viewgrid.m

gridgen是一款强大的网格生成程序

function viewgrid(prm, v)
% VIEWGRID Visualises grids generated by `gridgen'.
% Usage:
%   viewgrid('<gridgen prm file>')       -- display grid only
%   viewgrid('<gridgen prm file>', 'v')  -- display grid and image on one
%                                           chart, vertically one under another
%   viewgrid('<gridgen prm file>', 'h')  -- display grid and image on one
%                                           chart, horizontally one aside other
%   viewgrid('<gridgen prm file>', '<any other character than 'v' or 'h'>) --
%                                           display grid and image on two
%                                           different charts
%
%   For the image display to work, an entry `rectangle' must be
%   specified in the `gridgen' parameter file.

  if (exist('v','var'))
    warning off;
    [geom,data,rect] = rfnames(prm);
    warning on;
    if (~exist('rect','var'))
      fprintf('  Warning: the image file not specified in \"%s\"\n', prm);
    end
  else
    [geom,data] = rfnames(prm);
  end
  
  f = fopen(geom);
  count = 0;
  if (f >= 0)
    count = 0;
    str = fgetl(f);
    while (str >= 0)
      if (str(1) ~= '#')
	count = count + 1;
	xy = sscanf(str, '%f %f %f');
	xc(count) = xy(1);
	yc(count) = xy(2);
	if (length(xy) > 2)
	  zc(count) = xy(3);
	else
	  zc(count) = 0;
	end
      end
      str = fgetl(f);
    end
    
    xc_pos = xc(zc > 0);
    xc_neg = xc(zc < 0);
    yc_pos = yc(zc > 0);
    yc_neg = yc(zc < 0);
    
    if (xc(count) ~= xc(1) | yc(count) ~= yc(1))
      count = count + 1;
      xc(count) = xc(1);
      yc(count) = yc(1);
    end
    fclose(f);
  end
  
  f = fopen(data);
  if (f > 0)
    count = 0;
    str = fgetl(f);
    while (str >= 0)
      if (str(1) ~= '#')
        count = count + 1;
	xy = sscanf(str, '%f %f');
	x(count) = xy(1);
	y(count) = xy(2);
      end
      str = fgetl(f);
    end
    fclose(f);
  end

  figure1 = figure;
  if (exist('rect','var'))
    if (exist('v','var') & v == 'v')
      subplot(2,1,2);
    elseif (exist('v','var') & v == 'h')
      subplot(1,2,2);
    else
      figure2 = figure;
    end
    r = load(rect);
    xr = r(:, 1);
    yr = r(:, 2);
    n = length(xr);
    xr(n + 1) = xr(1);
    yr(n + 1) = yr(1);
    plot(xr, yr, 'k-', xr, yr, 'k.');
    title('Image');
    axis equal;
    xmin = min(xr);
    xmax = max(xr);
    ymin = min(yr);
    ymax = max(yr);
    dx = (xmax - xmin) * 0.05;
    dy = (ymax - ymin) * 0.05;
    axis([(xmin - dx) (xmax + dx) (ymin - dy) (ymax + dy)]);
    grid on;
  end

  figure(figure1);
  if (exist('rect','var'))
    if (exist('v','var') & v == 'v')
      subplot(2,1,1);
    elseif (exist('v','var') & v == 'h')
      subplot(1,2,1);
    end
  end
  if (exist('xc','var'))
    if (length(xc_neg) > 0)
      plot(x, y, '.', xc, yc, 'k-', xc, yc, 'k.', xc_pos, yc_pos, 'go', xc_neg, yc_neg, 'rd');
      legend('grid nodes', 'boundary', 'boundary vertices', 'positive turn points', 'negative turn points');
    else
      plot(x, y, '.', xc, yc, 'k-', xc, yc, 'k.', xc_pos, yc_pos, 'go');
      legend('grid nodes', 'boundary', 'boundary vertices', 'turn points');
    end
  else
    plot(x, y, '.');
  end
  title(strcat('Original polygon and generated nodes ("', data, '")'));
  axis equal;
  xmin = min(xc);
  xmax = max(xc);
  ymin = min(yc);
  ymax = max(yc);
  dx = (xmax - xmin) * 0.05;
  dy = (ymax - ymin) * 0.05;
  axis([(xmin - dx) (xmax + dx) (ymin - dy) (ymax + dy)]);

return;

function [geom,data,rect] = rfnames(prm);
  f = fopen(prm);
  if (f < 0)
    return;
  end
  
  seps = char([32,92]);
  str = fgetl(f);
  while (str >= 0)
    if (str(1) ~= '#')
      [first,str] = strtok(str, seps);
      if (strcmpi(first, 'input'))
	geom = strtok(str, seps);
      elseif (strcmpi(first, 'output'))
	data = strtok(str, seps);
      elseif (strcmpi(first, 'rectangle'))
	rect = strtok(str, seps);
      end
    end
    str = fgetl(f);
  end
  
  fclose(f);
  return