Re: [platform-text-dev] RevisionRulerColumn in textViewer

[Tom Eicher <eclipse@xxxxxxxxxxxxxxx>]

Eugene Kuleshov wrote:

> So, what I am suggesting is to have some sort of simplier UI that 
> would take care of all the canvas rendering, etc and can be extended 
> in the future to provide more high level API.

If I understand correctly, you suggest an AbstractRulerColumn base class 
that would call a method similar to the following for every line that 
needs painting:

/**
* Paint the ruler representation for the given document line on the GC.
* 
* @param documentLine a line in the document displayed in the text viewer
* @param gc the graphics context to draw on
* @param y_offset the y offset on the GC corresponding
*        to the document line in the text viewer.
*/
protected abstract void paintLine(int documentLine, GC gc, int y_offset);


It should also allow the contributor to trigger redrawing of a line 
range based on its UI model (for example to render focus or to react to 
model changes):

/**
* Triggers a redraw of a certain line range.
*/
protected final void redraw(ILineRange range);


This would be enough for most line-based ruler columns (such as the line 
number column) but would limit contributions that want to do more. The 
Quick Diff and Revision columns for example have a notion of contiguous 
line ranges (ChangeRegions or 'Hunks') that are painted as a whole, not 
line based. It would be possible to adapt them to line based painting, 
though.

Of course, the other open questions (ordering etc.) still remain.

-tom