用 C++ 和 libgd 来绘图
[TOC]
旧文转贴, 代码很久以前写的, 大约至今有十年了, 最近看到有人问如何用 C++ 来生成图表.
有一个 graphviz 的开源库可以用, 它用了自己的领域特定语言 DSL: dot 来生成图表, 具体应用可见 http://graphviz.org/
当然也可以不用这么重的开源库, 这里介绍了以前写的一个chart 库, 几百行代码, 采用了比较原始的作法, 调用了 libgd 基础API, 如画点, 画线等原子方法来绘制图表, 可以应用于一些比较简单的场合
实例
先看看生成的图表实例
折线图和鱼骨头图
这里写图片描述
圆饼图和直方图
这里写图片描述
示例代码
上面两个图表由以下几十行代码来实现
#include "TinyUtil.h"
#include "TinyChart.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <memory>
int main(int argc, char **argv)
{
printf("-- write image by gd ---");
{
STR_VEC xScales;
xScales.reserve(10);
xScales.push_back("11-09");
xScales.push_back("11-10");
xScales.push_back("11-11");
xScales.push_back("11-12");
xScales.push_back("11-13");
xScales.push_back("11-14");
xScales.push_back("11-15");
xScales.push_back("11-16");
xScales.push_back("11-17");
xScales.push_back("11-18");
xScales.push_back("11-19");
xScales.push_back("11-20");
xScales.push_back("11-21");
xScales.push_back("11-22");
INT_VEC yScales;
yScales.reserve(10);
yScales.push_back(200);
yScales.push_back(130);
yScales.push_back(3456);
yScales.push_back(2345);
yScales.push_back(1320);
yScales.push_back(30);
yScales.push_back(2200);
yScales.push_back(1330);
yScales.push_back(3330);
yScales.push_back(332);
yScales.push_back(788);
yScales.push_back(200);
yScales.push_back(13890);
yScales.push_back(200);
TinyTrendlineDiagram* pt = new TinyTrendlineDiagram(
"latency_trendline.png", 800, 250);
pt->SetTitle("Trend of Latency (the middle network latency is the value of 0 coordinate)");
pt->SetLabels(xScales);
pt->SetValues(yScales);
pt->Draw();
pt->WriteImage();
delete pt;
}
{
STR_VEC xScales;
xScales.push_back("America");
xScales.push_back("China");
xScales.push_back("Japan");
xScales.push_back("England");
xScales.push_back("France");
xScales.push_back("Germany");
xScales.push_back("South Korean");
xScales.push_back("India");
INT_VEC yScales;
yScales.push_back(4800);
yScales.push_back(3008);
yScales.push_back(100);
yScales.push_back(20);
yScales.push_back(2000);
yScales.push_back(178);
yScales.push_back(258);
yScales.push_back(1789);
TinyDistributionDiagram* pd = new TinyDistributionDiagram(
"users_distribution.png", 800, 600);
pd->SetTitle("Daily active users distribution among the countries");
pd->SetLabels(xScales);
pd->SetValues(yScales);
pd->Draw();
pd->WriteImage();
delete pd;
}
return 0;
}
�设计与实现
其实, 也就是封装了libgd 的原子操作, 绘制了基本的图形单元
�1) 首先下载并编译依赖库 libgd
- 下载: Download libgd-2.2.1.tar.gz
- 解压: tar xvfz libgd-2.2.1.tar.gz
- 构建步骤 build steps
cd libgd-2.2.1
mkdir bld
cd bld
cmake -DENABLE_PNG=1 -DENABLE_JPEG=1 -DENABLE_FREETYPE=1 ..
make
make install
- 然后实现上图所示的类, 加上测试, 约有千余行代码, 放在 github 里
https://gist.github.com/walterfan/b7200fd3e5315ec1e16551fca096a67e
附以上类图的源码, 由 http://yuml.me 生成
// Cool Class Diagram
[Sharp]^[Arc]
[Arc]^[Eclipse]
[Arc]^[Circle]
[Sharp]^[Rectangle]
[Sharp]^[Scale]
[Sharp]^[Chart]
[Chart]^[CurveChart]
[Chart]^[ColumnChart]
[Chart]^[PieChart]
[Chart]^[HistogramChart]
[Diagram]-[note:Aggregate chart{bg:wheat}]
[Diagram]^[DistributionDiagram]
[Diagram]^[TrendlineDiagram]
[TrendlineDiagram]<>-0..*>[CurveChart]
[TrendlineDiagram]<>-0..*>[ColumnChart]
[DistributionDiagram]<>-0..*>[PieChart]
[DistributionDiagram]<>-0..*>[HistogramChart]
接口如下, 代码比较老, 欢迎指正
#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <time.h>
#include "gd.h"
#include "gdfonts.h"
#include "gdfontt.h"
using namespace std;
#define TinyPoint gdPoint
#define TinyFont gdFont
#define TinyColor int
#define WHITE 255,255,255
#define BLACK 0,0,0
#define GRAY 192,192,192
#define RED 255,0,0
#define GREEN 0,255,0
#define BLUE 0,0,255
#define MAGENTA 255,0,255
#define CYAN 0,255,255
#define YELLOW 255,255,0
#define AZURY 153,153,255
#define ORANGE_RED 255,36,00
#define PI 3.14159265357989
#ifdef NDEBUG
#define TRACE(msg)
#else
#define TRACE(msg) cout<<__FILE__<<", "<<__LINE__<<": "<<msg<<endl;
#endif
typedef map<string, int, less<string>, allocator<int> > STR2INT_MAP;
typedef vector<int, allocator<int> > INT_VEC;
typedef vector<string, allocator<string> > STR_VEC;
const int NAMESIZE=256;
const int DAYS=14;
class TinyShape
{
public:
TinyShape(gdImagePtr im)
{
m_pImage=im;
m_nBorderWidth=1;
SetBgColor(WHITE);
SetFrColor(BLACK);
SetBorderColor(BLACK);
m_nBorderWidth=1;
};
void SetBgColor(int r,int g,int b)
{
m_BgColor=gdImageColorAllocate(m_pImage, r, g, b);
};
void SetFrColor(int r,int g,int b)
{
m_FrColor=gdImageColorAllocate(m_pImage, r, g, b);
};
void SetBorderColor(int r,int g,int b)
{
m_BorderColor=gdImageColorAllocate(m_pImage, r, g, b);
};
void SetBgColor(TinyColor color)
{
m_BgColor=color;
};
TinyColor GetBgColor()
{
return m_BgColor;
};
TinyColor GetBorderColor()
{
return m_BorderColor;
};
void SetFrColor(TinyColor color)
{
m_FrColor=color;
};
void SetBorderColor(TinyColor color)
{
m_BorderColor=color;
};
void SetBorderWidth(int w)
{
m_nBorderWidth=w;
};
virtual ~TinyShape()
{
m_pImage=NULL;
};
virtual void Draw() = 0;
virtual void Fill() { };
protected:
int m_nBorderWidth;
gdImagePtr m_pImage;
TinyColor m_BorderColor;
TinyColor m_BgColor;
TinyColor m_FrColor;
};
class TinyScale:public TinyShape
{
public:
TinyScale(gdImagePtr im,TinyColor color):TinyShape(im)
{
m_FrColor=color;
m_pFont=gdFontSmall;//gdFontTiny
m_TopLeftPoint.x=0;
m_TopLeftPoint.y=0;
m_OffsetPoint.x=0;
m_OffsetPoint.y=0;
};
void Draw()
{
gdImageString(m_pImage, m_pFont, m_TopLeftPoint.x+m_OffsetPoint.x, m_TopLeftPoint.y+m_OffsetPoint.y, (unsigned char*)m_text, m_FrColor);
};
void Draw(char * text)
{
TRACE(" TinyScale:Draw(char * text): " <<m_TopLeftPoint.x<<", "<<m_TopLeftPoint.y<<","<<text);
gdImageString(m_pImage, m_pFont, m_TopLeftPoint.x+m_OffsetPoint.x, m_TopLeftPoint.y+m_OffsetPoint.y, (unsigned char*)text, m_FrColor);
};
void SetPosition(int x,int y)
{
m_TopLeftPoint.x=x;
m_TopLeftPoint.y=y;
};
void SetOffset(int x,int y)
{
m_OffsetPoint.x=x;
m_OffsetPoint.y=y;
};
void SetText(const char * text)
{
strncpy(m_text,text,10);
};
void SetFont(gdFontPtr font)
{
m_pFont=font;
};
TinyScale(gdImagePtr im,int x,int y):TinyShape(im)
{
m_TopLeftPoint.x=x;
m_TopLeftPoint.y=y;
SetFrColor(BLACK);
m_pFont=gdFontSmall;
m_OffsetPoint.x=0;
m_OffsetPoint.y=0;
};
virtual ~TinyScale()
{};
public:
TinyPoint m_TopLeftPoint;
TinyPoint m_OffsetPoint;
char m_text[10];
private:
gdFontPtr m_pFont;
};
class TinyRectangle:public TinyShape
{
public:
TinyRectangle(gdImagePtr im,int x1,int y1,int x2,int y2):TinyShape(im)
{
SetSize(x1,y1,x2,y2);
};
TinyRectangle(gdImagePtr im):TinyShape(im)
{
};
virtual ~TinyRectangle(){};
TinyPoint m_TopLeftPoint;
TinyPoint m_BottomRightPoint;
void SetSize(int x1,int y1,int x2,int y2)
{
m_TopLeftPoint.x=x1;
m_TopLeftPoint.y=y1;
m_BottomRightPoint.x=x2;
m_BottomRightPoint.y=y2;
};
void Draw()
{
gdImageRectangle(m_pImage,m_TopLeftPoint.x,m_TopLeftPoint.y,\
m_BottomRightPoint.x,m_BottomRightPoint.y,m_BorderColor);
};
void Fill()
{
//gdImageFilledRectangle(m_pImage,m_TopLeftPoint.x,m_TopLeftPoint.y,\
// m_BottomRightPoint.x,m_BottomRightPoint.y,m_BgColor);
int x=(m_TopLeftPoint.x+m_BottomRightPoint.x)/2;
int y=(m_TopLeftPoint.y+m_BottomRightPoint.y)/2;
gdImageFillToBorder(m_pImage,x,y,m_BorderColor,m_BgColor);
};
};
class TinyArc:public TinyShape
{
public:
TinyArc(gdImagePtr im,int x,int y):TinyShape(im)
{
SetCentre(x,y);
SetAngel(0,0);
SetSize(0,0);
};
TinyArc(gdImagePtr im):TinyShape(im)
{
};
virtual ~TinyArc()
{};
TinyPoint GetCentre() {
return m_Centre;
}
void SetCentre(int x,int y)
{
m_Centre.x=x;
m_Centre.y=y;
};
void SetAngel(float start,float end)
{
m_nStartAngle=start;
m_nEndAngle=end;
};
void SetSize(int w,int h)
{
m_nWidth=w;
m_nHeight=h;
};
void Draw()
{
gdImageArc(m_pImage,m_Centre.x,m_Centre.y,m_nWidth,m_nHeight,(int)ceil(m_nStartAngle),(int)ceil(m_nEndAngle),m_BorderColor);
};
void Fill()
{
gdImageFillToBorder(m_pImage,m_Centre.x,m_Centre.y,m_BorderColor,m_BgColor);
};
void Fill(TinyColor bordercolor,TinyColor bgcolor)
{
gdImageFillToBorder(m_pImage,m_Centre.x,m_Centre.y,bordercolor,bgcolor);
};
protected:
TinyPoint m_Centre;
int m_nWidth;
int m_nHeight;
float m_nStartAngle;
float m_nEndAngle;
};
class TinyCircle:public TinyArc
{
public:
TinyCircle(gdImagePtr im,int x,int y,int r):TinyArc(im,x,y)
{
SetRadius(r);
m_nStartAngle=0;
m_nEndAngle=360;
};
TinyCircle(gdImagePtr im):TinyArc(im)
{
};
void SetRadius(int r)
{
m_Radius=r;
m_nWidth=2*r;
m_nHeight=2*r;
};
virtual ~TinyCircle()
{};
private:
int m_Radius;
};
class TinyEclipse:public TinyArc
{
public:
TinyEclipse(gdImagePtr im,int x,int y,int r):TinyArc(im,x,y)
{
SetRadius(r);
m_nStartAngle=0;
m_nEndAngle=0;
};
TinyEclipse(gdImagePtr im):TinyArc(im)
{
};
void SetRadius(int r)
{
m_Radius=r;
m_nWidth=2*r;
m_nHeight=2*r;
};
void Draw()
{
float fAngle=m_nEndAngle-m_nStartAngle;
if(fAngle<1)
return;
m_Points[0].x=m_Centre.x;
m_Points[0].y=m_Centre.y;
m_Points[1].x=m_Centre.x+(int)ceil(m_Radius*cos(m_nStartAngle*PI/180));
m_Points[1].y=m_Centre.y-(int)ceil(m_Radius*sin(m_nStartAngle*PI/180));
m_Points[2].x=m_Centre.x+(int)ceil(m_Radius*cos(m_nEndAngle*PI/180));
m_Points[2].y=m_Centre.y-(int)ceil(m_Radius*sin(m_nEndAngle*PI/180));
gdImageLine(m_pImage,m_Points[0].x,m_Points[0].y,m_Points[1].x,m_Points[1].y,m_BorderColor);
gdImageLine(m_pImage,m_Points[0].x,m_Points[0].y,m_Points[2].x,m_Points[2].y,m_BorderColor);
};
void Fill()
{
int nAngle=(int)ceil(m_nEndAngle-m_nStartAngle);
int x,y;
TRACE("Angle: "<<m_nStartAngle<<"-"<<m_nEndAngle<<"="<<nAngle);
if(nAngle<1)
return;
else if(nAngle<=10)
{
x=(m_Points[0].x+(m_Points[1].x+m_Points[2].x)/2)/2;
y=(m_Points[0].y+(m_Points[1].y+m_Points[2].y)/2)/2;
}
else if(nAngle<=180)
{
x=(m_Points[1].x+m_Points[2].x)/2;
y=(m_Points[1].y+m_Points[2].y)/2;
}
else
{
x=2*m_Centre.x-(m_Points[1].x+m_Points[2].x)/2;
y=2*m_Centre.y-(m_Points[1].y+m_Points[2].y)/2;
}
TRACE("see "<<x<<","<<y);
//gdImageFillToBorder(m_pImage,x,y,m_BgColor,m_BorderColor);
gdImageFill(m_pImage,x,y,m_BgColor);
//gdImageFilledPolygon(m_pImage, m_Points, 3, m_BgColor);
};
virtual ~TinyEclipse()
{};
private:
int m_Radius;
TinyPoint m_Points[3];
};
class TinyChart:public TinyShape
{
protected:
TinyColor m_FrameColor;
TinyColor m_GridColor;
TinyColor m_TitleColor;
char m_szTitle[NAMESIZE];
int m_nGridWidth;
int m_nShapeWidth;
TinyPoint m_TopLeftPoint;
TinyPoint m_BottomRightPoint;
TinyPoint m_FrameTopLeftPoint;
TinyPoint m_FrameBottomRightPoint;
int m_nLeftMargin;
int m_nRightMargin;
int m_nTopMargin;
int m_nBottomMargin;
int GetBigerScale(int nScale);
public:
TinyChart(gdImagePtr im):TinyShape(im)
{
SetGridColor(BLACK);
SetFrameColor(GRAY);
SetTitleColor(AZURY);
m_nGridWidth=1;
m_nShapeWidth=10;
m_nLeftMargin=0;
m_nRightMargin=0;
m_nTopMargin=0;
m_nBottomMargin=0;
strncpy(m_szTitle,"",NAMESIZE);
};
virtual ~TinyChart()
{
for(int i = 0;i<m_Shapes.size();i++)
delete m_Shapes[i];
m_Shapes.clear();
for(int j = 0;j<m_xScale.size();j++)
delete m_xScale[j];
m_xScale.clear();
for(int k = 0;k<m_yScale.size();k++)
delete m_yScale[k];
m_yScale.clear();
};
void SetPosition(int x1,int y1,int x2,int y2)
{
m_TopLeftPoint.x=x1;
m_TopLeftPoint.y=y1;
m_BottomRightPoint.x=x2;
m_BottomRightPoint.y=y2;
}
void SetMargin(int top,int bottom,int left,int right)
{
m_nLeftMargin=left;
m_nRightMargin=right;
m_nTopMargin=top;
m_nBottomMargin=bottom;
}
void SetShapeWidth(int width)
{
m_nShapeWidth=width;
};
void SetGridColor(int r,int g,int b)
{
m_GridColor=gdImageColorAllocate(m_pImage, r, g, b);
};
void SetTitleColor(int r,int g,int b)
{
m_TitleColor=gdImageColorAllocate(m_pImage, r, g, b);
};
void SetFrameColor(int r,int g,int b)
{
m_FrameColor=gdImageColorAllocate(m_pImage, r, g, b);
};
virtual void SetVerticalScale(INT_VEC& vecYScale){};
virtual void SetHorziontalScale(STR_VEC& vecXScale);
//virtual void SetData(){};
virtual void SetTitle(char* title);
virtual void Plot(){};
virtual void DrawTitle();
virtual void DrawGrid();
void DrawFrame();
void DrawBorder();
void Draw();
protected:
INT_VEC m_nData;
vector<TinyShape*> m_Shapes;
vector<TinyScale*> m_xScale;
vector<TinyScale*> m_yScale;
int m_nVerticalScale;
int m_nHorziontalScale;
};
class TinyCurveChart:public TinyChart
{
public:
void Plot();
//void SetData();
void SetVerticalScale(INT_VEC& vecYScale);
//void SetHorziontalScale(STR_VEC& vecXScale,int nXScale){};
TinyCurveChart(gdImagePtr im):TinyChart(im)
{
SetFrColor(RED);
};
virtual ~TinyCurveChart()
{};
void DrawTitle(){};
};
class TinyColumnChart:public TinyChart
{
public:
void Plot();
void SetVerticalScale(INT_VEC& vecYScale);
//void SetHorziontalScale(STR_VEC& vecXScale,int nXScale){};
TinyColumnChart(gdImagePtr im):TinyChart(im)
{};
virtual ~TinyColumnChart()
{};
};
class TinyHistogram:public TinyChart
{
public:
void Plot();
void SetHorziontalScale(STR_VEC& vecXScale);
void SetVerticalScale(INT_VEC& vecYScale);
//void SetHorziontalScale(STR_VEC& vecXScale,int nXScale){};
TinyHistogram(gdImagePtr im):TinyChart(im)
{};
virtual ~TinyHistogram()
{};
};
class TinyPieChart:public TinyChart
{
public:
void Draw();
void DrawLegend();
void DrawFrame();
void Plot();
void SetHorziontalScale(STR_VEC& vecXScale);
void SetVerticalScale(INT_VEC& vecYScale);
TinyColor GetRandColor(int index=-1);
TinyPieChart(gdImagePtr im):TinyChart(im), m_nSum(0)
{
};
virtual ~TinyPieChart()
{};
private:
int m_nSum;
};
class TinyDiagram
{
public:
TinyDiagram(const char* filename,int width,int height);
virtual ~TinyDiagram();
int SetFileName(const char* szFilename);
int SetTitle(const char* szTitle);
virtual void Draw() {};
void DrawBorder();
void SetLabels(STR_VEC& xScales);
void SetValues(INT_VEC& yScales);
gdImagePtr GetImage()
{
return m_pImage;
};
void WriteImage();
protected:
gdImagePtr m_pImage;
int m_nWidth;
int m_nHeight;
char m_szFileName[NAMESIZE];
char m_szTitle[NAMESIZE];
INT_VEC m_vecData;
STR_VEC m_vecName;
};
class TinyTrendlineDiagram:public TinyDiagram
{
public:
TinyCurveChart* m_pCurveChart;
TinyColumnChart* m_pColumnChart;
TinyTrendlineDiagram(const char* filename,int width,int height);
virtual ~TinyTrendlineDiagram();
void Draw();
};
class TinyDistributionDiagram:public TinyDiagram
{
public:
TinyPieChart* m_pPieChart;
TinyHistogram* m_pHistogram;
void Draw();
TinyDistributionDiagram(const char* filename,int width,int height);
virtual ~TinyDistributionDiagram();
};
#endif /* UTIL_TINYCHART_H_ */
