draw.c

   1 #include <fcntl.h>
   2 #include <linux/fb.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <sys/ioctl.h>
   6 #include <sys/mman.h>
   7 #include <unistd.h>
   8 #include <string.h>
   9 #include "config.h"
  10 #include "draw.h"
  11 #include "util.h"
  12
  13 #define FBDEV_PATH      "/dev/fb0"
  14 #define MAXWIDTH        (1 << 12)
  15 #define BPP             sizeof(fbval_t)
  16
  17 static int fd;
  18 static unsigned char *fb;
  19 static struct fb_var_screeninfo vinfo;
  20 static struct fb_fix_screeninfo finfo;
  21
  22 static int fb_len()
  23 {
  24         return vinfo.xres_virtual * vinfo.yres_virtual * BPP;
  25 }
  26
  27 #define NLEVELS 1 << 8
  28 void fb_cmap(void)
  29 {
  30         unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  31         struct fb_cmap cmap;
  32         int mr = 1 << vinfo.red.length;
  33         int mg = 1 << vinfo.green.length;
  34         int mb = 1 << vinfo.blue.length;
  35         int i;
  36         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  37                 return;
  38
  39         for (i = 0; i < mr; i++)
  40                 red[i] = (65535 / (mr - 1)) * i;
  41         for (i = 0; i < mg; i++)
  42                 green[i] = (65535 / (mg - 1)) * i;
  43         for (i = 0; i < mb; i++)
  44                 blue[i] = (65535 / (mb - 1)) * i;
  45
  46         cmap.start = 0;
  47         cmap.len = MAX(mr, MAX(mg, mb));
  48         cmap.red = red;
  49         cmap.green = green;
  50         cmap.blue = blue;
  51         cmap.transp = 0;
  52
  53         ioctl(fd, FBIOPUTCMAP, &cmap);
  54 }
  55
  56 void fb_init(void)
  57 {
  58         fd = open(FBDEV_PATH, O_RDWR);
  59         if (fd == -1)
  60                 xerror("can't open " FBDEV_PATH);
  61         if (ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) == -1)
  62                 xerror("ioctl failed");
  63         if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
  64                 xerror("ioctl failed");
  65         fb = mmap(NULL, fb_len(), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  66         if (fb == MAP_FAILED)
  67                 xerror("can't map the framebuffer");
  68         fb_cmap();
  69 }
  70
  71 void fb_set(int r, int c, fbval_t *mem, int len)
  72 {
  73         long loc = (c + vinfo.xoffset) * BPP +
  74                 (r + vinfo.yoffset) * finfo.line_length;
  75         memcpy(fb + loc, mem, len * BPP);
  76 }
  77
  78 void fb_free()
  79 {
  80         munmap(fb, fb_len());
  81         close(fd);
  82 }
  83
  84 static fbval_t color_bits(struct fb_bitfield *bf, fbval_t v)
  85 {
  86         fbval_t moved = v >> (8 - bf->length);
  87         return moved << bf->offset;
  88 }
  89
  90 fbval_t fb_color(unsigned char r, unsigned char g, unsigned char b)
  91 {
  92         return color_bits(&vinfo.red, r) |
  93                 color_bits(&vinfo.green, g) |
  94                 color_bits(&vinfo.blue, b);
  95 }
  96
  97 int fb_rows(void)
  98 {
  99         return vinfo.yres;
 100 }
 101
 102 int fb_cols(void)
 103 {
 104         return vinfo.xres;
 105 }
 106
 107 static unsigned char *rowaddr(int r)
 108 {
 109         return fb + (r + vinfo.yoffset) * finfo.line_length;
 110 }
 111
 112 static unsigned long cache[MAXWIDTH];
 113 void fb_box(int sr, int sc, int er, int ec, fbval_t val)
 114 {
 115         int i;
 116         int pc = sizeof(cache[0]) / sizeof(val);
 117         int cn = MIN((ec - sc) / pc + 1, ARRAY_SIZE(cache));
 118         unsigned long nv = val;
 119         for (i = 1; i < pc; i++)
 120                 nv = (nv << (sizeof(val) * 8)) | val;
 121         for (i = 0; i < cn; i++)
 122                 cache[i] = nv;
 123         for (i = sr; i < er; i++)
 124                 memcpy(rowaddr(i) + sc * BPP, cache, (ec - sc) * BPP);
 125 }
 126
 127 void fb_scroll(int sr, int nr, int n, fbval_t val)
 128 {
 129         memmove(rowaddr(sr + n), rowaddr(sr), nr * finfo.line_length);
 130         if (n > 0)
 131                 fb_box(sr, 0, sr + n, fb_cols(), val);
 132         else
 133                 fb_box(sr + nr + n, 0, sr + nr, fb_cols(), val);
 134 }