Class: PBMReader

• Inheritance
• Description
• Class protocol
  • class initialization
  • testing
• Instance protocol
  • private-reading
  • private-writing
  • reading
  • writing
• Examples

Inheritance:

   Object
   |
   +--ImageReader
      |
      +--PBMReader

Package:

stx:libview2

Category:

Graphics-Images-Readers

Version:

rev: 1.46 date: 2023/05/04 15:02:41

user: cg

file: PBMReader.st directory: libview2

module: stx stc-classLibrary: libview2

Description:

this class provides methods for loading and saving Portable BitMap-file 
images (Jef Poskanzers portable bitmap package).

Reading is supported for 1bit (pbm), greyscale (pgm) and 24bit (ppm) formats.
(i.e. P1, P3, P4, P5, P6 and P7 formats)

Writing is (currently) only supported for the binary formats;
i.e. 1-bit images as (pbm P4), 8-bit gray as (pgm P5) and 24-bit images as (pnm P6).

Q: should we broil this one to perfection and base all others on
   pipe-readers to the various pbmplus converters ?

copyright
COPYRIGHT (c) 1992 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 initialize

install myself in the Image classes fileFormat table
for the `.pbm', '.pgm' and '.pnm' extensions.

 canRepresent: anImage

return true, if anImage can be represented in my file format.
Currently, only 1bit B&W, 8bit-grey and 24bit RGB images are supported.

 isValidImageStream: inStream

return true, if inStream contains a PBM image (which I can read)

Instance protocol:

 readMaxVal

 readWidthAndHeight

 readWidthAndHeightAndMaxVal

 skipPBMJunk

this method removes any superfluous characters from the input stream.

 writeCommonHeader: format on: aStream

common header for P4, P5 and P5 formats

 fromStream: aStream

read a Portable bitmap file format as of Jeff Poskanzers Portable Bitmap Package.
supported are PPM, PBM, PGM and PNM files.

 readDepth1AsciiPBMStream

import portable bitmap ascii (PBM, P1 format); P1 is already read

 readDepth1PBMStream

import portable bitmap (PBM, P4 format); P4 is already read

 readDepth24AsciiPBMStream

import ascii portable pixmap (PBM, P3 format); P3 is already read

 readDepth24PPMStream

import portable pixmap (PPM, P6 format); P6 is already read

 readDepth8PGMStream

import portable gray map (PGM, P5 format); P5 is already read

 readDepth8PPMStream

import portable pixmap (PPM, P7 format); P7 is already read

 save: image onStream: aStream

save image as PBM/PGM/PNM file on aFileName

 writePBMFileOn: aStream

Saves the receivers image on the file fileName in Portable Bitmap format.

 writePGMFileOn: aStream

Saves the receiver's image on the file fileName in Portable Greymap format.

 writePNMFileOn: aStream

Saves the receivers image on the file fileName in Portable Anymap format.

Examples:

(PBMReader fromFile:'../../support/libjpeg-9/testimg.ppm')
    inspect