GSoC progress for week #3 and week #4.

Group selection does not work with raster images / Writer

Writer can group Drawing objects. For example shapes(rectangles, circles), text boxes and draw images can be grouped together to drag & drop.

However, when copy/paste or drag&drop an image into the writer document canvas, (raster/bitmap)images are handled as Frame objects (holding images/bitmaps), not Drawing objects. Drawing objects have the group feature, but this feature is not implemented for Graphics(Frame objects/bitmap). This is why Writer can’t group raster images.



In week #3 and #4, I tried to understand the logic behind the grouping Drawing objects. It seems more complex than it looks. To keep the blog post simple and short, I will share only the key points of my research.

Code pointers:

Technical Details

SAL_DEBUG( rMrkList.GetMarkDescription() ); output: (in SwFEShell::SelectObj)

For shapes: shapes
For 2+ shapes: 2 shapes
For draw images: Image with transparency
For text box: Text Frame
For raster images: [Drawing object]

Raster images seem to have NONE object name:

#define STR_ObjNameSingulNONE    NC_("STR_ObjNameSingulNONE", "Drawing object")

rMrkList.GetMarkDescription() can’t classify the raster images?

SAL_DEBUG( rMrkList.GetMarkCount() ); always increases by 1 when selecting drawing objects via SHIFT+CLICK. But always gives 1 when selecting raster images.

All selected objects store in rMrkList list:

const SdrMarkList &rMrkList = pDView->GetMarkedObjectList();

This means raster images added to the list but always be unmarked when GetMarkCount reaches 1. The actual reason of unmarking issue is:

// call Unmark when !bAddSelect or if fly was selected
bool bUnmark = !bAddSelect; // bUnmark is 'false' here 

if ( rMrkList.GetMarkCount() == 1 )
    // if fly was selected, deselect it first
    pOldSelFly = ::GetFlyFromMarked( &rMrkList, this );

    if ( pOldSelFly )

    /* ... */

    bUnmark = true;


    /* ... */

    if ( bUnmark )
        if (pOldSelFly)

With SHIFT+CLICK, pOldSelFly = ::GetFlyFromMarked( &rMrkList, this ); returns 0(null) when selecting the second, third … shape (which is expected); and it doesn’t set bUnmark = true, so it doesn’t execute pDView->UnmarkAll().

However, pOldSelFly = ::GetFlyFromMarked( &rMrkList, this ); always returns an address which is evaluated true in an if ( pOldSelFly ) case. This causes bUnmark = true; and executes if ( bUnmark ). Therefore, when rMrkList.GetMarkCount() == 1 and ::GetFlyFromMarked( &rMrkList, this ) returns an address; rMrkList doesn’t add the second selected raster image to itself and do unmark it.

Frame is not accessible


Another interesting issue is when trying to add(select) a raster image to the shape list (unmarking disabled) debugging warns warn: /*...*/ frame is not accessible.


// ...

bool bShapeSelected = false;

// ...

            else if( pFESh->IsObjSelected() > 0 )
                bShapeSelected = true;
                aFrameOrObj = static_cast<const SwFrame *>( nullptr );

// ... 

    OSL_ENSURE( bShapeSelected || aFrameOrObj.IsAccessible(GetShell()->IsPreview()),
            "frame is not accessible" );

pFESh->IsObjSelected() should return GetMarkCount(), not 0. Otherwise bShapeSelected stays false and OSL_ENSURE warns "frame is not accessible".

/sw/source/core/frmedt/feshview.cxx : SwFEShell::IsObjSelected() and SwFEShell::IsFrameSelected():

size_t SwFEShell::IsObjSelected() const
    if ( IsFrameSelected() || !Imp()->HasDrawView() )
        return 0;

    return Imp()->GetDrawView()->GetMarkedObjectList().GetMarkCount();

bool SwFEShell::IsFrameSelected() const
    if ( !Imp()->HasDrawView() )
        return false;
        return nullptr != ::GetFlyFromMarked( &Imp()->GetDrawView()->GetMarkedObjectList(),
                                        const_cast<SwFEShell*>(this) );

When selecting raster images, in SwFEShell::IsFrameSelected():

return nullptr != ::GetFlyFromMarked( &Imp()->GetDrawView()->GetMarkedObjectList(),
                                        const_cast<SwFEShell*>(this) );

GetFlyFromMarked should return false (0(null)), not an address which make nullptr != 0x01... true.


I also looked at Draw and Calc to see how images are handled. Images are converted a drawing objects and have the same attributes like shapes. But in Writer, images have different attributes and handling.

Summary of last 2 weeks

  • Tried to understand how shapes grouped together
  • Debugging

Next Week TO-DO

  • Make raster images selectable(group) with SHIFT+CLICK