NAME

img-ppm - Img, Portable Pixmap format (ppm)

SYNOPSIS

package require Tk

package require img::ppm ?1.4?

image create photo ?name? ?options?

DESCRIPTION

The package img::ppm is a sub-package of Img. It can be loaded as a part of the complete Img support, via package require Img, or on its own, via package require img::ppm.

Like all packages of Img it does not provide new commands, but extends the existing Tk command image so that it supports files containing raster images in the Portable Pixmap format (ppm). More specifically img::ppm extends Tk's photo image type.

The name of the new format handler is ppm. This handler provides additional configuration options. See section PPM OPTIONS for more detailed explanations.

All of the above means that in a call like

image create photo ?name? ?options?

[1]: Image data in ppm format (options -data and -file) is detected automatically.
[2]: The format name ppm is recognized by the option -format. In addition the value for the option is treated as list and may contain any of the special options listed in section PPM OPTIONS.

SUPPORTED PPM TYPES

This handler supports the PPM (Truecolor) and PGM (Greyscale) image formats. There are two types of PPM/PGM files: RAW (binary) and ASCII. The values stored in PPM/PGM files can be unsigned 8-bit or unsigned 16-bit values.

 Grayscale (PGM): 8-bit and 16-bit, 1 channel per pixel.
 Truecolor (PPM): 8-bit and 16-bit, 3 channels per pixel.
 List of currently supported features:
 Type              |     Read      |     Write     |
                   | -file | -data | -file | -data |
 ---------------------------------------------------
 PGM  8-bit ASCII  | Yes   | Yes   | No    | No    |
 PGM  8-bit BINARY | Yes   | Yes   | No    | No    |
 PGM 16-bit ASCII  | Yes   | Yes   | No    | No    |
 PGM 16-bit BINARY | Yes   | Yes   | No    | No    |
 PPM  8-bit ASCII  | Yes   | Yes   | Yes   | Yes   |
 PPM  8-bit BINARY | Yes   | Yes   | Yes   | Yes   |
 PPM 16-bit ASCII  | Yes   | Yes   | No    | No    |
 PPM 16-bit BINARY | Yes   | Yes   | No    | No    |

PPM OPTIONS

The handler provides the following options:

-verbose bool: This option is supported for reading and writing.
If set to true, additional information about the loaded/stored image is printed to stdout. Default is false.
-scanorder string: This option is supported for reading only.
Specify the scanline order of the input image. Possible values: TopDown or BottomUp. Default is TopDown.
-gamma float: This option is supported for reading only.
Specify a gamma correction to be applied when mapping 16-bit input data to 8-bit image values. Default is 1.0.
-min float: This option is supported for reading only.
Specify the minimum pixel value to be used for mapping 16-bit input data to 8-bit image values. Default is the minimum value found in the image data.
-max float: This option is supported for reading only.
Specify the maximum pixel value to be used for mapping 16-bit input data to 8-bit image values. Default is the maximum value found in the image data.
-ascii bool: This option is supported for writing only. If set to true, the file is written in PPM 8-bit ASCII format (P3). Default is false, i.e. write in PPM 8-bit binary format (P6).

KEYWORDS

image handling, ppm, tk

COPYRIGHT

Copyright (c) 1995-2009 Jan Nijtmans <nijtmans@users.sourceforge.net>