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MDL-55445 gdlib: Support for resizing an image

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This commit is contained in:
Frederic Massart 2016-08-10 15:32:54 +08:00
parent 6f302b17b9
commit 92b9ef9917
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GPG Key ID: AC343CE142B12FB9
3 changed files with 222 additions and 76 deletions
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24
lib/filestorage/stored_file.php
View File

@ -1063,4 +1063,28 @@ class stored_file {
// Generate the thumbnail.
return generate_image_thumbnail_from_image($original, $imageinfo, $width, $height);
}
/**
* Generate a resized image for this stored_file.
*
* @param int|null $width The desired width, or null to only use the height.
* @param int|null $height The desired height, or null to only use the width.
* @return string|false False when a problem occurs, else the image data.
*/
public function resize_image($width, $height) {
global $CFG;
require_once($CFG->libdir . '/gdlib.php');
// Fetch the image information for this image.
$imageinfo = @getimagesizefromstring($this->get_content());
if (empty($imageinfo)) {
return false;
}
// Create a new image from the file.
$original = @imagecreatefromstring($this->get_content());
// Generate the resized image.
return resize_image_from_image($original, $imageinfo, $width, $height);
}
}

206
lib/gdlib.php
View File

@ -270,20 +270,21 @@ function process_new_icon($context, $component, $filearea, $itemid, $originalfil
return $file1->get_id();
}
/**
* Generates a thumbnail for the given image
* Resize an image from an image path.
*
* 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.
* This maintains the aspect ratio of the image.
* This will not enlarge the image.
*
* @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
* @param string $filepath The full path to the original image file.
* @param int|null $width The max width of the resized image, or null to only use the height.
* @param int|null $height The max height of the resized image, or null to only use the width.
* @param bool $forcecanvas Whether the final dimensions should be set to $width and $height.
* @return string|bool False if a problem occurs, else the resized image data.
*/
function generate_image_thumbnail($filepath, $width, $height) {
if (empty($filepath) or empty($width) or empty($height)) {
function resize_image($filepath, $width, $height, $forcecanvas = false) {
if (empty($filepath)) {
return false;
}
@ -297,7 +298,119 @@ function generate_image_thumbnail($filepath, $width, $height) {
$original = @imagecreatefromstring(file_get_contents($filepath));
// Generate the thumbnail.
return generate_image_thumbnail_from_image($original, $imageinfo, $width, $height);
return resize_image_from_image($original, $imageinfo, $width, $height, $forcecanvas);
}
/**
* Resize an image from an image object.
*
* @param resource $original The image to work on.
* @param array $imageinfo Contains [0] => originalwidth, [1] => originalheight.
* @param int|null $width The max width of the resized image, or null to only use the height.
* @param int|null $height The max height of the resized image, or null to only use the width.
* @param bool $forcecanvas Whether the final dimensions should be set to $width and $height.
* @return string|bool False if a problem occurs, else the resized image data.
*/
function resize_image_from_image($original, $imageinfo, $width, $height, $forcecanvas = false) {
global $CFG;
if (empty($width) && empty($height) || ($forcecanvas && (empty($width) || empty($height)))) {
// We need do not have the required ddimensions to work with.
return false;
}
if (empty($imageinfo)) {
return false;
}
$originalwidth = $imageinfo[0];
$originalheight = $imageinfo[1];
if (empty($originalwidth) or empty($originalheight)) {
return false;
}
if (function_exists('imagepng')) {
$imagefnc = 'imagepng';
$filters = PNG_NO_FILTER;
$quality = 1;
} else if (function_exists('imagejpeg')) {
$imagefnc = 'imagejpeg';
$filters = null;
$quality = 90;
} else {
debugging('Neither JPEG nor PNG are supported at this server, please fix the system configuration.');
return false;
}
if (empty($height)) {
$ratio = $width / $originalwidth;
} else if (empty($width)) {
$ratio = $height / $originalheight;
} else {
$ratio = min($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;
}
$canvaswidth = $targetwidth;
$canvasheight = $targetheight;
$dstx = 0;
$dsty = 0;
if ($forcecanvas) {
$canvaswidth = $width;
$canvasheight = $height;
$dstx = floor(($width - $targetwidth) / 2);
$dsty = floor(($height - $targetheight) / 2);
}
if (function_exists('imagecreatetruecolor')) {
$newimage = imagecreatetruecolor($canvaswidth, $canvasheight);
if ($imagefnc === 'imagepng') {
imagealphablending($newimage, false);
imagefill($newimage, 0, 0, imagecolorallocatealpha($newimage, 0, 0, 0, 127));
imagesavealpha($newimage, true);
}
} else {
$newimage = imagecreate($canvaswidth, $canvasheight);
}
imagecopybicubic($newimage, $original, $dstx, $dsty, 0, 0, $targetwidth, $targetheight, $originalwidth, $originalheight);
// Capture the image as a string object, rather than straight to file.
ob_start();
if (!$imagefnc($newimage, null, $quality, $filters)) {
ob_end_clean();
return false;
}
$data = ob_get_clean();
imagedestroy($original);
imagedestroy($newimage);
return $data;
}
/**
* 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, $height) {
return resize_image($filepath, $width, $height, true);
}
/**
@ -337,71 +450,12 @@ function generate_image_thumbnail_from_string($filedata, $width, $height) {
* 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 $original The image content as a string
* @return string|bool false if a problem occurs, the thumbnail image data otherwise
* @param resource $original The image to work on.
* @param array $imageinfo Contains [0] => originalwidth, [1] => originalheight.
* @param int $width The width of the requested thumbnail.
* @param int $height The height of the requested thumbnail.
* @return string|bool False if a problem occurs, the thumbnail image data otherwise.
*/
function generate_image_thumbnail_from_image($original, $imageinfo, $width, $height) {
global $CFG;
if (empty($imageinfo)) {
return false;
}
$originalwidth = $imageinfo[0];
$originalheight = $imageinfo[1];
if (empty($originalwidth) or empty($originalheight)) {
return false;
}
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, $originalheight);
// Capture the image as a string object, rather than straight to file.
ob_start();
if (!$imagefnc($thumbnail, null, $quality, $filters)) {
ob_end_clean();
return false;
}
$data = ob_get_clean();
imagedestroy($original);
imagedestroy($thumbnail);
return $data;
return resize_image_from_image($original, $imageinfo, $width, $height, true);
}

68
lib/tests/gdlib_test.php
View File

@ -86,4 +86,72 @@ class core_gdlib_testcase extends basic_testcase {
$this->assertEquals(24, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
}
public function test_resize_image() {
global $CFG;
require_once($CFG->libdir . '/gdlib.php');
$pngpath = $this->fixturepath . 'gd-logo.png';
// Preferred height.
$newpng = resize_image($pngpath, null, 24);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(89, $imageinfo[0]);
$this->assertEquals(24, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
// Preferred width.
$newpng = resize_image($pngpath, 100, null);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(100, $imageinfo[0]);
$this->assertEquals(26, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
// Preferred width and height.
$newpng = resize_image($pngpath, 50, 50);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(50, $imageinfo[0]);
$this->assertEquals(13, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
}
public function test_resize_image_from_image() {
global $CFG;
require_once($CFG->libdir . '/gdlib.php');
$pngpath = $this->fixturepath . 'gd-logo.png';
$origimageinfo = getimagesize($pngpath);
$imagecontent = file_get_contents($pngpath);
// Preferred height.
$imageresource = imagecreatefromstring($imagecontent);
$newpng = resize_image_from_image($imageresource, $origimageinfo, null, 24);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(89, $imageinfo[0]);
$this->assertEquals(24, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
// Preferred width.
$imageresource = imagecreatefromstring($imagecontent);
$newpng = resize_image_from_image($imageresource, $origimageinfo, 100, null);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(100, $imageinfo[0]);
$this->assertEquals(26, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
// Preferred width and height.
$imageresource = imagecreatefromstring($imagecontent);
$newpng = resize_image_from_image($imageresource, $origimageinfo, 50, 50);
$this->assertTrue(is_string($newpng));
$imageinfo = getimagesizefromstring($newpng);
$this->assertEquals(50, $imageinfo[0]);
$this->assertEquals(13, $imageinfo[1]);
$this->assertEquals('image/png', $imageinfo['mime']);
}
}