<?php
/*
Script Name: GD Gradient Fill
Script URI: http://planetozh.com/blog/my-projects/images-php-gd-gradient-fill/
Description: Creates a gradient fill of any shape (rectangle, ellipse, vertical, horizontal, diamond)
Author: Ozh
Version: 1.1
Author URI: http://planetozh.com/
*/
/* Release history :
* 1.1
* - changed : more nicely packaged as a class
* - fixed : not displaying proper gradient colors with image dimension greater than 255 (because of a limitation in imagecolorallocate)
* - added : optional parameter 'step', more options for 'direction'
* 1.0
* - initial release
*/
/* Usage :
*
* require_once('/path/to/gd-gradient-fill.php');
* $image = new gd_gradient_fill($width,$height,$direction,$startcolor,$endcolor,$step);
*
* Parameters :
* - width and height : integers, dimesions of your image.
* - direction : string, shape of the gradient.
* Can be : vertical, horizontal, rectangle (or square), ellipse, ellipse2, circle, circle2, diamond.
* - startcolor : string, start color in 3 or 6 digits hexadecimal.
* - endcolor : string, end color in 3 or 6 digits hexadecimal.
* - step : integer, optional, default to 0. Step that breaks the smooth blending effect.
* Returns a resource identifier.
*
* Examples :
*
* 1.
* require_once('/home/ozh/www/includes/gd-gradient-fill.php');
* $image = new gd_gradient_fill(200,200,'horizontal','#fff','#f00');
*
* 2.
* require_once('c:/iis/inet/include/gd-gradient-fill.php');
* $myimg = new gd_gradient_fill(80,20,'diamond','#ff0010','#303060');
*
*/
// Test it :
// $image = new gd_gradient_fill(400,200,'ellipse','#f00','#000',0);
class gd_gradient_fill {
// Constructor. Creates, fills and returns an image
function gd_gradient_fill($w=400,$h=200,$d="horizontal",$s="#000000",$e="#FFFFFF",$step=0) {
$this->width = $w;
$this->height = $h;
$this->direction = $d;
$this->startcolor = $s;
$this->endcolor = $e;
$this->step = intval(abs($step));
// Attempt to create a blank image in true colors, or a new palette based image if this fails
if (function_exists('imagecreatetruecolor')) {
$this->image = imagecreatetruecolor($this->width,$this->height);
} elseif (function_exists('imagecreate')) {
$this->image = imagecreate($this->width,$this->height);
} else {
die('Unable to create an image');
}
// Fill it
$this->fill($this->image,$this->direction,$this->startcolor,$this->endcolor);
// Show it
// $this->display($this->image);
// Return it
return $this->image;
}
// Displays the image with a portable function that works with any file type
// depending on your server software configuration
function display ($im) {
if (function_exists("imagepng")) {
header("Content-type: image/png");
imagepng($im);
}
elseif (function_exists("imagegif")) {
header("Content-type: image/gif");
imagegif($im);
}
elseif (function_exists("imagejpeg")) {
header("Content-type: image/jpeg");
imagejpeg($im, "", 0.5);
}
elseif (function_exists("imagewbmp")) {
header("Content-type: image/vnd.wap.wbmp");
imagewbmp($im);
} else {
die("Doh ! No graphical functions on this server ?");
}
return true;
}
// The main function that draws the gradient
function fill($im,$direction,$start,$end) {
switch($direction) {
case 'horizontal':
$line_numbers = imagesx($im);
$line_width = imagesy($im);
list($r1,$g1,$b1) = $this->hex2rgb($start);
list($r2,$g2,$b2) = $this->hex2rgb($end);
break;
case 'vertical':
$line_numbers = imagesy($im);
$line_width = imagesx($im);
list($r1,$g1,$b1) = $this->hex2rgb($start);
list($r2,$g2,$b2) = $this->hex2rgb($end);
break;
case 'ellipse':
$width = imagesx($im);
$height = imagesy($im);
$rh=$height>$width?1:$width/$height;
$rw=$width>$height?1:$height/$width;
$line_numbers = min($width,$height);
$center_x = $width/2;
$center_y = $height/2;
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
imagefill($im, 0, 0, imagecolorallocate( $im, $r1, $g1, $b1 ));
break;
case 'ellipse2':
$width = imagesx($im);
$height = imagesy($im);
$rh=$height>$width?1:$width/$height;
$rw=$width>$height?1:$height/$width;
$line_numbers = sqrt(pow($width,2)+pow($height,2));
$center_x = $width/2;
$center_y = $height/2;
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
break;
case 'circle':
$width = imagesx($im);
$height = imagesy($im);
$line_numbers = sqrt(pow($width,2)+pow($height,2));
$center_x = $width/2;
$center_y = $height/2;
$rh = $rw = 1;
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
break;
case 'circle2':
$width = imagesx($im);
$height = imagesy($im);
$line_numbers = min($width,$height);
$center_x = $width/2;
$center_y = $height/2;
$rh = $rw = 1;
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
imagefill($im, 0, 0, imagecolorallocate( $im, $r1, $g1, $b1 ));
break;
case 'square':
case 'rectangle':
$width = imagesx($im);
$height = imagesy($im);
$line_numbers = max($width,$height)/2;
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
break;
case 'diamond':
list($r1,$g1,$b1) = $this->hex2rgb($end);
list($r2,$g2,$b2) = $this->hex2rgb($start);
$width = imagesx($im);
$height = imagesy($im);
$rh=$height>$width?1:$width/$height;
$rw=$width>$height?1:$height/$width;
$line_numbers = min($width,$height);
break;
default:
}
for ( $i = 0; $i < $line_numbers; $i=$i+1+$this->step ) {
// old values :
$old_r=$r;
$old_g=$g;
$old_b=$b;
// new values :
$r = ( $r2 - $r1 != 0 ) ? intval( $r1 + ( $r2 - $r1 ) * ( $i / $line_numbers ) ): $r1;
$g = ( $g2 - $g1 != 0 ) ? intval( $g1 + ( $g2 - $g1 ) * ( $i / $line_numbers ) ): $g1;
$b = ( $b2 - $b1 != 0 ) ? intval( $b1 + ( $b2 - $b1 ) * ( $i / $line_numbers ) ): $b1;
// if new values are really new ones, allocate a new color, otherwise reuse previous color.
// There's a "feature" in imagecolorallocate that makes this function
// always returns '-1' after 255 colors have been allocated in an image that was created with
// imagecreate (everything works fine with imagecreatetruecolor)
if ( "$old_r,$old_g,$old_b" != "$r,$g,$b")
$fill = imagecolorallocate( $im, $r, $g, $b );
switch($direction) {
case 'vertical':
imagefilledrectangle($im, 0, $i, $line_width, $i+$this->step, $fill);
break;
case 'horizontal':
imagefilledrectangle( $im, $i, 0, $i+$this->step, $line_width, $fill );
break;
case 'ellipse':
case 'ellipse2':
case 'circle':
case 'circle2':
imagefilledellipse ($im,$center_x, $center_y, ($line_numbers-$i)*$rh, ($line_numbers-$i)*$rw,$fill);
break;
case 'square':
case 'rectangle':
imagefilledrectangle ($im,$i*$width/$height,$i*$height/$width,$width-($i*$width/$height), $height-($i*$height/$width),$fill);
break;
case 'diamond':
imagefilledpolygon($im, array (
$width/2, $i*$rw-0.5*$height,
$i*$rh-0.5*$width, $height/2,
$width/2,1.5*$height-$i*$rw,
1.5*$width-$i*$rh, $height/2 ), 4, $fill);
break;
default:
}
}
}
// #ff00ff -> array(255,0,255) or #f0f -> array(255,0,255)
function hex2rgb($color) {
$color = str_replace('#','',$color);
$s = strlen($color) / 3;
$rgb[]=hexdec(str_repeat(substr($color,0,$s),2/$s));
$rgb[]=hexdec(str_repeat(substr($color,$s,$s),2/$s));
$rgb[]=hexdec(str_repeat(substr($color,2*$s,$s),2/$s));
return $rgb;
}
}
?>
ライブラリ関連のソースコードは、『PHP : 既存 GD 関連ライブラリで、背景をグラデーション』を参照して下さい。グラデーションクラスと、GD 基本クラスを紹介しています。 それらのクラスを使用して実行していますが、PHP 自体を画像としてブラウザに返すコードなので、ここでの実行は、IMG 要素の SRC 属性に QueryString を引き渡して随時実行しています。 ※ 今回は、コードの中に他のサイトから実行した場合に以下の画像が表示されるようにするコードを付加しています。
( ▲ クリックすると、フリーフォントで簡単ロゴ作成に移動します ) example_02.php(UTF-8N)
※ エキスパートモードで表示しています
アーカイブとカテゴリページはこのように簡単に設定できますが、タグページは HTML 設定を直接変更して、以下の『タグページでのみ表示される内容』の記述方法で設定する必要があります
