PHP scaling Image

For images uploaded at the front end of a website, it is necessary to scale the images in the background to generate a thumbnail of a uniform size. In PHP, you can easily use the GD library to complete this task. The following CImage static method CreateThumbnail () function can use parameters such as the original image file name, thumbnail width and height, and the generated thumbnail file name to generate a thumbnail that maintains the aspect ratio of the original image. The function basically shows the PHP method for generating thumbnails, which can be further expanded, for example, generating thumbnails in the specified format based on the thumbnail file name.

The complete code is as follows (Win7 + XAMPP2.5 and Linuxdev 2.6.18-128 + apache have passed the test ):

// By MoreWindows (http://www.bkjia.com)

Class CImage
{
/**
* Generate an image with the source image portrait to support. PNG. jpg. gif.
* The graphic layout is in. PNG format.
* $ SrcFile Original Image File Name
* $ ToW thumbnail width
* $ ToH thumbnail height
* $ ToFile: the name of the thumbnail file. If it is null, it overwrites the original image file.
* @ Return bool
*/
Public static function CreateThumbnail ($ srcFile, $ toW, $ toH, $ toFile = "")
{
If ($ toFile = "")
{
$ ToFile = $ srcFile;
}
$ Info = "";
// Return an array containing four units, 0-width, 1-height, 2-image type, and 3-width text description.
// If the request fails, false is returned and a warning is generated.
$ Data = getimagesize ($ srcFile, $ info );
If (! $ Data)
Return false;

// Load the file into the resource variable im
Switch ($ data [2]) // 1-GIF, 2-JPG, 3-PNG
{
Case 1:
If (! Function_exists ("imagecreatefromgif "))
{
Echo "the GD can't support. gif, please use. jpeg or. png! <A href = 'javascript: history. back (); '> back </a> ";
Exit ();
}
$ Im = imagecreatefromgif ($ srcFile );
Break;

Case 2:
If (! Function_exists ("imagecreatefromjpeg "))
{
Echo "the GD can't support. jpeg, please use other picture! <A href = 'javascript: history. back (); '> back </a> ";
Exit ();
}
$ Im = imagecreatefromjpeg ($ srcFile );
Break;

Case 3:
$ Im = imagecreatefrompng ($ srcFile );
Break;
}

// Calculate the width and height of the thumbnail
$ SrcW = imagesx ($ im );
$ SrcH = imagesy ($ im );
$ ToWH = $ toW/$ toH;
$ SrcWH = $ srcW/$ srcH;
If ($ toWH <= $ srcWH)
{
$ FtoW = $ toW;
$ FtoH = (int) ($ ftoW * ($ srcH/$ srcW ));
}
Else
{
$ FtoH = $ toH;
$ FtoW = (int) ($ ftoH * ($ srcW/$ srcH ));
}

If (function_exists ("imagecreatetruecolor "))
{
$ Ni = imagecreatetruecolor ($ ftoW, $ ftoH); // create a true color image
If ($ ni)
{
// Copy part of the image and adjust the size to ensure better clarity.
Imagecopyresampled ($ ni, $ im, 0, 0, 0, 0, $ ftoW, $ ftoH, $ srcW, $ srcH );
}
Else
{
// Copy part of the image and resize it
$ Ni = imagecreate ($ ftoW, $ ftoH );
Imagecopyresized ($ ni, $ im, 0, 0, 0, 0, $ ftoW, $ ftoH, $ srcW, $ srcH );
}
}
Else
{
$ Ni = imagecreate ($ ftoW, $ ftoH );
Imagecopyresized ($ ni, $ im, 0, 0, 0, 0, $ ftoW, $ ftoH, $ srcW, $ srcH );
}
 
// Save the file to the. PNG format.
Imagepng ($ ni, $ toFile); // output the image to a browser or file in PNG format
ImageDestroy ($ ni );
ImageDestroy ($ im );
Return true;
}

From MoreWindows