Method bufferSignal

texteditor/editor.go:394–436

bufferSignal receives a signal from the Buffer when the underlying text is changed.

(sig bufferSignals, tbe *text.Edit)

// bufferSignal receives a signal from the Buffer when the underlying text
// is changed.
func (ed *Editor) bufferSignal(sig bufferSignals, tbe *text.Edit) {
	switch sig {
	case bufferDone:
	case bufferNew:
		ed.resetState()
		ed.SetCursorShow(ed.CursorPos)
		ed.NeedsLayout()
	case bufferMods:
		ed.NeedsLayout()
	case bufferInsert:
		if ed == nil || ed.This == nil || !ed.IsVisible() {
			return
		}
		ndup := ed.renders == nil
		// fmt.Printf("ed %v got %v\n", ed.Nm, tbe.Reg.Start)
		if tbe.Reg.Start.Ln != tbe.Reg.End.Ln {
			// fmt.Printf("ed %v lines insert %v - %v\n", ed.Nm, tbe.Reg.Start, tbe.Reg.End)
			ed.linesInserted(tbe) // triggers full layout
		} else {
			ed.layoutLine(tbe.Reg.Start.Ln) // triggers layout if line width exceeds
		}
		if ndup {
			ed.Update()
		}
	case bufferDelete:
		if ed == nil || ed.This == nil || !ed.IsVisible() {
			return
		}
		ndup := ed.renders == nil
		if tbe.Reg.Start.Ln != tbe.Reg.End.Ln {
			ed.linesDeleted(tbe) // triggers full layout
		} else {
			ed.layoutLine(tbe.Reg.Start.Ln)
		}
		if ndup {
			ed.Update()
		}
	case bufferMarkupUpdated:
		ed.NeedsLayout() // comes from another goroutine
	case bufferClosed:
		ed.SetBuffer(nil)
	}
}

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//    Undo / Redo