How to draw a rectangle on the screen using coordinates with texture view?

Question

I am previewing camera feed to texture view using cameraX. How to draw a rectangle on the screen using coordinates that i have? I don't want a complex function. I simply want to draw a rectangle. I am using kotlin and android studio 4.0.

Answer 1

I would go for an ImageView overlapping on top of the Textureview at the same xml. This imageview will load a transparent bitmap that will have only the rectangle drawn. If you have the coordinates u have to do:

val myRectPaint = Paint()
myRectPaint.strokeWidth = 5F
myRectPaint.color = Color.RED
myRectPaint.style = Paint.Style.STROKE

// Create a Canvas object for drawing on the original bitmap provided
val tempBitmap =
    Bitmap.createBitmap(bitmap!!.width, bitmap.height, Bitmap.Config.ARGB_8888)
val tempCanvas = Canvas(tempBitmap)
tempCanvas.drawBitmap(bitmap, 0F, 0F, null)

tempCanvas.drawRoundRect(
            RectF(x1.toFloat(), y1.toFloat(), x2.toFloat(), y2.toFloat()),
            2f,
            2f,
            myRectPaint
        )

// Use this to widen picture on top or bottom
    val croppedFaceBitmap =
        Bitmap.createBitmap(tempBitmap, x1, y1, x2, y2)

In any case you can also follow this example from tensorflow github where round boxes are drawn when object is detected.

Hope I helped