Picture

A picture (in png, jpg, ... format) for use in a Geometry, to be converted to an expression. It will not be combined with the other shapes in Geometry, and only the picture that is added last to the Geometry will be used.

Constructor:

• Picture(picturename, n_min=x, n_max=y): creates a picture object from filename picturename to be used in a Geometry.

The picture will be converted to grayscale, with white being mapped to a material with refractive index n_min and black to n_max. The indices for grayscales are obtained through linear interpolation.

When using the Geometry function

to_expression(prop0, prop1, d_prop, verbose=True,rescaling='ANTIALIAS'), the following will happen. The values of prop0 and prop1 will set the conversion from pixel units to physical length units. The parameter d_prop determines the resolution: when set to 0 (the default), no information is lost in the picture and every pixel is used as is. In case the thickness of the slice d_prop is set to such a value that results in a coarser picture than the original one, the following down-sample mechanisms can be used:

• NEAREST: 'Nearest' algorithm from the PIL library. As this method takes the nearest point, no new gray colours will be created.
• ANTIALIAS: 'Average' algorithm from the PIL library. This will create a grayscale image.
• INV_AVERAGE: Similar to ANTIALIAS, but use geometric averaging.

See section Geometry

This document was generated by root on August, 27 2008 using texi2html 1.76.