5.9.163 (2012-06-05)

- Method getGDgamma() was changed.
- Rendering performances of PNG images with alpha channel were improved.

CHANGELOG.TXT

@@ -1,3 +1,7 @@
+5.9.163 (2012-06-05)
+	- Method getGDgamma() was changed.
+	- Rendering performances of PNG images with alpha channel were improved.
+
 5.9.162 (2012-05-11)
 	- A bug related to long text on TD cells was fixed.
 

README.TXT

@@ -8,8 +8,8 @@ http://sourceforge.net/donate/index.php?group_id=128076
 ------------------------------------------------------------
 
 Name: TCPDF
-Version: 5.9.162
+Version: 5.9.163
-Release date: 2012-05-11
+Release date: 2012-06-05
 Author:	Nicola Asuni
 
 Copyright (c) 2002-2012:

tcpdf.php

@@ -1,9 +1,9 @@
 <?php
 //============================================================+
 // File name   : tcpdf.php
-// Version     : 5.9.162
+// Version     : 5.9.163
 // Begin       : 2002-08-03
-// Last Update : 2012-05-11
+// Last Update : 2012-06-05
 // Author      : Nicola Asuni - Tecnick.com LTD - Manor Coach House, Church Hill, Aldershot, Hants, GU12 4RQ, UK - www.tecnick.com - info@tecnick.com
 // License     : http://www.tecnick.com/pagefiles/tcpdf/LICENSE.TXT GNU-LGPLv3
 // -------------------------------------------------------------------
@@ -137,7 +137,7 @@
  * Tools to encode your unicode fonts are on fonts/utils directory.</p>
  * @package com.tecnick.tcpdf
  * @author Nicola Asuni
- * @version 5.9.162
+ * @version 5.9.163
  */
 
 // Main configuration file. Define the K_TCPDF_EXTERNAL_CONFIG constant to skip this file.
@@ -149,7 +149,7 @@ require_once(dirname(__FILE__).'/config/tcpdf_config.php');
  * TCPDF project (http://www.tcpdf.org) has been originally derived in 2002 from the Public Domain FPDF class by Olivier Plathey (http://www.fpdf.org), but now is almost entirely rewritten.<br>
  * @package com.tecnick.tcpdf
  * @brief PHP class for generating PDF documents without requiring external extensions.
- * @version 5.9.162
+ * @version 5.9.163
  * @author Nicola Asuni - info@tecnick.com
  */
 class TCPDF {
@@ -160,7 +160,7 @@ class TCPDF {
 	 * Current TCPDF version.
 	 * @private
 	 */
-	private $tcpdf_version = '5.9.162';
+	private $tcpdf_version = '5.9.163';
 
 	// Protected properties
 
@@ -1879,6 +1879,13 @@ class TCPDF {
 	 */
 	protected $tcpdflink = true;
 
+	/**
+	 * Cache array for computed GD gamma values.
+	 * @protected
+	 * @since 5.9.1632 (2012-06-05)
+	 */
+	protected $gdgammacache = array();
+
 	//------------------------------------------------------------
 	// METHODS
 	//------------------------------------------------------------
@@ -8435,9 +8442,7 @@ class TCPDF {
 			for ($xpx = 0; $xpx < $wpx; ++$xpx) {
 				for ($ypx = 0; $ypx < $hpx; ++$ypx) {
 					$color = imagecolorat($img, $xpx, $ypx);
-					$alpha = ($color >> 24); // shifts off the first 24 bits (where 8x3 are used for each color), and returns the remaining 7 allocated bits (commonly used for alpha)
+					$alpha = $this->getGDgamma($color); // correct gamma
-					$alpha = (((127 - $alpha) / 127) * 255); // GD alpha is only 7 bit (0 -> 127)
-					$alpha = $this->getGDgamma($alpha); // correct gamma
 					imagesetpixel($imgalpha, $xpx, $ypx, $alpha);
 				}
 			}
@@ -8461,13 +8466,27 @@ class TCPDF {
 	}
 
 	/**
-	 * Correct the gamma value to be used with GD library
+	 * Get the GD-corrected PNG gamma value from alpha color
-	 * @param $v (float) the gamma value to be corrected
+	 * @param $c (int) alpha color
 	 * @protected
 	 * @since 4.3.007 (2008-12-04)
 	 */
-	protected function getGDgamma($v) {
+	protected function getGDgamma($c) {
-		return (pow(($v / 255), 2.2) * 255);
+		if (!isset($this->gdgammacache[$c])) {
+			// shifts off the first 24 bits (where 8x3 are used for each color),
+			// and returns the remaining 7 allocated bits (commonly used for alpha)
+			$alpha = ($c >> 24);
+			// GD alpha is only 7 bit (0 -> 127)
+			$alpha = (((127 - $alpha) / 127) * 255);
+			// correct gamma
+			$this->gdgammacache[$c] = (pow(($alpha / 255), 2.2) * 255);
+			// store the latest values on cache to improve performances
+			if (count($this->gdgammacache) > 8) {
+				// remove one element from the cache array
+				array_shift($this->gdgammacache);
+			}
+		}
+		return $this->gdgammacache[$c];
 	}
 
 	/**