caret.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

{
  ME_DisplayItem *pNext, *pLastRun;
  pNext = ME_FindItemFwd(pRow, diRunOrStartRow);
  assert(pNext->type == diRun);
  pLastRun = pNext;
  *pbCaretAtEnd = FALSE;
  do {
    int run_x = pNext->member.run.pt.x;
    int width = pNext->member.run.nWidth;
    if (x < run_x)
    {
      if (pOffset) *pOffset = 0;
      return pNext;
    }
    if (x >= run_x && x < run_x+width)
    {
      int ch = ME_CharFromPointCursor(editor, x-run_x, &pNext->member.run);
      ME_String *s = pNext->member.run.strText;
      if (ch < s->nLen) {
        if (pOffset)
          *pOffset = ch;
        return pNext;          
      }
    }
    pLastRun = pNext;
    pNext = ME_FindItemFwd(pNext, diRunOrStartRow);
  } while(pNext && pNext->type == diRun);
  
  if ((pLastRun->member.run.nFlags & MERF_ENDPARA) == 0)
  {
    pNext = ME_FindItemFwd(pNext, diRun);
    if (pbCaretAtEnd) *pbCaretAtEnd = 1;
    if (pOffset) *pOffset = 0;
    return pNext;
  } else {
    if (pbCaretAtEnd) *pbCaretAtEnd = 0;
    if (pOffset) *pOffset = 0;
    return pLastRun;
  }
}

static int ME_GetXForArrow(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRun = pCursor->pRun;
  int x;

  if (editor->nUDArrowX != -1)
    x = editor->nUDArrowX;
  else {
    if (editor->bCaretAtEnd)
    {
      pRun = ME_FindItemBack(pRun, diRun);
      assert(pRun);
      x = pRun->member.run.pt.x + pRun->member.run.nWidth;
    }
    else {
      x = pRun->member.run.pt.x;
      x += ME_PointFromChar(editor, &pRun->member.run, pCursor->nOffset);
    }
    editor->nUDArrowX = x;
  }
  return x;
}


static void
ME_MoveCursorLines(ME_TextEditor *editor, ME_Cursor *pCursor, int nRelOfs)
{
  ME_DisplayItem *pRun = pCursor->pRun;
  ME_DisplayItem *pItem;
  int x = ME_GetXForArrow(editor, pCursor);

  if (editor->bCaretAtEnd && !pCursor->nOffset)
    pRun = ME_FindItemBack(pRun, diRun);
  if (!pRun)
    return;
  if (nRelOfs == -1)
  {
    /* start of this row */
    pItem = ME_FindItemBack(pRun, diStartRow);
    assert(pItem);
    /* start of the previous row */
    pItem = ME_FindItemBack(pItem, diStartRow);
  }
  else
  {
    /* start of the next row */
    pItem = ME_FindItemFwd(pRun, diStartRow);
    /* FIXME If diParagraph is before diStartRow, wrap the next paragraph?
    */
  }
  if (!pItem)
  {
    /* row not found - ignore */
    return;
  }
  pCursor->pRun = ME_FindRunInRow(editor, pItem, x, &pCursor->nOffset, &editor->bCaretAtEnd);
  assert(pCursor->pRun);
  assert(pCursor->pRun->type == diRun);
}


static void ME_ArrowPageUp(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRun = pCursor->pRun;
  ME_DisplayItem *pLast, *p;
  int x, y, ys, yd, yp, yprev;
  ME_Cursor tmp_curs = *pCursor;
  
  x = ME_GetXForArrow(editor, pCursor);
  if (!pCursor->nOffset && editor->bCaretAtEnd)
    pRun = ME_FindItemBack(pRun, diRun);
  
  p = ME_FindItemBack(pRun, diStartRowOrParagraph);
  assert(p->type == diStartRow);
  yp = ME_FindItemBack(p, diParagraph)->member.para.nYPos;
  yprev = ys = y = yp + p->member.row.nYPos;
  yd = y - editor->sizeWindow.cy;
  pLast = p;
  
  do {
    p = ME_FindItemBack(p, diStartRowOrParagraph);
    if (!p)
      break;
    if (p->type == diParagraph) { /* crossing paragraphs */
      if (p->member.para.prev_para == NULL)
        break;
      yp = p->member.para.prev_para->member.para.nYPos;
      continue;
    }
    y = yp + p->member.row.nYPos;
    if (y < yd)
      break;
    pLast = p;
    yprev = y;
  } while(1);
  
  pCursor->pRun = ME_FindRunInRow(editor, pLast, x, &pCursor->nOffset, &editor->bCaretAtEnd);
  ME_UpdateSelection(editor, &tmp_curs);
  if (yprev < editor->sizeWindow.cy)
  {
    ME_EnsureVisible(editor, ME_FindItemFwd(editor->pBuffer->pFirst, diRun));
    ME_Repaint(editor);
  }
  else 
  {
    ME_ScrollUp(editor, ys-yprev);
  }
  assert(pCursor->pRun);
  assert(pCursor->pRun->type == diRun);
}

/* FIXME: in the original RICHEDIT, PageDown always scrolls by the same amount 
   of pixels, even if it makes the scroll bar position exceed its normal maximum.
   In such a situation, clicking the scrollbar restores its position back to the
   normal range (ie. sets it to (doclength-screenheight)). */

static void ME_ArrowPageDown(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRun = pCursor->pRun;
  ME_DisplayItem *pLast, *p;
  int x, y, ys, yd, yp, yprev;
  ME_Cursor tmp_curs = *pCursor;
  
  x = ME_GetXForArrow(editor, pCursor);
  if (!pCursor->nOffset && editor->bCaretAtEnd)
    pRun = ME_FindItemBack(pRun, diRun);
  
  p = ME_FindItemBack(pRun, diStartRowOrParagraph);
  assert(p->type == diStartRow);
  yp = ME_FindItemBack(p, diParagraph)->member.para.nYPos;
  yprev = ys = y = yp + p->member.row.nYPos;
  yd = y + editor->sizeWindow.cy;
  pLast = p;
  
  do {
    p = ME_FindItemFwd(p, diStartRowOrParagraph);
    if (!p)
      break;
    if (p->type == diParagraph) {
      yp = p->member.para.nYPos;
      continue;
    }
    y = yp + p->member.row.nYPos;
    if (y >= yd)
      break;
    pLast = p;
    yprev = y;
  } while(1);
  
  pCursor->pRun = ME_FindRunInRow(editor, pLast, x, &pCursor->nOffset, &editor->bCaretAtEnd);
  ME_UpdateSelection(editor, &tmp_curs);
  if (yprev >= editor->nTotalLength-editor->sizeWindow.cy)
  {
    ME_EnsureVisible(editor, ME_FindItemBack(editor->pBuffer->pLast, diRun));
    ME_Repaint(editor);
  }
  else 
  {
    ME_ScrollUp(editor,ys-yprev);
  }
  assert(pCursor->pRun);
  assert(pCursor->pRun->type == diRun);
}

static void ME_ArrowHome(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRow = ME_FindItemBack(pCursor->pRun, diStartRow);
  /* bCaretAtEnd doesn't make sense if the cursor isn't set at the
  first character of the next row */
  assert(!editor->bCaretAtEnd || !pCursor->nOffset);
  ME_WrapMarkedParagraphs(editor);
  if (pRow) {
    ME_DisplayItem *pRun;
    if (editor->bCaretAtEnd && !pCursor->nOffset) {
      pRow = ME_FindItemBack(pRow, diStartRow);
      if (!pRow)
        return;
    }
    pRun = ME_FindItemFwd(pRow, diRun);
    if (pRun) {
      pCursor->pRun = pRun;
      pCursor->nOffset = 0;
    }
  }
  editor->bCaretAtEnd = FALSE;
}

static void ME_ArrowCtrlHome(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRow = ME_FindItemBack(pCursor->pRun, diTextStart);
  if (pRow) {
    ME_DisplayItem *pRun = ME_FindItemFwd(pRow, diRun);
    if (pRun) {
      pCursor->pRun = pRun;
      pCursor->nOffset = 0;
    }
  }
}

static void ME_ArrowEnd(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *pRow;
  
  if (editor->bCaretAtEnd && !pCursor->nOffset)
    return;
  
  pRow = ME_FindItemFwd(pCursor->pRun, diStartRowOrParagraphOrEnd);
  assert(pRow);
  if (pRow->type == diStartRow) {
    /* FIXME WTF was I thinking about here ? */
    ME_DisplayItem *pRun = ME_FindItemFwd(pRow, diRun);
    assert(pRun);
    pCursor->pRun = pRun;
    pCursor->nOffset = 0;
    editor->bCaretAtEnd = 1;
    return;
  }
  pCursor->pRun = ME_FindItemBack(pRow, diRun);
  assert(pCursor->pRun && pCursor->pRun->member.run.nFlags & MERF_ENDPARA);
  pCursor->nOffset = 0;
  editor->bCaretAtEnd = FALSE;
}
      
static void ME_ArrowCtrlEnd(ME_TextEditor *editor, ME_Cursor *pCursor)
{
  ME_DisplayItem *p = ME_FindItemFwd(pCursor->pRun, diTextEnd);
  assert(p);
  p = ME_FindItemBack(p, diRun);
  assert(p);
  assert(p->member.run.nFlags & MERF_ENDPARA);
  pCursor->pRun = p;
  pCursor->nOffset = 0;
  editor->bCaretAtEnd = FALSE;
}

BOOL ME_IsSelection(ME_TextEditor *editor)
{
  return memcmp(&editor->pCursors[0], &editor->pCursors[1], sizeof(ME_Cursor))!=0;
}

static int ME_GetSelCursor(ME_TextEditor *editor, int dir)
{
  int cdir = ME_GetCursorOfs(editor, 0) - ME_GetCursorOfs(editor, 1);
  
  if (cdir*dir>0)
    return 0;
  else
    return 1;
}
      
BOOL ME_UpdateSelection(ME_TextEditor *editor, ME_Cursor *pTempCursor)
{
  ME_Cursor old_anchor = editor->pCursors[1];
  
  if (GetKeyState(VK_SHIFT)>=0) /* cancelling selection */
  {
    /* any selection was present ? if so, it's no more, repaint ! */
    editor->pCursors[1] = editor->pCursors[0];
    if (memcmp(pTempCursor, &old_anchor, sizeof(ME_Cursor))) {
      return TRUE;
    }
    return FALSE;
  }
  else
  {
    if (!memcmp(pTempCursor, &editor->pCursors[1], sizeof(ME_Cursor))) /* starting selection */
    {
      editor->pCursors[1] = *pTempCursor;
      return TRUE;
    }
  }

  ME_Repaint(editor);
  return TRUE;
}

void ME_DeleteSelection(ME_TextEditor *editor)
{
  int from, to;
  ME_GetSelection(editor, &from, &to);
  ME_DeleteTextAtCursor(editor, ME_GetSelCursor(editor,-1), to-from);
}

ME_Style *ME_GetSelectionInsertStyle(ME_TextEditor *editor)
{
  ME_Style *style;
  int from, to;
  ME_Cursor c;
  
  ME_GetSelection(editor, &from, &to);
  ME_CursorFromCharOfs(editor, from, &c);
  if (from != to) {
    style = c.pRun->member.run.style;
    ME_AddRefStyle(style); /* ME_GetInsertStyle has already done that */
  }
  else
    style = ME_GetInsertStyle(editor, 0);
  return style;
}

void ME_SendSelChange(ME_TextEditor *editor)
{
  SELCHANGE sc;

  ME_ClearTempStyle(editor);
  
  if (!(editor->nEventMask & ENM_SELCHANGE))
    return;
  
  sc.nmhdr.hwndFrom = editor->hWnd;
  sc.nmhdr.idFrom = GetWindowLongW(editor->hWnd, GWLP_ID);
  sc.nmhdr.code = EN_SELCHANGE;
  SendMessageW(editor->hWnd, EM_EXGETSEL, 0, (LPARAM)&sc.chrg);
  sc.seltyp = SEL_EMPTY;
  if (sc.chrg.cpMin != sc.chrg.cpMax)
    sc.seltyp |= SEL_TEXT;
  if (sc.chrg.cpMin < sc.chrg.cpMax+1) /* wth were RICHEDIT authors thinking ? */
    sc.seltyp |= SEL_MULTICHAR;
  SendMessageW(GetParent(editor->hWnd), WM_NOTIFY, sc.nmhdr.idFrom, (LPARAM)&sc);
}


BOOL
ME_ArrowKey(ME_TextEditor *editor, int nVKey, BOOL extend, BOOL ctrl)
{
  int nCursor = 0;
  ME_Cursor *p = &editor->pCursors[nCursor];
  ME_Cursor tmp_curs = *p;
  BOOL success = FALSE;
  
  ME_CheckCharOffsets(editor);
  editor->nUDArrowX = -1;
  switch(nVKey) {
    case VK_LEFT:
      editor->bCaretAtEnd = 0;
      if (ctrl)
        success = ME_MoveCursorWords(editor, &tmp_curs, -1);
      else
        success = ME_MoveCursorChars(editor, &tmp_curs, -1);
      break;
    case VK_RIGHT:
      editor->bCaretAtEnd = 0;
      if (ctrl)
        success = ME_MoveCursorWords(editor, &tmp_curs, +1);
      else
        success = ME_MoveCursorChars(editor, &tmp_curs, +1);
      break;
    case VK_UP:
      ME_MoveCursorLines(editor, &tmp_curs, -1);
      break;
    case VK_DOWN:
      ME_MoveCursorLines(editor, &tmp_curs, +1);
      break;
    case VK_PRIOR:
      ME_ArrowPageUp(editor, &tmp_curs);
      break;
    case VK_NEXT:
      ME_ArrowPageDown(editor, &tmp_curs);
      break;
    case VK_HOME: {
      if (ctrl)
        ME_ArrowCtrlHome(editor, &tmp_curs);
      else
        ME_ArrowHome(editor, &tmp_curs);
      editor->bCaretAtEnd = 0;
      break;
    }
    case VK_END: 
      if (ctrl)
        ME_ArrowCtrlEnd(editor, &tmp_curs);
      else
        ME_ArrowEnd(editor, &tmp_curs);
      break;
  }
  
  if (!extend)
    editor->pCursors[1] = tmp_curs;
  *p = tmp_curs;
  
  ME_InvalidateSelection(editor);
  ME_Repaint(editor);
  HideCaret(editor->hWnd);
  ME_EnsureVisible(editor, tmp_curs.pRun); 
  ME_ShowCaret(editor);
  ME_SendSelChange(editor);
  return success;
}