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 MAXFBWIDTH      (1 << 12)
  14 #define BPP             sizeof(fbval_t)
  15 #define NLEVELS         (1 << 8)
  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 static void fb_cmap_save(int save)
  28 {
  29         static unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  30         struct fb_cmap cmap;
  31         int mr = 1 << vinfo.red.length;
  32         int mg = 1 << vinfo.green.length;
  33         int mb = 1 << vinfo.blue.length;
  34         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  35                 return;
  36         cmap.start = 0;
  37         cmap.len = MAX(mr, MAX(mg, mb));
  38         cmap.red = red;
  39         cmap.green = green;
  40         cmap.blue = blue;
  41         cmap.transp = 0;
  42         ioctl(fd, save ? FBIOGETCMAP : FBIOPUTCMAP, &cmap);
  43 }
  44
  45 void fb_cmap(void)
  46 {
  47         unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  48         struct fb_cmap cmap;
  49         int mr = 1 << vinfo.red.length;
  50         int mg = 1 << vinfo.green.length;
  51         int mb = 1 << vinfo.blue.length;
  52         int i;
  53         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  54                 return;
  55
  56         for (i = 0; i < mr; i++)
  57                 red[i] = (65535 / (mr - 1)) * i;
  58         for (i = 0; i < mg; i++)
  59                 green[i] = (65535 / (mg - 1)) * i;
  60         for (i = 0; i < mb; i++)
  61                 blue[i] = (65535 / (mb - 1)) * i;
  62
  63         cmap.start = 0;
  64         cmap.len = MAX(mr, MAX(mg, mb));
  65         cmap.red = red;
  66         cmap.green = green;
  67         cmap.blue = blue;
  68         cmap.transp = 0;
  69
  70         ioctl(fd, FBIOPUTCMAP, &cmap);
  71 }
  72
  73 static void xerror(char *msg)
  74 {
  75         perror(msg);
  76         exit(1);
  77 }
  78
  79 static void xdie(char *msg)
  80 {
  81         fprintf(stderr, "%s\n", msg);
  82         exit(1);
  83 }
  84
  85 void fb_init(void)
  86 {
  87         fd = open(FBDEV_PATH, O_RDWR);
  88         if (fd == -1)
  89                 xerror("can't open " FBDEV_PATH);
  90         if (ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) == -1)
  91                 xerror("ioctl failed");
  92         if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
  93                 xerror("ioctl failed");
  94         if ((vinfo.bits_per_pixel + 7) >> 3 != BPP)
  95                 xdie("fbval_t does not match framebuffer depth");
  96         fb = mmap(NULL, fb_len(), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  97         if (fb == MAP_FAILED)
  98                 xerror("can't map the framebuffer");
  99         fb_cmap_save(1);
 100         fb_cmap();
 101 }
 102
 103 void fb_set(int r, int c, fbval_t *mem, int len)
 104 {
 105         long loc = (c + vinfo.xoffset) * BPP +
 106                 (r + vinfo.yoffset) * finfo.line_length;
 107         memcpy(fb + loc, mem, len * BPP);
 108 }
 109
 110 void fb_free()
 111 {
 112         fb_cmap_save(0);
 113         munmap(fb, fb_len());
 114         close(fd);
 115 }
 116
 117 static fbval_t color_bits(struct fb_bitfield *bf, fbval_t v)
 118 {
 119         fbval_t moved = v >> (8 - bf->length);
 120         return moved << bf->offset;
 121 }
 122
 123 fbval_t fb_color(unsigned char r, unsigned char g, unsigned char b)
 124 {
 125         return color_bits(&vinfo.red, r) |
 126                 color_bits(&vinfo.green, g) |
 127                 color_bits(&vinfo.blue, b);
 128 }
 129
 130 int fb_rows(void)
 131 {
 132         return vinfo.yres;
 133 }
 134
 135 int fb_cols(void)
 136 {
 137         return vinfo.xres;
 138 }
 139
 140 static unsigned char *rowaddr(int r)
 141 {
 142         return fb + (r + vinfo.yoffset) * finfo.line_length;
 143 }
 144
 145 static unsigned long cache[MAXFBWIDTH];
 146 void fb_box(int sr, int sc, int er, int ec, fbval_t val)
 147 {
 148         int i;
 149         int pc = sizeof(cache[0]) / sizeof(val);
 150         int cn = MIN((ec - sc) / pc + 1, MAXFBWIDTH);
 151         unsigned long nv = val;
 152         for (i = 1; i < pc; i++)
 153                 nv = (nv << (sizeof(val) * 8)) | val;
 154         for (i = 0; i < cn; i++)
 155                 cache[i] = nv;
 156         for (i = sr; i < er; i++)
 157                 memcpy(rowaddr(i) + sc * BPP, cache, (ec - sc) * BPP);
 158 }