| \section{Standard Module \sectcode{imghdr}} |
| \label{module-imghdr} |
| \stmodindex{imghdr} |
| |
| The \module{imghdr} module determines the type of image contained in a |
| file or byte stream. |
| |
| The \module{imghdr} module defines the following function: |
| |
| |
| \begin{funcdesc}{what}{filename\optional{, h}} |
| Tests the image data contained in the file named by \var{filename}, |
| and returns a string describing the image type. If optional \var{h} |
| is provided, the \var{filename} is ignored and \var{h} is assumed to |
| contain the byte stream to test. |
| \end{funcdesc} |
| |
| The following image types are recognized, as listed below with the |
| return value from \function{what()}: |
| |
| \begin{tableii}{|l|l|}{code}{Value}{Image format} |
| \lineii{'rgb'}{SGI ImgLib Files} |
| \lineii{'gif'}{GIF 87a and 89a Files} |
| \lineii{'pbm'}{Portable Bitmap Files} |
| \lineii{'pgm'}{Portable Graymap Files} |
| \lineii{'ppm'}{Portable Pixmap Files} |
| \lineii{'tiff'}{TIFF Files} |
| \lineii{'rast'}{Sun Raster Files} |
| \lineii{'xbm'}{X Bitmap Files} |
| \lineii{'jpeg'}{JPEG data in JIFF format} |
| \end{tableii} |
| |
| You can extend the list of file types \module{imghdr} can recognize by |
| appending to this variable: |
| |
| \begin{datadesc}{tests} |
| A list of functions performing the individual tests. Each function |
| takes two arguments: the byte-stream and an open file-like object. |
| When \function{what()} is called with a byte-stream, the file-like |
| object will be \code{None}. |
| |
| The test function should return a string describing the image type if |
| the test succeeded, or \code{None} if it failed. |
| \end{datadesc} |
| |
| Example: |
| |
| \begin{verbatim} |
| >>> import imghdr |
| >>> imghdr.what('/tmp/bass.gif') |
| 'gif' |
| \end{verbatim} |