Hello,

I need to custom draw the cells of my table nodes.
The problem I encounter is related (I think) with the Diagram.PageUnit which is set to the default millimeter in my app. And I want in my custom draw cell event handler to draw a line by 1 pixel width:

e.Graphics.DrawLine(new Pen(e.Table.Pen.Color),
                   new PointF(e.Bounds.Left, e.Bounds.Bottom), new PointF(e.Bounds.Right, e.Bounds.Bottom));
 

But the drawn line appears to be 3 pixels wide. That's I abelive because the diagram has its PageUnit set to millimeter. A I can't change the diagram PageUnit (all distances are already set in code using millimeters), how can I draw 1 pixel wide lines here?

I've tried the following but the the lines were not properly positioned inside the table:

                e.Graphics.PageUnit = GraphicsUnit.Pixel;

                float DpmX = e.Graphics.DpiX / MM_PER_INCH;
                float DpmY = e.Graphics.DpiY / MM_PER_INCH;

                float boundsLeftDots = e.Bounds.Left * DpmX;
                float boundsRightDots = e.Bounds.Right * DpmX;
                float boundsBottomDots = e.Bounds.Bottom * DpmY;

                e.Graphics.DrawLine(new Pen(e.Table.Pen.Color),
                    new PointF(boundsLeftDots, boundsBottomDots - 1), new PointF(boundsRightDots, boundsBottomDots - 1));
                e.Graphics.DrawLine(new Pen(Color.White),
                    new PointF(boundsLeftDots, boundsBottomDots), new PointF(boundsRightDots, boundsBottomDots));

                e.Graphics.PageUnit = GraphicsUnit.Millimeter;
 

where

private const float MM_PER_INCH = 25.4F;
 

So, I've tried to convert all the dimensions from MM to pixels, draw the lines (I wand a shadow like border cell) and the return to the default PageUnit.
But it doesn't seems to work like this.

So, how can I draw in "pixel" mode in the custom draw event handler even the diagram's PageUnit is set to Millimeter?

Thanks,
Bogdan

Hi Stoyan,

I've set the pen width to 0, the line width is smaller indeed but there are still some artifacts, the lines are sometimes 1 pixel width, sometime 2 pixels and the color is not preserved between all lines drawn with the same color. And there is a strange space between the 2 lines that should consist the cell custom border.

 void Diagram_DrawCell(object sender, DrawCellEventArgs e)
        {
            Pen pen1 = new Pen(Color.Red, 0);
            Pen pen2 = new Pen(Color.Green, 0);

            e.Graphics.DrawLine(pen1,
                new PointF(e.Bounds.Left, e.Bounds.Bottom - 1), new PointF(e.Bounds.Right, e.Bounds.Bottom - 1));

            e.Graphics.DrawLine(pen2,
                new PointF(e.Bounds.Left, e.Bounds.Bottom), new PointF(e.Bounds.Right, e.Bounds.Bottom));

           }
 

Red and Green colors are test colors (are more visible), they should be a yellow and a white between it to show like a shadow.

So, the Red lines are not all 1 pixel width and also they are not all (255,0,0) (some xor between pixels?). The same issue appears to the green lines. And, more of that, the 2 lines do not appear one above the other (as the code suggest) but there are 2-3 pixels empty space between them.

Is there a workaround for this issue too? We really do want to paint a custom border that consist of 2 1px width lines.

Thanks,
Bogdan

Hi Stoyan,

Thanks, if I set the graphics object's SmoothingMode to none, the first problem dissappears, the lines are correctly drawn.

Bu it seems I can't handle the second one (painting in pixels coordinate, instead of millimeters)

here is my code:

[code]
void Diagram_DrawCell(object sender, DrawCellEventArgs e)
{
SmoothingMode smoothingMode = e.Graphics.SmoothingMode;
e.Graphics.SmoothingMode = SmoothingMode.None;

Matrix t = e.Graphics.Transform;
e.Graphics.ResetTransform();

System.Drawing.Pen pen1 = (new MindFusion.Drawing.Pen(Color.Red, 0)).CreateGdiPen();
System.Drawing.Pen pen2 = (new MindFusion.Drawing.Pen(Color.Green, 0)).CreateGdiPen();

Point p1 = this.UnitToPixel(new PointF(e.Bounds.Left, e.Bounds.Bottom-1));
Point p2 = this.UnitToPixel(new PointF(e.Bounds.Right, e.Bounds.Bottom-1));

Point p3 = new Point(p1.X, p1.Y + 1);
Point p4 = new Point(p2.X, p2.Y + 1);

e.Graphics.DrawLine(pen1, p1, p2);
e.Graphics.DrawLine(pen2, p3, p4);

e.Graphics.Transform = t;

e.Graphics.SmoothingMode = smoothingMode;
}
[/code]

So, I've saved the Matrix, called the ResetTransform, then paint the two lines. But something is still wrong as I can't see the lines, or I see them incorrectly positioned.

Can you please detail a little bit how to properly reset the matrix in order to draw in pixel coordinates?

Thanks,
Bogdan

PS. I placed the [b]e.Graphics.ResetTransform();[/b] line before as well as after the [b]UnitToPixel[/b] methods call but same result.

Hi Stoyan,

I've replaced Diagram.UnitToPixel with DiagramView.DocToClient and place ResetTransform after the DocToClient is called but same result, no line is drawn on table surface.

  void Diagram_DrawCell(object sender, DrawCellEventArgs e)
        {
            SmoothingMode smoothingMode = e.Graphics.SmoothingMode;
            e.Graphics.SmoothingMode = SmoothingMode.None;

            System.Drawing.Pen pen1 = (new MindFusion.Drawing.Pen(Color.Red, 0)).CreateGdiPen();
            System.Drawing.Pen pen2 = (new MindFusion.Drawing.Pen(Color.Green, 0)).CreateGdiPen();

            DiagramView view = FormQuery.QueryDiagramPane.DiagramViewPanel.DiagramView;

          Rectangle rect = view.DocToClient(e.Bounds);

            Matrix t = e.Graphics.Transform;
            e.Graphics.ResetTransform();

            //e.Graphics.DrawLine(pen1, rect.Left, rect.Bottom - 1, rect.Right, rect.Bottom - 1);
            e.Graphics.DrawLine(pen2, rect.Left, rect.Bottom, rect.Right, rect.Bottom);

            e.Graphics.Transform = t;
}
 

Any help (new hints?) appreciated. Thanks!

Bogdan

Seems ResetTransform doesn't reset the PageUnit, so you should also assign Pixel to it:

Matrix t = e.Graphics.Transform;
e.Graphics.PageUnit = GraphicsUnit.Pixel;
e.Graphics.ResetTransform();

//e.Graphics.DrawLine(pen1, rect.Left, rect.Bottom - 1, rect.Right, rect.Bottom - 1);
e.Graphics.DrawLine(pen2, rect.Left, rect.Bottom, rect.Right, rect.Bottom);

e.Graphics.Transform = t;
e.Graphics.PageUnit = GraphicsUnit.Millimeter;
 

I hope that helps,
Stoyan

Hi Bogdan,

The Diagram.DrawStyledText method does that.

I hope that helps,
Stoyan

What are the cell.Text and e.Bounds values with which you are seeing the text clipped?

Hi Bogdan,

I think the diagram uses diagram.MeasureUnit when font.Unit is set to World, so that problem could happen because the text layout is calculated for font's size in millimeters, but you draw it in pixels. Try using a Font whose unit is set to Pixel.

I hope that helps,
Stoyan