Hack: inset the selection highlight by 3 in the main view

This makes it possible to see what lines delta renders as red or green.

It's not pretty, but makes testing easier for now. Needs a better
solution eventually.

pkg/gocui/view.go

@@ -156,6 +156,8 @@ type View struct {
 	// instead of Sel{Bg,Fg}Colors for highlighting selected lines.
 	HighlightInactive bool
 
+	HighlightInset int
+
 	// If Frame is true, a border will be drawn around the view.
 	Frame bool
 
@@ -674,7 +676,8 @@ func (v *View) setCharacter(x, y int, ch string, fgColor, bgColor Attribute) {
 			rangeSelectEnd = max(relativeRangeSelectStart, v.cy)
 		}
 
-		if y >= rangeSelectStart && y <= rangeSelectEnd {
+		inset := v.HighlightInset
+		if y >= rangeSelectStart && y <= rangeSelectEnd && x >= inset && x < v.InnerWidth()-inset {
 			// this ensures we use the bright variant of a colour upon highlight
 			fgColorComponent := fgColor & ^AttrAll
 			if fgColorComponent >= AttrIsValidColor && fgColorComponent < AttrIsValidColor+8 {

pkg/gui/views.go

@@ -106,6 +106,9 @@ func (gui *Gui) createAllViews() error {
 		view.AutoRenderHyperLinks = true
 	}
 
+	gui.Views.Main.HighlightInset = 3
+	gui.Views.Secondary.HighlightInset = 3
+
 	gui.Views.Staging.Wrap = true
 	gui.Views.StagingSecondary.Wrap = true
 	gui.Views.PatchBuilding.Wrap = true