php は画像のサムネイルを生成します (JPEG、GIT、PNG、BMP をサポート)

class Thumb
{

 public function create($srcPath, $dstPath, $dstWidth, $dstHeight)
 {
 if (!file_exists($srcPath)) {
 return false;
 }

 @$srcSize = getimagesize($srcPath);
 if (empty($srcSize)) {
 return false;
 }

 $srcWith = intval($srcSize[0]);
 $srcHeight = intval($srcSize) [1]);

 //元の画像のサイズが指定されたサムネイルのサイズより大きい場合はサムネイルを生成し、それ以外の場合は元のファイルをコピーします
 if ($srcWith <= $dstWidth && $srcHeight <; = $dstHeight) {
 return copy($srcPath, $dstPath);
 }

 //元の画像リソースを読み込みます
 @$srcImage = imagecreatefromjpeg($srcPath);
 if (empty($srcImage)) {
 @ $srcImage = imagecreatefromgif( $srcPath);
 }
 if (empty($srcImage)) {
 @$srcImage = imagecreatefrompng($srcPath);
 }
 if (empty($srcImage)) {
 @$srcImage = $ this->_imageCreateFromBMP ($srcPath);
 }

 if (empty($srcImage)) {
 return false;
 }

 //サムネイルのサイズを取得し、それに応じて新しい画像を生成します
 $dstSize = $ this->getDstSize(
 $srcWith, $srcHeight, $dstWidth, $dstHeight
 );

 @$dstImage = imagecreatetruecolor(
 $dstSize['width'], $dstSize['height']
 );

 @imagecopyresampled(
 $dstImage, $srcImage , 0, 0, 0, 0,
 $dstSize['width'], $dstSize['height'],
 $srcWith, $srcHeight
 );

 return @imagepng( $srcPath, $ dstPath);
 }

 プライベート関数 _imageCreateFromBMP($filePath)
 {
 $fileHandle = fopen($filePath, 'rb');
 if (empty($fileHandle)) {
 return false;
 }

 $file = unpack(
 'vfile_type/Vfile_size/Vreserved/Vbitmap_offset',
 fread($fileHandle, 14)
 );

 if ($file['file_type'] != 19778) {
 return false;
 }

 $ bmp = unpack(
 'Vheader_size/Vwidth/Vheight/vplanes/'.
 'vbits_per_pixel/Vcompression/Vsize_bitmap/'.
 'Vhoriz_resolution/Vvert_resolution/Vcolors_used/Vcolors_ important',
 fread($fileHandle, 40)
 );
 $ bmp['colors'] = pow(2, $bmp['bits_per_pixel']);
 if ($bmp['size_bitmap'] == 0) {
 $bmp['size_bitmap'] = $file ['file_size' ] - $file['bitmap_offset'];
 }
 $bmp['bytes_per_pixel'] = $bmp['bits_per_pixel'] / 8;
 $bmp['bytes_per_pixel2'] = ceil($bmp[' bytes_per_pixel']) ;
 $bmp['decal'] = $bmp['width'] * $bmp['bytes_per_pixel'] / 4;
 $bmp['decal'] -= Floor($bmp['width' ] * $bmp ['bytes_per_pixel'] / 4);
 $bmp['decal'] = 4 - (4 * $bmp['decal']);
 if ($bmp['decal'] == 4) {
 $bmp ['decal'] = 0;
 }

 $palette = array();
 if ($bmp['colors'] < 16777216) {
 $palette = unpack(
 'V' . $ bmp['colors '],
 fread($fileHandle, $bmp['colors'] * 4)
 );
 }
 $image = fread($fileHandle, $bmp['size_bitmap']);
 $vide = chr(0) ;
 $res = imagecreatetruecolor($bmp['width'], $bmp['height']);
 $p = 0;

 $y = $bmp['height'] - 1;
 while ($y >= 0) {
 $x = 0;
 while ($x < $bmp['width']) {
 if ($bmp['bits_per_pixel'] == 24) {
 $color = unpack(' V', substr($image, $p, 3) . $vide);
 } else if ($bmp['bits_per_pixel'] == 16) {
 $color = unpack('n', substr ($image, $p, 2));
 $color[1] = $palette[$color[1]+1];
 } else if ($bmp['bits_per_pixel'] == 8) {
 $color = unpack(' n', $vide . substr ($image, $p, 1));
 $color[1] = $palette[$color[1]+1];
 } else if ($bmp[' bits_per_pixel'] = =4) {
 $color = unpack('n', $vide .substr($image, Floor($p), 1));
 if (($p * 2) % 2 == 0 ) {
 $ color[1] = ($color[1] >> 4);
 } else {
 $color[1] = ($color[1] & 0x0F);
 }
 $color[1 ] = $palette [$color[1] + 1];
 }else if ($bmp['bits_per_pixel'] == 1) {
 $color = unpack('n', $vide . substr($image, Floor($p), 1));
 switch (($p * 8) % 8) {
 case 0:
 $color[1] = ($color[1] >> 7);
 Break;
 case 1:
 $color[1] = ($color[1] & 0x40) >> 6;
 ブレーク;
 ケース 2:
 $color[1] = ($color[1] & 0x20) >> 5;
 ブレーク;
 ケース 3:
 $color[1] = ($color[1] & 0x10) >> 4;
 ブレーク;
 ケース 4:
 $color[1] = ($color[1] & 0x8) >> 3;
 ブレーク;
 ケース 5:
 $color[1] = ($color[1] & 0x4) >> 2;
 ブレーク;
 ケース 6:
 $color[1] = ($color[1] & 0x2) >> 1;
 ブレーク;
 ケース 7:
 $color[1] = ($color[1] & 0x1);
 ブレーク;
 }
 $color[1] = $palette[$color[1] + 1];
 } else {
 return false;
 }
 imagesetpixel($res, $x, $y, $color[1]);
 $x++;
 $p += $bmp['bytes_per_pixel'];
 }
 $ y--;
 $p += $bmp['decal'];
 }
 fclose($fileHandle);
 return $res;
 }

 プライベート関数 _getDstSize($srcWith, $srcHeight, $dstWidth, $dstHeight )
 {
 $size = array('width' => $srcWith, 'height' => $srcHeight);
 if ($dstWidth > 0 && $dstHeight > 0) {
 if ($srcWith > ; 0 && $srcHeight > 0) {
 if ($srcWith / $srcHeight >= $dstWidth / $dstHeight) {
 if ($srcWith > $dstWidth) {
 $size['width'] = $dstWidth ;
 $size['height'] = $srcHeight * $dstWidth / $srcWith;
 }
 } else {
 if ($srcHeight >; $dstHeight) {
 $size['width'] = $srcWith * $dstHeight / $srcHeight;
 $size['height'] = $dstHeight;
 }
 }
 }
 }
 return $size;
 }
 }

JPEG、php、GIT