重建缩略图时保留GIF tansparencies
在上传图像时，代码会创建几个不同的缩略图。在某些情况下，缩略图可能比原始图像大，在这种情况下应用填充。在JPEG的情况下，填充是白色的，一切都很好。对于GIF和PNG，填充应该是透明的。它是。或不。这很奇怪。
如果我得到一个完全黑色或透明的填充，我会知道问题所在，但我得到的填充物在某些地方是透明的而在其他地方是黑色的，这没有任何意义。
在http://filedump.xn--es-zka.info/broken_thumbs/处拍摄PNG和GIF图像（在令人震惊的粉红色背景色上，以便您可以看到白色和透明之间的差异）。
有什么好主意吗？
class Image {
public static function exec($path) {
// This function receives the path to an image.
// Logic here skipped: For each thumbnail, check whether Crop is set. If it is, call self::crop(). Otherwise, call self::resize().
return true;
}
public static function resize($file, $class, $width='-', $height='-', $fit=0) {
$a = getimagesize($file);
switch ($a[2]) {
case 1:
$tag = 'gif';
break;
case 2:
$tag = 'jpeg';
break;
case 3:
$tag = 'png';
break;
default:
return;
}
$w = $a[0];
$h = $a[1];
if ($width == 0) {
$fw = 0;
$fh = $h / $height;
} elseif ($height == 0) {
$fw = $w / $width;
$fh = 0;
} else {
$fw = $w / $width;
$fh = $h / $height;
}
if (($fw == 1) and ($fh == 1)) {
$file2 = dirname($file) . '/' . $class . basename($file);
copy($file, $file2);
return true;
} elseif (($fw >= 1) and ($fh >= 1)) {
if ($fw > $fh) {
$w = $width;
$h = floor($h / $fw);
} else {
$h = $height;
$w = floor($w / $fh);
}
} elseif ($fh == 0) {
if ($fw > 1) {
$fit = 0;
$w = $width;
$h = floor($h / $fw);
} else {
if ($fit) {
$height = $h;
}
}
} elseif ($fw == 0) {
if ($fh > 1) {
$fit = 0;
$w = floor($w / $fh);
$h = $height;
} else {
if ($fit) {
$width = $w;
}
}
} elseif (($fw < 1) and ($fh < 1)) {
//
} elseif ($fw > $fh) {
if ($fw >= 1) {
$w = $width;
$h = floor($h / $fw);
}
} elseif ($fh > $fw) {
if ($fh >= 1) {
$w = floor($w / $fh);
$h = $height;
}
}
if ($fit) {
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
$cw = $width;
$ch = $height;
} else {
$x = 0;
$y = 0;
$cw = $w;
$ch = $h;
}
$file2 = dirname($file) . '/' . $class . basename($file);
$f1 = 'imagecreatefrom' . $tag;
$src = $f1($file);
$new = imagecreatetruecolor($cw, $ch);
return self::create($new, $src, $file2, $x, $y, $w, $h, $a);
}
public static function crop($file, $class, $width='-', $height='-', $fit=0) {
if (!$class) return trigger_error('ExecImage: Original image can not be overwritten.');
$small = 0;
$a = getimagesize($file);
switch ($a[2]) {
case 1:
$tag = 'gif';
break;
case 2:
$tag = 'jpeg';
break;
case 3:
$tag = 'png';
break;
default:
return;
}
$w = $a[0];
$h = $a[1];
if ($height == 0) {
//resize by width -- height will follow
$fh = 0;
$fw = $w / $width;
} elseif ($width == 0) {
//resize by height -- width will follow
$fw = 0;
$fh = $h / $height;
} else {
$fw = $w / $width;
$fh = $h / $height;
}
if (($fw <= 1) and ($fh <= 1)) {
$small = 1;
//don't resize
} else {
$fit = 1;
//chop by the smallest
if ($fh < $fw) {
//Crop By Height
$h = $height;
$w = floor($w / $fh);
//$w = $width;
//$h = floor($h /$fw);
//$w = $width;
} else {
//Crop By Width
$w = $width;
$h = floor($h /$fw);
//$h = $height;
//$w = floor($w / $fh);
}
}
$file2 = dirname($file) . '/' . $class . basename($file);
$f1 = 'imagecreatefrom' . $tag;
$src = $f1($file);
if ($small) {
if ($fit) {
//image must be padded
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
} else {
//image goes as is -- shrinked
$x = 0;
$y = 0;
}
} else {
//image must be centered -- this should be a square from js
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
}
if ($small) {
if ($fit) {
//create with the full size
$new = imagecreatetruecolor($width, $height);
} else {
//nah, just with the original size
$new = imagecreatetruecolor($w, $h);
}
} else {
if ($fit) {
$new = imagecreatetruecolor($width, $height);
} else {
$new = imagecreatetruecolor($w, $h);
}
}
return self::create($new, $src, $file2, $x, $y, $w, $h, $a);
}
private static function create($new, $src, $file2, $x, $y, $w, $h, $a) {
switch ($a[2]) {
case 1: // GIF
case 3: // PNG
// http://www.akemapa.com/2008/07/10/php-gd-resize-transparent-image-png-gif/
// http://www.mummey.org/2008/11/transparent-gifs-with-php-and-gd/
imagealphablending($new, false);
imagesavealpha($new, true);
$back = imagecolorallocatealpha($new, 255, 255, 255, 127);
imagefilledrectangle($new, 0, 0, $w, $h, $back);
imagecolortransparent($new, $back);
break;
case 2: // JPEG
$back = imagecolorallocate($new, 255, 255, 255);
break;
}
imagefill($new, 0, 0, $back);
imagecopyresampled($new, $src, $x, $y, 0, 0, $w, $h, $a[0], $a[1]);
if (file_exists($file2)) unlink($file2);
switch ($a[2]) {
case 1:
imagegif($new, $file2);
break;
case 2:
imagejpeg($new, $file2, 100);
break;
case 3:
imagepng($new, $file2, 0);
break;
}
imagedestroy($src);
imagedestroy($new);
return true;
}
}
修订/编辑以添加：
好吧，我已经解决了主要问题：添加到PNG或GIF图像的填充现在是透明的，而不是黑色。 GIF透明度变黑的问题仍然存在，但我并没有使用GIF透明度。
<?php
class Image {
public static function exec($path) {
$file = Nearest::file('.config.php', dirname($path) . '/', BD . '/images/');
if (!file_exists($file)) exit('The ".config.php" file doesnt exist');
require $file;
foreach ($config['operations'] as $k => $v) {
if (!isset($v['class'])) $v['class'] = '.' . $k . '.';
if (Core::val($v, 'crop')) {
self::crop($path, $v['class'], Core::val($v, 'width', '-'), Core::val($v, 'height', '-'), Core::val($v, 'fit', 0));
} else {
self::resize($path, $v['class'], Core::val($v, 'width', '-'), Core::val($v, 'height', '-'), Core::val($v, 'fit', 0));
}
}
return true;
}
public static function delete($path) {
$a = glob(dirname($path) . '/.*.' . basename($path));
foreach ($a as $v) unlink($v);
unlink($path);
}
public static function resize($file, $class, $width='-', $height='-', $fit=0) {
$a = getimagesize($file);
switch ($a[2]) {
case 1:
$tag = 'gif';
break;
case 2:
$tag = 'jpeg';
break;
case 3:
$tag = 'png';
break;
default:
return;
}
$w = $a[0];
$h = $a[1];
if ($width == 0) {
$fw = 0;
$fh = $h / $height;
} elseif ($height == 0) {
$fw = $w / $width;
$fh = 0;
} else {
$fw = $w / $width;
$fh = $h / $height;
}
if (($fw == 1) and ($fh == 1)) {
$file2 = dirname($file) . '/' . $class . basename($file);
copy($file, $file2);
return true;
} elseif (($fw >= 1) and ($fh >= 1)) {
if ($fw > $fh) {
$w = $width;
$h = floor($h / $fw);
} else {
$h = $height;
$w = floor($w / $fh);
}
} elseif ($fh == 0) {
if ($fw > 1) {
$fit = 0;
$w = $width;
$h = floor($h / $fw);
} else {
if ($fit) {
$height = $h;
}
}
} elseif ($fw == 0) {
if ($fh > 1) {
$fit = 0;
$w = floor($w / $fh);
$h = $height;
} else {
if ($fit) {
$width = $w;
}
}
} elseif (($fw < 1) and ($fh < 1)) {
//
} elseif ($fw > $fh) {
if ($fw >= 1) {
$w = $width;
$h = floor($h / $fw);
}
} elseif ($fh > $fw) {
if ($fh >= 1) {
$w = floor($w / $fh);
$h = $height;
}
}
if ($fit) {
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
$cw = $width;
$ch = $height;
} else {
$x = 0;
$y = 0;
$cw = $w;
$ch = $h;
}
$file2 = dirname($file) . '/' . $class . basename($file);
$f1 = 'imagecreatefrom' . $tag;
$src = $f1($file);
$new = imagecreatetruecolor($cw, $ch);
return self::create($new, $src, $file2, $x, $y, $w, $h, $cw, $ch, $a);
}
public static function crop($file, $class, $width='-', $height='-', $fit=0) {
if (!$class) exit('ExecImage: Original image can not be overwrite.');
$small = 0;
$a = getimagesize($file);
switch ($a[2]) {
case 1:
$tag = 'Gif';
break;
case 2:
$tag = 'Jpeg';
break;
case 3:
$tag = 'Png';
break;
default:
return;
}
$w = $a[0];
$h = $a[1];
if ($height == 0) {
//resize by width -- height will follow
$fh = 0;
$fw = $w / $width;
} elseif ($width == 0) {
//resize by height -- width will follow
$fw = 0;
$fh = $h / $height;
} else {
$fw = $w / $width;
$fh = $h / $height;
}
if (($fw <= 1) and ($fh <= 1)) {
$small = 1;
//dont resize
} else {
$fit = 1;
//chop by the smallest
if ($fh < $fw) {
//Crop By Height
$h = $height;
$w = floor($w / $fh);
//$w = $width;
//$h = floor($h /$fw);
//$w = $width;
} else {
//Crop By Width
$w = $width;
$h = floor($h /$fw);
//$h = $height;
//$w = floor($w / $fh);
}
}
$file2 = dirname($file) . '/' . $class . basename($file);
$f1 = 'ImageCreateFrom' . $tag;
$src = $f1($file);
if ($small) {
if ($fit) {
//image must be padded
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
} else {
//image goes as is -- shrinked
$x = 0;
$y = 0;
}
} else {
//image must be centered -- this should be a square from js
$x = ($width - $w) / 2;
$y = ($height - $h) / 2;
}
if ($small) {
if ($fit) {
//create with the full size
$new = imagecreatetruecolor($width, $height);
return self::create($new, $src, $file2, $x, $y, $w, $h, $width, $height, $a);
} else {
//nah, just with the original size
$new = imagecreatetruecolor($w, $h);
return self::create($new, $src, $file2, $x, $y, $w, $h, $w, $h, $a);
}
} else {
if ($fit) {
//create with the full size
$new = imagecreatetruecolor($width, $height);
return self::create($new, $src, $file2, $x, $y, $w, $h, $width, $height, $a);
} else {
//nah, just with the original size
$new = imagecreatetruecolor($w, $h);
return self::create($new, $src, $file2, $x, $y, $w, $h, $w, $h, $a);
}
}
}
private static function create($new, $src, $file2, $x, $y, $w, $h, $cw, $ch, $a) {
switch ($a[2]) {
case 1: // GIF
case 3: // PNG
// http://www.akemapa.com/2008/07/10/php-gd-resize-transparent-image-png-gif/
// http://www.mummey.org/2008/11/transparent-gifs-with-php-and-gd/
imagealphablending($new, false);
imagesavealpha($new, true);
$back = imagecolorallocatealpha($new, 255, 255, 255, 127);
imagefilledrectangle($new, 0, 0, $cw, $ch, $back);
imagecolortransparent($new, $back);
break;
case 2: // JPEG
$back = imagecolorallocate($new, 255, 255, 255);
break;
}
imagefill($new, 0, 0, $back);
imagecopyresampled($new, $src, $x, $y, 0, 0, $w, $h, $a[0], $a[1]);
if (file_exists($file2)) unlink($file2);
switch ($a[2]) {
case 1:
imagegif($new, $file2);
break;
case 2:
imagejpeg($new, $file2, 100);
break;
case 3:
imagepng($new, $file2, 0);
break;
}
imagedestroy($src);
imagedestroy($new);
return true;
}
}
那么，有关如何保持GIF透明度的任何提示吗？
1 个答案:
答案 0 :(得分：0)
您将a link与答案放在一起;）
你正在使用imageCopyResampled，它与alpha一样奇怪。请改用imageCopyResized。
http://www.mummey.org/2008/11/transparent-gifs-with-php-and-gd/comment-page-1/#comment-94
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