Tricks of the Windows Gam…ming Gurus (2nd Edition)/Disc2.iso/msdn_vcb/samples/vc98/mfc/advanced/chkbook/rowview.cpp

C/C++ Source or Header | 1998-03-27 | 10.3 KB | 361 lines

// rowview.cpp : implementation of the CRowView class
//
// This is a part of the Microsoft Foundation Classes C++ library.
// Copyright (C) 1992-1998 Microsoft Corporation
// All rights reserved.
//
// This source code is only intended as a supplement to the
// Microsoft Foundation Classes Reference and related
// electronic documentation provided with the library.
// See these sources for detailed information regarding the
// Microsoft Foundation Classes product.

#include "stdafx.h"
#include "chkbook.h"
#include <stdlib.h>
#include <limits.h> // for INT_MAX

#ifdef _DEBUG
#undef THIS_FILE
static char BASED_CODE THIS_FILE[] = __FILE__;
#endif

IMPLEMENT_DYNAMIC(CRowView, CScrollView)

/////////////////////////////////////////////////////////////////////////////
// CRowView

BEGIN_MESSAGE_MAP(CRowView, CScrollView)
    //{{AFX_MSG_MAP(CRowView)
    ON_WM_KEYDOWN()
    ON_WM_SIZE()
    ON_WM_LBUTTONDOWN()
    //}}AFX_MSG_MAP
    // Standard printing commands
    ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
    ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CRowView construction, initialization, and destruction

CRowView::CRowView()
{
    m_nPrevSelectedRow = 0;
}

CRowView::~CRowView()
{
}

/////////////////////////////////////////////////////////////////////////////
// CRowView updating and drawing

void CRowView::OnInitialUpdate()
{
    m_nPrevRowCount = GetRowCount();
    m_nPrevSelectedRow = GetActiveRow();
}

void CRowView::UpdateRow(int nInvalidRow)
{
    int nRowCount = GetRowCount();
    // If the number of rows has changed, then adjust the scrolling range.
    if (nRowCount != m_nPrevRowCount)
    {
        UpdateScrollSizes();
        m_nPrevRowCount = nRowCount;
    }

    // When the currently selected row changes:
    // scroll the view so that the newly selected row is visible, and
    // ask the derived class to repaint the selected and previously
    // selected rows.

    CClientDC dc(this);
    OnPrepareDC(&dc);

    // Determine the range of the rows that are currently fully visible
    // in the window.  We want to do discrete scrolling by so that
    // the next or previous row is always fully visible.
    int nFirstRow, nLastRow;
    CRect rectClient;
    GetClientRect(&rectClient);
    dc.DPtoLP(&rectClient);
    RectLPtoRowRange(rectClient, nFirstRow, nLastRow, FALSE);

    // If necessary, scroll the window so the newly selected row is
    // visible.
    POINT pt;
    pt.x = 0;
    BOOL bNeedToScroll = TRUE;
    if (nInvalidRow < nFirstRow)
    {
        // The newly selected row is above those currently visible
        // in the window.  Scroll so the newly selected row is at the
        // very top of the window.  The last row in the window might
        // be only partially visible.
        pt.y = RowToYPos(nInvalidRow);
    }
    else if (nInvalidRow > nLastRow)
    {
        // The newly selected row is below those currently visible
        // in the window.  Scroll so the newly selected row is at the
        // very bottom of the window.  The first row in the window might
        // be only partially visible.
        pt.y = max(0, RowToYPos(nInvalidRow+1) - rectClient.Height());
    }
    else
    {
        bNeedToScroll = FALSE;
    }
    if (bNeedToScroll)
    {
        ScrollToDevicePosition(pt);
        // Scrolling will cause the newly selected row to be
        // redrawn in the invalidated area of the window.

        OnPrepareDC(&dc);  // Need to prepare the DC again because
            // ScrollToDevicePosition() will have changed the viewport
            // origin.  The DC is used some more below.
    }

    CRect rectInvalid = RowToWndRect(&dc, nInvalidRow);
    InvalidateRect(&rectInvalid);

    // Give the derived class an opportunity to repaint the
    // previously selected row, perhaps to un-highlight it.

    int nSelectedRow = GetActiveRow();
    if (m_nPrevSelectedRow != nSelectedRow)
    {
        CRect rectOldSelection = RowToWndRect(&dc, m_nPrevSelectedRow);
        InvalidateRect(&rectOldSelection);
        m_nPrevSelectedRow = nSelectedRow;
    }


}

void CRowView::UpdateScrollSizes()
{
    // UpdateScrollSizes() is called when it is necessary to adjust the
    // scrolling range or page/line sizes.  There are two occassions
    // where this is necessary:  (1) when a new row is added-- see
    // UpdateRow()-- and (2) when the window size changes-- see OnSize().

    CRect rectClient;
    GetClientRect(&rectClient);

    CClientDC dc(this);
    CalculateRowMetrics(&dc);

    // The vert scrolling range is the total display height of all
    // of the rows.
    CSize sizeTotal(m_nRowWidth,
        m_nRowHeight * (min(GetRowCount(), LastViewableRow())));

    // The vertical per-page scrolling distance is equal to the
    // how many rows can be displayed in the current window, less
    // one row for paging overlap.
    CSize sizePage(m_nRowWidth/5,
            max(m_nRowHeight,
                ((rectClient.bottom/m_nRowHeight)-1)*m_nRowHeight));

    // The vertical per-line scrolling distance is equal to the
        // height of the row.
    CSize sizeLine(m_nRowWidth/20, m_nRowHeight);

    SetScrollSizes(MM_TEXT, sizeTotal, sizePage, sizeLine);
}


void CRowView::OnDraw(CDC* pDC)
{
    if (GetRowCount() == 0)
        return;

    // The window has been invalidated and needs to be repainted;
    // or a page needs to be printed (or previewed).
    // First, determine the range of rows that need to be displayed or
    // printed.

    int nFirstRow, nLastRow;
    CRect rectClip;
    pDC->GetClipBox(&rectClip); // Get the invalidated region.
    RectLPtoRowRange(rectClip, nFirstRow, nLastRow, TRUE);

    // Draw each row in the invalidated region of the window,
    // or on the printed (previewed) page.
    int nActiveRow = GetActiveRow();
    int nRow, y;
    int nLastViewableRow = LastViewableRow();
    for (nRow = nFirstRow,
            y = m_nRowHeight * nFirstRow;
            nRow <= nLastRow;
            nRow++, y += m_nRowHeight)
    {
        if (nRow > nLastViewableRow)
        {
            CString strWarning;
            strWarning.LoadString(IDS_TOO_MANY_ROWS);
            pDC->TextOut(0, y, strWarning);
            break;
        }
        OnDrawRow(pDC, nRow, y, nRow == nActiveRow);
    }
}


/////////////////////////////////////////////////////////////////////////////
// Implementation

int CRowView::RowToYPos(int nRow)
{
    return (nRow * m_nRowHeight);
}

CRect CRowView::RowToWndRect(CDC* pDC, int nRow)
{
    int nHorzRes = pDC->GetDeviceCaps(HORZRES);;
    CRect rect(0, nRow * m_nRowHeight,
        nHorzRes, (nRow + 1) * m_nRowHeight);
    pDC->LPtoDP(&rect);
    return rect;
}


int CRowView::LastViewableRow()
{
    return (INT_MAX / m_nRowHeight - 1);
}

void CRowView::RectLPtoRowRange(const CRect& rect,
            int& nFirstRow, int& nLastRow,
            BOOL bIncludePartiallyShownRows)
{
    int nRounding = bIncludePartiallyShownRows? 0 : (m_nRowHeight - 1);
    nFirstRow = (rect.top + nRounding) / m_nRowHeight;
    nLastRow = min( (rect.bottom - nRounding) / m_nRowHeight,
        GetRowCount() - 1);
}

void CRowView::OnPrepareDC(CDC* pDC, CPrintInfo* pInfo)
{
    // The size of text that is displayed, printed or previewed changes
    // depending on the DC.  We explicitly call OnPrepareDC() to prepare
    // CClientDC objects used for calculating text positions and to
    // prepare the text metric member variables of the CRowView object.
    // The framework also calls OnPrepareDC() before passing the DC to
    // OnDraw().

    CScrollView::OnPrepareDC(pDC, pInfo);
    CalculateRowMetrics(pDC);
}

/////////////////////////////////////////////////////////////////////////////
// Overrides of CView for implementing printing.

BOOL CRowView::OnPreparePrinting(CPrintInfo* pInfo)
{
    return DoPreparePrinting(pInfo);
}

void CRowView::OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo)
{
    // OnBeginPrinting() is called after the user has committed to
    // printing by OK'ing the Print dialog, and after the framework
    // has created a CDC object for the printer or the preview view.

    // This is the right opportunity to set up the page range.
    // Given the CDC object, we can determine how many rows will
    // fit on a page, so we can in turn determine how many printed
    // pages represent the entire document.

    int nPageHeight = pDC->GetDeviceCaps(VERTRES);
    CalculateRowMetrics(pDC);
    m_nRowsPerPrintedPage = nPageHeight / m_nRowHeight;
    int nPrintableRowCount = LastViewableRow() + 1;
    if (GetRowCount() < nPrintableRowCount)
        nPrintableRowCount = GetRowCount();
    pInfo->SetMaxPage((nPrintableRowCount + m_nRowsPerPrintedPage - 1)
        / m_nRowsPerPrintedPage);
    pInfo->m_nCurPage = 1;  // start previewing at page# 1
}

void CRowView::OnPrint(CDC* pDC, CPrintInfo* pInfo)
{
    // Print the rows for the current page.

    int yTopOfPage = (pInfo->m_nCurPage -1) * m_nRowsPerPrintedPage
        * m_nRowHeight;

    // Orient the viewport so that the first row to be printed
    // has a viewport coordinate of (0,0).
    pDC->SetViewportOrg(0, -yTopOfPage);

    // Draw as many rows as will fit on the printed page.
    // Clip the printed page so that there is no partially shown
    // row at the bottom of the page (the same row which will be fully
    // shown at the top of the next page).

    int nPageWidth = pDC->GetDeviceCaps(HORZRES);
    CRect rectClip = CRect(0, yTopOfPage, nPageWidth,
         yTopOfPage + m_nRowsPerPrintedPage * m_nRowHeight);
    pDC->IntersectClipRect(&rectClip);
    OnDraw(pDC);
}

/////////////////////////////////////////////////////////////////////////////
// CRowView commands


void CRowView::OnSize(UINT nType, int cx, int cy)
{
    UpdateScrollSizes();
    CScrollView::OnSize(nType, cx, cy);
}

void CRowView::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
    switch (nChar)
    {
        case VK_HOME:
            ChangeSelectionToRow(0);
            break;
        case VK_END:
            ChangeSelectionToRow(GetRowCount() - 1);
            break;
        case VK_UP:
            ChangeSelectionNextRow(FALSE);
            break;
        case VK_DOWN:
            ChangeSelectionNextRow(TRUE);
            break;
        case VK_PRIOR:
            OnVScroll(SB_PAGEUP,
                0,  // nPos not used for PAGEUP
                GetScrollBarCtrl(SB_VERT));
            break;
        case VK_NEXT:
            OnVScroll(SB_PAGEDOWN,
                0,  // nPos not used for PAGEDOWN
                GetScrollBarCtrl(SB_VERT));
            break;
        default:
            CScrollView::OnKeyDown(nChar, nRepCnt, nFlags);
    }
}

void CRowView::OnLButtonDown(UINT, CPoint point)
{
    CClientDC dc(this);
    OnPrepareDC(&dc);
    dc.DPtoLP(&point);
    CRect rect(point, CSize(1,1));
    int nFirstRow, nLastRow;
    RectLPtoRowRange(rect, nFirstRow, nLastRow, TRUE);
    if (nFirstRow <= (GetRowCount() - 1))
        ChangeSelectionToRow(nFirstRow);
}