PICTURE TO BLOB
PICTURE TO BLOB ( picture ; pictureBlob ; codec )
| Parameter | Type | Description | |
|---|---|---|---|
| picture | Picture | → | Picture field or variable |
| pictureBlob | Blob | ← | BLOB to receive the converted picture |
| codec | Text | → | Picture Codec ID |
Description
The PICTURE TO BLOB command converts a picture stored in a 4D variable or field to another format and places the resulting picture in a BLOB.
A picture 4D field or variable is passed in the picture parameter. In the pictureBlob parameter is passed a BLOB variable or field which should contain the converted picture.
Pass in the codec parameter a string setting the conversion format.
A Codec can be an extension (for example, “.gif”) or a Mime type (for example “image/jpeg”). You can get a list of available Codecs via the PICTURE CODEC LIST command.
Once the command has been executed, the pictureBlob contains the picture in the specified format.
If the conversion was successful, the system variable OK is set to 1. If the conversion has failed (converter not available), OK is set to 0 and the generated BLOB is empty (0 byte).
Example
You want to convert an image from a proprietary format to GIF format and display it on a static web page. You can use a code such as:
var $picture : Picture
var $BLOB : Blob
var $path : Text
$path:=Get 4D folder(Current resources folder)+"Images"+Folder separator+"Sunrise.psd" //find the picture in the Images folder within the Resources folder
READ PICTURE FILE($path;$picture) //put the picture in the picture variable
PICTURE TO BLOB($picture;$BLOB;".gif") //convert the picture to ".gif" format
WEB SEND BLOB($BLOB;"image/gif")
See also
BLOB TO PICTURE
PICTURE CODEC LIST
WRITE PICTURE FILE
Properties
| Command number | 692 |
| Thread safe | ✓ |
| Modifies variables | OK |