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gdlib.php
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gdlib.php
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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* gdlib.php - Collection of routines in Moodle related to
* processing images using GD
*
* @package core
* @copyright 1999 onwards Martin Dougiamas {@link http://moodle.com}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* Copies a rectangular portion of the source image to another rectangle in the destination image
*
* This function calls imagecopyresampled() if it is available and GD version is 2 at least.
* Otherwise it reimplements the same behaviour. See the PHP manual page for more info.
*
* @link http://php.net/manual/en/function.imagecopyresampled.php
* @param resource $dst_img the destination GD image resource
* @param resource $src_img the source GD image resource
* @param int $dst_x vthe X coordinate of the upper left corner in the destination image
* @param int $dst_y the Y coordinate of the upper left corner in the destination image
* @param int $src_x the X coordinate of the upper left corner in the source image
* @param int $src_y the Y coordinate of the upper left corner in the source image
* @param int $dst_w the width of the destination rectangle
* @param int $dst_h the height of the destination rectangle
* @param int $src_w the width of the source rectangle
* @param int $src_h the height of the source rectangle
* @return bool tru on success, false otherwise
*/
function imagecopybicubic($dst_img, $src_img, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h) {
global $CFG;
if (function_exists('imagecopyresampled')) {
return imagecopyresampled($dst_img, $src_img, $dst_x, $dst_y, $src_x, $src_y,
$dst_w, $dst_h, $src_w, $src_h);
}
$totalcolors = imagecolorstotal($src_img);
for ($i=0; $i<$totalcolors; $i++) {
if ($colors = imagecolorsforindex($src_img, $i)) {
imagecolorallocate($dst_img, $colors['red'], $colors['green'], $colors['blue']);
}
}
$scalex = ($src_w - 1) / $dst_w;
$scaley = ($src_h - 1) / $dst_h;
$scalex2 = $scalex / 2.0;
$scaley2 = $scaley / 2.0;
for ($j = 0; $j < $dst_h; $j++) {
$sy = $j * $scaley;
for ($i = 0; $i < $dst_w; $i++) {
$sx = $i * $scalex;
$c1 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx, (int)$sy + $scaley2));
$c2 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx, (int)$sy));
$c3 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx + $scalex2, (int)$sy + $scaley2));
$c4 = imagecolorsforindex($src_img, imagecolorat($src_img, (int)$sx + $scalex2, (int)$sy));
$red = (int) (($c1['red'] + $c2['red'] + $c3['red'] + $c4['red']) / 4);
$green = (int) (($c1['green'] + $c2['green'] + $c3['green'] + $c4['green']) / 4);
$blue = (int) (($c1['blue'] + $c2['blue'] + $c3['blue'] + $c4['blue']) / 4);
$color = imagecolorclosest($dst_img, $red, $green, $blue);
imagesetpixel($dst_img, $i + $dst_x, $j + $dst_y, $color);
}
}
}
/**
* Stores optimised icon images in icon file area
*
* @param context $context
* @param string $component
* @param string filearea
* @param int $itemid
* @param string $originalfile
* @return mixed new unique revision number or false if not saved
*/
function process_new_icon($context, $component, $filearea, $itemid, $originalfile) {
global $CFG;
if (!is_file($originalfile)) {
return false;
}
$imageinfo = getimagesize($originalfile);
if (empty($imageinfo)) {
return false;
}
$image = new stdClass();
$image->width = $imageinfo[0];
$image->height = $imageinfo[1];
$image->type = $imageinfo[2];
$t = null;
switch ($image->type) {
case IMAGETYPE_GIF:
if (function_exists('imagecreatefromgif')) {
$im = imagecreatefromgif($originalfile);
} else {
debugging('GIF not supported on this server');
return false;
}
// Guess transparent colour from GIF.
$transparent = imagecolortransparent($im);
if ($transparent != -1) {
$t = imagecolorsforindex($im, $transparent);
}
break;
case IMAGETYPE_JPEG:
if (function_exists('imagecreatefromjpeg')) {
$im = imagecreatefromjpeg($originalfile);
} else {
debugging('JPEG not supported on this server');
return false;
}
break;
case IMAGETYPE_PNG:
if (function_exists('imagecreatefrompng')) {
$im = imagecreatefrompng($originalfile);
} else {
debugging('PNG not supported on this server');
return false;
}
break;
default:
return false;
}
if (function_exists('imagepng')) {
$imagefnc = 'imagepng';
$imageext = '.png';
$filters = PNG_NO_FILTER;
$quality = 1;
} else if (function_exists('imagejpeg')) {
$imagefnc = 'imagejpeg';
$imageext = '.jpg';
$filters = null; // not used
$quality = 90;
} else {
debugging('Jpeg and png not supported on this server, please fix server configuration');
return false;
}
if (function_exists('imagecreatetruecolor')) {
$im1 = imagecreatetruecolor(100, 100);
$im2 = imagecreatetruecolor(35, 35);
$im3 = imagecreatetruecolor(512, 512);
if ($image->type != IMAGETYPE_JPEG and $imagefnc === 'imagepng') {
if ($t) {
// Transparent GIF hacking...
$transparentcolour = imagecolorallocate($im1 , $t['red'] , $t['green'] , $t['blue']);
imagecolortransparent($im1 , $transparentcolour);
$transparentcolour = imagecolorallocate($im2 , $t['red'] , $t['green'] , $t['blue']);
imagecolortransparent($im2 , $transparentcolour);
$transparentcolour = imagecolorallocate($im3 , $t['red'] , $t['green'] , $t['blue']);
imagecolortransparent($im3 , $transparentcolour);
}
imagealphablending($im1, false);
$color = imagecolorallocatealpha($im1, 0, 0, 0, 127);
imagefill($im1, 0, 0, $color);
imagesavealpha($im1, true);
imagealphablending($im2, false);
$color = imagecolorallocatealpha($im2, 0, 0, 0, 127);
imagefill($im2, 0, 0, $color);
imagesavealpha($im2, true);
imagealphablending($im3, false);
$color = imagecolorallocatealpha($im3, 0, 0, 0, 127);
imagefill($im3, 0, 0, $color);
imagesavealpha($im3, true);
}
} else {
$im1 = imagecreate(100, 100);
$im2 = imagecreate(35, 35);
$im3 = imagecreate(512, 512);
}
$cx = $image->width / 2;
$cy = $image->height / 2;
if ($image->width < $image->height) {
$half = floor($image->width / 2.0);
} else {
$half = floor($image->height / 2.0);
}
imagecopybicubic($im1, $im, 0, 0, $cx - $half, $cy - $half, 100, 100, $half * 2, $half * 2);
imagecopybicubic($im2, $im, 0, 0, $cx - $half, $cy - $half, 35, 35, $half * 2, $half * 2);
imagecopybicubic($im3, $im, 0, 0, $cx - $half, $cy - $half, 512, 512, $half * 2, $half * 2);
$fs = get_file_storage();
$icon = array('contextid'=>$context->id, 'component'=>$component, 'filearea'=>$filearea, 'itemid'=>$itemid, 'filepath'=>'/');
ob_start();
if (!$imagefnc($im1, NULL, $quality, $filters)) {
// keep old icons
ob_end_clean();
return false;
}
$data = ob_get_clean();
imagedestroy($im1);
$icon['filename'] = 'f1'.$imageext;
$fs->delete_area_files($context->id, $component, $filearea, $itemid);
$file1 = $fs->create_file_from_string($icon, $data);
ob_start();
if (!$imagefnc($im2, NULL, $quality, $filters)) {
ob_end_clean();
$fs->delete_area_files($context->id, $component, $filearea, $itemid);
return false;
}
$data = ob_get_clean();
imagedestroy($im2);
$icon['filename'] = 'f2'.$imageext;
$fs->create_file_from_string($icon, $data);
ob_start();
if (!$imagefnc($im3, NULL, $quality, $filters)) {
ob_end_clean();
$fs->delete_area_files($context->id, $component, $filearea, $itemid);
return false;
}
$data = ob_get_clean();
imagedestroy($im3);
$icon['filename'] = 'f3'.$imageext;
$fs->create_file_from_string($icon, $data);
return $file1->get_id();
}
/**
* Generates a thumbnail for the given image
*
* If the GD library has at least version 2 and PNG support is available, the returned data
* is the content of a transparent PNG file containing the thumbnail. Otherwise, the function
* returns contents of a JPEG file with black background containing the thumbnail.
*
* @param string $filepath the full path to the original image file
* @param int $width the width of the requested thumbnail
* @param int $height the height of the requested thumbnail
* @return string|bool false if a problem occurs, the thumbnail image data otherwise
*/
function generate_image_thumbnail($filepath, $width, $height) {
global $CFG;
if (empty($filepath) or empty($width) or empty($height)) {
return false;
}
$imageinfo = getimagesize($filepath);
if (empty($imageinfo)) {
return false;
}
$originalwidth = $imageinfo[0];
$originalheight = $imageinfo[1];
if (empty($originalwidth) or empty($originalheight)) {
return false;
}
$original = imagecreatefromstring(file_get_contents($filepath));
if (function_exists('imagepng')) {
$imagefnc = 'imagepng';
$filters = PNG_NO_FILTER;
$quality = 1;
} else if (function_exists('imagejpeg')) {
$imagefnc = 'imagejpeg';
$filters = null;
$quality = 90;
} else {
debugging('Neither JPEG nor PNG are supported at this server, please fix the system configuration.');
return false;
}
if (function_exists('imagecreatetruecolor')) {
$thumbnail = imagecreatetruecolor($width, $height);
if ($imagefnc === 'imagepng') {
imagealphablending($thumbnail, false);
imagefill($thumbnail, 0, 0, imagecolorallocatealpha($thumbnail, 0, 0, 0, 127));
imagesavealpha($thumbnail, true);
}
} else {
$thumbnail = imagecreate($width, $height);
}
$ratio = min($width / $originalwidth, $height / $originalheight);
if ($ratio < 1) {
$targetwidth = floor($originalwidth * $ratio);
$targetheight = floor($originalheight * $ratio);
} else {
// do not enlarge the original file if it is smaller than the requested thumbnail size
$targetwidth = $originalwidth;
$targetheight = $originalheight;
}
$dstx = floor(($width - $targetwidth) / 2);
$dsty = floor(($height - $targetheight) / 2);
imagecopybicubic($thumbnail, $original, $dstx, $dsty, 0, 0, $targetwidth, $targetheight, $originalwidth, $originalheight);
ob_start();
if (!$imagefnc($thumbnail, null, $quality, $filters)) {
ob_end_clean();
return false;
}
$data = ob_get_clean();
imagedestroy($original);
imagedestroy($thumbnail);
return $data;
}