From 96d75b3c03e0bf47b19f170b7921695bc5937132 Mon Sep 17 00:00:00 2001
From: Christoph Reiter <reiter.christoph@gmail.com>
Date: Wed, 21 Oct 2020 13:14:37 +0200
Subject: [PATCH] Only extract the image data when we need it
---
packages/qr-code-scanner/src/qr-code-scanner.js | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/packages/qr-code-scanner/src/qr-code-scanner.js b/packages/qr-code-scanner/src/qr-code-scanner.js
index 28b9d15f..9b91aa2f 100644
--- a/packages/qr-code-scanner/src/qr-code-scanner.js
+++ b/packages/qr-code-scanner/src/qr-code-scanner.js
@@ -259,11 +259,10 @@ export class QrCodeScanner extends ScopedElementsMixin(DBPLitElement) {
canvasElement.width = video.videoWidth;
canvas.drawImage(video, 0, 0, canvasElement.width, canvasElement.height);
- let maskWidth = 0;
- let maskHeight = 0;
- let maskStartX = canvasElement.width;
- let maskStartY = canvasElement.height;
- let imageData;
+ let maskWidth = canvasElement.width;
+ let maskHeight = canvasElement.height;
+ let maskStartX = 0;
+ let maskStartY = 0;
if (that.clipMask) {
//draw mask
@@ -299,10 +298,6 @@ export class QrCodeScanner extends ScopedElementsMixin(DBPLitElement) {
canvas.rect(maskStartX + clip - 10, maskStartY + clip/3*2, 10, clip/3);
canvas.fill();
-
- imageData = canvas.getImageData(maskStartX , maskStartY, maskWidth, maskHeight);
- } else {
- imageData = canvas.getImageData(0 , 0, canvasElement.width, canvasElement.height);
}
let code = null;
@@ -310,6 +305,7 @@ export class QrCodeScanner extends ScopedElementsMixin(DBPLitElement) {
let shouldAnalyze = Math.abs(lastVideoScanTime - video.currentTime) >= 1/3;
if (shouldAnalyze) {
lastVideoScanTime = video.currentTime;
+ let imageData = canvas.getImageData(maskStartX, maskStartY, maskWidth, maskHeight);
code = jsQR(imageData.data, imageData.width, imageData.height, {
inversionAttempts: "dontInvert",
});
--
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