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 static int rl, rr, gl, gr, bl, br;
  22 static int nr, ng, nb;
  23
  24 static int fb_len()
  25 {
  26         return vinfo.xres_virtual * vinfo.yres_virtual * BPP;
  27 }
  28
  29 static void fb_cmap_save(int save)
  30 {
  31         static unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  32         struct fb_cmap cmap;
  33         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  34                 return;
  35         cmap.start = 0;
  36         cmap.len = MAX(nr, MAX(ng, nb));
  37         cmap.red = red;
  38         cmap.green = green;
  39         cmap.blue = blue;
  40         cmap.transp = 0;
  41         ioctl(fd, save ? FBIOGETCMAP : FBIOPUTCMAP, &cmap);
  42 }
  43
  44 void fb_cmap(void)
  45 {
  46         unsigned short red[NLEVELS], green[NLEVELS], blue[NLEVELS];
  47         struct fb_cmap cmap;
  48         int i;
  49         if (finfo.visual == FB_VISUAL_TRUECOLOR)
  50                 return;
  51
  52         for (i = 0; i < nr; i++)
  53                 red[i] = (65535 / (nr - 1)) * i;
  54         for (i = 0; i < ng; i++)
  55                 green[i] = (65535 / (ng - 1)) * i;
  56         for (i = 0; i < nb; i++)
  57                 blue[i] = (65535 / (nb - 1)) * i;
  58
  59         cmap.start = 0;
  60         cmap.len = MAX(nr, MAX(ng, nb));
  61         cmap.red = red;
  62         cmap.green = green;
  63         cmap.blue = blue;
  64         cmap.transp = 0;
  65
  66         ioctl(fd, FBIOPUTCMAP, &cmap);
  67 }
  68
  69 static void xerror(char *msg)
  70 {
  71         perror(msg);
  72         exit(1);
  73 }
  74
  75 static void xdie(char *msg)
  76 {
  77         fprintf(stderr, "%s\n", msg);
  78         exit(1);
  79 }
  80
  81 static void init_colors(void)
  82 {
  83         nr = 1 << vinfo.red.length;
  84         ng = 1 << vinfo.green.length;
  85         nb = 1 << vinfo.blue.length;
  86         rr = 8 - vinfo.red.length;
  87         rl = vinfo.red.offset;
  88         gr = 8 - vinfo.green.length;
  89         gl = vinfo.green.offset;
  90         br = 8 - vinfo.blue.length;
  91         bl = vinfo.blue.offset;
  92 }
  93
  94 void fb_init(void)
  95 {
  96         fd = open(FBDEV_PATH, O_RDWR);
  97         if (fd == -1)
  98                 xerror("can't open " FBDEV_PATH);
  99         if (ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) == -1)
 100                 xerror("ioctl failed");
 101         if (ioctl(fd, FBIOGET_FSCREENINFO, &finfo) == -1)
 102                 xerror("ioctl failed");
 103         if ((vinfo.bits_per_pixel + 7) >> 3 != BPP)
 104                 xdie("fbval_t does not match framebuffer depth");
 105         init_colors();
 106         fb = mmap(NULL, fb_len(), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 107         if (fb == MAP_FAILED)
 108                 xerror("can't map the framebuffer");
 109         fb_cmap_save(1);
 110         fb_cmap();
 111 }
 112
 113 void fb_set(int r, int c, fbval_t *mem, int len)
 114 {
 115         long loc = (c + vinfo.xoffset) * BPP +
 116                 (r + vinfo.yoffset) * finfo.line_length;
 117         memcpy(fb + loc, mem, len * BPP);
 118 }
 119
 120 void fb_free()
 121 {
 122         fb_cmap_save(0);
 123         munmap(fb, fb_len());
 124         close(fd);
 125 }
 126
 127 fbval_t fb_color(unsigned char r, unsigned char g, unsigned char b)
 128 {
 129         return ((r >> rr) << rl) | ((g >> gr) << gl) | ((b >> br) << bl);
 130 }
 131
 132 int fb_rows(void)
 133 {
 134         return vinfo.yres;
 135 }
 136
 137 int fb_cols(void)
 138 {
 139         return vinfo.xres;
 140 }
 141
 142 static unsigned char *rowaddr(int r)
 143 {
 144         return fb + (r + vinfo.yoffset) * finfo.line_length;
 145 }
 146
 147 static unsigned long cache[MAXFBWIDTH];
 148 void fb_box(int sr, int sc, int er, int ec, fbval_t val)
 149 {
 150         int i;
 151         int pc = sizeof(cache[0]) / sizeof(val);
 152         int cn = MIN((ec - sc) / pc + 1, MAXFBWIDTH);
 153         unsigned long nv = val;
 154         for (i = 1; i < pc; i++)
 155                 nv = (nv << (sizeof(val) * 8)) | val;
 156         for (i = 0; i < cn; i++)
 157                 cache[i] = nv;
 158         for (i = sr; i < er; i++)
 159                 memcpy(rowaddr(i) + sc * BPP, cache, (ec - sc) * BPP);
 160 }