CODEWITHSUNDEEP
android
developer
developer

Reputation: 87

Drawing a rectangle in center of the screen

please see the following code. I want draw a rectangle in center of the screen.But it draws a rectangle in the left corner.

protected  void onDraw(Canvas canvas) {
        paint.setColor(Color.GREEN);
        canvas.drawRect(getLeft()/2,getTop()/2,getRight()/2,getBottom()/2,paint);
        super.onDraw(canvas);
    }

Upvotes: 6

Views: 12889

Answers (5)

ibrokhim
ibrokhim

Reputation: 81

    var rectWidth = 200f
    var rectHeight = 300f

    val left = (width-rectWidth)/2
    val top = (height-rectHeight)/2
    val right = left+rectWidth
    val bottom = top+rectHeight

    canvas.drawRect(left, top, right, bottom, paint)

Upvotes: 0

Farman Ullah Marwat
Farman Ullah Marwat

Reputation: 19

Tested answer:

 override fun onDraw(canvas: Canvas?) {
        super.onDraw(canvas)
        val canvasCenter = PointF(width/2f,height/2f)
        val rectW = 300f
        val rectH = 300f
        val rect = RectF(canvasCenter.x - rectW,canvasCenter.y -rectH,
            canvasCenter.x + rectW,canvasCenter.y + rectH)
        canvas?.drawRect(rect,mPaintDest)
    }

Upvotes: 1

codencandy
codencandy

Reputation: 1721

  1. Find the center of the screen

    x = width / 2.0
y = height / 2.0

  2. Calculate the top left corner of your rect

    topX = x - (rectWidth / 2.0)
topY = y - (rectHeight / 2.0)

Upvotes: 4

Tronum
Tronum

Reputation: 717

Something like that? 

    protected void onDraw(Canvas canvas) {
        int canvasW = getWidth();
        int canvasH = getHeight();
        Point centerOfCanvas = new Point(canvasW / 2, canvasH / 2);
        int rectW = 100;
        int rectH = 100;
        int left = centerOfCanvas.x - (rectW / 2);
        int top = centerOfCanvas.y - (rectH / 2);
        int right = centerOfCanvas.x + (rectW / 2);
        int bottom = centerOfCanvas.y + (rectH / 2);
        Rect rect = new Rect(left, top, right, bottom);
        canvas.drawRect(rect, new Paint());
    }

Upvotes: 16

tomsv
tomsv

Reputation: 7277

Try this

protected  void onDraw(Canvas canvas) {
    paint.setColor(Color.GREEN);
    canvas.drawRect(
        getLeft()+(getRight()-getLeft())/3,
        getTop()+(getBottom()-getTop())/3,
        getRight()-(getRight()-getLeft())/3,
        getBottom()-(getBottom()-getTop())/3,paint);
    super.onDraw(canvas);
}

Upvotes: 7

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