From cbc0ff435fa99230ba950117fbed683d58e91b7e Mon Sep 17 00:00:00 2001
From: Markus Fisch <markus.fisch@kurzdigital.com>
Date: Sun, 3 Sep 2017 12:26:49 +0200
Subject: [PATCH] Invert every second frame

Forgot to invert every second frame to also read inverted
barcodes while simplifying image processing.
---
 .../de/markusfisch/android/binaryeye/rs/YuvToGray.kt   | 10 +++++++++-
 app/src/main/rs/yuv2gray.rs                            | 10 ++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/app/src/main/kotlin/de/markusfisch/android/binaryeye/rs/YuvToGray.kt b/app/src/main/kotlin/de/markusfisch/android/binaryeye/rs/YuvToGray.kt
index 5092292c..5c3f7472 100644
--- a/app/src/main/kotlin/de/markusfisch/android/binaryeye/rs/YuvToGray.kt
+++ b/app/src/main/kotlin/de/markusfisch/android/binaryeye/rs/YuvToGray.kt
@@ -21,6 +21,7 @@ class YuvToGray(context: Context) {
 	private var rgbaAlloc: Allocation? = null
 	private var destAlloc: Allocation? = null
 	private var dest: Bitmap? = null
+	private var odd = true
 
 	fun destroy() {
 		yuvType?.destroy()
@@ -76,7 +77,14 @@ class YuvToGray(context: Context) {
 		// width/height are uint_32 but Kotlin wants toLong()
 		yuv2grayScript._inWidth = width.toLong()
 		yuv2grayScript._inHeight = height.toLong()
-		yuv2grayScript.forEach_yuv2gray(rgbaAlloc)
+
+		// invert every second frame to also read inverted barcodes
+		if (odd) {
+			yuv2grayScript.forEach_yuv2gray(rgbaAlloc)
+		} else {
+			yuv2grayScript.forEach_yuv2inverted(rgbaAlloc)
+		}
+		odd = odd xor true
 
 		rotatorScript._inImage = rgbaAlloc
 		rotatorScript._inWidth = width
diff --git a/app/src/main/rs/yuv2gray.rs b/app/src/main/rs/yuv2gray.rs
index 8cca4cc9..a8c33d2f 100644
--- a/app/src/main/rs/yuv2gray.rs
+++ b/app/src/main/rs/yuv2gray.rs
@@ -15,3 +15,13 @@ uchar4 RS_KERNEL yuv2gray(uint32_t x, uint32_t y) {
 	out.a = 255;
 	return out;
 }
+
+uchar4 RS_KERNEL yuv2inverted(uint32_t x, uint32_t y) {
+	uchar Y = 255 - rsGetElementAt_uchar(inYUV, x, y);
+	uchar4 out;
+	out.r = Y;
+	out.g = Y;
+	out.b = Y;
+	out.a = 255;
+	return out;
+}