The features described in this topic are obsolete
and should not be used in new IDL code.

DEVICE

The following keywords to the DEVICE procedure are obsolete.

Keywords

DEPTH

(LJ)

The DEPTH keyword specifies the number of significant bits in a pixel. The LJ250 can support between 1 and 4 significant bits (known also as planes). The number of available colors is related to the number of significant planes by the equation:

Colors = 2^#planes

Therefore, the LJ250 can support 2, 4, 8, or 16 separate colors on a single page of output. The default is to use a single plane, producing monochrome output.

Since IDL is based around 8-bit pixels, it is necessary to define which bits in a 8-bit pixel are used by the LJ250 driver, and which are ignored. When using a depth of 1 (monochrome), dithering techniques are used to render images. In this case, all 8 bits are used. If more than a single plane is used, the least significant n bits of a 8-bit pixel are used, where n is the selected depth. For example, using a depth of 4, pixel values of 15, 31, and 47 are all considered to have the value 15 because all three values have the same binary representation in their 4 least significant digits.

When the depth is changed, the standard color map given in Table 7-5 of the LJ250/LJ252 Companion Color Printer Programmer Reference Manual is automatically loaded. Therefore, color maps should be loaded with TVLCT after changing the depth.

FONT

(WIN, X)

This keyword is now obsolete and has been replaced by the SET_FONT keyword. Code that uses the FONT keyword will continue to function as before, but we suggest that all new code use SET_FONT.