framebuffer设备测试操作

最新推荐文章于 2024-08-14 23:29:23 发布

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最新推荐文章于 2024-08-14 23:29:23 发布

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分类专栏：代码编程

本文链接：https://blog.youkuaiyun.com/chengm8/article/details/17005305

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本博客详细介绍了如何使用Linux framebuffer设备进行彩色显示测试，包括设备打开、信息获取、内存映射以及不同位深的显示区域绘制。

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#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<sys/mman.h>
#include<linux/fb.h>

#define COLOR565_RED 0XF800
#define COLOR565_GREEN 0X07E0
#define COLOR565_BLUE 0X001F

int fdfb=-1;
struct fb_fix_screeninfo fbfix={0};
struct fb_var_screeninfo fbvar={0};
long screensize=0;
unsigned short *fb565=NULL;

int x=0;
int y=0;
long location=0;

int main(int argc,char**argv){

fdfb=open("/dev/fb0",O_RDWR);
if(fdfb<0){
printf("failure to open framebuffer device!\n");
exit(-1);
}
printf("success to open framebuffer device!\n");
if(ioctl(fdfb,FBIOGET_FSCREENINFO,&fbfix)){
printf("faiure to get fixed screen information!\n");
exit(-2);
}
printf("success to get varible screen information!\n");

screensize=fbvar.xres*fbvar.yres*(fbvar.bits_per_pixel/8);
printf("Vscreeninfo.xres=%d,Vscreeninfo.yres=%d\nVscreeninfo.bits_per_pixel=%dpp,ScreenSize=%d!\n",fbvar.xres,fbvar.yres,fbvar.bits_per_pixel,screensize);

fb565=(unsigned short*)mmap(0,screensize,PROT_READ|PROT_WRITE,MAP_SHARED,fdfb,0);
if(fb565==NULL){
printf("failure to map framebuffer device memory to process't memory!\n");
exit(-4);
}
printf("success to map framebuffer device memory to proccess't memory!\n");

if(8==fbvar.bits_per_pixel){
printf("starting 8bpp framebuffer testing...\n");
}
else if(16==fbvar.bits_per_pixel){
printf("starting 16bpp framebuffer testing...\n");
printf("starting to show RED area...");
for(y=0;y<fbvar.yres/3;y++)
for(x=0;x<fbvar.xres;x++)
*(fb565+y*fbvar.xres+x)=COLOR565_RED;
printf("starting to show GREEN area...\n");
for(y=fbvar.yres/3;y<((fbvar.yres/3)*2);y++)
for(x=0;x<fbvar.xres;x++)
*(fb565+y*fbvar.xres+x)=COLOR565_GREEN;
printf("starting to show BLUE area...\n");
for(y=(fbvar.yres/3)*2;y<fbvar.yres;y++)
for(x=0;x<fbvar.xres;x++)
*(fb565+y*fbvar.xres+x)=COLOR565_BLUE;
}
else if(24==fbvar.bits_per_pixel){
printf("starting 24bpp framebuffer testing...\n");
}
else{
printf("supporting 5/16/24bpp framebuffer testing only...\n");
}
munmap(fb565,screensize);
close(fdfb);
printf("finished to demo to operate framebuffer!\n");
return 0;

}