[Tioga-users] monochrome image

[Edwin]

Hi all,

I have a lot of x,y data, with corresponding z values and am trying to  
plot a contourplot. A normal contourplot is working well using the  
following:
t.show_plot( [0, 1, 1, 0] ) {
	image = t.create_image_data( zs,
		'min_value' => -0.8, 'max_value' => 0.8 )
	t.show_image( 'll' => [0, 0],
               	'lr' => [1, 0],
                 	'ul' => [0, 1],
                 	'color_space' => t.mellow_colormap,
                 	'data' => image, 'w' => steps+1, 'h' => steps+1)
}

But I'm actually only interested if the value is above or below 0 and want  
to plot everything above 0 grey and keep everything else white. I think I  
need the create_monochrome_image_data for that but can't figure it out.

I tried just setting:
t.create_image_data( zs,  'boundary' => 0.0 ) and 'color_space' => 'mono',
but this doesn't seem to work (I get a plot, but it doesn't match in  
anyway with the data).
I also tried setting the stencil_mask in show_image, but got the following  
error:
	undefined method `each_key' for #<String:0xb7a7e308>  [version: 1.2.1]

What is the correct way to do this?

Edwin