Smrf.NodeXL.Visualization.Wpf.VertexLabelDrawer.AdjustForTextAlignment C# (CSharp) Method

    AdjustForTextAlignment
    (
        Double dLabelWidth,
        Double dLabelHeight,
        VertexLabelPosition eLabelPosition,
        FormattedText oFormattedText,
        ref Double dDrawX,
        ref Double dDrawY,
        ref Double dLabelBoundsLeft,
        ref Double dLabelBoundsRight
    )
    {
        Debug.Assert(dLabelWidth >= 0);
        Debug.Assert(dLabelHeight >= 0);
        Debug.Assert(oFormattedText != null);
        AssertValid();

        Double dHalfLabelHeight = dLabelHeight / 2.0;
        Double dHalfLabelWidth = dLabelWidth / 2.0;
        Double dMaxTextWidth = oFormattedText.MaxTextWidth;
        Double dHalfMaxTextWidth = dMaxTextWidth / 2.0;

        // This is the adjustment that needs to be made to the x-coordinate
        // passed to DrawingContext.DrawText() to compensate for the way
        // centered and right-justified text is positioned.
        //
        // When wrapping is turned off (FormattedText.MaxTextWidth = 0) and
        // FormattedText.TextAlignment = TextAlignment.Center, for example,
        // the text gets centered horizontally at the specified drawing point.
        // When wrapping is turned on, however (FormattedText.MaxTextWidth
        // > 0), the text gets centered horizontally at the point halfway
        // between the specified drawing point and the MaxTextWidth value.

        Double dAdjustmentForTextAlignmentX = 0;

        switch (eLabelPosition)
        {
            case VertexLabelPosition.TopLeft:

                dAdjustmentForTextAlignmentX = -dMaxTextWidth;
                dDrawY -= (dLabelHeight + VerticalMargin);
                dLabelBoundsLeft = dDrawX - dLabelWidth;
                dLabelBoundsRight = dDrawX;

                break;

            case VertexLabelPosition.TopCenter:

                dAdjustmentForTextAlignmentX = -dHalfMaxTextWidth;
                dDrawY -= (dLabelHeight + VerticalMargin);
                dLabelBoundsLeft = dDrawX - dHalfLabelWidth;
                dLabelBoundsRight = dDrawX + dHalfLabelWidth;

                break;

            case VertexLabelPosition.TopRight:

                dDrawY -= (dLabelHeight + VerticalMargin);
                dLabelBoundsLeft = dDrawX;
                dLabelBoundsRight = dDrawX + dLabelWidth;

                break;

            case VertexLabelPosition.MiddleLeft:

                dAdjustmentForTextAlignmentX = -dMaxTextWidth;
                dDrawX -= HorizontalMargin;
                dDrawY -= dHalfLabelHeight;
                dLabelBoundsLeft = dDrawX - dLabelWidth;
                dLabelBoundsRight = dDrawX;

                break;

            case VertexLabelPosition.MiddleCenter:

                dAdjustmentForTextAlignmentX = -dHalfMaxTextWidth;
                dDrawY -= dHalfLabelHeight;
                dLabelBoundsLeft = dDrawX - dHalfLabelWidth;
                dLabelBoundsRight = dDrawX + dHalfLabelWidth;

                break;

            case VertexLabelPosition.MiddleRight:

                dDrawX += HorizontalMargin;
                dDrawY -= dHalfLabelHeight;
                dLabelBoundsLeft = dDrawX;
                dLabelBoundsRight = dDrawX + dLabelWidth;

                break;

            case VertexLabelPosition.BottomLeft:

                dAdjustmentForTextAlignmentX = -dMaxTextWidth;
                dDrawY += VerticalMargin;
                dLabelBoundsLeft = dDrawX - dLabelWidth;
                dLabelBoundsRight = dDrawX;

                break;

            case VertexLabelPosition.BottomCenter:

                dAdjustmentForTextAlignmentX = -dHalfMaxTextWidth;
                dDrawY += VerticalMargin;
                dLabelBoundsLeft = dDrawX - dHalfLabelWidth;
                dLabelBoundsRight = dDrawX + dHalfLabelWidth;

                break;

            case VertexLabelPosition.BottomRight:

                dDrawY += VerticalMargin;
                dLabelBoundsLeft = dDrawX;
                dLabelBoundsRight = dDrawX + dLabelWidth;

                break;

            case VertexLabelPosition.Nowhere:

                // (This was handled at the top of the method.)

            default:

                Debug.Assert(false);
                break;
        }

        dDrawX += dAdjustmentForTextAlignmentX;
    }