fbvis.c

   1 /*
   2  * fbvis - a framebuffer image viewer
   3  *
   4  * Copyright (C) 2013 Ali Gholami Rudi
   5  *
   6  * This file is released under the modified BSD license.
   7  */
   8 #include <ctype.h>
   9 #include <signal.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14 #include <pty.h>
  15 #include "draw.h"
  16 #include "lodepng.h"
  17
  18 /* optimized version of fb_val() */
  19 #define FB_VAL(r, g, b) (((r) << 16) | ((g) << 8) | (b))
  20
  21 #define PAGESTEPS       8
  22 #define CTRLKEY(x)      ((x) - 96)
  23 #define MIN(a, b)       ((a) < (b) ? (a) : (b))
  24 #define MAX(a, b)       ((a) > (b) ? (a) : (b))
  25 #define REGION(a, b, x) (MIN(b, MAX(x, a)))
  26
  27 static int cols, rows, ch;
  28 static char *buf;
  29 static int head, left;
  30 static int count;
  31 static struct termios termios;
  32 static int fullscreen;
  33
  34 static void draw(void)
  35 {
  36         char row[1 << 14];
  37         int bpp = FBM_BPP(fb_mode());
  38         int rs = head;
  39         int re = rs + MIN(rows - rs, fb_rows());
  40         int cs = left;
  41         int ce = cs + MIN(cols - cs, fb_cols());
  42         int fbr = (fb_rows() - (re - rs)) >> 1;
  43         int fbc = (fb_cols() - (ce - cs)) >> 1;
  44         int i, j;
  45         for (i = rs; i < re; i++) {
  46                 for (j = cs; j < ce; j++) {
  47                         unsigned char *src = (void *) (buf + (i * cols + j) * ch);
  48                         unsigned int *dst = (void *) (row + (j - cs) * bpp);
  49                         *dst = FB_VAL(src[0], src[1], src[2]);
  50                 }
  51                 fb_set(fbr + i - rs, fbc, row, ce - cs);
  52         }
  53 }
  54
  55 static void drawfs(void)
  56 {
  57         char row[1 << 14];
  58         int fsrows = rows * fb_cols() / cols;
  59         int rs = head * MAX(0, fsrows - fb_rows()) / MAX(1, rows - fb_rows());
  60         int bpp = FBM_BPP(fb_mode());
  61         int i, j;
  62         for (i = 0; i < fb_rows(); i++) {
  63                 int r = (rs + i) * rows / fsrows;
  64                 if (r >= rows)
  65                         memset(row, 0, fb_cols() * bpp);
  66                 for (j = 0; j < fb_cols() && r < rows; j++) {
  67                         int c = j * cols / fb_cols();
  68                         unsigned char *src = (void *) (buf + (r * cols + c) * ch);
  69                         unsigned int *dst = (void *) (row + j * bpp);
  70                         *dst = FB_VAL(src[0], src[1], src[2]);
  71                 }
  72                 fb_set(i, 0, row, fb_cols());
  73         }
  74 }
  75
  76 static int readkey(void)
  77 {
  78         unsigned char b;
  79         if (read(0, &b, 1) <= 0)
  80                 return -1;
  81         return b;
  82 }
  83
  84 static int getcount(int def)
  85 {
  86         int result = count ? count : def;
  87         count = 0;
  88         return result;
  89 }
  90
  91 static void term_setup(void)
  92 {
  93         struct termios newtermios;
  94         tcgetattr(0, &termios);
  95         newtermios = termios;
  96         newtermios.c_lflag &= ~ICANON;
  97         newtermios.c_lflag &= ~ECHO;
  98         tcsetattr(0, TCSAFLUSH, &newtermios);
  99 }
 100
 101 static void term_cleanup(void)
 102 {
 103         tcsetattr(0, 0, &termios);
 104 }
 105
 106 static void mainloop(void)
 107 {
 108         int step = fb_rows() / PAGESTEPS;
 109         int hstep = fb_cols() / PAGESTEPS;
 110         int c;
 111         term_setup();
 112         draw();
 113         while ((c = readkey()) != -1) {
 114                 switch (c) {
 115                 case 'd':
 116                         sleep(getcount(1));
 117                         break;
 118                 case 'q':
 119                         term_cleanup();
 120                         return;
 121                 case 27:
 122                         count = 0;
 123                         break;
 124                 default:
 125                         if (isdigit(c))
 126                                 count = count * 10 + c - '0';
 127                 }
 128                 switch (c) {
 129                 case 'j':
 130                         head += step * getcount(1);
 131                         break;
 132                 case 'k':
 133                         head -= step * getcount(1);
 134                         break;
 135                 case 'l':
 136                         left += hstep * getcount(1);
 137                         break;
 138                 case 'h':
 139                         left -= hstep * getcount(1);
 140                         break;
 141                 case 'H':
 142                         head = 0;
 143                         break;
 144                 case 'L':
 145                         head = MAX(0, rows - fb_rows());
 146                         break;
 147                 case 'M':
 148                         head = MAX(0, (rows - fb_rows()) >> 1);
 149                         break;
 150                 case ' ':
 151                 case CTRL('d'):
 152                         head += fb_rows() * getcount(1) - step;
 153                         break;
 154                 case 127:
 155                 case CTRL('u'):
 156                         head -= fb_rows() * getcount(1) - step;
 157                         break;
 158                 case 'f':
 159                         if (cols > fb_cols())
 160                                 fullscreen = 1 - fullscreen;
 161                         break;
 162                 case 'r':
 163                 case CTRLKEY('l'):
 164                         break;
 165                 default:
 166                         /* no need to redraw */
 167                         continue;
 168                 }
 169                 head = REGION(0, MAX(0, rows - fb_rows()), head);
 170                 left = REGION(0, MAX(0, cols - fb_cols()), left);
 171                 if (fullscreen)
 172                         drawfs();
 173                 else
 174                         draw();
 175         }
 176 }
 177
 178 unsigned char *stbi_load(char const *filename, int *x, int *y, int *comp, int req_comp);
 179
 180 static char *loadstbi(char *path, int *h, int *w, int *ch)
 181 {
 182         return (void *) stbi_load(path, w, h, ch, 3);
 183 }
 184
 185 static char *loadlode(char *path, int *h, int *w, int *ch)
 186 {
 187         char *s = NULL;
 188         *ch = 4;
 189         lodepng_decode32_file((void *) &s, (void *) w, (void *) h, path);
 190         return s;
 191 }
 192
 193 int main(int argc, char *argv[])
 194 {
 195         if (argc < 2) {
 196                 printf("usage: %s file\n", argv[0]);
 197                 return 0;
 198         }
 199         buf = loadlode(argv[1], &rows, &cols, &ch);
 200         if (!buf)
 201                 buf = loadstbi(argv[1], &rows, &cols, &ch);
 202         if (!buf) {
 203                 printf("failed to load image <%s>\n", argv[1]);
 204                 return 1;
 205         }
 206         if (fb_init())
 207                 return 1;
 208         mainloop();
 209         fb_free();
 210         printf("\n");
 211         free(buf);
 212         return 0;
 213 }