php產生影像縮圖（支援：JPEG，GIT，PNG，BMP）

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

 //如果原始圖片的尺寸大於指定縮圖的尺寸，則產生縮圖，否則拷貝原始圖片
 if ($srcWith  return copy($ srcPath, $dstPath);
 }

 //讀取原始圖片資源
 @$srcImage = imagecreatefromjpeg($srcPath);
 if (empty($srcImage)) { @$srcImage = imagecreatefromgif($srcPath);
 }
 if (empty($srcImage)) {
 @$srcImage = imagecreatefrompng($srcPath);
 }
 }
);
 } @$srcImage = $this->_imageCreateFromBMP($srcPath);
 }

 if (empty($srcImage)) {

 if (empty($srcImage)) {

 if (empty($srcImage)) {
 }

 //取得縮圖的尺寸，並據此產生新的圖片
 $dstSize = $this->_getDstSize(
 $srcWith, $srcHeight, $dstWidth, $dstHeight
 );

 @$dstImage = imagecreatetruecolor(
 $dstSize['width'], $dstSize['height']
 ); $dstImage, $srcImage , 0, 0, 0, 0,
 $dstSize['width'], $dstSize['height'],
 $srcWith, $srcHeight
 );
 $srcWith, $srcHeight
 );
 );
 return @imagepng($srcPath, $dstPath);
 }

 private function _imageCreateFromBMP($filePath)
 {
 $fileHandle = fopendfilePath, 'fileHandle ;
 if (empty($fileHandle)) {
 return false;
 }

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

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

  'Vheader_size/Vwidth/Vheight/vplanes/'.
 'vbits_per_pixel/Vcompression/Vsize_bitmap/'.
 'Vhoriz_resolution/Vcolor_resperatution/Vcolor_fidofsed(3)(3D), fidunc_resport) 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']  $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  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) {
 情況0:
 $color[1] = ($color[1] >> 7);
 中斷;
 情況1:
 $color[1] = ($color[1] & 0x40) >>> 6;
 中斷;
 情況2:
 $color[1] = ($color[1] & 0x20) > >> 5;
 中斷;
情況3:
 $color[1] = ($color[1] & 0x10) >>> 4;
 中斷;
情況4:
 $color[1] = ($color[1] & 0x8) >>> 3;
 中斷;
 情況5:
 $color[1] = ($color[1] & 0x4 ) >>> 2;
 中斷;
 情況6:
 $color[1] = ($color[1] & 0x2) >>> 1;
 中斷;
 情況7 :
 $color[1] = ($color[1] & 0x1);
 中斷;
 }
 $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;
 }

 private function _getDstSize($srcWith, $srcHeight, $dstWidth, $dstHeight)
 {
 $size = array('width' = 'ight ' => $srcHeight);
 if ($dstWidth > 0 && $dstHeight > 0) {
 if ($srcWith > 0 && $srcHeight > 0) {
 if ($srcWith / $srcHeight > 0) {
 if ($srcWith / $srcHeight > = $dstWidth / $dstHeight) {
 if ($srcWith >; $dstWidth) {
 $size['width'] = $dstWidth;
 $size['height'] = $srcHeight * $srcHeight * dstWidth / $srcWith;
 }
 } else {
 if ($srcHeight > $dstHeight) {
 $size['width'] = $srcWith * $dstHeight / $srcight; $size['height'] = $dstHeight;
 }
 }
 }
 }
 return $size;
 }
}

JPEG、PHP、GIT