guarding scrollbar

[wxWidgets.git] / src / generic / dragimgg.cpp

diff --git a/src/generic/dragimgg.cpp b/src/generic/dragimgg.cpp
index 8c1b4ab485d33dc22f1470ae00c76fd7c17b8a10..31dcc04f7a051620446b53eddea702dd796e2961 100644 (file)
--- a/src/generic/dragimgg.cpp
+++ b/src/generic/dragimgg.cpp
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////

-// Name:        dragimgg.cpp
+// Name:        src/generic/dragimgg.cpp

 // Purpose:     Generic wxDragImage implementation
 // Author:      Julian Smart
 // Modified by:
 // Purpose:     Generic wxDragImage implementation
 // Author:      Julian Smart
 // Modified by:


@@ -17,42 +17,29 @@
 // headers
 // ----------------------------------------------------------------------------
 
 // headers
 // ----------------------------------------------------------------------------
 

-#ifdef __GNUG__
-#pragma implementation "dragimgg.h"
-#endif
-

 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__
 // For compilers that support precompilation, includes "wx.h".
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__

-#pragma hdrstop
+    #pragma hdrstop

 #endif
 
 #if wxUSE_DRAGIMAGE
 
 #ifndef WX_PRECOMP
 #endif
 
 #if wxUSE_DRAGIMAGE
 
 #ifndef WX_PRECOMP

-#include <stdio.h>
-#include "wx/setup.h"
-#include "wx/window.h"
-#include "wx/frame.h"
-#include "wx/dcclient.h"
-#include "wx/dcscreen.h"
-#include "wx/dcmemory.h"
-#include "wx/settings.h"
+    #include <stdio.h>
+    #include "wx/window.h"
+    #include "wx/frame.h"
+    #include "wx/dcclient.h"
+    #include "wx/dcscreen.h"
+    #include "wx/dcmemory.h"
+    #include "wx/settings.h"
+    #include "wx/intl.h"
+    #include "wx/log.h"
+    #include "wx/image.h"

 #endif
 
 #endif
 

-#include "wx/log.h"
-#include "wx/intl.h"
-
-#ifdef __WIN16__
-#define wxUSE_IMAGE_IN_DRAGIMAGE 0
-#else

 #define wxUSE_IMAGE_IN_DRAGIMAGE 1
 #define wxUSE_IMAGE_IN_DRAGIMAGE 1

-#endif
-
-#if wxUSE_IMAGE_IN_DRAGIMAGE
-#include "wx/image.h"
-#endif

 
 #include "wx/generic/dragimgg.h"
 
 
 #include "wx/generic/dragimgg.h"
 


@@ -80,14 +67,67 @@ wxGenericDragImage::~wxGenericDragImage()
 
 void wxGenericDragImage::Init()
 {
 
 void wxGenericDragImage::Init()
 {

-    m_isDirty = FALSE;
-    m_isShown = FALSE;
-    m_windowDC = (wxDC*) NULL;
-    m_window = (wxWindow*) NULL;
-    m_fullScreen = FALSE;
-    m_pBackingBitmap = (wxBitmap*) NULL;
+    m_isDirty = false;
+    m_isShown = false;
+    m_windowDC = NULL;
+    m_window = NULL;
+    m_fullScreen = false;
+#ifdef wxHAS_NATIVE_OVERLAY
+    m_dcOverlay = NULL;
+#else
+    m_pBackingBitmap = NULL;
+#endif
+}
+
+#if WXWIN_COMPATIBILITY_2_6
+wxGenericDragImage::wxGenericDragImage(const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    Init();
+    Create(cursor);
+}
+
+wxGenericDragImage::wxGenericDragImage(const wxBitmap& image, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    Init();
+
+    Create(image, cursor);
+}
+
+wxGenericDragImage::wxGenericDragImage(const wxIcon& image, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    Init();
+
+    Create(image, cursor);
+}
+
+wxGenericDragImage::wxGenericDragImage(const wxString& str, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    Init();
+
+    Create(str, cursor);
+}
+
+bool wxGenericDragImage::Create(const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    return Create(cursor);

 }
 
 }
 

+bool wxGenericDragImage::Create(const wxBitmap& image, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    return Create(image, cursor);
+}
+
+bool wxGenericDragImage::Create(const wxIcon& image, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    return Create(image, cursor);
+}
+
+bool wxGenericDragImage::Create(const wxString& str, const wxCursor& cursor, const wxPoint& WXUNUSED(cursorHotspot))
+{
+    return Create(str, cursor);
+}
+#endif // WXWIN_COMPATIBILITY_2_6
+

 // Attributes
 ////////////////////////////////////////////////////////////////////////////
 
 // Attributes
 ////////////////////////////////////////////////////////////////////////////
 


@@ -100,7 +140,7 @@ bool wxGenericDragImage::Create(const wxCursor& cursor)
 {
     m_cursor = cursor;
 
 {
     m_cursor = cursor;
 

-    return TRUE;
+    return true;

 }
 
 // Create a drag image from a bitmap and optional cursor
 }
 
 // Create a drag image from a bitmap and optional cursor


@@ -112,7 +152,7 @@ bool wxGenericDragImage::Create(const wxBitmap& image, const wxCursor& cursor)
     m_cursor = cursor;
     m_bitmap = image;
 
     m_cursor = cursor;
     m_bitmap = image;
 

-    return TRUE ;
+    return true ;

 }
 
 // Create a drag image from an icon and optional cursor
 }
 
 // Create a drag image from an icon and optional cursor


@@ -124,7 +164,7 @@ bool wxGenericDragImage::Create(const wxIcon& image, const wxCursor& cursor)
     m_cursor = cursor;
     m_icon = image;
 
     m_cursor = cursor;
     m_icon = image;
 

-    return TRUE ;
+    return true ;

 }
 
 // Create a drag image from a string and optional cursor
 }
 
 // Create a drag image from a string and optional cursor


@@ -132,22 +172,22 @@ bool wxGenericDragImage::Create(const wxString& str, const wxCursor& cursor)
 {
     wxFont font(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
 
 {
     wxFont font(wxSystemSettings::GetFont(wxSYS_DEFAULT_GUI_FONT));
 

-    long w, h;
+    wxCoord w = 0, h = 0;

     wxScreenDC dc;
     dc.SetFont(font);
     dc.GetTextExtent(str, & w, & h);
     dc.SetFont(wxNullFont);
 
     wxMemoryDC dc2;
     wxScreenDC dc;
     dc.SetFont(font);
     dc.GetTextExtent(str, & w, & h);
     dc.SetFont(wxNullFont);
 
     wxMemoryDC dc2;

-    dc2.SetFont(font);

 
     // Sometimes GetTextExtent isn't accurate enough, so make it longer
     wxBitmap bitmap((int) ((w+2) * 1.5), (int) h+2);
     dc2.SelectObject(bitmap);
 
 
     // Sometimes GetTextExtent isn't accurate enough, so make it longer
     wxBitmap bitmap((int) ((w+2) * 1.5), (int) h+2);
     dc2.SelectObject(bitmap);
 

+    dc2.SetFont(font);

     dc2.SetBackground(* wxWHITE_BRUSH);
     dc2.Clear();
     dc2.SetBackground(* wxWHITE_BRUSH);
     dc2.Clear();

-    dc2.SetBackgroundMode(wxTRANSPARENT);
+    dc2.SetBackgroundMode(wxBRUSHSTYLE_TRANSPARENT);

     dc2.SetTextForeground(* wxLIGHT_GREY);
     dc2.DrawText(str, 0, 0);
     dc2.DrawText(str, 1, 0);
     dc2.SetTextForeground(* wxLIGHT_GREY);
     dc2.DrawText(str, 0, 0);
     dc2.DrawText(str, 1, 0);


@@ -162,7 +202,7 @@ bool wxGenericDragImage::Create(const wxString& str, const wxCursor& cursor)
 
     dc2.SelectObject(wxNullBitmap);
 
 
     dc2.SelectObject(wxNullBitmap);
 

-#if wxUSE_IMAGE_IN_DRAGIMAGE
+#if wxUSE_IMAGE_IN_DRAGIMAGE && (!defined(__WXMSW__) || wxUSE_WXDIB)

     // Make the bitmap masked
     wxImage image = bitmap.ConvertToImage();
     image.SetMaskColour(255, 255, 255);
     // Make the bitmap masked
     wxImage image = bitmap.ConvertToImage();
     image.SetMaskColour(255, 255, 255);


@@ -172,19 +212,23 @@ bool wxGenericDragImage::Create(const wxString& str, const wxCursor& cursor)
     return Create(bitmap, cursor);
 }
 
     return Create(bitmap, cursor);
 }
 

+#if wxUSE_TREECTRL

 // Create a drag image for the given tree control item
 bool wxGenericDragImage::Create(const wxTreeCtrl& treeCtrl, wxTreeItemId& id)
 {
     wxString str = treeCtrl.GetItemText(id);
     return Create(str);
 }
 // Create a drag image for the given tree control item
 bool wxGenericDragImage::Create(const wxTreeCtrl& treeCtrl, wxTreeItemId& id)
 {
     wxString str = treeCtrl.GetItemText(id);
     return Create(str);
 }

+#endif

 
 

+#if wxUSE_LISTCTRL

 // Create a drag image for the given list control item
 bool wxGenericDragImage::Create(const wxListCtrl& listCtrl, long id)
 {
     wxString str = listCtrl.GetItemText(id);
     return Create(str);
 }
 // Create a drag image for the given list control item
 bool wxGenericDragImage::Create(const wxListCtrl& listCtrl, long id)
 {
     wxString str = listCtrl.GetItemText(id);
     return Create(str);
 }

+#endif

 
 // Begin drag
 bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,
 
 // Begin drag
 bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,


@@ -192,7 +236,7 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,
                                    bool fullScreen,
                                    wxRect* rect)
 {
                                    bool fullScreen,
                                    wxRect* rect)
 {

-    wxASSERT_MSG( (window != 0), wxT("Window must not be null in BeginDrag."));
+    wxCHECK_MSG( window, false, wxT("Window must not be null in BeginDrag."));

 
     // The image should be offset by this amount
     m_offset = hotspot;
 
     // The image should be offset by this amount
     m_offset = hotspot;


@@ -202,25 +246,22 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,
     if (rect)
         m_boundingRect = * rect;
 
     if (rect)
         m_boundingRect = * rect;
 

-    m_isDirty = FALSE;
-    m_isDirty = FALSE;
+    m_isDirty = false;
+    m_isDirty = false;

 
 

-    if (window)
+    if (m_cursor.Ok())

     {
     {

-        window->CaptureMouse();
-
-        if (m_cursor.Ok())
-        {
-            m_oldCursor = window->GetCursor();
-            window->SetCursor(m_cursor);
-        }
+        m_oldCursor = window->GetCursor();
+        window->SetCursor(m_cursor);

     }
 
     }
 

+    window->CaptureMouse();
+

     // Make a copy of the window so we can repair damage done as the image is
     // dragged.
 
     wxSize clientSize;
     // Make a copy of the window so we can repair damage done as the image is
     // dragged.
 
     wxSize clientSize;

-    wxPoint pt(0, 0);
+    wxPoint pt;

     if (!m_fullScreen)
     {
         clientSize = window->GetClientSize();
     if (!m_fullScreen)
     {
         clientSize = window->GetClientSize();


@@ -244,10 +285,12 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,
         }
     }
 
         }
     }
 

+#ifndef wxHAS_NATIVE_OVERLAY

     wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
 
     if (!backing->Ok() || (backing->GetWidth() < clientSize.x || backing->GetHeight() < clientSize.y))
         (*backing) = wxBitmap(clientSize.x, clientSize.y);
     wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
 
     if (!backing->Ok() || (backing->GetWidth() < clientSize.x || backing->GetHeight() < clientSize.y))
         (*backing) = wxBitmap(clientSize.x, clientSize.y);

+#endif // !wxHAS_NATIVE_OVERLAY

 
     if (!m_fullScreen)
     {
 
     if (!m_fullScreen)
     {


@@ -266,7 +309,7 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot,
             m_boundingRect.width, m_boundingRect.height);
     }
 
             m_boundingRect.width, m_boundingRect.height);
     }
 

-    return TRUE;
+    return true;

 }
 
 // Begin drag. hotspot is the location of the drag position relative to the upper-left
 }
 
 // Begin drag. hotspot is the location of the drag position relative to the upper-left


@@ -278,7 +321,7 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot, wxWindow* window, wxW
 
     int x = fullScreenRect->GetPosition().x;
     int y = fullScreenRect->GetPosition().y;
 
     int x = fullScreenRect->GetPosition().x;
     int y = fullScreenRect->GetPosition().y;

-    
+

     wxSize sz = fullScreenRect->GetSize();
 
     if (fullScreenRect->GetParent() && !fullScreenRect->IsKindOf(CLASSINFO(wxFrame)))
     wxSize sz = fullScreenRect->GetSize();
 
     if (fullScreenRect->GetParent() && !fullScreenRect->IsKindOf(CLASSINFO(wxFrame)))


@@ -287,7 +330,7 @@ bool wxGenericDragImage::BeginDrag(const wxPoint& hotspot, wxWindow* window, wxW
     rect.x = x; rect.y = y;
     rect.width = sz.x; rect.height = sz.y;
 
     rect.x = x; rect.y = y;
     rect.width = sz.x; rect.height = sz.y;
 

-    return BeginDrag(hotspot, window, TRUE, & rect);
+    return BeginDrag(hotspot, window, true, & rect);

 }
 
 // End drag
 }
 
 // End drag


@@ -295,7 +338,13 @@ bool wxGenericDragImage::EndDrag()
 {
     if (m_window)
     {
 {
     if (m_window)
     {

-        m_window->ReleaseMouse();
+#ifdef __WXMSW__
+        // Under Windows we can be pretty sure this test will give
+        // the correct results
+        if (wxWindow::GetCapture() == m_window)
+#endif
+            m_window->ReleaseMouse();
+

         if (m_cursor.Ok() && m_oldCursor.Ok())
         {
             m_window->SetCursor(m_oldCursor);
         if (m_cursor.Ok() && m_oldCursor.Ok())
         {
             m_window->SetCursor(m_oldCursor);


@@ -304,21 +353,27 @@ bool wxGenericDragImage::EndDrag()
 
     if (m_windowDC)
     {
 
     if (m_windowDC)
     {

+#ifdef wxHAS_NATIVE_OVERLAY
+        m_overlay.Reset();
+#else

         m_windowDC->DestroyClippingRegion();
         m_windowDC->DestroyClippingRegion();

+#endif

         delete m_windowDC;
         delete m_windowDC;

-        m_windowDC = (wxDC*) NULL;
+        m_windowDC = NULL;

     }
 
     }
 

+#ifndef wxHAS_NATIVE_OVERLAY

     m_repairBitmap = wxNullBitmap;
     m_repairBitmap = wxNullBitmap;

+#endif

 
 

-    return TRUE;
+    return true;

 }
 
 // Move the image: call from OnMouseMove. Pt is in window client coordinates if window
 // is non-NULL, or in screen coordinates if NULL.
 bool wxGenericDragImage::Move(const wxPoint& pt)
 {
 }
 
 // Move the image: call from OnMouseMove. Pt is in window client coordinates if window
 // is non-NULL, or in screen coordinates if NULL.
 bool wxGenericDragImage::Move(const wxPoint& pt)
 {

-    wxASSERT_MSG( (m_windowDC != (wxDC*) NULL), wxT("No window DC in wxGenericDragImage::Move()") );
+    wxASSERT_MSG( (m_windowDC != NULL), wxT("No window DC in wxGenericDragImage::Move()") );

 
     wxPoint pt2(pt);
     if (m_fullScreen)
 
     wxPoint pt2(pt);
     if (m_fullScreen)


@@ -328,22 +383,22 @@ bool wxGenericDragImage::Move(const wxPoint& pt)
     wxPoint oldPos = m_position;
 
     bool eraseOldImage = (m_isDirty && m_isShown);
     wxPoint oldPos = m_position;
 
     bool eraseOldImage = (m_isDirty && m_isShown);

-    
+

     if (m_isShown)
     if (m_isShown)

-        RedrawImage(oldPos - m_offset, pt2 - m_offset, eraseOldImage, TRUE);
+        RedrawImage(oldPos - m_offset, pt2 - m_offset, eraseOldImage, true);

 
     m_position = pt2;
 
     if (m_isShown)
 
     m_position = pt2;
 
     if (m_isShown)

-        m_isDirty = TRUE;
+        m_isDirty = true;

 
 

-    return TRUE;
+    return true;

 }
 
 bool wxGenericDragImage::Show()
 {
 }
 
 bool wxGenericDragImage::Show()
 {

-    wxASSERT_MSG( (m_windowDC != (wxDC*) NULL), wxT("No window DC in wxGenericDragImage::Show()") );
-    
+    wxASSERT_MSG( (m_windowDC != NULL), wxT("No window DC in wxGenericDragImage::Show()") );
+

     // Show at the current position
 
     if (!m_isShown)
     // Show at the current position
 
     if (!m_isShown)


@@ -351,6 +406,7 @@ bool wxGenericDragImage::Show()
         // This is where we restore the backing bitmap, in case
         // something has changed on the window.
 
         // This is where we restore the backing bitmap, in case
         // something has changed on the window.
 

+#ifndef wxHAS_NATIVE_OVERLAY

         wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
         wxMemoryDC memDC;
         memDC.SelectObject(* backing);
         wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
         wxMemoryDC memDC;
         memDC.SelectObject(* backing);


@@ -359,14 +415,15 @@ bool wxGenericDragImage::Show()
 
         //memDC.Blit(0, 0, m_boundingRect.width, m_boundingRect.height, m_windowDC, m_boundingRect.x, m_boundingRect.y);
         memDC.SelectObject(wxNullBitmap);
 
         //memDC.Blit(0, 0, m_boundingRect.width, m_boundingRect.height, m_windowDC, m_boundingRect.x, m_boundingRect.y);
         memDC.SelectObject(wxNullBitmap);

+#endif // !wxHAS_NATIVE_OVERLAY

 
 

-        RedrawImage(m_position - m_offset, m_position - m_offset, FALSE, TRUE);
+        RedrawImage(m_position - m_offset, m_position - m_offset, false, true);

     }
 
     }
 

-    m_isShown = TRUE;
-    m_isDirty = TRUE;
+    m_isShown = true;
+    m_isDirty = true;

 
 

-    return TRUE;
+    return true;

 }
 
 bool wxGenericDragImage::UpdateBackingFromWindow(wxDC& windowDC, wxMemoryDC& destDC,
 }
 
 bool wxGenericDragImage::UpdateBackingFromWindow(wxDC& windowDC, wxMemoryDC& destDC,


@@ -378,31 +435,41 @@ bool wxGenericDragImage::UpdateBackingFromWindow(wxDC& windowDC, wxMemoryDC& des
 
 bool wxGenericDragImage::Hide()
 {
 
 bool wxGenericDragImage::Hide()
 {

-    wxASSERT_MSG( (m_windowDC != (wxDC*) NULL), wxT("No window DC in wxGenericDragImage::Hide()") );
+    wxASSERT_MSG( (m_windowDC != NULL), wxT("No window DC in wxGenericDragImage::Hide()") );

 
     // Repair the old position
 
     if (m_isShown && m_isDirty)
     {
 
     // Repair the old position
 
     if (m_isShown && m_isDirty)
     {

-        RedrawImage(m_position - m_offset, m_position - m_offset, TRUE, FALSE);
+        RedrawImage(m_position - m_offset, m_position - m_offset, true, false);

     }
 
     }
 

-    m_isShown = FALSE;
-    m_isDirty = FALSE;
+    m_isShown = false;
+    m_isDirty = false;

 
 

-    return TRUE;
+    return true;

 }
 
 // More efficient: erase and redraw simultaneously if possible
 }
 
 // More efficient: erase and redraw simultaneously if possible

-bool wxGenericDragImage::RedrawImage(const wxPoint& oldPos, const wxPoint& newPos,
+bool wxGenericDragImage::RedrawImage(const wxPoint& oldPos,
+                                     const wxPoint& newPos,

                                      bool eraseOld, bool drawNew)
 {
     if (!m_windowDC)
                                      bool eraseOld, bool drawNew)
 {
     if (!m_windowDC)

-        return FALSE;
+        return false;
+
+#ifdef wxHAS_NATIVE_OVERLAY
+    wxUnusedVar(oldPos);

 
 

+    wxDCOverlay dcoverlay( m_overlay, (wxWindowDC*) m_windowDC ) ;
+    if ( eraseOld )
+        dcoverlay.Clear() ;
+    if (drawNew)
+        DoDrawImage(*m_windowDC, newPos);
+#else // !wxHAS_NATIVE_OVERLAY

     wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
     if (!backing->Ok())
     wxBitmap* backing = (m_pBackingBitmap ? m_pBackingBitmap : (wxBitmap*) & m_backingBitmap);
     if (!backing->Ok())

-        return FALSE;
+        return false;

 
     wxRect oldRect(GetImageRect(oldPos));
     wxRect newRect(GetImageRect(newPos));
 
     wxRect oldRect(GetImageRect(oldPos));
     wxRect newRect(GetImageRect(newPos));


@@ -465,8 +532,9 @@ bool wxGenericDragImage::RedrawImage(const wxPoint& oldPos, const wxPoint& newPo
 
     memDCTemp.SelectObject(wxNullBitmap);
     memDC.SelectObject(wxNullBitmap);
 
     memDCTemp.SelectObject(wxNullBitmap);
     memDC.SelectObject(wxNullBitmap);

+#endif // wxHAS_NATIVE_OVERLAY/!wxHAS_NATIVE_OVERLAY

 
 

-    return TRUE;
+    return true;

 }
 
 // Override this if you are using a virtual image (drawing your own image)
 }
 
 // Override this if you are using a virtual image (drawing your own image)


@@ -475,15 +543,15 @@ bool wxGenericDragImage::DoDrawImage(wxDC& dc, const wxPoint& pos) const
     if (m_bitmap.Ok())
     {
         dc.DrawBitmap(m_bitmap, pos.x, pos.y, (m_bitmap.GetMask() != 0));
     if (m_bitmap.Ok())
     {
         dc.DrawBitmap(m_bitmap, pos.x, pos.y, (m_bitmap.GetMask() != 0));

-        return TRUE;
+        return true;

     }
     else if (m_icon.Ok())
     {
         dc.DrawIcon(m_icon, pos.x, pos.y);
     }
     else if (m_icon.Ok())
     {
         dc.DrawIcon(m_icon, pos.x, pos.y);

-        return TRUE;
+        return true;

     }
     else
     }
     else

-        return FALSE;
+        return false;

 }
 
 // Override this if you are using a virtual image (drawing your own image)
 }
 
 // Override this if you are using a virtual image (drawing your own image)