public void insetContentRect(int deltaLeft, int deltaTop, int deltaRight, int deltaBottom) {
        contentRectMinusAxesMargins.left = contentRectMinusAxesMargins.left + deltaLeft;
        contentRectMinusAxesMargins.top = contentRectMinusAxesMargins.top + deltaTop;
        contentRectMinusAxesMargins.right = contentRectMinusAxesMargins.right - deltaRight;
        contentRectMinusAxesMargins.bottom = contentRectMinusAxesMargins.bottom - deltaBottom;

        insetContentRectByInternalMargins(deltaLeft, deltaTop, deltaRight, deltaBottom);
    }
Calculates available width and height. Should be called when chart dimensions change. ContentRect is relative to
chart view not the device's screen.
hellocharts-library/src/lecho/lib/hellocharts/computator/ChartComputator.java