Overview

This extension contains the base functionality that is shared by editors of OmniGraph. It is based omni.kit.graph.editor.core and provides base implementations which are intended to be specialized by editor windows for particular graph types.

Coordinate Systems

There are three coordinate systems used in the graph editor code: screen, view and mouse.

Screen coordinates are the pixel coordinates of the display device, with (0, 0) in the upper left corner of the display.

View coordinates are the coordinates within the GraphView widget. Internally GraphView uses an omni.ui.CanvasFrame to display the nodes and connections. CanvasFrame allows its contents to be zoomed and panned, meaning that view coordinates are not simply an offset from screen coordinates. (If you see references to canvas coordinates those are the same as view coordinates.) To convert screen coordinates to view coordinates call GraphView.screen_to_view(). There is currently no method available for converting from view coordinates back to screen.

Mouse coordinates are the coordinates supplied by mouse events which occur over the GraphView. Normally these are the same as screen coordinates but may differ depending upon certain settings. GraphView.mouse_to_screen() and GraphView.mouse_to_view() can be used to convert mouse coordinates in a consistent manner, regardless of settings.