Another go at building the pagetool sprite with a script

This time PHP and libGD is used so it should work on Windows as well.
The image quality is much better this time and the active highlight
color is read directly from the template's style.ini

lib/tpl/dokuwiki/images/pagetools-build.php

@@ -0,0 +1,121 @@
+<?php
+/**
+ * This script generates a sprite from the unprocessed pagetool icons by combining them
+ * and overlaying a color layer for the active state.
+ *
+ * This script requires a current libGD to be available.
+ *
+ * The color for the active state is read from the style.ini's __link__ replacement
+ *
+ * The final sprite is optimized with optipng if available.
+ *
+ * @author Andreas Gohr <andi@splitbrain.org>
+ * @todo   Maybe add some more error checking
+ */
+$GAMMA = 0.8;
+$OPTIPNG = '/usr/bin/optipng';
+
+// load input images
+$input = glob('pagetools/*.png');
+sort($input);
+$cnt   = count($input);
+if(!$cnt){
+    die("No input images found. This script needs to be called from within the image directory!\n");
+}
+
+// create destination image
+$DST = imagecreatetruecolor(30,$cnt*45*2);
+imagesavealpha($DST, true);
+$C_trans = imagecolorallocatealpha($DST, 0, 0, 0, 127);
+imagefill($DST, 0, 0, $C_trans);
+
+// load highlight color from style.ini
+$ini = parse_ini_file('../style.ini',true);
+$COLOR = hex2rgb($ini['replacements']['__link__']);
+$C_active = imagecolorallocate($DST, $COLOR['r'],$COLOR['g'],$COLOR['b']);
+
+// add all the icons to the sprite image
+for($i=0; $i<$cnt; $i++){
+    $base = $i*90;
+
+    $IN = imagecreatefrompng($input[$i]);
+    imagesavealpha($IN, true);
+    imagecolorscale($IN,$GAMMA);
+    imagecopy($DST,$IN, 0,$base, 0,0, 30,30);
+    imagedestroy($IN);
+
+    $IN = imagecreatefrompng($input[$i]);
+    imagesavealpha($IN, true);
+    imagecolorscale($IN,$GAMMA);
+    imagecopy($DST,$IN, 0,$base+45, 0,0, 30,30);
+    imagedestroy($IN);
+
+    imagelayereffect($DST, IMG_EFFECT_OVERLAY);
+    imagefilledrectangle($DST, 0,$base+45, 30,$base+45+30, $C_active);
+    imagelayereffect($DST, IMG_EFFECT_NORMAL);
+}
+
+// output sprite
+imagepng($DST,'pagetools-sprite.png');
+imagedestroy($DST);
+
+// optimize if possible
+if(is_executable($OPTIPNG)){
+    system("$OPTIPNG -o5 'pagetools-sprite.png'");
+}
+
+/**
+ * Convert a hex color code to an rgb array
+ */
+function hex2rgb($hex) {
+    // strip hash
+    $hex = str_replace('#', '', $hex);
+
+    // normalize short codes
+    if(strlen($hex) == 3){
+        $hex = substr($hex,0,1).
+               substr($hex,0,1).
+               substr($hex,1,1).
+               substr($hex,1,1).
+               substr($hex,2,1).
+               substr($hex,2,1);
+    }
+
+    // calc rgb
+    return array(
+       'r' => hexdec(substr($hex, 0, 2)),
+       'g' => hexdec(substr($hex, 2, 2)),
+       'b' => hexdec(substr($hex, 4, 2))
+    );
+}
+
+/**
+ * Scale (darken/lighten) a given image
+ *
+ * @param ressource $img    The truetype GD image to work on
+ * @param float     $scale  Scale the colors by this value ( <1 darkens, >1 lightens)
+ */
+function imagecolorscale(&$img, $scale){
+    $w = imagesx($img);
+    $h = imagesy($img);
+
+    imagealphablending($img, false);
+    for($x = 0; $x < $w; $x++){
+        for($y = 0; $y < $h; $y++){
+            $rgba   = imagecolorat($img, $x, $y);
+            $a = ($rgba >> 24) & 0xFF;
+            $r = ($rgba >> 16) & 0xFF;
+            $g = ($rgba >> 8) & 0xFF;
+            $b = $rgba & 0xFF;
+
+            $r = max(min(round($r*$scale),255),0);
+            $g = max(min(round($g*$scale),255),0);
+            $b = max(min(round($b*$scale),255),0);
+
+            $color = imagecolorallocatealpha($img, $r, $g, $b, $a);
+            imagesetpixel($img, $x, $y, $color);
+        }
+    }
+    imagealphablending($img, true);
+}
+