From d095a6554cd87cbdf5e1bdc05b41c4626403043d Mon Sep 17 00:00:00 2001
From: Christian Rocha <christian@rocha.is>
Date: Thu, 18 Jun 2020 18:25:57 -0400
Subject: [PATCH] Retire the internal viewport renderer

---
 viewport/renderer.go | 101 -------------------------------------------
 1 file changed, 101 deletions(-)
 delete mode 100644 viewport/renderer.go

diff --git a/viewport/renderer.go b/viewport/renderer.go
deleted file mode 100644
index 594ce3f..0000000
--- a/viewport/renderer.go
+++ /dev/null
@@ -1,101 +0,0 @@
-package viewport
-
-import (
-	"bytes"
-	"fmt"
-	"io"
-	"strings"
-
-	te "github.com/muesli/termenv"
-)
-
-type renderer struct {
-	// Out is the io.Writer to which we should render. Generally, this will
-	// be stdout.
-	Out io.Writer
-
-	// Y is the vertical offset of the rendered area in relation to the
-	// terminal window.
-	Y int
-
-	// Height is the number of rows to render.
-	Height int
-
-	// TerminalHeight is the total height of the terminal.
-	TerminalHeight int
-}
-
-// clear clears the viewport region.
-func (r *renderer) clear() {
-	buf := new(bytes.Buffer)
-	moveTo(buf, r.Y, 0)
-	for i := 0; i < r.Height; i++ {
-		clearLine(buf)
-		cursorDown(buf, 1)
-	}
-	r.Out.Write(buf.Bytes())
-}
-
-// sync paints the whole area.
-func (r *renderer) sync(lines []string) {
-	r.clear()
-	moveTo(r.Out, r.Y, 0)
-	r.writeLines(lines)
-}
-
-// write writes to the set writer.
-func (r *renderer) writeLines(lines []string) {
-	if len(lines) == 0 {
-		return
-	}
-	io.WriteString(r.Out, strings.Join(lines, "\r\n"))
-}
-
-// Effectively scroll up. That is, insert a line at the top, pushing
-// everything else down. This is roughly how ncurses does it.
-func (r *renderer) insertTop(lines []string) {
-	changeScrollingRegion(r.Out, r.Y, r.Y+r.Height)
-	moveTo(r.Out, r.Y, 0)
-	insertLine(r.Out, len(lines))
-	r.writeLines(lines)
-	changeScrollingRegion(r.Out, 0, r.TerminalHeight)
-}
-
-// Effectively scroll down. That is, insert a line at the bottom, pushing
-// everything else up. This is roughly how ncurses does it.
-func (r *renderer) insertBottom(lines []string) {
-	changeScrollingRegion(r.Out, r.Y, r.Y+r.Height)
-	moveTo(r.Out, r.Y+r.Height, 0)
-	io.WriteString(r.Out, "\r\n"+strings.Join(lines, "\r\n"))
-	changeScrollingRegion(r.Out, 0, r.TerminalHeight)
-}
-
-// Terminal Control
-
-func changeScrollingRegion(w io.Writer, top, bottom int) {
-	fmt.Fprintf(w, te.CSI+"%d;%dr", top, bottom)
-}
-
-func moveTo(w io.Writer, row, col int) {
-	fmt.Fprintf(w, te.CSI+te.CursorPositionSeq, row, col)
-}
-
-func cursorDown(w io.Writer, numLines int) {
-	fmt.Fprintf(w, te.CSI+te.CursorDownSeq, numLines)
-}
-
-func clearLine(w io.Writer) {
-	fmt.Fprintf(w, te.CSI+te.EraseLineSeq, 2)
-}
-
-func insertLine(w io.Writer, numLines int) {
-	fmt.Fprintf(w, te.CSI+"%dL", numLines)
-}
-
-func saveCursorPosition(w io.Writer) {
-	fmt.Fprint(w, te.CSI+"s")
-}
-
-func restoreCursorPosition(w io.Writer) {
-	fmt.Fprint(w, te.CSI+"u")
-}