From 00f96aae769be244ea5f14811d58d8adddf587f7 Mon Sep 17 00:00:00 2001
From: Junegunn Choi <junegunn.c@gmail.com>
Date: Wed, 21 Sep 2016 01:23:41 +0900
Subject: Avoid rendering delay when displaying extremely long lines

Related #666
---
 src/terminal.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/terminal.go b/src/terminal.go
index c036117e..0e9436a7 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -401,6 +401,8 @@ func displayWidth(runes []rune) int {
 const (
 	minWidth  = 16
 	minHeight = 4
+
+	maxDisplayWidthCalc = 1024
 )
 
 func calculateSize(base int, size sizeSpec, margin int, minSize int) int {
@@ -651,6 +653,11 @@ func displayWidthWithLimit(runes []rune, prefixWidth int, limit int) int {
 }
 
 func trimLeft(runes []rune, width int) ([]rune, int32) {
+	if len(runes) > maxDisplayWidthCalc && len(runes) > width {
+		trimmed := len(runes) - width
+		return runes[trimmed:], int32(trimmed)
+	}
+
 	currentWidth := displayWidth(runes)
 	var trimmed int32
 
-- 
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