Locations, Offsets, and Positions

There are several ways to reference the location of characters within an IEditorView, each with their own benefits.

Offsets and Positions

As mentioned in the Offsets, Ranges, and Positions topic, offsets are zero-based integer numbers indicating a character index from the beginning of a string or snapshot and text positions are similar but specify a line index and a character index within that line instead.

Offsets and positions are used within IEditorView objects to provide layout information to the view lines. However, it is important to note that while a TextPosition (4,0) is the fifth line in a view's CurrentSnapshot, it may not be the fifth view line in the view, even when the view is scrolled all the way to the top. Things that can cause this scenario are word wrap, collapsed outlining nodes, etc. So, in the same scenario, assume word wrap is on and the second line wrapped once. This would mean that TextPosition (4,0) would appear as the sixth line.

Scrolling a View to a Position

The ITextView.ScrollState property returns the current resolved scroll state for the view.

See the Scrolling topic for details on how to programmatically scroll a view to show a position's view line.

Locations

When related to a view, locations are the term used to describe the x,y layout position such as mouse coordinates, etc. They are specified using the Windows Point structure.

Converting Between Locations and Offsets/Positions

Locations can be translated to a TextPosition by using the IEditorView.LocationToPosition method. This method accepts a Point in text area-relative coordinates. The TransformToTextArea method can transform a view-relative coordinate to the text area. A LocationToPositionAlgorithm enumeration value is also passed, indicating how the logic used to convert the x,y coordinate to a TextPosition.

The GetCharacterBounds method can return the Rect coordinates that contain the character at a particular offset or TextPosition.

Hit Testing

SyntaxEditor features a very powerful hit testing mechanism where you indicate a Point relative to the SyntaxEditor control and it returns very detailed information about what is at the location. Information includes related character offsets, positions, etc. as well.

See the Hit Testing topic for information on how to perform hit testing.