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package gofb
/*
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
int OpenFrameBuffer(char * name) {
return open(name, O_RDWR);
}
static int GetFixedScreenInformation(int fd,struct fb_fix_screeninfo *finfo)
{
return ioctl(fd, FBIOGET_FSCREENINFO, finfo);
}
static int GetVarScreenInformation(int fd,struct fb_var_screeninfo *vinfo) {
return ioctl(fd, FBIOGET_VSCREENINFO, vinfo);
}
*/
import "C"
import (
"errors"
"fmt"
"image"
"os/exec"
"unsafe"
)
// Framebuffer -
type Framebuffer struct {
Fd int
BitsPerPixel int
Xres int
Yres int
Data []byte
Xoffset int
Yoffset int
LineLength int
Screensize int
}
// NewFramebuffer -
func NewFramebuffer() *Framebuffer {
return &Framebuffer{}
}
func _HideCursor() {
fmt.Print("\033[?25l")
exec.Command(`kill `)
}
func _ShowCursor() {
fmt.Printf("\033[?25h")
}
// Init -
func (f *Framebuffer) Init(dev string) {
if len(dev) == 0 {
dev = "/dev/fb0"
}
_HideCursor()
dev_file := C.CString(dev)
fd, err := C.OpenFrameBuffer(dev_file)
C.free(unsafe.Pointer(dev_file))
if err != nil {
panic(errors.New("Open the framebuffer failed"))
}
var finfo C.struct_fb_fix_screeninfo
if _, err := C.GetFixedScreenInformation(fd, &finfo); err != nil {
fmt.Println(err)
}
var vinfo C.struct_fb_var_screeninfo
if _, err := C.GetVarScreenInformation(fd, &vinfo); err != nil {
fmt.Println(err)
}
f.Xres = int(vinfo.xres)
f.Yres = int(vinfo.yres)
f.BitsPerPixel = int(vinfo.bits_per_pixel)
f.Xoffset = int(vinfo.xoffset)
f.Yoffset = int(vinfo.yoffset)
f.LineLength = int(finfo.line_length)
f.Screensize = int(finfo.smem_len)
addr := uintptr(C.mmap(nil, C.size_t(f.Screensize), C.PROT_READ|C.PROT_WRITE, C.MAP_SHARED, fd, 0))
var sl = struct {
addr uintptr
len int
cap int
}{addr, f.Screensize, f.Screensize}
f.Data = *(*[]byte)(unsafe.Pointer(&sl))
}
// Release open file
func (f *Framebuffer) Release() {
C.munmap(unsafe.Pointer(&f.Data[0]), C.size_t(f.Screensize))
C.close(C.int(f.Fd))
_ShowCursor()
}
func (f *Framebuffer) SetPixel(x int, y int, r uint32, g uint32, b uint32, a uint32) {
if x < 0 || x > f.Xres {
panic(errors.New("X is too big or is negative"))
}
if y < 0 || y > f.Yres {
panic(errors.New("Y is too big or is negative"))
}
location := (x+f.Xoffset)*(f.BitsPerPixel/8) + (y+f.Yoffset)*f.LineLength
f.Data[location+3] = byte(a & 0xff)
f.Data[location+2] = byte(r & 0xff)
f.Data[location+1] = byte(g & 0xff)
f.Data[location] = byte(b & 0xff)
}
func (f *Framebuffer) DrawImage(xoffset int, yoffset int, image image.Image) {
b := image.Bounds()
for y := 0; y < b.Max.Y; y++ {
for x := 0; x < b.Max.X; x++ {
r, g, b, a := image.At(x, y).RGBA()
f.SetPixel(x+xoffset, y+yoffset, r&0xff, g&0xff, b&0xff, a&0xff)
}
}
}
func (f *Framebuffer) DrawData(xoffset int, yoffset int, data []byte, w int, h int) {
if w > f.Xres {
panic(errors.New("The width of data must NOT be bigger the Xres of the framebuffer"))
}
for y := 0; y < h; y++ {
if (y+1)*w > len(data) {
panic(errors.New("The length of image data is too small or w(h) argument is wrong"))
}
line_start := (xoffset+f.Xoffset)*(f.BitsPerPixel/8) + (y+yoffset+f.Yoffset)*f.LineLength
line_end := (xoffset+f.Xoffset)*(f.BitsPerPixel/8) + (y+1+yoffset+f.Yoffset)*f.LineLength - 1
if line_start+w > line_end {
panic(errors.New("The lines is too long beyond the framebuffer"))
}
data_line := data[y*w*4 : (y+1)*w*4]
copy(f.Data[line_start:line_start+w*4], data_line)
}
}
func (f *Framebuffer) Fill(r, g, b, a uint32) {
for y := 0; y < f.Yres; y++ {
for x := 0; x < f.Xres; x++ {
f.SetPixel(x, y, r, g, b, a)
}
}
}