Is there a painless way to get a column ruler at the top of a TSynEdit, without having to do something like having multiple controls in a frame and forcing sideways scrolling to track?

Mark Morgan Lloyd wrote

Is there a painless way to get a column ruler at the top of a TSynEdit, without having to do something like having multiple controls in a frame and forcing sideways scrolling to track?

You can write a subclass of SynEdit, similar (but smaller than) to TIDESynEditor (in ide SourceSynEditor.pas)

using something like (this displays the procedure top hint)
     FTopInfoDisplay: TSourceLazSynTopInfoView;

That is reserving one line of the display for whatever you want it to be. It is some work though....

Or go the full 9 yards: Implement a top/bottom gutter (and submit it as patch).

In synedit, you have
     FPaintArea: TLazSynSurfaceManager;
   FPaintArea := TLazSynSurfaceManager.Create(Self);
   FPaintArea.TextArea := FTextArea;
   FPaintArea.LeftGutterArea := FLeftGutterArea;
   FPaintArea.RightGutterArea := FRightGutterArea;
   FPaintArea.DisplayView := FDisplayView;

So that allows to add top/bottom gutter, and reserve the space needed (set correct boundaries for all other elements.

Note there must be no gaps between them. Gaps will not be painted at all.

Just a note, about optimizing painting. purely optional.

On some widgetset, invalidate always is the minimum enclosure rectangle for all invalidated parts.

So invalidating a bit of text at the visible bottom of the editor paints this bit of text (actually the full line)

But invalidating a bit of text at the visible bottom AND a bit of text (or gutter) on the top, will paint ALL lines inbetween too.

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For that reason the overview gutter (which often invalidates on a different Y pos, than the rest of synEdit) creates a wincontrol of its own. This is a child to the SynEdit.

e.g. column 7 is on a punched card image.