorName = [colorName substringFromIndex:1];
	}
	colorName = [colorName lowercaseString];
	UIColor * result = [colorLookup objectForKey:colorName];
	
	if (result != nil)
	{
		return result;
	}
	
	result = [Webcolor colorForHex:colorName];
	
	if (result == nil)
	{
		result = [Webcolor colorForRGBFunction:colorName];
	}
	
	if (result != nil) 
	{
		[colorLookup setObject:result forKey:colorName];
	}
	
	return result;
}

+(UIColor*)colorForRGBFunction:(NSString*)functionString
{
	int stringLength=[functionString length];
	NSRange openParensRange = [functionString rangeOfString:@"("];
	if (openParensRange.location == NSNotFound) 
	{
		return nil;
	}
	
	//Last char must be terminating ).
	if ([functionString characterAtIndex:stringLength-1] != ')') 
	{
		return nil;
	}
	
	NSRange searchRange;
	NSRange nextTokenRange;
	int segmentLength;
	
	searchRange.location = openParensRange.location + 1; //Skipping starting (
	searchRange.length = stringLength - searchRange.location - 1; //-1 for terminating ).
	
	nextTokenRange = [functionString rangeOfString:@"," options:NSLiteralSearch range:searchRange];
	if (nextTokenRange.location == NSNotFound)
	{
		return nil;
	}
	
	segmentLength = nextTokenRange.location - searchRange.location; //This does NOT include a comma.
	float firstArg = [[functionString substringWithRange:NSMakeRange(searchRange.location, segmentLength)] floatValue];
	
	searchRange.location += segmentLength + 1;	searchRange.length -= segmentLength + 1;
	
	nextTokenRange = [functionString rangeOfString:@"," options:NSLiteralSearch range:searchRange];
	if (nextTokenRange.location == NSNotFound) 
	{
		return nil;
	}
	
	segmentLength = nextTokenRange.location - searchRange.location; //This does NOT include a comma.
	float secondArg = [[functionString substringWithRange:NSMakeRange(searchRange.location, segmentLength)] floatValue];
	
	searchRange.location += segmentLength + 1;	searchRange.length -= segmentLength + 1;
	
	nextTokenRange = [functionString rangeOfString:@"," options:NSLiteralSearch range:searchRange];
	
	float thirdArg, fourthArg = 1.0;
	if (nextTokenRange.location == NSNotFound) 
	{
		thirdArg = [[functionString substringWithRange:searchRange] floatValue];
	} 
	else 
	{
		segmentLength = nextTokenRange.location - searchRange.location;
		thirdArg = [[functionString substringWithRange:NSMakeRange(searchRange.location, segmentLength)] floatValue];
		fourthArg = [[functionString substringWithRange:NSMakeRange(nextTokenRange.location+1,searchRange.length - segmentLength - 1)] floatValue];
	}
	
	return RGBACOLOR(firstArg,secondArg,thirdArg,fourthArg);
}

+(UIColor*)colorForHex:(NSString*)hexCode
{
    unsigned length = [hexCode length];
	float alpha = 1.0;
    if ((length != 3) && (length != 4) && (length != 6) && (length!=7) && (length != 8))
	{
		DebugLog(@"[WARN] Hex color passed looks invalid: %@",hexCode);
        return nil;
	}
    unsigned value = 0;
	
    for (size_t i = 0; i < length; ++i) 
	{
		unichar thisChar = [hexCode characterAtIndex:i];
		if (thisChar=='#') continue;
        if (!isASCIIHexDigit(thisChar))
		{
            return nil;
		}
        value <<= 4;
        value |= toASCIIHexValue(thisChar);
    }
	
	if (length < 6) 
	{
		value = ((value & 0xF000) << 16) |
		((value & 0xFF00) << 12) |
		((value & 0xFF0) << 8) |
		((value & 0xFF) << 4) |
		(value & 0xF);
	}
	
	if((length % 4)==0)
	{
		alpha = ((value >> 24) & 0xFF) / 255.0;
	}
	
	int red = (value >> 16) & 0xFF;
	int green = (value >> 8) & 0xFF;
	int blue = value & 0xFF;
	
	return RGBACOLOR(red,green,blue,alpha);
}

+(void)flushCache
{
	RELEASE_TO_NIL(colorLookup);
	RELEASE_TO_NIL(checkmarkColor);
}

+(BOOL)isDarkColor:(UIColor*)color
{
	const CGFloat * components = CGColorGetComponents([color CGColor]);
	CGFloat red = components[0];
	CGFloat green = components[1];
	CGFloat blue = components[2];
	CGFloat formula = (red*299) + (green*587) + (blue*114) / 1000;
	return formula < 125;
}

@end