Smrf.NodeXL.Visualization.Wpf.EdgeDrawer.DrawLabel C# (CSharp) Method

    DrawLabel
    (
        IEdge oEdge,
        DrawingContext oDrawingContext,
        GraphDrawingContext oGraphDrawingContext,
        Boolean bDrawAsSelected,
        Color oEdgeColor,
        VisibilityKeyValue eVisibility,
        Point oEdgeEndpoint1,
        Point oEdgeEndpoint2,
        PathGeometry oBezierCurve,
        Point oBezierControlPoint,
        String sLabel
    )
    {
        Debug.Assert(oEdge != null);
        Debug.Assert(oDrawingContext != null);
        Debug.Assert(oGraphDrawingContext != null);
        Debug.Assert(sLabel != null);
        AssertValid();

        if (sLabel.Length == 0)
        {
            return;
        }

        sLabel = TruncateLabel(sLabel);

        Double dFontSize = GetLabelFontSize(oEdge);

        Color oLabelTextColor = GetLabelTextColor(oEdge, bDrawAsSelected,
            oEdgeColor, eVisibility);

        FormattedText oFormattedText =
            m_oFormattedTextManager.CreateFormattedText(sLabel,
                oLabelTextColor, dFontSize, m_dGraphScale);

        oFormattedText.Trimming = TextTrimming.CharacterEllipsis;

        // Don't let the FormattedText class break long lines when drawing
        // Bezier curves.  DrawBezierLabel(), which draws the label
        // character-by-character, is unable to tell where such line breaks
        // occur, because FormattedText doesn't expose this information.
        //
        // For consistency, do the same when drawing straight edges.

        oFormattedText.MaxLineCount = sLabel.Count(c => c == '\n') + 1;

        // The ends of the label text are between one and two "buffer units"
        // from the ends of the edge.  The buffer unit is the width of an
        // arbitrary character.

        Double dBufferWidth =
            m_oFormattedTextManager.CreateFormattedText("i", oLabelTextColor,
                dFontSize, m_dGraphScale).Width;

        Double dEdgeLength = WpfGraphicsUtil.GetDistanceBetweenPoints(
            oEdgeEndpoint1, oEdgeEndpoint2);

        Double dEdgeLengthMinusBuffers = dEdgeLength - 2 * dBufferWidth;

        if (dEdgeLengthMinusBuffers <= 0)
        {
            return;
        }

        // Determine where to draw the label text.

        Double dTextWidth = oFormattedText.Width;
        Double dLabelOriginAsFractionOfEdgeLength;

        if (dTextWidth > dEdgeLengthMinusBuffers)
        {
            // The label text should start one buffer unit from the first
            // endpoint, and terminate with ellipses approximately one buffer
            // length from the second endpoint.

            dLabelOriginAsFractionOfEdgeLength = dBufferWidth / dEdgeLength;

            oFormattedText.MaxTextWidth = dEdgeLengthMinusBuffers;
        }
        else
        {
            // The label should be centered along the edge's length.

            dLabelOriginAsFractionOfEdgeLength = 
                ( (dEdgeLength - dTextWidth) / 2.0 ) / dEdgeLength;
        }

        // Note: Don't make the translucent rectangle any more opaque than the
        // edge, which might be translucent itself.

        Color oTranslucentRectangleColor = WpfGraphicsUtil.SetWpfColorAlpha(
            oGraphDrawingContext.BackColor,
            Math.Min(LabelBackgroundAlpha, oEdgeColor.A)
            );

        if (this.ShouldDrawBezierCurve)
        {
            DrawBezierLabel(oDrawingContext, oGraphDrawingContext,
                oFormattedText, oEdgeEndpoint1, oEdgeEndpoint2, oBezierCurve,
                dLabelOriginAsFractionOfEdgeLength, dEdgeLength,
                dBufferWidth, oLabelTextColor, oTranslucentRectangleColor,
                dFontSize);
        }
        else
        {
            DrawStraightLabel(oDrawingContext, oGraphDrawingContext,
                oFormattedText, oEdgeEndpoint1, oEdgeEndpoint2,
                dLabelOriginAsFractionOfEdgeLength, dEdgeLength, dBufferWidth,
                oTranslucentRectangleColor);
        }
    }