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 #define NLEVELS         (1 << 8)
  17
  18 static int fd;
  19 static unsigned char *fb;
  20 static struct fb_var_screeninfo vinfo;
  21 static struct fb_fix_screeninfo finfo;
  22
  23 static int fb_len()
  24 {
  25         return vinfo.xres_virtual * vinfo.yres_virtual * BPP;
  26 }
  27
  28 static void fb_cmap_save(int save)
  29 {
  30         static 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         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  36                 return;
  37         cmap.start = 0;
  38         cmap.len = MAX(mr, MAX(mg, mb));
  39         cmap.red = red;
  40         cmap.green = green;
  41         cmap.blue = blue;
  42         cmap.transp = 0;
  43         if (save)
  44                 ioctl(fd, FBIOGETCMAP, &cmap);
  45         else
  46                 ioctl(fd, FBIOPUTCMAP, &cmap);
  47 }
  48
  49 void fb_cmap(void)
  50 {
  51         unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  52         struct fb_cmap cmap;
  53         int mr = 1 << vinfo.red.length;
  54         int mg = 1 << vinfo.green.length;
  55         int mb = 1 << vinfo.blue.length;
  56         int i;
  57         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  58                 return;
  59
  60         for (i = 0; i < mr; i++)
  61                 red[i] = (65535 / (mr - 1)) * i;
  62         for (i = 0; i < mg; i++)
  63                 green[i] = (65535 / (mg - 1)) * i;
  64         for (i = 0; i < mb; i++)
  65                 blue[i] = (65535 / (mb - 1)) * i;
  66
  67         cmap.start = 0;
  68         cmap.len = MAX(mr, MAX(mg, mb));
  69         cmap.red = red;
  70         cmap.green = green;
  71         cmap.blue = blue;
  72         cmap.transp = 0;
  73
  74         ioctl(fd, FBIOPUTCMAP, &cmap);
  75 }
  76
  77 static void xdie(char *msg)
  78 {
  79         fprintf(stderr, "%s\n", msg);
  80         exit(1);
  81 }
  82
  83 void fb_init(void)
  84 {
  85         fd = open(FBDEV_PATH, O_RDWR);
  86         if (fd == -1)
  87                 xerror("can't open " FBDEV_PATH);
  88         if (ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) == -1)
  89                 xerror("ioctl failed");
  90         if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
  91                 xerror("ioctl failed");
  92         if ((vinfo.bits_per_pixel + 7) >> 3 != BPP)
  93                 xdie("fbval_t does not match framebuffer depth");
  94         fb = mmap(NULL, fb_len(), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  95         if (fb == MAP_FAILED)
  96                 xerror("can't map the framebuffer");
  97         fb_cmap_save(1);
  98         fb_cmap();
  99 }
 100
 101 void fb_set(int r, int c, fbval_t *mem, int len)
 102 {
 103         long loc = (c + vinfo.xoffset) * BPP +
 104                 (r + vinfo.yoffset) * finfo.line_length;
 105         memcpy(fb + loc, mem, len * BPP);
 106 }
 107
 108 void fb_free()
 109 {
 110         fb_cmap_save(0);
 111         munmap(fb, fb_len());
 112         close(fd);
 113 }
 114
 115 static fbval_t color_bits(struct fb_bitfield *bf, fbval_t v)
 116 {
 117         fbval_t moved = v >> (8 - bf->length);
 118         return moved << bf->offset;
 119 }
 120
 121 fbval_t fb_color(unsigned char r, unsigned char g, unsigned char b)
 122 {
 123         return color_bits(&vinfo.red, r) |
 124                 color_bits(&vinfo.green, g) |
 125                 color_bits(&vinfo.blue, b);
 126 }
 127
 128 int fb_rows(void)
 129 {
 130         return vinfo.yres;
 131 }
 132
 133 int fb_cols(void)
 134 {
 135         return vinfo.xres;
 136 }
 137
 138 static unsigned char *rowaddr(int r)
 139 {
 140         return fb + (r + vinfo.yoffset) * finfo.line_length;
 141 }
 142
 143 static unsigned long cache[MAXWIDTH];
 144 void fb_box(int sr, int sc, int er, int ec, fbval_t val)
 145 {
 146         int i;
 147         int pc = sizeof(cache[0]) / sizeof(val);
 148         int cn = MIN((ec - sc) / pc + 1, ARRAY_SIZE(cache));
 149         unsigned long nv = val;
 150         for (i = 1; i < pc; i++)
 151                 nv = (nv << (sizeof(val) * 8)) | val;
 152         for (i = 0; i < cn; i++)
 153                 cache[i] = nv;
 154         for (i = sr; i < er; i++)
 155                 memcpy(rowaddr(i) + sc * BPP, cache, (ec - sc) * BPP);
 156 }