public void setViewportTopLeft(float left, float top) {
        /**
         * Constrains within the scroll range. The scroll range is simply the viewport extremes (AXIS_X_MAX,
         * etc.) minus
         * the viewport size. For example, if the extrema were 0 and 10, and the viewport size was 2, the scroll range
         * would be 0 to 8.
         */

        final float curWidth = currentViewport.width();
        final float curHeight = currentViewport.height();

        left = Math.max(maxViewport.left, Math.min(left, maxViewport.right - curWidth));
        top = Math.max(maxViewport.bottom + curHeight, Math.min(top, maxViewport.top));
        constrainViewport(left, top, left + curWidth, top - curHeight);
    }
Sets the current viewport (defined by {@link #currentViewport}) to the given X and Y positions.
hellocharts-library/src/lecho/lib/hellocharts/computator/ChartComputator.java