Mac下使用CImg

环境

macOS 10.14.4

准备

下载CImg.h 编译

  #include "CImg.h"

g++ test.cpp -o main

报错

In file included from test.cpp:1:
./CImg.h:371:10: fatal error: 'X11/Xlib.h' file not found
#include <X11/Xlib.h>
         ^~~~~~~~~~~~
1 error generated

安装xquartz

brew cask install xquartz

重新编译

g++ test.cpp -o main -I/opt/X11/include

修改下test.cpp

#include "CImg.h"
int main(int argc, char const *argv[])
{
  /* code */
  return 0;
}

重新编译

g++ test.cpp -o main -I/opt/X11/include

编译成功修改下test.cpp

#include "CImg.h"
using namespace cimg_library;

int main() {
    //读取图片
    CImg<unsigned char> img("1.bmp");
    //显示图片
    img.display("Ex1");
    return 0;
}

重新编译

g++ test.cpp -o main -I/opt/X11/include

编译成功运行

./main

报错

[CImg] *** CImgDisplayException *** CImgDisplay::screen_width(): Failed to open X11 display.
libc++abi.dylib: terminating with uncaught exception of type cimg_library::CImgDisplayException: CImgDisplay::screen_width(): Failed to open X11 display.
Abort trap: 6

下载安装 XQuartz 重启

运行成功

代码

1.读入 1.bmp 文件，并用 CImg.display() 显示。

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0
int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  SrcImg.display();

 return 0;
}

把 1.bmp 文件的白色区域变成红色，黑色区域变成绿色。

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0
int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  cimg_forXY(SrcImg, x, y) {
    if (SrcImg(x, y, 0) == 0 && SrcImg(x, y, 1) == 0 && SrcImg(x, y, 2) == 0) {
      SrcImg(x, y, 0) = 0;
      SrcImg(x, y, 1) = 255;
      SrcImg(x, y, 2) = 0; 
    }

    if (SrcImg(x, y, 0) == 255 && SrcImg(x, y, 1) == 255 && SrcImg(x, y, 2) == 255) {
      SrcImg(x, y, 0) = 255;
      SrcImg(x, y, 1) = 0;
      SrcImg(x, y, 2) = 0;
    }
  }
  SrcImg.display();

 return 0;
}

在图上绘制一个等边三角形区域，其中心坐标(50,50)，边长为 40，填充颜色为蓝色。蓝色RGB(0,0,255)

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0


void draw_triangle(CImg<unsigned char>& srcImg, int x1, int y1, 
  int x2, int y2, int x3, int y3) {
    int width = srcImg.width();
    int height = srcImg.height();
    for (int i = 0; i < width; i++) {
      for (int j = 0; j < height; j++) {
        double vx1 = x2 - x1, vy1 = y2 - y1, vx2 = x3 - x1, vy2 = y3 - y1;
        double vx0 = i - x1, vy0 = j - y1;
        double u = (vx2*vy0 - vx0*vy2) / (double)(vx2*vy1 - vx1*vy2),
        v = (vx1*vy0 - vx0*vy1) / (double)(vx1*vy2 - vx2*vy1);
        if (u >= 0 && v >= 0 && u+v <= 1) {
            srcImg(i, j, 0, 0) = 0;
            srcImg(i, j, 0, 1) = 0;
            srcImg(i, j, 0, 2) = 255;
        }
      }
    }
  
}
int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  draw_triangle(SrcImg, 50,73,30,38,70,38);
  SrcImg.display();

 return 0;
}

使用CImg绘图

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0

int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  // draw_triangle(SrcImg, 50,73,30,38,70,38);
  unsigned char asd[] = {0, 0, 255};
  SrcImg.draw_triangle(50,73,30,38,70,38, asd);
  SrcImg.display();

 return 0;
}

在图上绘制一个圆形区域，圆心坐标(50,50)，半径为 15，填充颜色为黄色。黄色RGB(255.255.0)

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0
void draw_circle(CImg<unsigned char>& srcImg, int x1, int y1, double radius){
  int width = srcImg.width();
  int height = srcImg.height();
  for (int i = 0; i < width; i++) {
      for (int j = 0; j < height; j++) {
        double a = (i - x1) * (i - x1);
        double b =(j - y1) * (j - y1);
        double distance = sqrt(a+b);
        if (distance <= radius) {
            srcImg(i, j, 0, 0) = 255;
            srcImg(i, j, 0, 1) = 255;
            srcImg(i, j, 0, 2) = 0;
        }
      }
    }

}
int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  draw_circle(SrcImg, 50,50,15);
  SrcImg.display();

 return 0;
}

使用CImg绘图

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0

int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  unsigned char asd[] = {255, 255, 0};
  SrcImg.draw_circle(50,50,15, asd);
  SrcImg.display();

 return 0;
}

在图上绘制一条长为 100 的直线段，起点坐标为(0, 0)，方向角为 135 度，直线的颜色为绿色。绿色RGB(0,255,0)

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0
void draw_line(CImg<unsigned char>& srcImg){
  for (int i = 0; i < 72; i++) {
            srcImg(i, i, 0, 0) = 0;
            srcImg(i, i, 0, 1) = 255;
            srcImg(i, i, 0, 2) = 0;
    }

}
int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  draw_line(SrcImg);
  SrcImg.display();

 return 0;
}

使用CImg绘图

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0

int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  unsigned char asd[] = {0, 255, 0};
  SrcImg.draw_line(0,0,71,71, asd);
  SrcImg.display();

 return 0;
}

把上面的操作结果保存为 2.bmp。

#include "CImg.h"
using namespace cimg_library;
#define cimg_display_type 0

int main()
{
  CImg<unsigned char> SrcImg;
  SrcImg.load_bmp("1.bmp");
  cimg_forXY(SrcImg, x, y) {
    if (SrcImg(x, y, 0) == 0 && SrcImg(x, y, 1) == 0 && SrcImg(x, y, 2) == 0) {
      SrcImg(x, y, 0) = 0;
      SrcImg(x, y, 1) = 255;
      SrcImg(x, y, 2) = 0; 
    }

    if (SrcImg(x, y, 0) == 255 && SrcImg(x, y, 1) == 255 && SrcImg(x, y, 2) == 255) {
      SrcImg(x, y, 0) = 255;
      SrcImg(x, y, 1) = 0;
      SrcImg(x, y, 2) = 0;
    }
  }
  unsigned char green[] = {0, 255, 0};
  unsigned char yellow[] = {255, 255, 0};
  unsigned char blue[] = {0, 0, 255};
  SrcImg.draw_triangle(50,73,30,38,70,38, blue);
  SrcImg.draw_circle(50,50,15, yellow);
  SrcImg.draw_line(0,0,71,71, green);
  SrcImg.save("2.bmp");

 return 0;
}

Mac下使用CImg

Mac下使用CImg

环境

准备

代码

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