Previewing and plotting a single sheet in AutoCAD using .NET

This week's posts take the code I threw together last week for single-sheet and multi-sheet plotting, and introduces the concept of "plot preview".

I'm learning as I go for much of this, so there are structural (although usually not functional) changes being made to the code as it develops. In this instance, for example, I've factored off common functionality needed by both previewing and plotting into a single helper function. This will no doubt evolve further (and change in structure) when I come to apply the principle to multi-sheet plotting later in the week.

Here's the C# code:

using Autodesk.AutoCAD.Runtime;

using Autodesk.AutoCAD.ApplicationServices;

using Autodesk.AutoCAD.DatabaseServices;

using Autodesk.AutoCAD.EditorInput;

using Autodesk.AutoCAD.PlottingServices;

namespace PlottingApplication

{

  public class PreviewCommands

  {

    [CommandMethod("simprev")]

    static public void SimplePreview()

    {

      Document doc =

        Application.DocumentManager.MdiActiveDocument;

      Editor ed = doc.Editor;

      Database db = doc.Database;

      // PlotEngines do the previewing and plotting

      if (PlotFactory.ProcessPlotState ==

          ProcessPlotState.NotPlotting)

      {

        // First we preview...

        PreviewEndPlotStatus stat;

        PlotEngine pre =

          PlotFactory.CreatePreviewEngine(

            (int)PreviewEngineFlags.Plot

          );

        using (pre)

        {

          stat =

            PlotOrPreview(

              pre,

              true,

              db.CurrentSpaceId,

              ""

            );

        }

        if (stat == PreviewEndPlotStatus.Plot)

        {

          // And if the user asks, we plot...

          PlotEngine ple =

            PlotFactory.CreatePublishEngine();

          stat =

            PlotOrPreview(

              ple,

              false,

              db.CurrentSpaceId,

              "c:\\previewed-plot"

            );

        }

      }

      else

      {

        ed.WriteMessage(

          "\nAnother plot is in progress."

        );

      }

    }

    static PreviewEndPlotStatus PlotOrPreview(

      PlotEngine pe,

      bool isPreview,

      ObjectId spaceId,

      string filename)

    {

      Document doc =

        Application.DocumentManager.MdiActiveDocument;

      Editor ed = doc.Editor;

      Database db = doc.Database;

      PreviewEndPlotStatus ret =

        PreviewEndPlotStatus.Cancel;

      Transaction tr =

        db.TransactionManager.StartTransaction();

      using (tr)

      {

        // We'll be plotting the current layout

        BlockTableRecord btr =

          (BlockTableRecord)tr.GetObject(

            spaceId,

            OpenMode.ForRead

          );

        Layout lo =

          (Layout)tr.GetObject(

            btr.LayoutId,

            OpenMode.ForRead

          );

        // We need a PlotInfo object

        // linked to the layout

        PlotInfo pi = new PlotInfo();

        pi.Layout = btr.LayoutId;

        // We need a PlotSettings object

        // based on the layout settings

        // which we then customize

        PlotSettings ps =

          new PlotSettings(lo.ModelType);

        ps.CopyFrom(lo);

        // The PlotSettingsValidator helps

        // create a valid PlotSettings object

        PlotSettingsValidator psv =

          PlotSettingsValidator.Current;

        // We'll plot the extents, centered and

        // scaled to fit

        psv.SetPlotType(

          ps,

          Autodesk.AutoCAD.DatabaseServices.PlotType.Extents

        );

        psv.SetUseStandardScale(ps, true);

        psv.SetStdScaleType(ps, StdScaleType.ScaleToFit);

        psv.SetPlotCentered(ps, true);

        // We'll use the standard DWF PC3, as

        // for today we're just plotting to file

        psv.SetPlotConfigurationName(

          ps,

          "DWF6 ePlot.pc3",

          "ANSI_A_(8.50_x_11.00_Inches)"

        );

        // We need to link the PlotInfo to the

        // PlotSettings and then validate it

        pi.OverrideSettings = ps;

        PlotInfoValidator piv =

          new PlotInfoValidator();

        piv.MediaMatchingPolicy =

          MatchingPolicy.MatchEnabled;

        piv.Validate(pi);

        // Create a Progress Dialog to provide info

        // and allow thej user to cancel

        PlotProgressDialog ppd =

          new PlotProgressDialog(isPreview, 1, true);

        using (ppd)

        {

          ppd.set_PlotMsgString(

            PlotMessageIndex.DialogTitle,

            "Custom Preview Progress"

          );

          ppd.set_PlotMsgString(

            PlotMessageIndex.SheetName,

            doc.Name.Substring(

              doc.Name.LastIndexOf("\\") + 1

            )

          );

          ppd.set_PlotMsgString(

            PlotMessageIndex.CancelJobButtonMessage,

            "Cancel Job"

          );

          ppd.set_PlotMsgString(

            PlotMessageIndex.CancelSheetButtonMessage,

            "Cancel Sheet"

          );

          ppd.set_PlotMsgString(

            PlotMessageIndex.SheetSetProgressCaption,

            "Sheet Set Progress"

          );

          ppd.set_PlotMsgString(

            PlotMessageIndex.SheetProgressCaption,

            "Sheet Progress"

          );

          ppd.LowerPlotProgressRange = 0;

          ppd.UpperPlotProgressRange = 100;

          ppd.PlotProgressPos = 0;

          // Let's start the plot/preview, at last

          ppd.OnBeginPlot();

          ppd.IsVisible = true;

          pe.BeginPlot(ppd, null);

          // We'll be plotting/previewing

          // a single document

          pe.BeginDocument(

            pi,

            doc.Name,

            null,

            1,

            !isPreview,

            filename

          );

          // Which contains a single sheet

          ppd.OnBeginSheet();

          ppd.LowerSheetProgressRange = 0;

          ppd.UpperSheetProgressRange = 100;

          ppd.SheetProgressPos = 0;

          PlotPageInfo ppi = new PlotPageInfo();

          pe.BeginPage(

            ppi,

            pi,

            true,

            null

          );

          pe.BeginGenerateGraphics(null);

          ppd.SheetProgressPos = 50;

          pe.EndGenerateGraphics(null);

          // Finish the sheet

          PreviewEndPlotInfo pepi =

            new PreviewEndPlotInfo();

          pe.EndPage(pepi);

          ret = pepi.Status;

          ppd.SheetProgressPos = 100;

          ppd.OnEndSheet();

          // Finish the document

          pe.EndDocument(null);

          // And finish the plot

          ppd.PlotProgressPos = 100;

          ppd.OnEndPlot();

          pe.EndPlot(null);

        }

        // Committing is cheaper than aborting

        tr.Commit();

      }

      return ret;

    }

  }

}

When you execute the SIMPREV command, you receive enter a "preview" mode, from where you can either cancel or plot. The trick was really in determining the button selected by the user, which we do by passing an appropriate object (of class PreviewEndPlotInfo) into the EndPage() function, to collect information on what the users selects. The next post will take this further, allowing the user to cycle through multiple sheets using "next" and "previous" buttons.

Comments

[Joseph Garrett]

first, thank you for posting to this blog. I have learned a lot from you and this site.

I copied the above code to a fresh project but wanted to plot to the StyleSheet "monochrome.ctb." however, I get the below error. am I missing something?

I place the below code between the
SetStdScaleType and SetPlotCentered lines.

psv.SetCurrentStyleSheet(ps, "monochrome.ctb");

--------
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> Autodesk.AutoCAD.Runtime.Exception: eInvalidInput
at Autodesk.AutoCAD.DatabaseServices.PlotSettingsValidator.SetCurrentStyleSheet(PlotSettings plotSet, String styleSheetName)
at ClassLibrary.PreviewCommands.PlotOrPreview

[Kean]

I see what you're experiencing... interestingly when I add this call before yours (even if I don't use the results directly), the code works:

System.Collections.Specialized.StringCollection sc = psv.GetPlotStyleSheetList();

Regards,

Kean