双缓存只能实现图片画刷什么的么？能不能实现自己的绘图函数
我在网上看了看双缓存的介绍，基本上都是SelectObject一个图片，但是我想要在内存中调用自己的绘图函数，该怎么做呢。
CClientDC dc(this);
CDC dcMem;
CRect rc;
GetClientRect(&rc);
dcMem.CreateCompatibl
。。。。。。。
DrawCard(point.x-m_nJlX,point.y+ i * M_CDJL1-m_nJlY,b);
dc.BitBlt(0,0,rc.Width(),rc.Height(),&dcMem,0,0,SRCCOPY);eDC(&dc);
这个DrawCard就是我自己的函数，有什么办法实现？
[解决办法]
DrawCard这个函数你起码得把dc句柄传进去，表示在此dc上画图。在你的例子里就是：
DrawCard(dcMem.GetSafeHDC()，point.x-m_nJlX,point.y+ i * M_CDJL1-m_nJlY,b);
有了dc句柄，你就可以调用gdi绘图系列的函数，如drawrect,drawtext等等。
所谓双缓冲就是先将所有的绘图都绘制到内存dc上，然后一次性的输出到显示器上（通过BitBlt）
[解决办法]
你的MemDC使用SelectObject可以选择你自己建立的空的CBitmap
然后可以操作MemDC来对这个CBitmap来绘图和控制
最后再利用控件的CDC来将MemDC读取出来。达到显示的目标
[解决办法]
传递DC指针
void CXXXX::OnPaint(){ CClientDC dc(this); CDC dcMem; CRect rc; GetClientRect(&rc); dcMem.CreateCompatibl //................. Draw1(&dcMem,a1,b1,c1,d1); Draw2(&dcMem,a2,b2,c2,d2);//参数个数,自己定,第一个参数就是传递DC //................. dc.BitBlt(0,0,rc.Width(),rc.Height(),&dcMem,0,0,SRCCOPY);eDC(&dc);}
[解决办法]
参考
// DrawTest.cpp : implementation file
//
#include "stdafx.h"
#include "DlgDraw.h"
#include "DrawTest.h"
#include <time.h>
#include <math.h>
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CDrawTest dialog
CDrawTest::CDrawTest(CWnd* pParent /*=NULL*/)
: CDialog(CDrawTest::IDD, pParent)
{
//{{AFX_DATA_INIT(CDrawTest)
// NOTE: the ClassWizard will add member initialization here
//}}AFX_DATA_INIT
}
void CDrawTest::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CDrawTest)
// NOTE: the ClassWizard will add DDX and DDV calls here
//}}AFX_DATA_MAP
}
BEGIN_MESSAGE_MAP(CDrawTest, CDialog)
//{{AFX_MSG_MAP(CDrawTest)
ON_WM_PAINT()
ON_WM_TIMER()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CDrawTest message handlers
BOOL CDrawTest::OnInitDialog()
{
CDialog::OnInitDialog();
// TODO: Add extra initialization here
m_Low = 0;
m_High = 1024;
m_now =0;
SetTimer(1,100,NULL);
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
void CDrawTest::OnPaint()
{
CPaintDC dc(this); // device context for painting
// TODO: Add your message handler code here
// Do not call CDialog::OnPaint() for painting messages
}
void CDrawTest::DrawWave(CDC *pDC)
{
CRect rect;
CString str;
int i;
int m_left,m_top,m_right,m_bottom;
int m_Interval = (m_High - m_Low)/10;
if (m_Interval < 1) m_Interval = 1;
// 获取绘制坐标的文本框
CWnd* pWnd = GetDlgItem(IDC_COORD);
pWnd->GetClientRect(&rect);
pDC->Rectangle(&rect);
m_left = rect.left+10;
m_top = rect.top+10;
m_right = rect.right-10;
m_bottom = rect.bottom-20;
int m_IntervalPan = (m_right - m_left)/11;
if (m_IntervalPan < 1 ) m_IntervalPan =1;
// 创建画笔对象
CPen* pPenRed = new CPen;
// 红色画笔
pPenRed->CreatePen(PS_SOLID,1,RGB(255,0,0));
// 创建画笔对象
CPen* pPenBlue = new CPen;
// 蓝色画笔
pPenBlue->CreatePen(PS_SOLID,1,RGB(0,0, 255));
// 创建画笔对象
CPen* pPenGreen = new CPen;
// 绿色画笔
pPenGreen->CreatePen(PS_DOT,1,RGB(0,255,0));
// 选中当前红色画笔，并保存以前的画笔
CGdiObject* pOldPen = pDC->SelectObject(pPenRed);
// 绘制坐标轴
pDC->MoveTo(m_left,m_top);
// 垂直轴
pDC->LineTo(m_left,m_bottom);
// 水平轴
pDC->LineTo(m_right,m_bottom);
// 写X轴刻度值
for(i=0;i<10;i++)
{
//str.Format(_T("%d"),m_Min+i*m_Interval);
str.Format(_T("%d"),m_Low+i*m_Interval);
pDC->TextOut(m_left+i*m_IntervalPan,m_bottom+3,str);
}
//str.Format(_T("%d"),m_Max);
str.Format(_T("%d"),m_High);
pDC->TextOut(m_left+10*m_IntervalPan,m_bottom+3,str);
// 绘制X轴刻度
for (i = m_left; i < m_right-20; i += 5)
{
if ((i & 1) == 0)
{
// 10的倍数
pDC->MoveTo(i + 10, m_bottom);
pDC->LineTo(i + 10, m_bottom+4);
}
else
{
// 10的倍数
pDC->MoveTo(i + 10, m_bottom);
pDC->LineTo(i + 10, m_bottom+2);
}
}
// 绘制Y轴箭头
pDC->MoveTo(m_right-5,m_bottom-5);
pDC->LineTo(m_right,m_bottom);
pDC->LineTo(m_right-5,m_bottom+5);
// 绘制X轴箭头
pDC->MoveTo(m_left-5,m_top+5);
pDC->LineTo(m_left,m_top);
pDC->LineTo(m_left+5,m_top+5);
// 绘制Y轴网格 选择绿色画笔
pDC->SelectObject(pPenGreen);
//
int iTemp = (m_bottom - m_top)/5;
for (i = 1 ;i <= 5 ;i++)
{
pDC->MoveTo(m_left,m_bottom - i*iTemp);
pDC->LineTo(m_right,m_bottom - i*iTemp);
}
//数组赋值
if(m_now<1024)
{
m_now++;
}
else
{
m_now = 0;
}
for(i = m_Low;i<m_High;i++)
{
//m_lCount[i]=(rand()%10+rand()%100+rand()%1000)%1024;
m_lCount[i] = (int)(sin(i-m_now)*204);
}
int xTemp;
int yTemp;
// 更改成蓝色画笔
pDC->SelectObject(pPenBlue);
for (i = m_Low; i <= m_High; i=i+3)
{
xTemp = m_left+(i-m_Low)*m_IntervalPan/m_Interval;
yTemp = m_bottom/2 - (int) (m_lCount[i] * m_bottom / 1024);
if (yTemp < m_top) yTemp = m_top;
if((xTemp >=m_left)&&(xTemp <=m_right))
{
pDC->MoveTo(xTemp, m_bottom/2);
pDC->LineTo(xTemp, yTemp);
}
}
// 恢复以前的画笔
pDC->SelectObject(pOldPen);
delete pPenRed;
delete pPenBlue;
delete pPenGreen;
return;
}
void CDrawTest::OnTimer(UINT nIDEvent)
{
// TODO: Add your message handler code here and/or call default
CRect rect;
// 获取绘制坐标的文本框
CWnd* pWnd = GetDlgItem(IDC_COORD);
pWnd->GetClientRect(&rect);
// 指针
pDC = pWnd->GetDC();
pWnd->Invalidate();
pWnd->UpdateWindow();
//pDC->Rectangle(&rect);
//内存绘图
CBitmap memBitmap;
CBitmap* pOldBmp = NULL;
memDC.CreateCompatibleDC(pDC);
memBitmap.CreateCompatibleBitmap(pDC,rect.right,rect.bottom);
pOldBmp = memDC.SelectObject(&memBitmap);
memDC.BitBlt(rect.left,rect.top,rect.right,rect.bottom,pDC,0,0,SRCCOPY);
DrawWave(&memDC);
pDC->BitBlt(rect.left,rect.top,rect.right,rect.bottom,&memDC,0,0,SRCCOPY);
memDC.SelectObject(pOldBmp);
memDC.DeleteDC();
memBitmap.DeleteObject();
CDialog::OnTimer(nIDEvent);