Thursday, October 1, 2009

Pro/WebLink: Replace Drawing Formats

Jürgen from Germany was asking me recently about replacing formats with Pro/WebLink. In the process of providing a solution, I found an interesting combination of disappointments, curiosities, and finally a very nice solution.


Looking through the API documentation, it's not too hard to find that the method call to replace drawing formats is SetSheetFormat() in the pfcSheetOwner class. One of the primary arguments is the drawing format object in the form of a pfcDrawingFormat object. Unfortunately, this object's class is not obviously documented. The docs say only that its parent class is a pfcModel. So how to you get a drawing format object when it seems to have no methods?

Since it's a subclass of pfcModel, you use pfcBaseSession methods such as OpenFile(), GetModel, and RetrieveModel(). Here's where the J-Link docs are bit better, because they list the methods inherited from parent classes and interfaces, just making it that much more obvious. To use RetrieveModel(), a pfcModelDescriptor object needs to be created which specifies what is to be retrieved and how.

Here is the core sequence of steps, assuming the current model is a drawing:

var session = pfcGetProESession();
var drawing = session.CurrentModel;
var drwSheetNum = drawing.CurrentSheetNumber; // use current sheet

var frmName = "c_size.frm";
var frmSheetNum = 1;
var frmDescr = pfcCreate("pfcModelDescriptor").CreateFromFileName(frmName);
var format = session.RetrieveModel(frmDescr);

var drwModel = null;
drawing.SetSheetFormat(drwSheetNum, format, frmSheetNum, drwModel);

Format Folder

You'll notice that the folder where the format is stored was not specified. Why? According to the docs, you can't specify the path to a folder containing a pfcModel when using RetrieveModel(). Although the pfcModelDescriptor object contains a Path property, it is ignored.

How does Pro/Engineer know where to find the format? It just does. Well, if the PRO_FORMAT_DIR option is set properly, then it just does. Fortunately, this option can handle folder paths, Intralink 3.x folders, and PDMLink folders. That should cover most scenarios.

Format Sheets

SetSheetFormat() also allows you to specify the sheet number of the format to use (should your format have more than one sheet). Unfortunately, since the pfcDrawing Format object does not implement the pfcSheetOwner interface, the developer has no way to determine how many sheets are in the format. You'll just have to know how many sheet your formats have ahead of time, not a major tragedy.

To be fair this is a Pro/Toolkit limitation first and foremost. The PFC APIs merely inherit Pro/Toolkit's limitations.

Drawings, layouts, and Pro/Report files (who uses these anyway?!) all are defined as pfcModel2D objects, which gives lots of info about sheets, tables, and detail items. Formats, although pretty much the same thing, are not pfcModel2D objects. As a result, we can get none of these things.

Drawing Model

The drawing model is the part or assembly documented on the current sheet. Although this can be specified as the last argument to SetSheetFormat(), we don't have the ability to know what the current model is (at least until WF4). null is used to here to indicate the current drawing model.

Format Tables

Just as with interactive use of Pro/Engineer, when drawing formats are replaced, the drawing tables from the previous format have to be dealt with. Typically, this involves deleting the tables. Since SetSheetFormat() does not provide a mechanism or option for removing the old format tables, this will have to be done with more code.

This is where it gets a little tricky. While there is a CheckIfIsFromFormat() method call that will tell us if a table came from a format, we'll need the table object first. To get the table object, first we'll have to use ListTables() from the pfcTableOwner class to get all of the tables for the entire drawing. ListTables() takes no argument, meaning that we have no way to pre-filter the collection of tables. It really should take a sheet number argument to return only the tables on that sheet. As an alternatives, had the pfcTable class been a pfcDetailItem (in addition to a pfcModelItem), we could have gathered the tables by sheet number using ListDetailItems(), from pfcDetailItemOwner.

var tables = drawing.ListTables();
The workflow for CheckIfIsFromFormat() is a bit odd as well. To check if a table is from a format, we need the pfcTableObject, and then we need to specify the sheet number. Now wait a minute, the function returns a boolean so logically the table is from the format or it is not. What does the sheet number have to do with that? Even if the table had been segmented, it's still going to be from the format or not.

if (table.CheckIfIsFromFormat(drwSheetNum) == true) {
// table is from format, delete it
drawing.DeleteTable(table, false);
This quirkiness turns out to be very useful because it's rather difficult to tell on what sheet the table exists. The pfcTableInfo class does not contain this info. While it's true that the GetSegmentSheet() method can be used for this, we would have to assume that segment zero is the proper segment to use.

Full Example: Replacing Formats

This example shows a complete code set for obtaining the drawing object, the format object, and their related info. It then procedes to call the ReplaceFormat() function, which removes the old format tables prior to replacing the format. The code replaces the format and tables very quickly.

// get current drawing and sheet number
var session = pfcGetProESession();
var drawing = session.CurrentModel;
var drwSheetNum = drawing.CurrentSheetNumber;

// get format name from html text field
var frmName = document.getElementById("frmName").value

// use format sheet 2 if drawing sheet is not sheet 1
var frmSheetNum = 1;
if (drwSheetNum > 1) { frmSheetNum = 2; }

// get the format
var frmDescr = pfcCreate("pfcModelDescriptor").CreateFromFileName(frmName);
var format = session.RetrieveModel(frmDescr);

// replace the format
ReplaceFormat(drawing, drwSheetNum, format, frmSheetNum);

// update the display (optional)
// session.CurrentWindow.Repaint();
// drawing.Regenerate();

function ReplaceFormat ( drawing, drwSheetNum, format, frmSheetNum ) {

var tables = null;

try {
// get sequence of tables in the drawing
tables = drawing.ListTables();
for (var i=0; i<tables.Count; i++) {
var table = tables.Item(i);
if (table.CheckIfIsFromFormat(drwSheetNum) == true) {
// table is from format, delete it
drawing.DeleteTable(table, false);
catch (e) {
// ignore, no tables in drawing

drawing.SetSheetFormat(drwSheetNum, format, frmSheetNum, null);

Another step to perform (marked as optional in the example) is to update the display using either Repaint() or Regenerate(). They both should accomplish the same goal, but one may work better in certain drawings than the other. You can be sure that if a large drawing is slow to repaint when performed in Pro/Engineer interactively, it will be just as slow via Pro/Web.Link.

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