src/apps/haikudepot/ui_generic/ScrollableGroupView.cpp

   1 /*
   2  * Copyright 2013-2014, Stephan Aßmus <superstippi@gmx.de>.
   3  * All rights reserved. Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include "ScrollableGroupView.h"
   8
   9 #include <ScrollBar.h>
  10 #include <SpaceLayoutItem.h>
  11
  12
  13 ScrollableGroupView::ScrollableGroupView()
  14         :
  15         BGroupView(B_VERTICAL, 0.0)
  16 {
  17         AddChild(BSpaceLayoutItem::CreateGlue());
  18 }
  19
  20
  21 BSize
  22 ScrollableGroupView::MinSize()
  23 {
  24         BSize minSize = BGroupView::MinSize();
  25         return BSize(minSize.width, 80);
  26 }
  27
  28
  29 void
  30 ScrollableGroupView::DoLayout()
  31 {
  32         BGroupView::DoLayout();
  33
  34         BScrollBar* scrollBar = ScrollBar(B_VERTICAL);
  35
  36         if (scrollBar == NULL)
  37                 return;
  38
  39         BRect layoutArea = GroupLayout()->LayoutArea();
  40         float layoutHeight = layoutArea.Height();
  41         // Min size is not reliable with HasHeightForWidth() children,
  42         // since it does not reflect how those children are currently
  43         // laid out, but what their theoretical minimum size would be.
  44
  45         BLayoutItem* lastItem = GroupLayout()->ItemAt(
  46                 GroupLayout()->CountItems() - 1);
  47         if (lastItem != NULL)
  48                 layoutHeight = lastItem->Frame().bottom;
  49
  50         float viewHeight = Bounds().Height();
  51
  52         float max = layoutHeight- viewHeight;
  53         scrollBar->SetRange(0, max);
  54         if (layoutHeight > 0)
  55                 scrollBar->SetProportion(viewHeight / layoutHeight);
  56         else
  57                 scrollBar->SetProportion(1);
  58 }