adding AutoFitTextuewView from the Camera2 sample

app/src/main/kotlin/com/simplemobiletools/camera/views/AutoFitTextureView.kt

@@ -0,0 +1,39 @@
+package com.simplemobiletools.camera.views
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.TextureView
+import android.view.View
+
+// taken from the official Camera2 sample at https://github.com/googlesamples/android-Camera2Basic
+class AutoFitTextureView @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyle: Int = 0) : TextureView(context, attrs, defStyle) {
+
+    private var mRatioWidth = 0
+    private var mRatioHeight = 0
+
+    fun setAspectRatio(width: Int, height: Int) {
+        if (width < 0 || height < 0) {
+            throw IllegalArgumentException("Size cannot be negative.")
+        }
+
+        mRatioWidth = width
+        mRatioHeight = height
+        requestLayout()
+    }
+
+    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
+        val width = View.MeasureSpec.getSize(widthMeasureSpec)
+        val height = View.MeasureSpec.getSize(heightMeasureSpec)
+
+        if (mRatioWidth == 0 || mRatioHeight == 0) {
+            setMeasuredDimension(width, height)
+        } else {
+            if (width < height * mRatioWidth / mRatioHeight) {
+                setMeasuredDimension(width, width * mRatioHeight / mRatioWidth)
+            } else {
+                setMeasuredDimension(height * mRatioWidth / mRatioHeight, height)
+            }
+        }
+    }
+}