Add code for persistent exposure functionality

Author: MHShetty

app/src/main/java/app/grapheneos/camera/CamConfig.kt

@@ -105,6 +105,10 @@ class CamConfig(private val mActivity: MainActivity) {
 
             const val REMOVE_EXIF_AFTER_CAPTURE = "remove_exif_after_capture"
 
+            const val PERSIST_EXPOSURE_LEVEL = "persist_exposure_level"
+
+            const val EXPOSURE_LEVEL = "exposure_level"
+
             const val GYROSCOPE_SUGGESTIONS = "gyroscope_suggestions"
 
             const val CAMERA_SOUNDS = "camera_sounds"
@@ -150,6 +154,10 @@ class CamConfig(private val mActivity: MainActivity) {
 
             const val REMOVE_EXIF_AFTER_CAPTURE = true
 
+            const val PERSIST_EXPOSURE_LEVEL = false
+
+            const val EXPOSURE_LEVEL = 0
+
             const val GYROSCOPE_SUGGESTIONS = false
 
             const val CAMERA_SOUNDS = true
@@ -539,6 +547,50 @@ class CamConfig(private val mActivity: MainActivity) {
             editor.apply()
         }
 
+    var persistExposureLevel: Boolean
+        get() {
+            return commonPref.getBoolean(
+                SettingValues.Key.PERSIST_EXPOSURE_LEVEL,
+                SettingValues.Default.PERSIST_EXPOSURE_LEVEL
+            )
+        }
+        set(value) {
+            val editor = commonPref.edit()
+            editor.putBoolean(
+                SettingValues.Key.PERSIST_EXPOSURE_LEVEL,
+                value
+            )
+            editor.apply()
+        }
+
+    private val exposureLevelKey: String
+        get() {
+
+            val pf = if (lensFacing == CameraSelector.LENS_FACING_FRONT) {
+                "FRONT"
+            } else {
+                "BACK"
+            }
+
+            return "${SettingValues.Key.EXPOSURE_LEVEL}_$pf"
+        }
+
+    var exposureLevel: Int
+        get() {
+            return modePref.getInt(
+                exposureLevelKey,
+                SettingValues.Default.EXPOSURE_LEVEL,
+            )
+        }
+        set(value) {
+            val editor = modePref.edit()
+            editor.putInt(
+                exposureLevelKey,
+                value
+            )
+            editor.apply()
+        }
+
     var gSuggestions: Boolean
         get() {
             return commonPref.getBoolean(
@@ -1262,6 +1314,10 @@ class CamConfig(private val mActivity: MainActivity) {
 
         mActivity.zoomBar.updateThumb(false)
 
+        if (persistExposureLevel) {
+            camera?.cameraControl?.setExposureCompensationIndex(exposureLevel)
+        }
+
         camera?.cameraInfo?.exposureState?.let { mActivity.exposureBar.setExposureConfig(it) }
 
         mActivity.settingsDialog.torchToggle.isChecked = false

app/src/main/java/app/grapheneos/camera/ui/seekbar/ExposureBar.kt

@@ -46,12 +46,7 @@ class ExposureBar : AppCompatSeekBar {
         max = exposureState.exposureCompensationRange.upper
         min = exposureState.exposureCompensationRange.lower
 
-        incrementProgressBy(exposureState.exposureCompensationIndex)
-
-        Log.i("TAG", "Setting progress from setExposureConfig")
-        progress = (exposureState.exposureCompensationStep.numerator
-                / exposureState.exposureCompensationStep.denominator) *
-                exposureState.exposureCompensationIndex
+        progress = exposureState.exposureCompensationIndex
 
         onSizeChanged(width, height, 0, 0)
     }
@@ -109,11 +104,10 @@ class ExposureBar : AppCompatSeekBar {
             MotionEvent.ACTION_DOWN, MotionEvent.ACTION_MOVE, MotionEvent.ACTION_UP -> {
                 progress = max - (max * event.y / (height / 2)).toInt()
 
-                Log.i("progress", progress.toString())
-                Log.i("max", max.toString())
+                Log.d("progress", progress.toString())
+                Log.d("max", max.toString())
 
-                mainActivity.camConfig.camera?.cameraControl
-                    ?.setExposureCompensationIndex(progress)
+                updateExposureCompensationIndex(progress)
 
                 showPanel()
 
@@ -124,4 +118,13 @@ class ExposureBar : AppCompatSeekBar {
         }
         return true
     }
+
+    private fun updateExposureCompensationIndex(exposureCompensationIndex: Int) {
+        mainActivity.camConfig.camera?.cameraControl
+            ?.setExposureCompensationIndex(progress)
+
+        if (mainActivity.camConfig.persistExposureLevel) {
+            mainActivity.camConfig.exposureLevel = exposureCompensationIndex
+        }
+    }
 }