Widget Graphic Board
Formerly known as Ghostscript View (GSView)
The Widget Graphic Board is a widget class implemented by the front-end and which
handles part of the interaction with the user. More specifically, it offers
following features :
- It displays the contents of a Ghostscript device (which is accessed as a
pixmap in shared memory).
- It handles the mouse movements and displays cross hairs if needed.
- It displays and handles grips on top of the Ghostscript output.
- It displays and handles scrollers to navigate in the view. The scrollers
are optional and they are defined by their offset and visible ratio.
The WidgetGraphicBoard class supports the OPiGUISyn
interface, which allows it to communicate directly with the GUISyn
library. It has therefore direct access to the GUI variables and get all the
information needed for its configuration.
The variable associated with WidgetGraphicBoard
is in fact a record, which
contains following fields :
- "device" : Ghostscript
- "x-offset" and "y-offset" :
offsets for the horizontal and vertical scrollers. The offset is expressed
by an integer in the 0..999999 range, where 0
means left/bottom and 999999 means
- "x-ratio" and "y-ratio" :
visibility ratios for the horizontal and vertical scrollers. A ratio of 100
means that the scroller is inactive, since the full range is visible; a
missing ratio means that the scroller should not be displayed. The ratio is
expressed by an integer in the 0..100 range.
- "x-step-inc" and "y-step-inc" :
amount by which a scroller advances when an arrow is clicked.
- "x-page-inc" and "y-page-inc" :
amount by which a scroller advances when a page arrow is clicked (or an
equivalent scrolling function is activated).