path: root/iup/src/win/iupwin_canvas.c

/** \file
 * \brief Canvas Control
 *
 * See Copyright Notice in "iup.h"
 */

#include <windows.h>

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <memory.h>
#include <limits.h>

#include "iup.h"
#include "iupcbs.h"

#include "iup_object.h"
#include "iup_childtree.h"
#include "iup_attrib.h"
#include "iup_dialog.h"
#include "iup_str.h"
#include "iup_drv.h"
#include "iup_drvfont.h"
#include "iup_canvas.h"
#include "iup_key.h"

#include "iupwin_drv.h"
#include "iupwin_handle.h"
#include "iupwin_brush.h"


static void winCanvasSetScrollInfo(HWND hWnd, int imin, int imax, int ipos, int ipage, int flag)
{
  SCROLLINFO scrollinfo;
  scrollinfo.cbSize = sizeof(SCROLLINFO);
  scrollinfo.fMask = SIF_RANGE | SIF_PAGE | SIF_POS;
  scrollinfo.nPage = ipage;
  scrollinfo.nPos = ipos;
  scrollinfo.nMax = imax;
  scrollinfo.nMin = imin;
  SetScrollInfo(hWnd, flag, &scrollinfo, TRUE);
}

static int winCanvasSetBgColorAttrib(Ihandle *ih, const char *value)
{
  (void)value;
  iupdrvPostRedraw(ih);
  return 1;
}

static int winCanvasSetDXAttrib(Ihandle *ih, const char *value)
{
  if (ih->data->sb & IUP_SB_HORIZ)
  {
    double posx, xmin, xmax;
    float dx;
    int iposx, ipagex;

    if (!iupStrToFloat(value, &dx))
      return 1;

    xmin = iupAttribGetFloat(ih, "XMIN");
    xmax = iupAttribGetFloat(ih, "XMAX");
    posx = ih->data->posx;

    iupCanvasCalcScrollIntPos(xmin, xmax, dx, posx, 
                              IUP_SB_MIN, IUP_SB_MAX, &ipagex, &iposx);

    if (dx >= (xmax-xmin))
    {
      if (iupAttribGetBoolean(ih, "XAUTOHIDE"))
        ShowScrollBar(ih->handle, SB_HORZ, FALSE);
      else
        EnableScrollBar(ih->handle, SB_HORZ, ESB_DISABLE_BOTH);
      return 1;
    }
    else
    {
      ShowScrollBar(ih->handle, SB_HORZ, TRUE);
      EnableScrollBar(ih->handle, SB_HORZ, ESB_ENABLE_BOTH);
    }

    winCanvasSetScrollInfo(ih->handle, IUP_SB_MIN, IUP_SB_MAX, iposx, ipagex, SB_HORZ);

    /* update position because it could be corrected */
    iupCanvasCalcScrollRealPos(xmin, xmax, &posx, 
                               IUP_SB_MIN, IUP_SB_MAX, ipagex, &iposx);

    ih->data->posx = (float)posx;
  }
  return 1;
}

static int winCanvasSetPosXAttrib(Ihandle *ih, const char *value)
{
  if (ih->data->sb & IUP_SB_HORIZ)
  {
    double xmin, xmax, dx;
    float posx;
    int iposx, ipagex;

    if (!iupStrToFloat(value, &posx))
      return 1;

    xmin = iupAttribGetFloat(ih, "XMIN");
    xmax = iupAttribGetFloat(ih, "XMAX");
    dx = iupAttribGetFloat(ih, "DX");

    if (posx < xmin) posx = (float)xmin;
    if (posx > (xmax - dx)) posx = (float)(xmax - dx);
    ih->data->posx = posx;

    iupCanvasCalcScrollIntPos(xmin, xmax, dx, posx, 
                              IUP_SB_MIN, IUP_SB_MAX, &ipagex, &iposx);

    SetScrollPos(ih->handle,SB_HORZ,iposx,TRUE);
  }
  return 1;
}

static int winCanvasSetDYAttrib(Ihandle *ih, const char *value)
{
  if (ih->data->sb & IUP_SB_VERT)
  {
    double posy, ymin, ymax;
    float dy;
    int iposy, ipagey;

    if (!iupStrToFloat(value, &dy))
      return 1;

    ymin = iupAttribGetFloat(ih, "YMIN");
    ymax = iupAttribGetFloat(ih, "YMAX");
    posy = ih->data->posy;

    iupCanvasCalcScrollIntPos(ymin, ymax, dy, posy, 
                              IUP_SB_MIN, IUP_SB_MAX, &ipagey, &iposy);

    if (dy >= (ymax-ymin))
    {
      if (iupAttribGetBoolean(ih, "YAUTOHIDE"))
        ShowScrollBar(ih->handle, SB_VERT, FALSE);
      else
        EnableScrollBar(ih->handle, SB_VERT, ESB_DISABLE_BOTH);
      return 1;
    }
    else
    {
      ShowScrollBar(ih->handle, SB_VERT, TRUE);
      EnableScrollBar(ih->handle, SB_VERT, ESB_ENABLE_BOTH);
    }

    winCanvasSetScrollInfo(ih->handle, IUP_SB_MIN, IUP_SB_MAX, iposy, ipagey, SB_VERT);

    /* update position because it could be corrected */
    iupCanvasCalcScrollRealPos(ymin, ymax, &posy, 
                               IUP_SB_MIN, IUP_SB_MAX, ipagey, &iposy);

    ih->data->posy = (float)posy;
  }
  return 1;
}

static int winCanvasSetPosYAttrib(Ihandle *ih, const char *value)
{
  if (ih->data->sb & IUP_SB_VERT)
  {
    double ymin, ymax, dy;
    float posy;
    int iposy, ipagey;

    if (!iupStrToFloat(value, &posy))
      return 1;

    ymin = iupAttribGetFloat(ih, "YMIN");
    ymax = iupAttribGetFloat(ih, "YMAX");
    dy = iupAttribGetFloat(ih, "DY");

    if (posy < ymin) posy = (float)ymin;
    if (posy > (ymax - dy)) posy = (float)(ymax - dy);
    ih->data->posy = posy;

    iupCanvasCalcScrollIntPos(ymin, ymax, dy, posy, 
                              IUP_SB_MIN, IUP_SB_MAX, &ipagey, &iposy);

    SetScrollPos(ih->handle,SB_VERT,iposy,TRUE);
  }
  return 1;
}

static void winCanvasGetScrollInfo(HWND hWnd, int *ipos, int *ipage, int flag, int track)
{
  SCROLLINFO scrollinfo;
  scrollinfo.cbSize = sizeof(SCROLLINFO);
  if (track)
    scrollinfo.fMask = SIF_PAGE | SIF_TRACKPOS;
  else
    scrollinfo.fMask = SIF_PAGE | SIF_POS;
  GetScrollInfo(hWnd, flag, &scrollinfo);
  *ipage = scrollinfo.nPage;
  if (track)
    *ipos = scrollinfo.nTrackPos;
  else
    *ipos = scrollinfo.nPos;
}

static void winCanvasUpdateHorScroll(Ihandle* ih, WORD winop)
{
  IFniff cb;
  double xmin, xmax, posx, linex;
  int ipagex, iposx, ilinex, op;

  /* unused */
  if (winop == SB_TOP ||
      winop == SB_BOTTOM ||
      winop == SB_ENDSCROLL)
    return;

  xmax = iupAttribGetFloat(ih,"XMAX");
  xmin = iupAttribGetFloat(ih,"XMIN");

  winCanvasGetScrollInfo(ih->handle, &iposx, &ipagex, SB_HORZ, winop==SB_THUMBTRACK||winop==SB_THUMBPOSITION? 1: 0);

  if (!iupAttribGet(ih,"LINEX"))
  {
    ilinex = ipagex/10;
    if (!ilinex)
      ilinex = 1;
  }
  else
  {
    /* line and page convertions are the same */
    linex = iupAttribGetFloat(ih,"LINEX");
    iupCanvasCalcScrollIntPos(xmin, xmax, linex, 0, 
                              IUP_SB_MIN, IUP_SB_MAX, &ilinex,  NULL);
  }

  switch (winop)
  {
  case SB_LINEDOWN:
    iposx = iposx + ilinex;
    op = IUP_SBRIGHT;
    break;
  case SB_LINEUP:
    iposx = iposx - ilinex;
    op = IUP_SBLEFT;
    break;
  case SB_PAGEDOWN:
    iposx = iposx + ipagex;
    op = IUP_SBPGRIGHT;
    break;
  case SB_PAGEUP:
    iposx = iposx - ipagex;
    op = IUP_SBPGLEFT;
    break;
  case SB_THUMBTRACK:
    op = IUP_SBDRAGH;
    break;
  case SB_THUMBPOSITION:
    op = IUP_SBPOSH;
    break;
  default:
    return;
  }

  iupCanvasCalcScrollRealPos(xmin, xmax, &posx, 
                             IUP_SB_MIN, IUP_SB_MAX, ipagex, &iposx);

  SetScrollPos(ih->handle,SB_HORZ,iposx,TRUE);
  ih->data->posx = (float)posx;

  cb = (IFniff)IupGetCallback(ih,"SCROLL_CB");
  if (cb)
    cb(ih,op,(float)posx,ih->data->posy);
  else
  {
    IFnff cb = (IFnff)IupGetCallback(ih,"ACTION");
    if (cb)
      cb (ih, (float)posx, ih->data->posy);
  }
}

static void winCanvasUpdateVerScroll(Ihandle* ih, WORD winop)
{
  IFniff cb;
  double ymin, ymax, posy, liney;
  int ipagey, iposy, iliney, op;

  /* unused */
  if (winop == SB_TOP ||
      winop == SB_BOTTOM ||
      winop == SB_ENDSCROLL)
    return;

  ymax = iupAttribGetFloat(ih,"YMAX");
  ymin = iupAttribGetFloat(ih,"YMIN");

  winCanvasGetScrollInfo(ih->handle, &iposy, &ipagey, SB_VERT, winop==SB_THUMBTRACK||winop==SB_THUMBPOSITION? 1: 0);

  if (!iupAttribGet(ih, "LINEY"))
  {
    iliney = ipagey/10;
    if (!iliney)
      iliney = 1;
  }
  else
  {
    /* line and page convertions are the same */
    liney = iupAttribGetFloat(ih,"LINEY");
    iupCanvasCalcScrollIntPos(ymin, ymax, liney, 0, 
                              IUP_SB_MIN, IUP_SB_MAX, &iliney,  NULL);
  }

  switch (winop)
  {
  case SB_LINEDOWN:
    iposy = iposy + iliney;
    op = IUP_SBDN;
    break;
  case SB_LINEUP:
    iposy = iposy - iliney;
    op = IUP_SBUP;
    break;
  case SB_PAGEDOWN:
    iposy = iposy + ipagey;
    op = IUP_SBPGDN;
    break;
  case SB_PAGEUP:
    iposy = iposy - ipagey;
    op = IUP_SBPGUP;
    break;
  case SB_THUMBTRACK:
    op = IUP_SBDRAGV;
    break;
  case SB_THUMBPOSITION:
    op = IUP_SBPOSV;
    break;
  default:
    return;
  }

  iupCanvasCalcScrollRealPos(ymin, ymax, &posy, 
                             IUP_SB_MIN, IUP_SB_MAX, ipagey, &iposy);

  SetScrollPos(ih->handle,SB_VERT,iposy,TRUE);
  ih->data->posy = (float)posy;

  cb = (IFniff)IupGetCallback(ih,"SCROLL_CB");
  if (cb)
    cb(ih, op, ih->data->posx,(float)posy);
  else
  {
    IFnff cb = (IFnff)IupGetCallback(ih,"ACTION");
    if (cb)
      cb (ih, ih->data->posx, (float)posy);
  }
}

static int winCanvasProc(Ihandle* ih, UINT msg, WPARAM wp, LPARAM lp, LRESULT *result)
{
  switch (msg)
  {
  case WM_ERASEBKGND:
    /* only paint background if ACTION is not defined */
    if (!IupGetCallback(ih, "ACTION")) 
    {
      RECT rect;
      HDC hdc = (HDC)wp;
      COLORREF color;
      iupwinGetColorRef(ih, "BGCOLOR", &color);
      GetClientRect(ih->handle, &rect); 
      FillRect(hdc, &rect, iupwinBrushGet(color)); 
    }
    else
      InvalidateRect(ih->handle,NULL,FALSE);  /* This will invalidate all area. 
                                                 Necessary in XP, or overlapping windows will have the effect of partial redrawing. */

    /* always return non zero value */
    *result = 1;
    return 1; 
  case WM_PAINT:
    {
      IFnff cb = (IFnff)IupGetCallback(ih, "ACTION");
      if (cb)
      {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(ih->handle, &ps);
        iupAttribSetStr(ih, "HDC_WMPAINT", (char*)hdc);
        iupAttribSetStrf(ih, "CLIPRECT", "%d %d %d %d", ps.rcPaint.left, ps.rcPaint.top, ps.rcPaint.right-ps.rcPaint.left, ps.rcPaint.bottom-ps.rcPaint.top);

        cb(ih, ih->data->posx, ih->data->posy);

        iupAttribSetStr(ih, "CLIPRECT", NULL);
        iupAttribSetStr(ih, "HDC_WMPAINT", NULL);
        EndPaint(ih->handle, &ps);
      }
      break;
    }
  case WM_SIZE:
    {
      IFnii cb = (IFnii)IupGetCallback(ih, "RESIZE_CB");
      if (cb)
      {
        RECT rect;
        GetClientRect(ih->handle, &rect);
        cb(ih, rect.right-rect.left, rect.bottom-rect.top);
        /* w=LOWORD (lp), h=HIWORD(lp) can not be used because and invalid size 
           at the first time of WM_SIZE with scroolbars. */
      }
      *result = 0;
      return 1;
    }
  case WM_GETDLGCODE:
    /* avoid beeps when keys are pressed */
    *result = DLGC_WANTCHARS|DLGC_WANTARROWS;
    return 1;
  case WM_MOUSEWHEEL:
    {
      IFnfiis cb = (IFnfiis)IupGetCallback(ih, "WHEEL_CB");
      short delta = (short)HIWORD(wp);
      if (cb)
      {
        char status[IUPKEY_STATUS_SIZE] = IUPKEY_STATUS_INIT;
        POINT p; 
        p.x = LOWORD(lp); p.y = HIWORD(lp);
        ScreenToClient(ih->handle, &p);

        iupwinButtonKeySetStatus(LOWORD(wp), status, 0);
        
        cb(ih, (float)delta/120.0f, p.x, p.y, status);
      }
      else
      {
        if (ih->data->sb & IUP_SB_VERT)
        {
          int i, winop = delta>0? SB_LINEUP: SB_LINEDOWN;
          delta = (short)abs(delta/120);
          for (i=0; i < delta; i++)
            SendMessage(ih->handle, WM_VSCROLL, MAKELONG(winop, 0), 0);
        }
      }

      *result = 0;
      return 1;
    }
  case WM_XBUTTONDBLCLK:
  case WM_LBUTTONDBLCLK:
  case WM_MBUTTONDBLCLK:
  case WM_RBUTTONDBLCLK:
  case WM_XBUTTONDOWN:
  case WM_LBUTTONDOWN:
  case WM_MBUTTONDOWN:
  case WM_RBUTTONDOWN:
    {
      /* Force focus on canvas click */
      if (iupAttribGetBoolean(ih, "CANFOCUS"))
        SetFocus(ih->handle);

      SetCapture(ih->handle);

      if (iupwinButtonDown(ih, msg, wp, lp))
      {
        /* refresh the cursor, it could have been changed in BUTTON_CB */
        SendMessage(ih->handle, WM_SETCURSOR, (WPARAM)ih->handle, MAKELPARAM(1,WM_MOUSEMOVE));
      }

      if (msg==WM_XBUTTONDOWN || msg==WM_XBUTTONDBLCLK)
        *result = 1;
      else
        *result = 0;
      return 1;
    }
  case WM_MOUSEMOVE:
    {
      if (iupwinMouseMove(ih, msg, wp, lp))
      {
        /* refresh the cursor, it could have been changed in MOTION_CB */
        SendMessage(ih->handle, WM_SETCURSOR, (WPARAM)ih->handle, MAKELPARAM(1,WM_MOUSEMOVE));
      }

      break; /* let iupwinBaseProc process enter/leavewin */
    }
  case WM_XBUTTONUP:
  case WM_LBUTTONUP:
  case WM_MBUTTONUP:
  case WM_RBUTTONUP:
    {
      ReleaseCapture();

      if (iupwinButtonUp(ih, msg, wp, lp))
      {
        /* refresh the cursor, it could have been changed in BUTTON_CB */
        SendMessage(ih->handle, WM_SETCURSOR, (WPARAM)ih->handle, MAKELPARAM(1,WM_MOUSEMOVE));
      }

      *result = 0;
      if (msg==WM_XBUTTONUP)
        *result = 1;
      return 1;
    }
  case WM_KILLFOCUS:
    {
      if (GetCapture() == ih->handle)
        ReleaseCapture();
      break;
    }
  case WM_SETCURSOR: 
    { 
      if (ih->handle == (HWND)wp && LOWORD(lp)==HTCLIENT)
      {
        HCURSOR hCur = (HCURSOR)iupAttribGet(ih, "_IUPWIN_HCURSOR");
        if (hCur)
        {
          SetCursor(hCur); 
          *result = 1;
          return 1;
        }
        else if (iupAttribGet(ih, "CURSOR"))
        {
          SetCursor(NULL); 
          *result = 1;
          return 1;
        }
      }
      break; 
    } 
  case WM_INITMENU:
    /* abort capture if a menu is opened */
    ReleaseCapture();
    break;
  case WM_VSCROLL:
    winCanvasUpdateVerScroll(ih, LOWORD(wp));
    *result = 0;
    return 1;
  case WM_HSCROLL:
    winCanvasUpdateHorScroll(ih, LOWORD(wp));
    *result = 0;
    return 1;
  }

  /* can be a container */
  if (ih->firstchild)
    return iupwinBaseContainerProc(ih, msg, wp, lp, result);
  else
    return iupwinBaseProc(ih, msg, wp, lp, result);
}

static int winCanvasMapMethod(Ihandle* ih)
{
  CLIENTCREATESTRUCT clientstruct;
  void *clientdata = NULL;
  char *classname;
  DWORD dwStyle = WS_CHILD|WS_CLIPSIBLINGS, 
      dwExStyle = 0;

  if (!ih->parent)
    return IUP_ERROR;

  if (ih->iclass->is_interactive)
  {
    if (iupAttribGetBoolean(ih, "CANFOCUS"))
      dwStyle |= WS_TABSTOP;
  }
                           
  if (ih->firstchild) /* can be a container */
    iupwinGetNativeParentStyle(ih, &dwExStyle, &dwStyle);
                           
  if (iupAttribGetBoolean(ih, "MDICLIENT"))  
  {
    /* creating a MDI Client that will be inside the MDI Frame, 
       it will work as parent of all MDI children */
    Ihandle *winmenu = IupGetAttributeHandle(ih, "MDIMENU");

    classname = "mdiclient";

    iupAttribSetStr(ih, "BORDER", "NO");

    iupAttribSetStr(IupGetDialog(ih), "MDICLIENT_HANDLE", (char*)ih);

    clientdata = &clientstruct;
    clientstruct.hWindowMenu = winmenu? winmenu->handle: NULL;

    /* The system increments the identifier 
       for each additional MDI child window the application creates, 
       and reassigns identifiers when the application 
       destroys a window to keep the range of identifiers contiguous. */
    clientstruct.idFirstChild = IUP_MDICHILD_START;
  }
  else 
    classname = "IupCanvas";

  if (iupAttribGetBoolean(ih, "BORDER"))
    dwStyle |= WS_BORDER;

  ih->data->sb = iupBaseGetScrollbar(ih);
  if (ih->data->sb & IUP_SB_HORIZ)
    dwStyle |= WS_HSCROLL;
  if (ih->data->sb & IUP_SB_VERT)
    dwStyle |= WS_VSCROLL;

  ih->serial = iupDialogGetChildId(ih);

  ih->handle = CreateWindowEx(dwExStyle,/* extended style */
          classname,                    /* window class */
          NULL,                         /* title */
          dwStyle,                      /* window style */
          0,                            /* x-position */
          0,                            /* y-position */
          10,                           /* default width to avoid 0 */
          10,                           /* default height to avoid 0 */
          iupChildTreeGetNativeParentHandle(ih),     /* window parent */
          (HMENU)ih->serial,            /* child identifier */
          iupwin_hinstance,             /* instance of app. */
          clientdata);

  if (!ih->handle)
    return IUP_ERROR;

  /* associate HWND with Ihandle*, all Win32 controls must call this. */
  iupwinHandleSet(ih);

  IupSetCallback(ih, "_IUPWIN_OLDPROC_CB", (Icallback)DefWindowProc);
  IupSetCallback(ih, "_IUPWIN_CTRLPROC_CB", (Icallback)winCanvasProc);

  /* configure for DRAG&DROP */
  if (IupGetCallback(ih, "DROPFILES_CB"))
    iupAttribSetStr(ih, "DRAGDROP", "YES");

  return IUP_NOERROR;
}

static void winCanvasMDICloseChildren(Ihandle* client)
{
  HWND hWndChild = (HWND)SendMessage(client->handle, WM_MDIGETACTIVE, 0, 0);

  /* As long as the MDI client has a child, close it */
  while (hWndChild)
  {
    Ihandle* child = iupwinHandleGet(hWndChild); 
    if (iupObjectCheck(child) && iupAttribGetBoolean(child, "MDICHILD"))
      IupDestroy(child);

    hWndChild = (HWND)SendMessage(client->handle, WM_MDIGETACTIVE, 0, 0);
  }
}

static void winCanvasUnMapMethod(Ihandle* ih)
{
  if (iupAttribGetBoolean(ih, "MDICLIENT")) 
  {
    /* hide the MDI client window to avoid multiple re-paints */
    ShowWindow(ih->handle, SW_HIDE);

    /* must destroy all MDI Children */
    winCanvasMDICloseChildren(ih);

    DestroyWindow(ih->handle);

    /* mdiclient class is not a IUP class, must return here */
    return;
  }

  /* remove the association before destroying */
  iupwinHandleRemove(ih);

  /* remove from parent and destroys window */
  SetParent(ih->handle, NULL);
  DestroyWindow(ih->handle);
}

static void winCanvasReleaseMethod(Iclass* ic)
{
  (void)ic;
  if (iupwinClassExist("IupCanvas"))
    UnregisterClass("IupCanvas", iupwin_hinstance);
}

static void winCanvasRegisterClass(void)
{
  WNDCLASS wndclass;
  ZeroMemory(&wndclass, sizeof(WNDCLASS));
  
  wndclass.hInstance      = iupwin_hinstance;
  wndclass.lpszClassName  = "IupCanvas";
  wndclass.lpfnWndProc    = (WNDPROC)iupwinBaseWinProc;
  wndclass.hCursor        = LoadCursor(NULL, IDC_ARROW);
  wndclass.style          = CS_DBLCLKS | CS_OWNDC | CS_HREDRAW | CS_VREDRAW; /* using CS_OWNDC will minimize the work of cdActivate in the CD library */
  wndclass.hbrBackground  = NULL;  /* remove the background to optimize redraw */
   
  RegisterClass(&wndclass);
}

void iupdrvCanvasInitClass(Iclass* ic)
{
  if (!iupwinClassExist("IupCanvas"))
    winCanvasRegisterClass();

  /* Driver Dependent Class functions */
  ic->Map = winCanvasMapMethod;
  ic->UnMap = winCanvasUnMapMethod;
  ic->Release = winCanvasReleaseMethod;

  /* Driver Dependent Attribute functions */

  /* Visual */
  iupClassRegisterAttribute(ic, "BGCOLOR", NULL, winCanvasSetBgColorAttrib, "255 255 255", NULL, IUPAF_DEFAULT);   /* force new default value */

  /* IupCanvas only */
  iupClassRegisterAttribute(ic, "DRAWSIZE", iupdrvBaseGetClientSizeAttrib, NULL, NULL, NULL, IUPAF_READONLY|IUPAF_NO_INHERIT);

  iupClassRegisterAttribute(ic, "DX", NULL, winCanvasSetDXAttrib, "0.1", NULL, IUPAF_NO_INHERIT);  /* force new default value */
  iupClassRegisterAttribute(ic, "DY", NULL, winCanvasSetDYAttrib, "0.1", NULL, IUPAF_NO_INHERIT);  /* force new default value */
  iupClassRegisterAttribute(ic, "POSX", iupCanvasGetPosXAttrib, winCanvasSetPosXAttrib, "0.0", NULL, IUPAF_NO_INHERIT);  /* force new default value */
  iupClassRegisterAttribute(ic, "POSY", iupCanvasGetPosYAttrib, winCanvasSetPosYAttrib, "0.0", NULL, IUPAF_NO_INHERIT);  /* force new default value */
  iupClassRegisterAttribute(ic, "XAUTOHIDE", NULL, NULL, "YES", NULL, IUPAF_NOT_MAPPED);
  iupClassRegisterAttribute(ic, "YAUTOHIDE", NULL, NULL, "YES", NULL, IUPAF_NOT_MAPPED);

  /* IupCanvas Windows only */
  iupClassRegisterAttribute(ic, "DRAGDROP", NULL, iupwinSetDragDropAttrib, NULL, NULL, IUPAF_NO_INHERIT);
  iupClassRegisterAttribute(ic, "HWND", iupBaseGetWidAttrib, NULL, NULL, NULL, IUPAF_NO_STRING|IUPAF_NO_INHERIT);
}