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

package com.simplemobiletools.camera.views

import android.content.Context
import android.util.AttributeSet
import android.view.TextureView

// 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 = MeasureSpec.getSize(widthMeasureSpec)
        val height = 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)
            }
        }
    }
}