Question

如何使用C++编写提取图像中特定像素点（给定x，y坐标）的RGB信息

Answer 1

win api 函数 ：getwindowpixel（）别忘加分呢。
#include<stdio.h>
int main()
{
int width,height,x,y;
unsigned short bitCount;
int offbits;
int bitPerLine;
unsigned char data;
FILE* bmpfp = fopen("E:\\风景\\风景1.bmp","rb");
fseek(bmpfp,18,SEEK_SET);
fread(&width,sizeof(int),1,bmpfp);
fread(&height,sizeof(int),1,bmpfp);
printf("width : %d , height : %d\n",width,height);
fseek(bmpfp,2,SEEK_CUR);
fread(&bitCount,sizeof(bitCount),1,bmpfp);
fseek(bmpfp,10,SEEK_SET);
fread(&offbits,sizeof(int),1,bmpfp);

if(bitCount==24){
bitPerLine = ( (width*3)%4==0 ) ? width*3 : ( (width*3)/4 )*4 + 4;
while(1){
printf("请输出坐标：");
scanf("%d%d",&x,&y);
if(x>width||y>height) return 0;
fseek(bmpfp, 18 + offbits + bitPerLine * y + 3*x , SEEK_SET);
fread(&data,sizeof(data),1,bmpfp);
printf("该点蓝色分量：%d",data);
fread(&data,sizeof(data),1,bmpfp);
printf("该点绿色分量：%d",data);
fread(&data,sizeof(data),1,bmpfp);
printf("该点红色分量：%d\n",data);
}
}else{
printf("不是真彩位图！");
}
}

Answer 2

给你找了份示例代码

#include<stdio.h>
int main()
{
int width,height,x,y;
unsigned short bitCount;
int offbits;
int bitPerLine;
unsigned char data;
FILE* bmpfp = fopen("E:\\风景\\风景1.bmp","rb");
fseek(bmpfp,18,SEEK_SET);
fread(&width,sizeof(int),1,bmpfp);
fread(&height,sizeof(int),1,bmpfp);
printf("width : %d , height : %d\n",width,height);
fseek(bmpfp,2,SEEK_CUR);
fread(&bitCount,sizeof(bitCount),1,bmpfp);
fseek(bmpfp,10,SEEK_SET);
fread(&offbits,sizeof(int),1,bmpfp);

if(bitCount==24){
bitPerLine = ( (width*3)%4==0 ) ? width*3 : ( (width*3)/4 )*4 + 4;
while(1){
printf("请输出坐标：");
scanf("%d%d",&x,&y);
if(x>width||y>height) return 0;
fseek(bmpfp, 18 + offbits + bitPerLine * y + 3*x , SEEK_SET);
fread(&data,sizeof(data),1,bmpfp);
printf("该点蓝色分量：%d",data);
fread(&data,sizeof(data),1,bmpfp);
printf("该点绿色分量：%d",data);
fread(&data,sizeof(data),1,bmpfp);
printf("该点红色分量：%d\n",data);
}
}else{
printf("不是真彩位图！");
}
}

/*

运行结果：

width : 700 , height : 382
请输出坐标：0 0
该点蓝色分量：68该点绿色分量：82该点红色分量：80

*/