package gradfont;
#------------------------------------------------------------------------
# gradfont.pl: 文字列グラデーション化ライブラリ Ver1.01
#
# 文字コードをシフトJISで判定している理由は、謎・・・
# EUCなら、もっと、簡単につくれるらしい？
# よくわからん。
#
# Copyright (c) 1999  qz@ca.sakura.ne.jp
#
# 著作権は放棄しませんが、自由に使用・改造・再配布可能です。
#
# ----------------------------------------------------------------
# 基本的な使い方
#    require "gradfont.pl";
#    print &gradfont'GradStr("あいうえお", "#000000", "#FFFFFF");
#    print &gradfont'GradStr2("あいうえお", "#000000", "#FF0000", "#FFFFFF");
# ----------------------------------------------------------------
# 最新版入手先
#    http://www.ca.sakura.ne.jp/~qz/
#
# 更新履歴:
#    1999.03.11 1.00 初版。
#    1999.03.14 1.01 ３点式グラデーション機能の追加。
#------------------------------------------------------------------------
#文字列グラデーション化(文字列、開始色、中間色、終了色)
sub GradStr2{
	local($Str, $ColorFrom, $ColorIn, $ColorTo, $Len, $FromLen, $ToLen
		, $FromStr, $ToStr, $FromTagStr, $ToTagStr, $i, @S);

	$Str = $_[0];
	$ColorFrom = $_[1];
	$ColorIn = $_[2];
	$ColorTo = $_[3];

	$Len = &Klength($Str);

	$FromLen = int($Len / 2);
	$ToLen = $Len - $FromLen;

	$FromStr = "";
	for($i = 1;$i <= $FromLen;$i++){
		$FromStr = $FromStr . &KcharAt($Str, $i);
	}

	$ToStr = "";
	for($i = $FromLen + 1;$i <= $Len;$i++){
		$ToStr = $ToStr . &KcharAt($Str, $i);
	}

	if($FromLen == $ToLen){
		$ToStr = &KcharAt($FromStr, $FromLen) . $ToStr;
	}else{
		$FromStr = $FromStr . &KcharAt($ToStr, 1);
	}

	$FromTagStr = &GradStr($FromStr, $ColorFrom, $ColorIn);
	$ToTagStr = &GradStr($ToStr, $ColorIn, $ColorTo);

	@S = split(/<\/FONT>/, $ToTagStr);
	shift(@S);
	$ToTagStr = join("</FONT>", @S, "");

	return $FromTagStr . $ToTagStr;
}

#文字列グラデーション化(文字列、開始色、終了色)
sub GradStr{
	local($Str, $ColorFrom, $ColorTo, %Red, %Green, %Blue, $Len
		, $TagStr, $i, $StaTag, $EndTag, $FColor);

	$Str = $_[0];
	$ColorFrom = $_[1];
	$ColorTo = $_[2];
	
	$StaTag = "<FONT COLOR=#";
	$EndTag = "</FONT>";

	$Len = &Klength($Str);

	if(substr($ColorFrom, 0, 1) eq "#"){
		$ColorFrom = substr($ColorFrom, 1, 6);
	}
	if(substr($ColorTo, 0, 1) eq "#"){
		$ColorTo = substr($ColorTo, 1, 6);
	}

	$Red{'from'} = hex(substr($ColorFrom, 0, 2));
	$Green{'from'} = hex(substr($ColorFrom, 2, 2));
	$Blue{'from'} = hex(substr($ColorFrom, 4, 2));

	$Red{'to'} = hex(substr($ColorTo, 0, 2));
	$Green{'to'} = hex(substr($ColorTo, 2, 2));
	$Blue{'to'} = hex(substr($ColorTo, 4, 2));

	$Red{'level'} = &GetLev($Red{'from'}, $Red{'to'}, $Len - 1);
	$Green{'level'} = &GetLev($Green{'from'}, $Green{'to'}, $Len - 1);
	$Blue{'level'} = &GetLev($Blue{'from'}, $Blue{'to'}, $Len - 1);

	$Red{'color'} = $Red{'from'} - $Red{'level'};
	$Green{'color'} = $Green{'from'} - $Green{'level'};
	$Blue{'color'} = $Blue{'from'} - $Blue{'level'};

	$TagStr ="";
	for ($i = 0 ;$i <= $Len - 1;$i++){
		$Red{'color'} = $Red{'color'} + $Red{'level'};
		$Green{'color'} = $Green{'color'} + $Green{'level'};
		$Blue{'color'} = $Blue{'color'} + $Blue{'level'};
		if ($i < $Len - 1 ){
			$FColor = sprintf("%02X", $Red{'color'}) 
					. sprintf("%02X", $Green{'color'})
					. sprintf("%02X", $Blue{'color'})
		}else{
			$FColor = $ColorTo;
		}
		$TagStr = $TagStr . $StaTag . $FColor . ">" . &KcharAt($Str, $i + 1) . $EndTag;
	}
	return $TagStr;
}
#グラデーション階調を算出 引数(開始色,終了色,段階)
sub GetLev{
	local($F, $T, $n, $sa, $am);
	$F = $_[0];
	$T = $_[1];
	$n = $_[2];
	$sa = $T - $F;
	if ($n == 0) {$am = 0;}
	else {$am = $sa % $n; $am = ($sa - $am) / $n;}
	return($am);
}

#--シフトJISコード：
#--１バイト目 : 0x81 - 0x9F, 0xE0 - 0xFC
#--２バイト目 : 0x40 - 0x7E, 0x80 - 0xFC
#--ＥＵＣコード：
#--0x80-0xff
#日本語混在の文字列の長さを取得(Shift JIS)(文字列)
sub Klength{
	local($moji, $klen, $ki, $c, $cb);
	$moji = $_[0];
	$klen = 0;
	for ($ki=0; $ki<length($moji); $ki++){
		$c = substr($moji, $ki, 1);
		$cb = ord($c);
		if ((($cb>=0x81) && ($cb<=0x9F)) || (($cb>=0xE0) && ($cb<=0xFC))){ $ki++; }
		$klen++;
	}
	return $klen;
}

#日本語混在の文字列から指定した１文字を取得(Shift JIS)(文字列、位置)
sub KcharAt{
	local($moji, $len, $ai, $c, $cb);
	$moji = $_[0];
	$pos = $_[1];
	$len = 1;
	for($ai=0; $ai<length($moji); $ai++){
		$c = substr($moji, $ai, 1);
		$cb = ord($c);
		if ((($cb>=0x81) && ($cb<=0x9F)) || (($cb>=0xE0) && ($cb<=0xFC))){
			$c = $c . substr($moji, $ai + 1, 1);
			$ai++;
		}
		if ($pos == $len){last;}
		$len++;
	}
	return $c;
}

1;

#______________________________________________________________________End Of Script