php generates image thumbnails (supports: JPEG, GIT, PNG, BMP)-PHP Tutorial-php.cn

php generates image thumbnails (supports: JPEG, GIT, PNG, BMP)

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Release： 2016-07-25 08:45:09

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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]);
//If the size of the original image is larger than the size of the specified thumbnail, generate a thumbnail, otherwise copy the original file
if ($srcWith <= $dstWidth && $srcHeight <= $dstHeight) {
return copy($srcPath, $dstPath);
}
//Read the original image resource
@$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;
}
//Get the size of the thumbnail and generate a new image accordingly
$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);
}
private function _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;
break;
case 2:
$color[1] = ($color[1] & 0x20) >> 5;
break;
case 3:
$color[1] = ($color[1] & 0x10) >> 4;
break;
case 4:
$color[1] = ($color[1] & 0x8) >> 3;
break;
case 5:
$color[1] = ($color[1] & 0x4) >> 2;
break;
case 6:
$color[1] = ($color[1] & 0x2) >> 1;
break;
case 7:
$color[1] = ($color[1] & 0x1);
break;
}
$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' => $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;
}
}

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JPEG, php, GIT