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[怎么选择seo优化公司]php bmp转jpg的实现方法

  

 

  php bmp转jpg的实现方法:首先开启gd扩展库;然后用“function_exist()”函数“ImageCreateFromBMP”检查是否存在;最后通过“ImageCreateFromBMP_private”方法实现转换即可。PHP问题后端开发

  

 

  推荐:《PHP视频教程》

  进行图片格式转换前,先输出phpinfo()查看php库信息,查看gd扩展库是否开启,若未开启,打开php.ini文件,用查找工具找到extension=php_gd2.dll,把extension=php_gd2.dll 前面的【;】,就可以了

  这里转换成为jpg格式需要JPEG Support支持,png需要 PNG Support支持,对应的先检查自己转的格式是否支持

  imagejpeg()函数失败也许是你的文件夹权限问题,[怎么选择seo优化公司]得多注意

  可以先用function_exist()函数ImageCreateFromBMP检查是否存在,下例中的ImageCreateFromBMP_private用来代替ImageCreateFromBMP方法

  示例代码如下:

  


 

  

<?php 
$srcFile ='test.bmp';//需要转换的图片$info = getimagesize($srcFile); 
$srcFileExt=$info['mime'];//判断是否是bmp格式if($srcFileExt=='image/x-ms-bmp'){ $result = changeBMPtoJPG($srcFile); if($result){ echo $result;
 }else{ echo "转换失败!";
 }
}else{ echo "该图片不是bmp格式";
} 
exit;function ImageCreateFromBMP_private($filename) { if (!$f1 = fopen($filename, "rb")) return false; $FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1, 14)); if ($FILE['file_type'] != 19778) return false; $BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel' .
 '/Vcompression/Vsize_bitmap/Vhoriz_resolution' .
 '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1, 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' . $BMP['colors'], fread($f1, $BMP['colors'] * 4));
 } $IMG = fread($f1, $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 < $BMP['width']) { switch ($BMP['bits_per_pixel']) { case 32: $COLOR = unpack("V", substr($IMG, $P, 3) . $VIDE); break; case 24: $COLOR = unpack("V", substr($IMG, $P, 3) . $VIDE); break; case 16: $COLOR = unpack("n", substr($IMG, $P, 2)); $COLOR[1] = $PALETTE[$COLOR[1] + 1]; break; case 8: $COLOR = unpack("n", $VIDE . substr($IMG, $P, 1)); $COLOR[1] = $PALETTE[$COLOR[1] + 1]; break; case 4: $COLOR = unpack("n", $VIDE . substr($IMG, 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]; break; case 1: $COLOR = unpack("n", $VIDE . substr($IMG, floor($P), 1)); if (($P * 8) % 8 == 0) $COLOR[1] = $COLOR[1] >> 7; elseif (($P * 8) % 8 == 1) $COLOR[1] = ($COLOR[1] & 0x40) >> 6; elseif (($P * 8) % 8 == 2) $COLOR[1] = ($COLOR[1] & 0x20) >> 5; elseif (($P * 8) % 8 == 3) $COLOR[1] = ($COLOR[1] & 0x10) >> 4; elseif (($P * 8) % 8 == 4) $COLOR[1] = ($COLOR[1] & 0x8) >> 3; elseif (($P * 8) % 8 == 5) $COLOR[1] = ($COLOR[1] & 0x4) >> 2; elseif (($P * 8) % 8 == 6) $COLOR[1] = ($COLOR[1] & 0x2) >> 1; elseif (($P * 8) % 8 == 7) $COLOR[1] = ($COLOR[1] & 0x1); $COLOR[1] = $PALETTE[$COLOR[1] + 1]; break; default: return false; break;
 }
 imagesetpixel($res, $X, $Y, $COLOR[1]); $X++; $P += $BMP['bytes_per_pixel'];
 } $Y--; $P+=$BMP['decal'];
 } fclose($f1); return $res;
}function changeBMPtoJPG($srcPathName){ $srcFile=$srcPathName; 
 $dstFile = str_replace('.bmp', '.jpg', $srcPathName); $photoSize = GetImageSize($srcFile); 
 $pw = $photoSize[0]; 
 $ph = $photoSize[1]; $dstImage = ImageCreateTrueColor($pw, $ph); 
 $white = imagecolorallocate($dstImage, 255, 255, 255); //用 $white 颜色填充图像
 imagefill( $dstImage, 0, 0, $white); //读取图片 
 $srcImage = ImageCreateFromBMP_private($srcFile); 
 //合拼图片 
 imagecopyresampled($dstImage, $srcImage, 0, 0, 0, 0, $pw, $ph, $pw, $ph); 
 $judge = imagejpeg($dstImage, $dstFile, 90); 
 imagedestroy($dstImage); if($judge){ return $dstFile;
 }else{ return false;
 }
}?>

 

  以上就是php bmp转jpg的实现方法的详细内容,更多请关注久澳传媒编程栏目其它相关文章![seo优化公司简介]什么情况下使用redis缓存

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