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