Merge pull request android#530 from jsaund/camera2extensions_add_zoom_and_focus_support

Camera2extensions add zoom and focus support

Author: donovanfm

Camera2Extensions/app/build.gradle

@@ -20,12 +20,12 @@ apply plugin: 'kotlin-kapt'
 apply plugin: "androidx.navigation.safeargs"
 
 android {
-    compileSdkVersion 'android-31'
+    compileSdkVersion 'android-33'
     defaultConfig {
         testInstrumentationRunner kotlin_version
         applicationId "com.android.example.camera2.extensions"
         minSdkVersion 31
-        targetSdkVersion 31
+        targetSdkVersion 33
         versionCode 1
         versionName "1.0.0"
     }

Camera2Extensions/app/src/main/java/com/example/android/camera2/extensions/ZoomUtil.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2023 The Android Open Source 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 com.example.android.camera2.extensions
+
+import android.graphics.Rect
+import android.hardware.camera2.CameraCharacteristics
+
+object ZoomUtil {
+
+    fun minZoom() = 1.0f
+
+    fun maxZoom(characteristics: CameraCharacteristics): Float {
+        val maxZoom = characteristics.get(CameraCharacteristics.SCALER_AVAILABLE_MAX_DIGITAL_ZOOM)
+            ?: return minZoom()
+
+        if (maxZoom < minZoom()) return minZoom()
+
+        return maxZoom
+    }
+
+    fun getZoomCropRect(zoomRatio: Float, characteristics: CameraCharacteristics): Rect {
+        val sensorRect = sensorRect(characteristics)
+        return cropRectByRatio(zoomRatio, sensorRect)
+    }
+
+    private fun cropRectByRatio(zoomRatio: Float, sensorRect: Rect): Rect {
+        val cropWidth = sensorRect.width() / zoomRatio
+        val cropHeight = sensorRect.height() / zoomRatio
+
+        val left = (sensorRect.width() - cropWidth) / 2.0f
+        val top = (sensorRect.height() - cropHeight) / 2.0f
+
+        return Rect(
+            left.toInt(),
+            top.toInt(),
+            (left + cropWidth).toInt(),
+            (top + cropHeight).toInt()
+        )
+    }
+
+    private fun sensorRect(characteristics: CameraCharacteristics): Rect =
+        characteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE)!!
+}