Change interface to plotvol.

Author: petercorke

plotvol.m

@@ -1,20 +1,36 @@
 %PLOTVOL Set the bounds for a 2D or 3D plot
 %
-% PLOTVOL(W) creates a new axis, and sets the bounds for a 2D plot with X and Y spanning
-% the interval -W to W.  The axes are labelled, grid is enabled, aspect ratio set to 1:1,
-% and hold is enabled for subsequent plots.
+% 2D plots::
+%
+% PLOTVOL([WX WY]) creates a new axis, and sets the bounds for a 2D plot,
+% with X spanning [-WX, WX] and Y spanning [-WY,WY].
 %
 % PLOTVOL([XMIN XMAX YMIN YMAX]) as above but the X and Y axis limits are explicitly provided.
 %
-% PLOTVOL([XMIN XMAX YMIN YMAX ZMIN ZMAX]) as above but the X, Y and Z axis limits are 
+% 3D plots::
+%
+% PLOTVOL(W) creates a new axis, and sets the bounds for a 3D plot with X, Y and Z spanning
+% the interval -W to W.  
+%
+% PLOTVOL([WX WY WZ]) as above with X spanning [-WX, WX], Y spanning [-WY, WY] and Z 
+% spanning [-WZ, WZ].
+%
+% Notes::
+% - The axes are labelled, grid is enabled, aspect ratio set to 1:1.
+% - Hold is enabled for subsequent plots.
+%
+% See also: axis.
+
+%
+% PLOTVOL([XMIN XMAX YMIN YMAX ZMIN ZMAX]) as above but the X, Y and Z axis limits are
 % explicitly provided.
 %
 % See also axis, xaxis, yaxis.
 
 % Copyright (C) 1993-2019 Peter I. Corke
 %
 % This file is part of The Spatial Math Toolbox for MATLAB (SMTB).
-% 
+%
 % Permission is hereby granted, free of charge, to any person obtaining a copy
 % of this software and associated documentation files (the "Software"), to deal
 % in the Software without restriction, including without limitation the rights
@@ -25,7 +41,7 @@
 % The above copyright notice and this permission notice shall be included in all
 % copies or substantial portions of the Software.
 %
-% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 % IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 % FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 % COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
@@ -35,34 +51,40 @@
 % https://github.com/petercorke/spatial-math
 
 function plotvol(bounds)
-
-    if ~any(length(bounds) == [1 4 6])
-        error('SMTB:plotvol:badarg', 'expecting vector of length 1, 4 or 6');
-    end
-    if length(bounds) == 1
-        bounds = bounds * [-1 1 -1 1];
-    end
 
+    assert(any(length(bounds) == [1 2 3 4 6]), 'SMTB:plotvol:badarg', 'expecting vector of length 1, 2, 3, 4 or 6');
+    
+    
+    clf
     axis equal
-    axis(bounds);
-
-    if length(bounds) == 4
-        % 2D case
-        
-        set(gca, 'XTick', floor(bounds(1)):floor(bounds(2)))
-        set(gca, 'YTick', floor(bounds(3)):floor(bounds(4)))
-        
-    elseif length(bounds) == 6
-        % 3D case
-        set(gca, 'XTick', floor(bounds(1)):floor(bounds(2)))
-        set(gca, 'YTick', floor(bounds(3)):floor(bounds(4)))
-        set(gca, 'ZTick', floor(bounds(5)):floor(bounds(6)))
-        
+    
+    switch length(bounds)
+        case 1
+            bounds = bounds * [-1 1 -1 1 -1 1];
+        case 3
+            bounds = bounds(:) * [-1 1];
+            bounds = bounds';
+            bounds = bounds(:)';
+        case 6
+            %         % 3D case
+            %         set(gca, 'XTick', floor(bounds(1)):floor(bounds(2)))
+            %         set(gca, 'YTick', floor(bounds(3)):floor(bounds(4)))
+            %         set(gca, 'ZTick', floor(bounds(5)):floor(bounds(6)))
+            bounds = bounds(:)';
+        case 2
+            bounds = bounds(:) * [-1 1];
+            bounds = bounds';
+            bounds = bounds(:)';
+        case 4
+            bounds = bounds(:)';
     end
 
+    axis(bounds)
+    
     % common code
     grid on;
     hold on
-
-
+    
+    
     xyzlabel
+end

unit_test/PlotTest.m

@@ -202,3 +202,20 @@ function xyzlabel_test(tc)
     plot3(1, 2, 3)
     xyzlabel()
 end
+
+function plotvol_test(tc)
+    
+    % 2D cases
+    plotvol([2 3])
+    tc.verifyEqual(axis, [-2 2 -3 3]);
+    plotvol([2 3 4 5])
+    tc.verifyEqual(axis, [2 3 4 5]);
+    
+    % 3D cases
+    plotvol(3)
+    tc.verifyEqual(axis, 3*[-1 1 -1 1 -1 1]);
+    plotvol([1 2 3]);
+    tc.verifyEqual(axis, [-1 1 -2 2 -3 3]);
+    plotvol([1 2 3 4 5 6]);
+    tc.verifyEqual(axis, [1 2 3 4 5 6]);
+end