使用PHP创建缩略图.(裁剪到正方形)

Question

我有一个目前正在使用的PHP脚本,它根据最大宽度和高度创建缩略图.但是,我希望它能够始终创建方形图像并在需要时裁剪图像.

这是我现在使用的:

    function makeThumb( $filename, $type ) {
  global $max_width, $max_height;
  if ( $type == 'jpg' ) {
   $src = imagecreatefromjpeg("blocks/img/gallery/" . $filename);
  } else if ( $type == 'png' ) {
   $src = imagecreatefrompng("blocks/img/gallery/" . $filename);
  } else if ( $type == 'gif' ) {
   $src = imagecreatefromgif("blocks/img/gallery/" . $filename);
  }
  if ( ($oldW = imagesx($src)) < ($oldH = imagesy($src)) ) {
   $newW = $oldW * ($max_width / $oldH);
   $newH = $max_height;
  } else {
   $newW = $max_width;
   $newH = $oldH * ($max_height / $oldW);
  }
  $new = imagecreatetruecolor($newW, $newH);
  imagecopyresampled($new, $src, 0, 0, 0, 0, $newW, $newH, $oldW, $oldH);
  if ( $type == 'jpg' ) {
   imagejpeg($new, 'blocks/img/gallery/thumbs/'.$filename);
  } else if ( $type == 'png' ) {
   imagepng($new, 'blocks/img/gallery/thumbs/'.$filename);
  } else if ( $type == 'gif' ) {
   imagegif($new, 'blocks/img/gallery/thumbs/'.$filename);
  }
  imagedestroy($new);
  imagedestroy($src);
 }

我怎么改变它来完成我想要的东西(方形拇指)？

提前致谢.

Answer 1

function makeThumb( $filename , $thumbSize=100 ){
  global $max_width, $max_height;
 /* Set Filenames */
  $srcFile = 'blocks/img/gallery/'.$filename;
  $thumbFile = 'blocks/img/gallery/thumbs/'.$filename;
 /* Determine the File Type */
  $type = substr( $filename , strrpos( $filename , '.' )+1 );
 /* Create the Source Image */
  switch( $type ){
    case 'jpg' : case 'jpeg' :
      $src = imagecreatefromjpeg( $srcFile ); break;
    case 'png' :
      $src = imagecreatefrompng( $srcFile ); break;
    case 'gif' :
      $src = imagecreatefromgif( $srcFile ); break;
  }
 /* Determine the Image Dimensions */
  $oldW = imagesx( $src );
  $oldH = imagesy( $src );
 /* Calculate the New Image Dimensions */
  if( $oldH > $oldW ){
   /* Portrait */
    $newW = $thumbSize;
    $newH = $oldH * ( $thumbSize / $newW );
  }else{
   /* Landscape */
    $newH = $thumbSize;
    $newW = $oldW * ( $thumbSize / $newH );
  }
 /* Create the New Image */
  $new = imagecreatetruecolor( $thumbSize , $thumbSize );
 /* Transcribe the Source Image into the New (Square) Image */
  imagecopyresampled( $new , $src , 0 , 0 , ( $newW-$thumbSize )/2 , ( $newH-$thumbSize )/2 , $thumbSize , $thumbSize , $oldW , $oldH );
  switch( $type ){
    case 'jpg' : case 'jpeg' :
      $src = imagejpeg( $new , $thumbFile ); break;
    case 'png' :
      $src = imagepng( $new , $thumbFile ); break;
    case 'gif' :
      $src = imagegif( $new , $thumbFile ); break;
  }
  imagedestroy( $new );
  imagedestroy( $src );
}

Answer 2

   /* Calculate the New Image Dimensions */
   $limiting_dim = 0;
    if( $oldH > $oldW ){
     /* Portrait */
      $limiting_dim = $oldW;
    }else{
     /* Landscape */
      $limiting_dim = $oldH;
    }
   /* Create the New Image */
    $new = imagecreatetruecolor( $thumbSize , $thumbSize );
   /* Transcribe the Source Image into the New (Square) Image */
    imagecopyresampled( $new , $src , 0 , 0 , ($oldW-$limiting_dim )/2 , ( $oldH-$limiting_dim )/2 , $thumbSize , $thumbSize , $limiting_dim , $limiting_dim );

我没有足够的业力评论接受的答案(Lucanos'),但我发现上面的答案在缩略图的一侧给出了黑条.

此代码段(与已接受的答案相结合)应复制src图像的相关部分,而不会超出界限并生成黑条.根据原始问题,缩略图仍然是正方形.