312 lines
8.6 KiB
C
312 lines
8.6 KiB
C
#include "gifenc.h"
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <fcntl.h>
|
|
#ifdef _WIN32
|
|
#include <io.h>
|
|
#else
|
|
#include <unistd.h>
|
|
#endif
|
|
|
|
/* helper to write a little-endian 16-bit number portably */
|
|
#define write_num(fd, n) write((fd), (uint8_t []) {(n) & 0xFF, (n) >> 8}, 2)
|
|
|
|
static uint8_t vga[0x30] = {
|
|
0x00, 0x00, 0x00,
|
|
0xAA, 0x00, 0x00,
|
|
0x00, 0xAA, 0x00,
|
|
0xAA, 0x55, 0x00,
|
|
0x00, 0x00, 0xAA,
|
|
0xAA, 0x00, 0xAA,
|
|
0x00, 0xAA, 0xAA,
|
|
0xAA, 0xAA, 0xAA,
|
|
0x55, 0x55, 0x55,
|
|
0xFF, 0x55, 0x55,
|
|
0x55, 0xFF, 0x55,
|
|
0xFF, 0xFF, 0x55,
|
|
0x55, 0x55, 0xFF,
|
|
0xFF, 0x55, 0xFF,
|
|
0x55, 0xFF, 0xFF,
|
|
0xFF, 0xFF, 0xFF,
|
|
};
|
|
|
|
struct Node {
|
|
uint16_t key;
|
|
struct Node *children[];
|
|
};
|
|
typedef struct Node Node;
|
|
|
|
static Node *
|
|
new_node(uint16_t key, int degree)
|
|
{
|
|
Node *node = calloc(1, sizeof(*node) + degree * sizeof(Node *));
|
|
if (node)
|
|
node->key = key;
|
|
return node;
|
|
}
|
|
|
|
static Node *
|
|
new_trie(int degree, int *nkeys)
|
|
{
|
|
Node *root = new_node(0, degree);
|
|
/* Create nodes for single pixels. */
|
|
for (*nkeys = 0; *nkeys < degree; (*nkeys)++)
|
|
root->children[*nkeys] = new_node(*nkeys, degree);
|
|
*nkeys += 2; /* skip clear code and stop code */
|
|
return root;
|
|
}
|
|
|
|
static void
|
|
del_trie(Node *root, int degree)
|
|
{
|
|
int i;
|
|
|
|
if (!root)
|
|
return;
|
|
for (i = 0; i < degree; i++)
|
|
del_trie(root->children[i], degree);
|
|
free(root);
|
|
}
|
|
|
|
static void put_loop(ge_GIF *gif, uint16_t loop);
|
|
|
|
#define OR_ABORT if (res == -1) { fprintf(stderr, "Cannot write to GIF\n"); return(NULL); }
|
|
#define OR_ABORT2 if (res == -1) { fprintf(stderr, "Cannot write to GIF\n"); return; }
|
|
|
|
ge_GIF *
|
|
ge_new_gif(
|
|
const char *fname, uint16_t width, uint16_t height,
|
|
uint8_t *palette, int depth, int loop
|
|
)
|
|
{
|
|
int i, r, g, b, v;
|
|
ssize_t res;
|
|
ge_GIF *gif = calloc(1, sizeof(*gif) + 2*width*height);
|
|
if (!gif)
|
|
goto no_gif;
|
|
gif->w = width; gif->h = height;
|
|
gif->depth = depth > 1 ? depth : 2;
|
|
gif->frame = (uint8_t *) &gif[1];
|
|
gif->back = &gif->frame[width*height];
|
|
gif->fd = creat(fname, 0666);
|
|
if (gif->fd == -1)
|
|
goto no_fd;
|
|
#ifdef _WIN32
|
|
setmode(gif->fd, O_BINARY);
|
|
#endif
|
|
res = write(gif->fd, "GIF89a", 6); OR_ABORT;
|
|
res = write_num(gif->fd, width); OR_ABORT;
|
|
res = write_num(gif->fd, height); OR_ABORT;
|
|
res = write(gif->fd, (uint8_t []) {0xF0 | (depth-1), 0x00, 0x00}, 3); OR_ABORT;
|
|
if (palette) {
|
|
res = write(gif->fd, palette, 3 << depth); OR_ABORT;
|
|
} else if (depth <= 4) {
|
|
res = write(gif->fd, vga, 3 << depth); OR_ABORT;
|
|
} else {
|
|
res = write(gif->fd, vga, sizeof(vga)); OR_ABORT;
|
|
i = 0x10;
|
|
for (r = 0; r < 6; r++) {
|
|
for (g = 0; g < 6; g++) {
|
|
for (b = 0; b < 6; b++) {
|
|
res = write(gif->fd, (uint8_t []) {r*51, g*51, b*51}, 3); OR_ABORT;
|
|
if (++i == 1 << depth)
|
|
goto done_gct;
|
|
}
|
|
}
|
|
}
|
|
for (i = 1; i <= 24; i++) {
|
|
v = i * 0xFF / 25;
|
|
res = write(gif->fd, (uint8_t []) {v, v, v}, 3); OR_ABORT;
|
|
}
|
|
}
|
|
done_gct:
|
|
if (loop >= 0 && loop <= 0xFFFF)
|
|
put_loop(gif, (uint16_t) loop);
|
|
return gif;
|
|
no_fd:
|
|
free(gif);
|
|
no_gif:
|
|
return NULL;
|
|
}
|
|
|
|
static void
|
|
put_loop(ge_GIF *gif, uint16_t loop)
|
|
{
|
|
ssize_t res;
|
|
|
|
res = write(gif->fd, (uint8_t []) {'!', 0xFF, 0x0B}, 3); OR_ABORT2;
|
|
res = write(gif->fd, "NETSCAPE2.0", 11); OR_ABORT2;
|
|
res = write(gif->fd, (uint8_t []) {0x03, 0x01}, 2); OR_ABORT2;
|
|
res = write_num(gif->fd, loop); OR_ABORT2;
|
|
res = write(gif->fd, "\0", 1); OR_ABORT2;
|
|
}
|
|
|
|
/* Add packed key to buffer, updating offset and partial.
|
|
* gif->offset holds position to put next *bit*
|
|
* gif->partial holds bits to include in next byte */
|
|
static void
|
|
put_key(ge_GIF *gif, uint16_t key, int key_size)
|
|
{
|
|
int byte_offset, bit_offset, bits_to_write;
|
|
ssize_t res;
|
|
|
|
byte_offset = gif->offset / 8;
|
|
bit_offset = gif->offset % 8;
|
|
gif->partial |= ((uint32_t) key) << bit_offset;
|
|
bits_to_write = bit_offset + key_size;
|
|
while (bits_to_write >= 8) {
|
|
gif->buffer[byte_offset++] = gif->partial & 0xFF;
|
|
if (byte_offset == 0xFF) {
|
|
res = write(gif->fd, "\xFF", 1); OR_ABORT2;
|
|
res = write(gif->fd, gif->buffer, 0xFF); OR_ABORT2;
|
|
byte_offset = 0;
|
|
}
|
|
gif->partial >>= 8;
|
|
bits_to_write -= 8;
|
|
}
|
|
gif->offset = (gif->offset + key_size) % (0xFF * 8);
|
|
}
|
|
|
|
static void
|
|
end_key(ge_GIF *gif)
|
|
{
|
|
int byte_offset;
|
|
ssize_t res;
|
|
|
|
byte_offset = gif->offset / 8;
|
|
if (gif->offset % 8)
|
|
gif->buffer[byte_offset++] = gif->partial & 0xFF;
|
|
res = write(gif->fd, (uint8_t []) {byte_offset}, 1); OR_ABORT2;
|
|
res = write(gif->fd, gif->buffer, byte_offset); OR_ABORT2;
|
|
res = write(gif->fd, "\0", 1); OR_ABORT2;
|
|
gif->offset = gif->partial = 0;
|
|
}
|
|
|
|
static void
|
|
put_image(ge_GIF *gif, uint16_t w, uint16_t h, uint16_t x, uint16_t y)
|
|
{
|
|
int nkeys, key_size, i, j;
|
|
Node *node, *child, *root;
|
|
ssize_t res;
|
|
int degree = 1 << gif->depth;
|
|
|
|
res = write(gif->fd, ",", 1); OR_ABORT2;
|
|
res = write_num(gif->fd, x); OR_ABORT2;
|
|
res = write_num(gif->fd, y); OR_ABORT2;
|
|
res = write_num(gif->fd, w); OR_ABORT2;
|
|
res = write_num(gif->fd, h); OR_ABORT2;
|
|
res = write(gif->fd, (uint8_t []) {0x00, gif->depth}, 2); OR_ABORT2;
|
|
root = node = new_trie(degree, &nkeys);
|
|
key_size = gif->depth + 1;
|
|
put_key(gif, degree, key_size); /* clear code */
|
|
for (i = y; i < y+h; i++) {
|
|
for (j = x; j < x+w; j++) {
|
|
uint8_t pixel = gif->frame[i*gif->w+j] & (degree - 1);
|
|
child = node->children[pixel];
|
|
if (child) {
|
|
node = child;
|
|
} else {
|
|
put_key(gif, node->key, key_size);
|
|
if (nkeys < 0x1000) {
|
|
if (nkeys == (1 << key_size))
|
|
key_size++;
|
|
node->children[pixel] = new_node(nkeys++, degree);
|
|
} else {
|
|
put_key(gif, degree, key_size); /* clear code */
|
|
del_trie(root, degree);
|
|
root = node = new_trie(degree, &nkeys);
|
|
key_size = gif->depth + 1;
|
|
}
|
|
node = root->children[pixel];
|
|
}
|
|
}
|
|
}
|
|
put_key(gif, node->key, key_size);
|
|
put_key(gif, degree + 1, key_size); /* stop code */
|
|
end_key(gif);
|
|
del_trie(root, degree);
|
|
}
|
|
|
|
static int
|
|
get_bbox(ge_GIF *gif, uint16_t *w, uint16_t *h, uint16_t *x, uint16_t *y)
|
|
{
|
|
int i, j, k;
|
|
int left, right, top, bottom;
|
|
left = gif->w; right = 0;
|
|
top = gif->h; bottom = 0;
|
|
k = 0;
|
|
for (i = 0; i < gif->h; i++) {
|
|
for (j = 0; j < gif->w; j++, k++) {
|
|
if (gif->frame[k] != gif->back[k]) {
|
|
if (j < left) left = j;
|
|
if (j > right) right = j;
|
|
if (i < top) top = i;
|
|
if (i > bottom) bottom = i;
|
|
}
|
|
}
|
|
}
|
|
if (left != gif->w && top != gif->h) {
|
|
*x = left; *y = top;
|
|
*w = right - left + 1;
|
|
*h = bottom - top + 1;
|
|
return 1;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* (From the docs)
|
|
* The `delay` parameter specifies how long the frame will be shown, in hundreths
|
|
* of a second. For example, `delay` == 100 means "show this frame for one second"
|
|
* and `delay` == 25 means "show this frame for a quarter of a second". Note that
|
|
* short delays may not be supported by some GIF viewers: it's recommended to keep
|
|
* a minimum of `delay` == 6. If `delay` == 0, no delay information will be stored
|
|
* for the frame. This can be used when creating still (single-frame) GIF images.
|
|
*/
|
|
static void
|
|
set_delay(ge_GIF *gif, uint16_t d)
|
|
{
|
|
ssize_t res;
|
|
|
|
res = write(gif->fd, (uint8_t []) {'!', 0xF9, 0x04, 0x04}, 4); OR_ABORT2;
|
|
res = write_num(gif->fd, d); OR_ABORT2;
|
|
res = write(gif->fd, "\0\0", 2); OR_ABORT2;
|
|
}
|
|
|
|
void
|
|
ge_add_frame(ge_GIF *gif, uint16_t delay)
|
|
{
|
|
uint16_t w, h, x, y;
|
|
uint8_t *tmp;
|
|
|
|
if (delay)
|
|
set_delay(gif, delay);
|
|
if (gif->nframes == 0) {
|
|
w = gif->w;
|
|
h = gif->h;
|
|
x = y = 0;
|
|
} else if (!get_bbox(gif, &w, &h, &x, &y)) {
|
|
/* image's not changed; save one pixel just to add delay */
|
|
w = h = 1;
|
|
x = y = 0;
|
|
}
|
|
put_image(gif, w, h, x, y);
|
|
gif->nframes++;
|
|
tmp = gif->back;
|
|
gif->back = gif->frame;
|
|
gif->frame = tmp;
|
|
}
|
|
|
|
void
|
|
ge_close_gif(ge_GIF* gif)
|
|
{
|
|
ssize_t res;
|
|
|
|
res = write(gif->fd, ";", 1); OR_ABORT2;
|
|
close(gif->fd);
|
|
free(gif);
|
|
}
|