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Changed scrollsub sample.

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4887 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
This commit is contained in:
Robert Roebling
1999-12-09 15:01:04 +00:00
parent d314c3bbb0
commit 178009938b
1 changed files with 49 additions and 7 deletions
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54
samples/scrollsub/scrollsub.cpp
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@@ -154,8 +154,8 @@ MyCanvas::MyCanvas( wxScrolledWindow *parent, wxWindowID id,
{
m_owner = parent;
(void)new wxButton( this, -1, "Hallo I", wxPoint(20,20), wxSize(100,30) );
(void)new wxButton( this, -1, "Hallo II", wxPoint(220,20), wxSize(100,30) );
(void)new wxButton( this, -1, "Hallo I", wxPoint(0,50), wxSize(100,25) );
(void)new wxButton( this, -1, "Hallo II", wxPoint(200,50), wxSize(100,25) );
SetBackgroundColour( *wxWHITE );
@@ -173,13 +173,55 @@ void MyCanvas::OnPaint( wxPaintEvent &WXUNUSED(event) )
dc.SetPen( *wxBLACK_PEN );
dc.DrawText( "Some text", 140, 140 );
// OK, let's assume we are a grid control and we have two
// grid cells. Here in OnPaint we want to know which cell
// to redraw so that we prevent redrawing cells that don't
// need to get redrawn. We have one cell at (0,0) and one
// more at (200,0), both having a size of (100,25).
dc.DrawRectangle( 100, 160, 200, 200 );
// We can query how much the window has been scrolled
// by calling CalcUnscrolledPosition()
dc.SetBrush( *wxTRANSPARENT_BRUSH );
int scroll_x = 0;
int scroll_y = 0;
m_owner->CalcUnscrolledPosition( scroll_x, scroll_y, &scroll_x, &scroll_y );
// We also need to know the size of the window to see which
// cells are completely hidden and not get redrawn
int size_x = 0;
int size_y = 0;
GetClientSize( &size_x, &size_y );
// First cell: (0,0)(100,25)
// It it on screen?
if ((0+100-scroll_x > 0) && (0+25-scroll_y > 0) &&
(0-scroll_x < size_x) && (0-scroll_y < size_y))
{
// Has the region an screen been exposed?
if (IsExposed(0,0,100,25))
{
printf( "Redraw first cell\n" );
dc.DrawRectangle( 0, 0, 100, 25 );
dc.DrawText( "First Cell", 5, 5 );
}
}
// Second cell: (0,200)(100,25)
// It it on screen?
if ((200+100-scroll_x > 0) && (0+25-scroll_y > 0) &&
(200-scroll_x < size_x) && (0-scroll_y < size_y))
{
// Has the region an screen been exposed?
if (IsExposed(200,0,100,25))
{
printf( "Redraw second cell\n" );
dc.DrawRectangle( 200, 0, 100, 25 );
dc.DrawText( "Second Cell", 205, 5 );
}
}
dc.DrawRectangle( 10, 10, 480, 980 );
}