next up previous contents
Next: Graphic Hard Copy Output Up: View Tool Previous: Graphics Options   Contents

Colour Maps

The display colour map can be selected from the following alternatives;
standard,   grey scale,  anaglyph, false colour
These maps are avaialable as either Psedo Color or True Color depending on whether the X server is in 8 bit or 16 bit colour mode or above (increasingly, modern computers are no longer resricted to 8 bit graphics). The ``grey scale" option is intended for cases where better image definition is required with 8 bit graphcs than is available with the Standard colour-map. False colour is intended for displaying images with quantitative grey level values. Anaglyphs are provided for stereoscopic display and display of complex images (ie: two value). Tina does not yet support full colour dislays of, for example, RGB's as there is no need for the algorithms currently supported. The default colours variable specifies the number of colours to be copied from the system colourmap. Sensible window managers will not switch back to the system colourmap when it is included as a subset of the tool colour map in this way. Very large values of this variable (ie: greater than 72) may move the graphical colours of the standard colour maps into the red overlay plane used for temporary graphics. This does not however, cause any undue execution errors.

The colour map can be interregated and examined via the use of the Show cmap and Show tv's cmap_lookup functions. Most windows managers runnning with 8 bit colour include an ``xcmap" utility which is eqivalent. The current Tv screen can be pushed directly into the Imcalc Tool if necessary, though this is not reccomended as a stage in data processing.

The default font for the current Tv can be changed. If a wildcard is included (ie: *) the nearest suitable font will be chosen.

Problems may be encountered when displaying 16 bit (or above) graphics on Linux machines from programmes rumming on a Sun workstation. A grey scale image will take colours which are typically green and purple. This is due to incompatabilities between integer number represenatation on these machines which is not correctly handled by the X server. When this happens the problem can be fixed by toglling the endian button. This re-orders the bytes passed to the graphics server so that all colours and grey scales are rendered as originally intended.


next up previous contents
Next: Graphic Hard Copy Output Up: View Tool Previous: Graphics Options   Contents
root 2017-11-17