如何给坐标轴添加刻度和数值

[ttttyanfeng]

画了个坐标系,
CRect rect;
CDC*pDC=GetDC();
GetClientRect(rect);
int x=rect.Width();
int y=rect.Height();
//X
pDC->MoveTo(0,y/2.0);
pDC->LineTo(x,y/2);
//Y
pDC->MoveTo(x/2.0,0);
pDC->LineTo(x/2,y);
如何给坐标轴添加刻度和数值

[写不动代码的人]

刻度可也画线呀 数值用TextOut输出

[傻X]

楼主接着要做的事情就比较麻烦了。

自己算像素和屏幕所要输出的内容有个比例，得出一个系数。

每次重画都要把这个系数乘上去。

刻度：需要MoveTo到自己计算出的平均点，然后LineTo，这个需要楼主自己计算。
标值：DrawText和TextOut都能满足楼主的需求。

[许文君]

最简单的办法是固定长宽比例，然后加载已绘制的图片，这样不用费心去算出来并绘制。

[qlizhang]

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);

[youngwolf]

www.st-curve.cn

[jiuzhoulh]

好像需要楼主自己来画了，这项工作比较繁琐了

[HuWenjin]

如果,大小不变的情况下,建议直接加载图片,这个方法比较简单

直接网上找一个别个画好的,计算出0点位置就可以在上面绘制你的数据了.

这样还更好看

自己绘也可以,算得麻烦,想改好看些,也难.

[Eleven]

MoveTo/LineTo画线， DrawText/TextOut()绘制文字

[whucv]

假设你要分为128等分

画刻度
for(int i=0;i<128;i++)
{ //
pDC->MoveTo(x/128*i,0);//x轴上坐标为x/128*i的点
pDC->LineTo(x/128*i,2);//向y轴正方向画线 2个单位 画刻度分划
pDC->TextOut(x/128*i-2,-4,刻度值);//在刻度分隔符下方4个像素处标识，
}
因为标识一般在x轴下方，y此时小于0，所以你在画图时，y轴在显示器上要给标识留一定宽度

[gz_qmc]

画线就是了