lineagehw: Introduce Reader mode backend

Currently just makes everything grayscale.
Might be expanded in the future.

Change-Id: I4b04c9050b9b465c9feb3b1d41b38bd2179dcf3b

1 files changed, 93 insertions, 0 deletions

diff --git a/src/org/lineageos/hardware/ReadingEnhancement.java b/src/org/lineageos/hardware/ReadingEnhancement.java
new file mode 100644
index 0000000..90839e9
--- /dev/null
+++ b/src/org/lineageos/hardware/ReadingEnhancement.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2018 The LineageOS Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.lineageos.hardware;
+
+import android.app.ActivityThread;
+import android.os.IBinder;
+import android.os.Parcel;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.util.Slog;
+
+import com.android.server.LocalServices;
+import com.android.server.display.DisplayTransformManager;
+import static com.android.server.display.DisplayTransformManager.LEVEL_COLOR_MATRIX_GRAYSCALE;
+
+import org.lineageos.internal.util.FileUtils;
+
+/**
+ * Reader mode
+ */
+public class ReadingEnhancement {
+
+    private static final String TAG = "ReadingEnhancement";
+
+    private static final int LEVEL_COLOR_MATRIX_READING = LEVEL_COLOR_MATRIX_GRAYSCALE + 1;
+
+    private static final int MODE_UNSUPPORTED          = 0;
+    private static final int MODE_HWC2_COLOR_TRANSFORM = 1;
+
+    private static final int sMode;
+
+    /**
+     * Matrix and offset used for converting color to grayscale.
+     * Copied from com.android.server.accessibility.DisplayAdjustmentUtils.MATRIX_GRAYSCALE
+     */
+    private static final float[] MATRIX_GRAYSCALE = new float[] {
+        .2126f, .2126f, .2126f, 0,
+        .7152f, .7152f, .7152f, 0,
+        .0722f, .0722f, .0722f, 0,
+             0,      0,      0, 1
+    };
+
+    /** Full color matrix and offset */
+    private static final float[] MATRIX_NORMAL = new float[] {
+        1, 0, 0, 0,
+        0, 1, 0, 0,
+        0, 0, 1, 0,
+        0, 0, 0, 1
+    };
+
+    private static DisplayTransformManager sDTMService;
+
+    static {
+        // Determine mode of operation.
+        if (ActivityThread.currentApplication().getApplicationContext().getResources().getBoolean(
+                    com.android.internal.R.bool.config_setColorTransformAccelerated)) {
+            sMode = MODE_HWC2_COLOR_TRANSFORM;
+        } else {
+            sMode = MODE_UNSUPPORTED;
+        }
+    }
+
+    public static boolean isSupported() {
+        return sMode != MODE_UNSUPPORTED;
+    }
+
+    public static boolean setGrayscale(boolean state) {
+        if (sDTMService == null) {
+            sDTMService = LocalServices.getService(DisplayTransformManager.class);
+            if (sDTMService == null) {
+                return false;
+            }
+        }
+        sDTMService.setColorMatrix(LEVEL_COLOR_MATRIX_READING,
+                state ? MATRIX_GRAYSCALE : MATRIX_NORMAL);
+        return true;
+    }
+
+}