Programming GDL Web Control

Table of Contents

Naming Conventions
Platforms and Browsers Supported
Operation
Embedding into HTML
- GDL Web Control
- GDL Web Plug-in
Setting Default Parameter Values at Loading
Example I - Embedding
Communicating with the Plug-in
Define plugin callback function (New in version 13.)
Example II - Communication
Example III - Plug-in Interface Functions

GDL Web Control
GDL Web Plug-in
This document uses 'plug-in' in both cases, when discussing GDL programming in general.

	MacOS X (PowerPC version)	MacOS X (Intel version)	Windows 2000, XP, Vista
Internet Explorer	-	-	supported
Firefox	supported*	supported	supported
Safari	supported*	supported	-

* From GDL Web Control 13 the PowerPC version of MacOS X does not supported.

Operation

GDL object file: can be standalone or assembly (macros used).
gdllist.txt: The catalog file. This lists all the files needed to display the object. This file is created by GDL Publisher.
master.gdl: this contains default material and texture definitions. If not found, the file installed on the client machine is used. The path to this file can be set via the Preferences dialog box.

Embedding into HTML

GDL Web Control

<object CLASSID="CLSID:64D9B72C-E42A-490e-9181-221E1E035A14"
        codebase="..."
        id="GDL_Control"
        WIDTH="128" HEIGHT="128">
      	<param NAME="..." VALUE="...">
      	<param NAME="..." VALUE="...">
</object>

GDL Web Plug-in

<EMBED type="model/vnd.gs-gdl"
       name="GDL_CONTROL"
       src="..."
       WIDTH="128" HEIGHT="128">
</EMBED>

Setting Default Parameter Values at Loading

Required Parameters
```
<object CLASSID="CLSID:64D9B72C-E42A-490e-9181-221E1E035A14"
        codebase="http://www.gdlcentral.com/bin/files/GDLCtl.cab"
        id="GDL_Control"
        WIDTH="128" HEIGHT="128">
  <param NAME="Src" VALUE="plugintest.gsm">
  <param NAME="GdlListTxt" VALUE="GDLList.txt">
  <param NAME="MasterGdl" VALUE="Master.gdl">
</object>
```
- classid: Used by the system to identify GDL ActiveX Control.
- codebase: To use automatic installation and update.
- id: To make the object instance available to Javascript.
```
<embed type="model/vnd.gs-gdl"
       name="GDL_Control"
       WIDTH="128" HEIGHT="128"
       SRC="plugintest.gsm"
       GDLListTxt="GDLList.txt"
       MasterGdl="Master.gdl">
</embed>
```
- type: This is used by the browser to identify GDL objects.
- name: To make the object instance available to Javascript.
- width, height: To set the size of the view rectangle.
- src: The path to the GDL object on the server.
- gdllisttxt: The path to the GDL catalog file, gdllist.txt on the server.
- mastergdl: The path to master.gdl file on the server.

Optional Parameters

To find the complete list of optional parameters, go to the Web Plug-in Reference page.

- disablemenus:

- lengthunitformat:

Value	Description
1	mm
2	cm
3	m
4	km
5	decimal feet
6	feet & decimal inches
7	decimal inches
8	feet & fractional inches
9	fractional inches

- projectioncode:

Value	Description
0	Front view
1	Back view
2	Over view
3	Top view
4	Left view
5	Right view
6	Frontal axonometry
7	Isometric axonometry
8	Monometric axonometry
9	Dimetric axonometry
10	Perspective projection
11	Bottom axonometry
12	Frontal bottom axonometry
13	Isometric bottom axonometry
14	Monometric bottom axonometry
15	Dimetric bottom axonometry

- setplugincode:

sales@gdltechnology.com

- showtype:

Value	Description
WIREFRAME	Draws the object in wireframe, shows all lines
HIDDENLINE	wireframe + invisible lines hidden
SHADING	hiddenline + color
PHOTORENDERING	Photorealistic view of the object
DRAWING2D	Draws the object in 2D
PREVIEW	Draws the preview picture of the object

- similar:

GDL Object Parameters

It is possible to set the GDL parameters of objects to override their default values, i.e. the ones with which the objects were saved in the authoring tool.

<object CLASSID="CLSID:64D9B72C-E42A-490e-9181-221E1E035A14"
        codebase="http://www.gdlcentral.com/bin/files/GDLCtl.cab"
        id="GDL_Control"
        WIDTH="128" HEIGHT="128">
  <param NAME="Src" VALUE="plugintest.gsm">
  <param NAME="GdlListTxt" VALUE="GDLList.txt">
  <param NAME="MasterGdl" VALUE="Master.gdl">
  <param NAME="GDLParams" VALUE="smyParam=1">
</object>

<embed type="model/vnd.gs-gdl"
       name="GDL_Control"
       WIDTH="128" HEIGHT="128"
       SRC="plugintest.gsm"
       GDLListTxt="GDLList.txt"
       MasterGdl="Master.gdl"
       smyParam=1>
</embed>

Parameters can be either strings or numbers in the world of GDL. When setting a string type parameter, start with the prefix 's'. When setting number type parameters, start with 'r' followed by the name of the parameter.

Example I - Embedding

This example embeds a GDL object into an HTML page.

<object CLASSID="CLSID:64D9B72C-E42A-490e-9181-221E1E035A14"
        codebase="http://www.gdlcentral.com/bin/files/GDLCtl.cab"
        id="GDL_Control"
        WIDTH="128" HEIGHT="128">
  <param NAME="Src" VALUE="plugintest.gsm">
  <param NAME="GdlListTxt" VALUE="GDLList.txt">
  <param NAME="MasterGdl" VALUE="Master.gdl">
  <param NAME="GDLParams" VALUE="smyParam=1">
  <embed type="model/vnd.gs-gdl"
         name="GDL_Control"
         WIDTH="128" HEIGHT="128"
         SRC="plugintest.gsm"
         GDLListTxt="GDLList.txt"
         MasterGdl="Master.gdl"
         smyParam=1>
  </embed>
</object>

View Example I

Communicating with the Plug-in

Checking Load Status
It is very important to check the status of the embedded objects, before starting any communication with the plug-in.

<script language=javascript>
  function DoMyStuff ()
  {
  }

  function CheckLoaded ()
  {
    document.GDL_Control.CallPlugin ("GetPluginStatus", "");
    if (document.GDL_Control.sResult == "BUSY") {
      intervalID = setTimeout('CheckLoaded()', 100);
    }
    else {
      clearTimeout (intervalId);
      DoMyStuff ();
    }
  }
</script>

This code snippet uses the page's onload event to call the check function. Once the plug-in has finished displaying the object, it can accept commands or handle queries.

Sending Commands
Commands are tasks which the plug-in can execute and there is no return value: e.g. setting view modes.

To send commands: GDL_Control.CallPlugin ("Command", "Parameter")

Query/Response
If return values are expected from the plug-in:

Setting Parameter Values
GDL_Control.CallPlugin ("SetParameter", "sMyParam=1&rMyParam2=2.000")

To set more than one parameter at a time, join the commands with the '&' sign.

Getting Parameter Values
GDL objects can have 1024 parameters. To get a parameter value, you should know its index in the parameter list of the object in question. The index starts with 1.

GDL_Control.CallPlugin ("GetParameter", i)

A loop can be used to get all the parameters at a time:

<script language=javascript>
  function GetParamVals (param)
  {
    var parameterString = "", aParameterString, myParamStr = "";
  
    for (i = 1; i <= 128; i++) {
      document.GDL_Control.CallPlugin ("GetParameter", String (i));
      aParameterString = document.GDL_Control.sResult;
      if (aParameterString != "") {
        stringsOfParameters = aParameterString.split (";");
        myParamStr += stringsOfParameters + "
"
        if (stringsOfParameters.length < 4)
          continue;
        if (stringsOfParameters[2].indexOf (param) != -1) {
          parameterString = stringsOfParameters[1];
          break;
        }
      }
    }				
    return parameterString;
  }
</script>

Define plugin callback function
From version 13 the plugin can call back a user defined JavaScript function. If a user defines a callback function, the plugin calls it every time when it's state has changed. With this function developers can keep the consistency of the JavaScript user interface.

This example sets the function which the plugin can call:

<script language=javascript>
  function PluginCallBack (message)
  {
    // plugin calls this with various messages
  }
  
  window.onload = function SetNotificationScript ()
  {
    if (document.GDL_Control) {
      document.GDL_Control.CallPlugin ("SETNOTIFICATIONSCRIPT", "PluginCallBack");
    }
  }
</script>

The message can be one of the followings:

Message	Event
Drawing2D	The showtype switched to Drawing2D.
Wireframe	The showtype switched to Wireframe.
HiddenLine	The showtype switched to HiddenLine.
Shading	The showtype switched to Shading.
PhotoRendering	The showtype switched to PhotoRendering.
ParameterChanged	Some of the parameters changed.
GraphicalEditing	The user switched on or off graphical editing mode.
InternalEngine	The rendering engine switched to Internal Engine.
OpenGL	The rendering engine switched to Internal Engine.

View CallBack Example

Example II - Communication
This example embeds a GDL object into the page by changing parameter 'myParam' from its default value 0 to 1.

It also changes the parameter 'Radius' to 45 degrees and sets the axonometry angle to 180 degrees at load time.

To change this parameter, click on the 'Set Parameter' button included on the example page.

View Example II

Example III - Plug-in Interface Functions
- Accessing the interface: CallPlugin ("MenuCommand", "Parameter")
- Setting Interface Modes: CallPlugin ("UI_MODE", "Parameter")
- Setting zoom: CallPlugin ("SETZOOM", "scaleX, scaleY, origoX, origoY")
- Getting zoom: CallPlugin ("GETZOOM", "")
View Example III

QuickLinks

Programming GDL Web Control