Hello.
I have a code I would like to share with the community. It draws a rectangle on the e-ink screen. To execute:
1. Cross-compile the code and upload it to Kindle (usbnet assumed)
Code:
$ arm-none-linux-gnueabi-gcc -o hello-kindle hello.c
$ cat hello-kindle | ssh root@192.168.2.2 "cat - > /var/tmp/root/hello-arm"
2. Execute the code on the kindle
Code:
[root@kindle root]# /usr/sbin/eips -c
[root@kindle root]# ./hello-arm
Size: 824 x 1200
[root@kindle root]# echo 2 > /proc/eink_fb/update_display
The code is below. Comments/Questions are welcomed.
Code:
#include <stdio.h>
// Read in header files
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <unistd.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
/*
ACCELEROMETER=/proc/accelerometer (cat works, tail -f doesnt)
/dev/input/event0 - keyboard
/dev/input/event1 - pointer
*/
#define putpixel(_x, _y, _c) \
if ((_x) & 01) { \
data[((_y)*width + (_x)) >> 1] &= 0xF0; \
data[((_y)*width + (_x)) >> 1] |= (_c & 0x0F); \
} else { \
data[((_y)*width + (_x)) >> 1] &= 0x0F; \
data[((_y)*width + (_x)) >> 1] |= ((_c & 0x0F) << 4); \
}
int main(int argc, char** argv) {
int width = 0;
int height = 0;
int row, column, i, j;
// open framebuffer device and read out info
int fd = open("/dev/fb0", O_RDWR);
struct fb_var_screeninfo screeninfo;
ioctl(fd, FBIOGET_VSCREENINFO, &screeninfo);
// determine size
width = screeninfo.xres;
height = screeninfo.yres;
printf("Size: %d x %d\n", width, height);
// embed framebuffer into memory
unsigned char *data = (unsigned char*)
mmap(0, width * height / 2,
PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
// Clear memory (4 bpp)
memset(data, 0, width * height / 2);
// Draw a box
for (i = 100; i <= 200; ++i) {
putpixel(300, i, 0xF);
putpixel(400, i, 0xF);
putpixel(i+200, 100, 0xF);
putpixel(i+200, 200, 0xF);
}
// mask framebuffer out of memory
munmap(data, width * height / 2);
}