code: private void calculateCircleOval() {
          Rect contentRect = computator.getContentRectMinusAllMargins();
          final float circleRadius = Math.min(contentRect.width() / 2f, contentRect.height() / 2f);
          final float centerX = contentRect.centerX();
          final float centerY = contentRect.centerY();
          final float left = centerX - circleRadius + touchAdditional;
          final float top = centerY - circleRadius + touchAdditional;
          final float right = centerX + circleRadius - touchAdditional;
          final float bottom = centerY + circleRadius - touchAdditional;
          originCircleOval.set(left, top, right, bottom);
          final float inest = 0.5f * originCircleOval.width() * (1.0f - circleFillRatio);
          originCircleOval.inset(inest, inest);
      }
docs: Calculates rectangle(square) that will constraint chart circle.