双缓冲绘图及滚动条问题

大家好，又要麻烦大家了。我想在picture控件里用双缓冲绘图，由于图形比较大，就采用滚动条。滚动条是picture自身带的，用m_static_wave.ShowScrollBar(SB_BOTH)实现的;m_static_wave是picture的关联静态变量。但问题是：运行的结果显示，图形是在整个对话框内绘制的，并且只要对话框的滚动条起作用，控件的滚动条不能移动。代码如下，麻烦各位了！谢谢！
void CTheLastDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;

// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CPaintDC dc(this);

        int nWidth = 1000;
        int nHeight = 1000;

        //随后建立与屏幕显示兼容的内存显示设备
        CDC MemDC; //定义一个显示设备对象
        CBitmap MemBitmap;//定义一个位图对象
CRect rect;
GetDlgItem(IDC_STATIC_WAVE)->GetWindowRect(&rect);//IDC_STATIC_WAVE是picture的ID号
     GetClientRect(rect);
        MemDC.CreateCompatibleDC(NULL);

        MemBitmap.CreateCompatibleBitmap(&dc,nWidth,nHeight);

        //将位图选入到内存显示设备中

        MemDC.SelectObject(&MemBitmap);
        MemDC.FillSolidRect(0,0,nWidth,nHeight,RGB(0,0,0));

        //绘图（这是我做实验随便绘制的图）
        //MemDC.Ellipse(m_nEclipseRect);
    CPen pen(PS_SOLID, 1, RGB(255,0,0)), *pOldPen;
        pOldPen = MemDC.SelectObject(&pen);
MemDC.MoveTo(rect.left,rect.top+rect.Height()/2);
MemDC.LineTo(rect.right,rect.bottom+rect.Height()/2);
MemDC.MoveTo(50,rect.top+rect.Height()/2);
        MemDC.LineTo(rect.right,rect.Height()/2);

        //将内存中的图拷贝到屏幕上进行显示
        dc.SetViewportOrg(-m_nHScrollPos,-m_nVScrollPos);
        dc.BitBlt(0,0,nWidth,nHeight,&MemDC,0,0,SRCCOPY);
        //绘图完成后的清理
        MemBitmap.DeleteObject();
        MemDC.DeleteDC();

        CDialog::OnPaint();
}
}
//下面是滚动条
void CTheLastDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
SCROLLINFO scrollinfo;
GetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
    switch (nSBCode)
    {
        case SB_LEFT:
            ScrollWindow((scrollinfo.nPos-scrollinfo.nMin)*10,0);
            scrollinfo.nPos = scrollinfo.nMin;
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            break;
        case SB_RIGHT:
            ScrollWindow((scrollinfo.nPos-scrollinfo.nMax)*10,0);
            scrollinfo.nPos = scrollinfo.nMax;
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            break;
        case SB_LINELEFT:
            scrollinfo.nPos -= 1;
            if (scrollinfo.nPos)
            {
                scrollinfo.nPos = scrollinfo.nMin;
                break;
            }
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            ScrollWindow(10,0);
            break;
        case SB_LINERIGHT:
            scrollinfo.nPos += 1;
            if (scrollinfo.nPos>scrollinfo.nMax)
            {
                scrollinfo.nPos = scrollinfo.nMax;
                break;
            }
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            ScrollWindow(-10,0);
            break;
        case SB_PAGELEFT:
            scrollinfo.nPos -= 5;
            if (scrollinfo.nPos)
            {
                scrollinfo.nPos = scrollinfo.nMin;
                break;
            }
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            ScrollWindow(10*5,0);               break;
        case SB_PAGERIGHT:
            scrollinfo.nPos += 5;
            if (scrollinfo.nPos>scrollinfo.nMax)
            {
                scrollinfo.nPos = scrollinfo.nMax;
                break;
            }
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            ScrollWindow(-10*5,0);
            break;
        case SB_THUMBPOSITION:
            break;
        case SB_THUMBTRACK:
            ScrollWindow((scrollinfo.nPos-nPos)*10,0);
            scrollinfo.nPos = nPos;
            SetScrollInfo(SB_HORZ,&scrollinfo,SIF_ALL);
            break;
        case SB_ENDSCROLL:
            break;
    }
    m_nHScrollPos = scrollinfo.nPos*10;

CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
}

void CTheLastDlg::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
  SCROLLINFO scrollinfo;
    GetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
    switch (nSBCode)
    {
        case SB_BOTTOM:
            ScrollWindow(0,(scrollinfo.nPos-scrollinfo.nMax)*10);
            scrollinfo.nPos = scrollinfo.nMax;
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            break;
        case SB_TOP:
            ScrollWindow(0,(scrollinfo.nPos-scrollinfo.nMin)*10);
            scrollinfo.nPos = scrollinfo.nMin;
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            break;           case SB_LINEUP:
            scrollinfo.nPos -= 1;
            if (scrollinfo.nPos)
            {
                scrollinfo.nPos = scrollinfo.nMin;
                break;
            }
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            ScrollWindow(0,10);
            break;
        case SB_LINEDOWN:
            scrollinfo.nPos += 1;
            if (scrollinfo.nPos>scrollinfo.nMax)
            {
                scrollinfo.nPos = scrollinfo.nMax;
                break;
            }
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            ScrollWindow(0,-10);
            break;
        case SB_PAGEUP:
            scrollinfo.nPos -= 5;
            if (scrollinfo.nPos)
            {
                scrollinfo.nPos = scrollinfo.nMin;
                break;
            }
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            ScrollWindow(0,10*5);
            break;
        case SB_PAGEDOWN:
            scrollinfo.nPos += 5;
            if (scrollinfo.nPos>scrollinfo.nMax)
            {
                scrollinfo.nPos = scrollinfo.nMax;
                break;
            }
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            ScrollWindow(0,-10*5);
            break;
        case SB_ENDSCROLL:
             break;
        case SB_THUMBPOSITION:               // ScrollWindow(0,(scrollinfo.nPos-nPos)*10);
            break;
        case SB_THUMBTRACK:
            ScrollWindow(0,(scrollinfo.nPos-nPos)*10);
            scrollinfo.nPos = nPos;
            SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            break;
    }
    m_nVScrollPos = scrollinfo.nPos*10;
CDialog::OnVScroll(nSBCode, nPos, pScrollBar);
}

13 个解决方案

#1

MARK、

#2



CPaintDC dc(this);      


int nWidth = 1000; 

int nHeight = 1000;

里面的CPaintDC dc(this); 修改为
CDC *pDC = GetDlgItem(你的picture控件ID)->GetDC();
后面用到dc的地方都改一下

#3

好像不对呀。是不是我下面的代码有问题啊？我用的是picture自身带的滚动条。但好像运行的结果是对整个对话框起作用的滚动结果。图片还是充满整个对话框。辛苦各位了！

#4

各位前辈，麻烦看看我的程序，不知道那里出了问题。麻烦各位帮帮忙了。谢谢！

#5

CRect rect;
GetDlgItem(IDC_STATIC_WAVE)->GetWindowRect(&rect);//IDC_STATIC_WAVE是picture的ID号
    GetClientRect(rect);
这里错了
改为
CWnd * pWnd=GetDlgItem(IDC_STATIC_WAVE);//取得pic控件窗口指针
    CRect rect;
  pWnd->GetClientRect(rect);//获得预览框客户区矩形
    CDC *dc=pWnd->GetDC();//载入设备环境
后面我没细看，类似的地方都要改

#6

还是不对啊，我将下面的相应要该得地方按照shihaojie1219的修改，但运行结果没什么变化啊。

#7

你的程序是基于什么的？

#8

基于对话框，滚动条是使用picture自身的。

#9

是不是你的图尺寸不对
你那picture尺寸多大呢
这个 int nWidth = 1000;
int nHeight = 1000; 1000是什么？

#10

我本来是想用picture显示一个曲线图，采用双缓冲绘图技术。int nWidth = 1000;
int nHeight = 1000是我在内存开辟的与设备兼容的位图的大小，然后在这个位图上绘图。最后采取BitBlt()将绘制好的图形拷贝到我的picture控件内显示。由于图形尺寸大于picture得大小，所以要采用滚动条。目前，我修改了BitBlt()已经实现图片在picture控件内显示了。但滚动条的问题还没解决。不知道该怎么驱动这个picture。不清楚picture自身带的滚动条与自己手动加上去的滚动条的使用有和区别。

#11

哪位前辈有这方面的例子能否分享一下？我是个VC初学者，对滚动条驱动picture的使用确实很不清楚。谢谢了。

#12

我感觉控件操作与双缓冲显示好像不沾边啊，双缓冲属于设备机制，而控件只要申请内存获取句柄就可以控制了，似乎没有什么问题吧？

#13

在我拖动滚动条的时候，picture控件内的图形及背景会移动，但是背景竟然超出picture区域范围。修改后的代码如下： CWnd * pWnd=GetDlgItem(IDC_STATIC_WAVE);//取得pic控件窗口指针
       CRect rect;
       pWnd->GetClientRect(rect);//获得预览框客户区矩形
       CDC *dc=pWnd->GetDC();//CDC *pDC=GetDlgItem(IDC_STATIC_WAVE)->GetDC();
        nWidth=1000;
nHeight=1000;


        //随后建立与屏幕显示兼容的内存显示设备
        CDC MemDC; //首先定义一个显示设备对象
        CBitmap MemBitmap;//定义一个位图对象

        MemDC.CreateCompatibleDC(NULL);

        MemBitmap.CreateCompatibleBitmap(dc,nWidth,nHeight);

        MemDC.SelectObject(&MemBitmap);

        MemDC.FillSolidRect(0,0,nWidth,nHeight,RGB(0,0,0));

        //绘图（我随便绘制的一个大于picture区域的两条直线）

    CPen pen(PS_SOLID, 1, RGB(255,0,0)), *pOldPen;
        pOldPen = MemDC.SelectObject(&pen);
MemDC.MoveTo(0,0);
MemDC.LineTo(nWidth/2,nHeight/2);
MemDC.MoveTo(1000,nHeight);
        MemDC.LineTo(nWidth,nHeight);
       //将内存中的图拷贝到屏幕上进行显示
    dc->SetViewportOrg(m_nHScrollPos,m_nVScrollPos);
    dc->BitBlt(0,0,rect.Width(),rect.Height(),&MemDC,0,0,SRCCOPY);
        //绘图完成后的清理
        MemBitmap.DeleteObject();
        MemDC.DeleteDC();

CDialog::OnPaint();
Invalidate(FALSE);
}
}
//下面是滚动条的控制，可能是下面的代码有误。现在滚动条采用的是自己手动加上的。
// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CTheLastDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}
void CTheLastDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
    SCROLLINFO hscrollinfo;
m_h_scroll.GetScrollInfo(&hscrollinfo,SIF_ALL);
switch (nSBCode)
    {
        case SB_LEFT:
    m_h_scroll.ScrollWindowEx(hscrollinfo.nPos-hscrollinfo.nMin,0,&rect,NULL,NULL,NULL,SW_ERASE);
            hscrollinfo.nPos = hscrollinfo.nMin;
            m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            break;
        case SB_RIGHT:
            m_h_scroll.ScrollWindowEx(hscrollinfo.nPos-hscrollinfo.nMax,0,&rect,NULL,NULL,NULL,SW_ERASE);
            hscrollinfo.nPos = hscrollinfo.nMax;
             m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            break;
        case SB_LINELEFT:
            hscrollinfo.nPos -= 1;
            if (hscrollinfo.nPos)
            {
                hscrollinfo.nPos = hscrollinfo.nMin;
                break;
            }
             m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            m_h_scroll.ScrollWindowEx(10,0,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_LINERIGHT:
            hscrollinfo.nPos += 1;
            if (hscrollinfo.nPos>hscrollinfo.nMax)
            {
                hscrollinfo.nPos = hscrollinfo.nMax;
                break;
            }
            m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            m_h_scroll.ScrollWindowEx(-10,0,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_PAGELEFT:
            hscrollinfo.nPos -= 5;
            if (hscrollinfo.nPos)
            {
                hscrollinfo.nPos = hscrollinfo.nMin;
                break;
            }
            m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            m_h_scroll.ScrollWindowEx(10*5,0,&rect,NULL,NULL,NULL,SW_ERASE);
break;
        case SB_PAGERIGHT:
            hscrollinfo.nPos += 5;
            if (hscrollinfo.nPos>hscrollinfo.nMax)
            {
                hscrollinfo.nPos = hscrollinfo.nMax;
                break;
            }
            m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            m_h_scroll.ScrollWindowEx(-10*5,0,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_THUMBPOSITION:
            break;
        case SB_THUMBTRACK:
            m_h_scroll.ScrollWindowEx(hscrollinfo.nPos-nPos,0,&rect,NULL,NULL,NULL,SW_ERASE);
            hscrollinfo.nPos = nPos;
            m_h_scroll.SetScrollInfo(&hscrollinfo,SIF_ALL);
            break;
        case SB_ENDSCROLL:
            break;
    }
    m_nHScrollPos = hscrollinfo.nPos;
m_h_scroll.UpdateWindow();
CDialog::OnHScroll(nSBCode, nPos, pScrollBar);
}

void CTheLastDlg::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO: Add your message handler code here and/or call default
SCROLLINFO vscrollinfo;
    m_v_scroll.GetScrollInfo(&vscrollinfo,SIF_ALL);
//    this->Invalidate(false);
    //InvalidateRect(NULL,TRUE);
    switch (nSBCode)
    {
        case SB_BOTTOM:
            m_v_scroll.ScrollWindowEx(0,vscrollinfo.nPos-vscrollinfo.nMax,&rect,NULL,NULL,NULL,SW_ERASE);
            vscrollinfo.nPos = vscrollinfo.nMax;
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            break;
        case SB_TOP:
            m_v_scroll.ScrollWindowEx(0,vscrollinfo.nPos-vscrollinfo.nMin,&rect,NULL,NULL,NULL,SW_ERASE);
            vscrollinfo.nPos = vscrollinfo.nMin;
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            break;
case SB_LINEUP:
            vscrollinfo.nPos -= 1;
            if (vscrollinfo.nPos)
            {
                vscrollinfo.nPos = vscrollinfo.nMin;
                break;
            }
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            m_v_scroll.ScrollWindowEx(0,10,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_LINEDOWN:
            vscrollinfo.nPos += 1;
            if (vscrollinfo.nPos>vscrollinfo.nMax)
            {
                vscrollinfo.nPos = vscrollinfo.nMax;
                break;
            }
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            m_v_scroll.ScrollWindowEx(0,-10,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_PAGEUP:
            vscrollinfo.nPos -= 5;
            if (vscrollinfo.nPos)
            {
                vscrollinfo.nPos = vscrollinfo.nMin;
                break;
            }
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            m_v_scroll.ScrollWindowEx(0,10*5,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_PAGEDOWN:
            vscrollinfo.nPos += 5;
            if (vscrollinfo.nPos>vscrollinfo.nMax)
            {
                vscrollinfo.nPos = vscrollinfo.nMax;
                break;
            }
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            m_v_scroll.ScrollWindowEx(0,-10*5,&rect,NULL,NULL,NULL,SW_ERASE);
            break;
        case SB_ENDSCROLL:
            // MessageBox("SB_ENDSCROLL");
            break;
        case SB_THUMBPOSITION:               // ScrollWindow(0,(scrollinfo.nPos-nPos)*10);
            // scrollinfo.nPos = nPos;
            // SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
            break;
        case SB_THUMBTRACK:
            m_v_scroll.ScrollWindowEx(0,vscrollinfo.nPos-nPos,&rect,NULL,NULL,NULL,SW_ERASE);
            vscrollinfo.nPos = nPos;
            m_v_scroll.SetScrollInfo(&vscrollinfo,SIF_ALL);
            break;
    }
    m_nVScrollPos = vscrollinfo.nPos;
m_h_scroll.UpdateWindow();
CDialog::OnVScroll(nSBCode, nPos, pScrollBar);
}
麻烦前辈们抽空帮我看看。谢谢!

#1