How to get the scroll position...

[dlyohan]

Now I am trying to make a application using WPF/c#.
In this application, I looked at prototyping this XChange viewer SDK
but do not know if I can get a scroll event notification from the control,
or if I can find the current scroll position of each page on the screen.

I am looking for an event such as ScrollPositionChanged (or document position changed) that would allow me to then interrogate the current HScollPos and VScrollPos on the instance raising the event and set these same values on the other layer control of WPF.

Is there any way to get this information from XChange Viewer SDK ?

regards,
yohan.

[Vasyl - PDF-XChange]

Hi, Yohan.

Sorry, no way for this in current version. Please wait for version V3.

Best
regards.

[vzgherea]

Looking for the same event as topic starter - scroll event notification.
Is it available in the current version of SDK?

[Vasyl - PDF-XChange]

Hi, vzgherea and yohan.

Now exists one new undocumented feature to synchronize scroll positions of two(or more) opened documents.

Methods:
Document::GetVPos()
Document::SetVPos()
Event:
Type=PXCVA_OnNamedNotify, Name="Notifications.ScrollChanged"

Look to attached C# example that displays it.

Also you may use next trick. To get current view position:

Code: Select all

struct ScrollPos
{
   int         pageIndex;
   double    x;  
   double    y;
}

ScroolPos spos;

object dataIn;
object dataOut;
GetDocumentProperty(docID, "Pages.Current", out dataOut, PXVA_Sync);

spos.pageIndex = dataOut;

// [0,0] screen point to pdf-coord. system of current page:
DoDocumentVerb(docID, "Pages[" + spos.pageIndex + "]", "TranslateScreenPoint", dataIn(0, 0), out dataOut, PXVA_Sync);
spos.x = dataOut[0];
spos.y = dataOut[1];

To restore the previously saved view position:

Code: Select all

DoDocumentVerb(docID, "Pages[" + spos.pageIndex + "]", "MovePointToScreenPoint", dataIn(spos.x, spos.y, 0, 0), null, PXVA_Sync);

HTH

[vzgherea]

Many thanks for your post, it is very helpful!

But I can't still solve my issue. I am implementing document compare functionality. Each document has only one page and is loaded in it's own control. It is necessary to synchronize scrolling in both controls and it has to be done proportionally, e.g. 50% of scrolling in first control has to set scrolling to 50% in the second control, even in case size of pages is different or orientation of pages is different.

Could you give me a hint how this could be achieved?

[Vasyl - PDF-XChange]

It is necessary to synchronize scrolling in both controls and it has to be done proportionally, e.g. 50% of scrolling in first control has to set scrolling to 50% in the second control, even in case size of pages is different or orientation of pages is different.

You may try to use one undocumented way:

Code: Select all

m_bSkipScrollEvent = false;
axCoPDFXCview1.SetProperty("Notifications.ScrollChanged.Enabled", 1, 0);
axCoPDFXCview2.SetProperty("Notifications.ScrollChanged.Enabled", 1, 0);
...
youreventhandker axCoPDFXCview1_OnEvent(type, name, dataIn)
{
     if (!m_bSkipScrollEvent && (type == PXCV_OnNamedNotify) AND (name == "Notifications.ScrollChanged"))
     {
           m_bSkipScrollEvent = true;
           LONG pageIndex  = dataIn[0];
           double dxPage = dataIn[3];
           double dyPage = dataIn[4];
           double pw, ph; 
           axCoPDFXCview1.GetDocumentProperty(0, "Pages[ + pageIndex + "].Width", out pw, PXCVA_NoUI | PXCVA_Sync);
           axCoPDFXCview1.GetDocumentProperty(0, "Pages[ + pageIndex + "].Height", out ph, PXCVA_NoUI | PXCVA_Sync);
           double xz = dxPage / pw;
           double yz = dyPage / ph;

           double pw, ph; 
           axCoPDFXCview2.GetDocumentProperty(0, "Pages[ + pageIndex + "].Width", out pw, PXCVA_NoUI | PXCVA_Sync);
           axCoPDFXCview2.GetDocumentProperty(0, "Pages[ + pageIndex + "].Height", out ph, PXCVA_NoUI | PXCVA_Sync);
           dxPage = pw * xz;
           dyPage = ph * yz;

           dataIn[3] = dxPage;
           dataIn[4] = dyPage;

           axCoPDFXCview2.DoDocumentVerb(0, "", "SetVPos", dataIn, null, PXCVA_NoUI | PXCVA_Sync);

           m_bSkipScrollEvent = false;
     }
}
...
youreventhandker axCoPDFXCview2_OnEvent(type, name, dataIn)
{
     if (!m_bSkipScrollEvent && (type == PXCV_OnNamedNotify) AND (name == "Notifications.ScrollChanged"))
     {
           m_bSkipScrollEvent = true;
           LONG pageIndex  = dataIn[0];
           double dxPage = dataIn[3];
           double dyPage = dataIn[4];
           double pw, ph; 
           axCoPDFXCview2.GetDocumentProperty(0, "Pages[ + pageIndex + "].Width", out pw, PXCVA_NoUI | PXCVA_Sync);
           axCoPDFXCview2.GetDocumentProperty(0, "Pages[ + pageIndex + "].Height", out ph, PXCVA_NoUI | PXCVA_Sync);
           double xz = dxPage / pw;
           double yz = dyPage / ph;

           double pw, ph; 
           axCoPDFXCview1.GetDocumentProperty(0, "Pages[ + pageIndex + "].Width", out pw, PXCVA_NoUI | PXCVA_Sync);
           axCoPDFXCview1.GetDocumentProperty(0, "Pages[ + pageIndex + "].Height", out ph, PXCVA_NoUI | PXCVA_Sync);
           dxPage = pw * xz;
           dyPage = ph * yz;

           dataIn[3] = dxPage;
           dataIn[4] = dyPage;

           axCoPDFXCview1.DoDocumentVerb(0, "", "SetVPos", dataIn, null, PXCVA_NoUI | PXCVA_Sync);

           m_bSkipScrollEvent = false;
     }
}

This method will work only for Pages.Layout == SinglePage or Pages.Layout == One Column Continuous

HTH