From cd779b678ac5848e906ed2fa59d88e5c7216dba1 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 3 Nov 2020 20:35:55 +0900
Subject: [PATCH] text: Add comments

---
 text/text.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/text/text.go b/text/text.go
index 4691d7377..95c06b5f3 100644
--- a/text/text.go
+++ b/text/text.go
@@ -291,6 +291,8 @@ func BoundString(face font.Face, text string) image.Rectangle {
 // cache and render it for each rune. This is very inefficient because creating a glyph image and rendering it are
 // different operations and can never be merged as one draw call. CacheGlyphs creates necessary glyphs without
 // rendering them so that these operations are likely merged into one draw call.
+//
+// If a rune's glyph is already cached, CacheGlyphs does nothing for the rune.
 func CacheGlyphs(face font.Face, text string) {
 	textM.Lock()
 	defer textM.Unlock()