resize_image.php

《PHP和MySQL Web开发》(第三版) Source

<?php

  $image = $_REQUEST['image'];
  $max_width = $_REQUEST['max_width'];
  $max_height = $_REQUEST['max_height'];

  if (!$max_width)
    $max_width = 80;
  if (!$max_height)
    $max_height = 60;

  $size = GetImageSize($image);
  $width = $size[0];
  $height = $size[1];

  $x_ratio = $max_width / $width;
  $y_ratio = $max_height / $height;

  if ( ($width <= $max_width) && ($height <= $max_height) ) {
    $tn_width = $width;
    $tn_height = $height;
  }
  else if (($x_ratio * $height) < $max_height) {
    $tn_height = ceil($x_ratio * $height);
    $tn_width = $max_width;
  }
  else {
    $tn_width = ceil($y_ratio * $width);
    $tn_height = $max_height;
  }

  $src = ImageCreateFromJpeg($image);
  $dst = ImageCreate($tn_width,$tn_height);
  ImageCopyResized($dst, $src, 0, 0, 0, 0,
      $tn_width,$tn_height,$width,$height);
  header('Content-type: image/jpeg');
  ImageJpeg($dst, null, -1);
  ImageDestroy($src);
  ImageDestroy($dst);

?>