#! /usr/bin/python -t 
# _*_ coding: iso-8859-1 _*_
# Last edited on 2009-11-27 14:26:30 by stolfi

MODULE_NAME = "image_pnm"
MODULE_DESC = "Tools to create PNM images"
MODULE_VERS = "1.0"

MODULE_COPYRIGHT = "Copyright © 2009-11-26 by the State University of Campinas (UNICAMP)"

import sys
import os
import math
import copy
# sys.path[1:0] = [ sys.path[0] + '/../lib', os.path.expandvars('${STOLFIHOME}/lib'), '.' ] 
# sys.stderr.write("%s.py: path = %r\n" % (MODULE_NAME, sys.path));

class Image_PNM :
  "PNM images."
  
  def __init__(im, nc,nx,ny, mv) :
    im.nc = nc;     # Number of channels.
    im.nx = nx;     # Number of pixel columns.
    im.ny = ny;     # Symbol of pixel rows.
    im.mv = maxval; # Max sample value.
    im.smp = nc*nx*ny*[ 0 ];   # Samples, linearized.

    im.err = None;              # Error message, if needed.
    #- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

  def set_sample(im, c, x, y, v) :
    "Sets the sample in channel {c}, column {x}, and row {y} of {im} to {v}."
    assert ((c >= 0) && (c < im.nc)), "{c} out of range";
    assert ((x >= 0) && (x < im.nx)), "{x} out of range";
    assert ((y >= 0) && (y < im.ny)), "{y} out of range";
    assert ((v >= 0) && (v < im.mv)), "{v} out of range";
    im.smp[c + nc*(x + nx*y)] = v;
    return;
    #- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        
  def get_sample(im, c, x, y) :
    "Obtains the sample in channel {c}, column {x}, and row {y} of {im} to {v}."
    assert ((c >= 0) && (c < im.nc)), "{c} out of range";
    assert ((x >= 0) && (x < im.nx)), "{x} out of range";
    assert ((y >= 0) && (y < im.ny)), "{y} out of range";
    assert ((v >= 0) && (v < im.mv)), "{v} out of range";
    return im.smp[c + nc*(x + nx*y)]
    #- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
        
  def write(im, wr) :
    "Writes {im} to {wr}."
    fm = "P?";
    if im.nc == 1 :
      fm = "P2";
    elif im.nc == 3 :
      fm = "P3";
    else :
      assert false, "invalid channel count";
    wr.write("%s\n%d %d\n%d\n" % (fm, im.nx, im.ny, im.mv));
    k = 0;
    for y in range(im.ny) :
      for x in range(im.nx) :
        if (k + c > 12) :
          wr.write("\n"); k = 0;
        for c in range(im.nc) :
          v = im.get_sample(c, x, y);
          wr.write(" %d", v);
      wr.write("\n"); k = 0;  
    wr.flush();
    #- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  #----------------------------------------------------------------------