d

depth

The depth of a window or pixmap is number of bits per pixel it has. The depth of a graphics context is the depth of the drawables it can be used in conjunction with for graphics output.

descendant

If W is an inferior of A, then W is a descendant of A.

device

Keyboards, mice, tablets, track-balls, button boxes, and so forth, are all collectively known as input devices. The core protocol only deals with two devices: the keyboard and the pointer.

direct color

A class of colormap in which a pixel value is decomposed into three separate subfields for indexing. One subfield indexes an array to produce red intensity values, the second subfield indexes a second array to produce blue intensity values, and the third subfield indexes a third array to produce green intensity values. The RGB values can be changed dynamically.

dispatching an event

The process of finding the appropriate contact and its actions.

double-click

A sequence of two clicks of the same button in rapid succession.

drawable

Both windows and pixmaps can be used as sources and destinations in graphics operations. These are collectively known as drawables . However, an :input-only window cannot be used as a source or destination in a graphics operation.