From 49c84dc6bb393f742e1077434f7ba8c312e0452e Mon Sep 17 00:00:00 2001
From: Michael Hanselmann <public@hansmi.ch>
Date: Tue, 14 Dec 2021 21:43:12 +0100
Subject: [PATCH] waveshare213v2: Avoid allocating for every row when drawing

Reuse the slice instead.
---
 waveshare2in13v2/waveshare213v2.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/waveshare2in13v2/waveshare213v2.go b/waveshare2in13v2/waveshare213v2.go
index 0afff2e..c95af24 100644
--- a/waveshare2in13v2/waveshare213v2.go
+++ b/waveshare2in13v2/waveshare213v2.go
@@ -340,11 +340,12 @@ func (d *Dev) sendImage(cmd byte, dstRect image.Rectangle, src *image1bit.Vertic
 	eh.sendCommand(cmd)
 
 	rows, cols := dataDimensions(d.opts)
+	data := make([]byte, cols)
 
 	for y := 0; y < rows; y++ {
-		data := make([]byte, cols)
-
 		for x := 0; x < cols; x++ {
+			data[x] = 0
+
 			for bit := 0; bit < 8; bit++ {
 				if src.BitAt((x*8)+bit, y) {
 					data[x] |= 0x80 >> bit