1.1.4 Creating Graph Preview GetN Dialog

This section shows how to create an X-Function graph preview GetN dialog , including how to initialize a preview graph, how to update the preview graph on a GUI change, and how to update the GUI on the rectangle moving on the graph.

Ocguide xf graphpreview dialog.png

Create an Empty GetN Graph Preview Dialog

  • Press F10 to Open X-Function Builder.
  • Type "PrevBox" into the X-Function EditBox as the X-Function name.
  • Add a second variable by right-clicking on the Variables list and choosing "Add variable". Change the variable names, labels, and other values to match the settings in the dialog below.
    Ocguide xf graphpreview variables.png
  • Click Tree View button Ocguide xf treeview button.png in X-Function Builder, open the branch Usage Context -> Menu, set Auto GetN Dialog to GetNGraphBox with Preview, then click the Save button to save this X-Function.
  • Close X-Function Builder, and run "PrevBox -d" in Command window. A GetN graph preview dialog will show.

Coding X-Function in Code Builder

  • Open Origin Code Builder, in the menu choose File -> Open, locate the X-Function saved above, make sure the Add to Workspace check box is checked in the Open dialog, and click OK. PrevBox.XFC is added to the User folder in Origin C Workspace view and shows the function body in Edit view.
  • Add the additional header file after the line //put additional include files here. For example:
    //put additional include files here
    #include <..\Originlab\grobj_utils.h>

Initialize Preview Graph

The GetNGraphPreview_OnInitGraph function is used to initialize a preview graph. Copy the following codes and paste them into the function, then click the Compile button. When the preview dialog box opens, a rectangle will display on the preview graph. Click Compile and run "PrevBox -d" in the Command window.

// cast pgTemp from PageBase class object to GraphPage object
GraphPage gp(pgTemp); 

// load this template to the graph in order to contain zoom 
// in/out button on the graph. If this is not required, 
// remove this line.
page_load(gp, "CurvePreview"); 

// get active graph layer in the graph page
GraphLayer gl = gp.Layers(); 

// add a rectangle, set x position reference to xfrom and xto 
// variables
GraphObject go;
add_rect(gl, go, trGetN.xfrom.dVal, 0, trGetN.xto.dVal, -1, 
    SYSCOLOR_BLUE, 2, LN_VERTICAL, true, false);

Update Preview Graph on GUI Change

  • To cause the preview graph to be updated, you need to include the UPDATE_GRAPH_CHANGED bit in the dwUpdateGraph variable in the GetNGraphPreview_OnChange function. For example:
    // include the bit to call GetNGraphPreview_OnUpdateGraph 
    // to update graph
    if( !(dwUpdateGraph & UPDATE_GRAPH_CHANGED) )
    	dwUpdateGraph |= UPDATE_GRAPH_CHANGED;
  • Add the following code into the GetNGraphPreview_OnUpdateGraph function to update the graph. Click the Compile button and run "PrevBox -d" in the Command window.
    // cast pgTemp from PageBase class object to GraphPage 
    // object
    GraphPage gp(pgTemp); 
    GraphLayer gl = gp.Layers(); // get active graph layer 
    GraphObject go = gl.GraphObjects("Rect"); 		
    double x0 = trGetN.xfrom.dVal;
    double x1 = trGetN.xto.dVal;
    // update x position of rectangle on GUI
    vector vv(4);
    vv[0] = x0; vv[1] = x1; vv[2] = x1; vv[3] = x0;
    Tree tr;
    tr.Root.Data.X.dVals = vv;	
    go.ApplyFormat(tr, true, true);
    // refresh graph window

Update GUI on Graph Object Event

If you want to update the GUI when you move/resize the rectangle on the preview graph, you need to:

  • Add the following to the GetNGraphPreview_OnInitGraph function after the add_rect function.
    // set event script to notify preview dialog when rectangle 
    // is moved or resized. For other event types see the GRCT_*
    // in oc_const.h file.
    set_LT_script(go, "run -oc notify_dlg_on_move_obj;", 
  • Add the following code to GetNGraphPreview_OnChange to update the new position of the rectangle to the GUI. Click the Compile button and run "PrevBox -d" in the Command window.
    if( bChangedByGraph )
    	// get rectangle x from/to and update GUI
    	GraphPage gp(pgTemp);
    	GraphLayer gl = gp.Layers();
    	GraphObject goRect = gl.GraphObjects("Rect");
    	Tree tr;
    	tr = goRect.GetFormat(FPB_DATA, FOB_ALL, TRUE, TRUE);
    	vector vv;
    	vv = tr.Root.Data.X.dVals;
    	trGetN.xfrom.dVal = vv[0];
    	trGetN.xto.dVal = vv[1];
    	// to include UPDATE_GRID_* bits to update GUI
    	if( !(dwUpdateGrid & UPDATE_GRID_SIMPLE) )
    		dwUpdateGrid |= UPDATE_GRID_SIMPLE; 

Add Preview buttons

To add a Preview button and an Auto Preview check box, please see X-Functions: Customizing an X-Function: Adding Custom Button on Dialog: Show Preview Button on Graph Preview GetN Dialog