gecko/layout/xul/base/src/nsScrollbarFrame.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 *
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//
// Eric Vaughan
// Netscape Communications
//
// See documentation in associated header file
//

#include "nsScrollbarFrame.h"
#include "nsScrollbarButtonFrame.h"
#include "nsGkAtoms.h"
#include "nsIScrollableFrame.h"
#include "nsIScrollbarMediator.h"

//
// NS_NewToolbarFrame
//
// Creates a new Toolbar frame and returns it
//
nsIFrame*
NS_NewScrollbarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsScrollbarFrame (aPresShell, aContext);
} // NS_NewScrollbarFrame

NS_QUERYFRAME_HEAD(nsScrollbarFrame)
  NS_QUERYFRAME_ENTRY(nsIScrollbarFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)

NS_IMETHODIMP
nsScrollbarFrame::Init(nsIContent* aContent,
                       nsIFrame*   aParent,
                       nsIFrame*   aPrevInFlow)
{
  nsresult  rv = nsBoxFrame::Init(aContent, aParent, aPrevInFlow);

  // We want to be a reflow root since we use reflows to move the
  // slider.  Any reflow inside the scrollbar frame will be a reflow to
  // move the slider and will thus not change anything outside of the
  // scrollbar or change the size of the scrollbar frame.
  mState |= NS_FRAME_REFLOW_ROOT;

  return rv;
}

NS_IMETHODIMP
nsScrollbarFrame::Reflow(nsPresContext*          aPresContext,
                         nsHTMLReflowMetrics&     aDesiredSize,
                         const nsHTMLReflowState& aReflowState,
                         nsReflowStatus&          aStatus)
{
  nsresult rv = nsBoxFrame::Reflow(aPresContext, aDesiredSize, aReflowState, aStatus);
  NS_ENSURE_SUCCESS(rv, rv);

  // nsGfxScrollFrame may have told us to shrink to nothing. If so, make sure our
  // desired size agrees.
  if (aReflowState.availableWidth == 0) {
    aDesiredSize.width = 0;
  }
  if (aReflowState.availableHeight == 0) {
    aDesiredSize.height = 0;
  }

  return NS_OK;
}

/* virtual */ PRBool
nsScrollbarFrame::IsContainingBlock() const
{
  // Return true so that the nsHTMLReflowState code is happy with us
  // being a reflow root.
  return PR_TRUE;
}

nsIAtom*
nsScrollbarFrame::GetType() const
{
  return nsGkAtoms::scrollbarFrame;
}

NS_IMETHODIMP
nsScrollbarFrame::AttributeChanged(PRInt32 aNameSpaceID,
                                   nsIAtom* aAttribute,
                                   PRInt32 aModType)
{
  nsresult rv = nsBoxFrame::AttributeChanged(aNameSpaceID, aAttribute,
                                             aModType);

  // if the current position changes, notify any nsGfxScrollFrame
  // parent we may have
  if (aAttribute != nsGkAtoms::curpos)
    return rv;

  nsIFrame* parent = GetParent();
  if (!parent)
    return rv;

  nsIScrollableFrame* scrollable = do_QueryFrame(parent);
  if (!scrollable)
    return rv;

  scrollable->CurPosAttributeChanged(mContent, aModType);
  return rv;
}

NS_IMETHODIMP
nsScrollbarFrame::HandlePress(nsPresContext* aPresContext, 
                     nsGUIEvent*     aEvent,
                     nsEventStatus*  aEventStatus)
{
  return NS_OK;
}

NS_IMETHODIMP
nsScrollbarFrame::HandleMultiplePress(nsPresContext* aPresContext, 
                     nsGUIEvent*     aEvent,
                     nsEventStatus*  aEventStatus)
{
  return NS_OK;
}

NS_IMETHODIMP 
nsScrollbarFrame::HandleDrag(nsPresContext* aPresContext, 
                              nsGUIEvent*     aEvent,
                              nsEventStatus*  aEventStatus)
{
  return NS_OK;
}

NS_IMETHODIMP 
nsScrollbarFrame::HandleRelease(nsPresContext* aPresContext, 
                                 nsGUIEvent*     aEvent,
                                 nsEventStatus*  aEventStatus)
{
  return NS_OK;
}

void
nsScrollbarFrame::SetScrollbarMediatorContent(nsIContent* aMediator)
{
  mScrollbarMediator = aMediator;
}

nsIScrollbarMediator*
nsScrollbarFrame::GetScrollbarMediator()
{
  if (!mScrollbarMediator)
    return nsnull;
  nsIFrame* f =
    PresContext()->PresShell()->GetPrimaryFrameFor(mScrollbarMediator);
  if (!f)
    return nsnull;

  // check if the frame is a scroll frame. If so, get the scrollable frame
  // inside it.
  nsIScrollableFrame* scrollFrame = do_QueryFrame(f);
  if (scrollFrame) {
    f = scrollFrame->GetScrolledFrame();
    if (!f)
      return nsnull;
  }

  nsIScrollbarMediator* sbm = do_QueryFrame(f);
  return sbm;
}