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GIFEncoder npm에서 관리

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Showing 7 changed files with 8 additions and 243 deletions
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......@@ -19,6 +19,8 @@
"webpack-cli": "^4.6.0"
},
"dependencies": {
"@babel/plugin-proposal-class-properties": "^7.13.0"
"@babel/plugin-proposal-class-properties": "^7.13.0",
"gifencoder": "^2.0.1",
"stream": "0.0.2"
}
}
......
import GIF from "./lib/GIFEncoder";
import GIF from "gifencoder";
class GifGenerator {
constructor(canvas) {
......@@ -7,32 +7,22 @@ class GifGenerator {
this.height = canvas.getHeight();
this.gif = new GIF(this.width, this.height);
this.gif.writeHeader();
this.gif.start();
this.gif.setTransparent(null);
this.gif.setRepeat(0);
this.gif.setQuality(10);
this.gif.setDither(false);
this.gif.setGlobalPalette(false);
}
addFrame(delay = 0) {
this.gif.setDelay(delay);
this.gif.addFrame(
this.canvas.getContext().getImageData(0, 0, this.width, this.height).data
);
this.gif.addFrame(this.canvas.getContext());
}
render() {
this.gif.finish();
const stream = this.gif.stream();
const byte = new Uint8Array(this.gif.out.data);
let bytes = [];
stream.pages.map((page) => {
bytes = bytes.concat([...page]);
});
bytes = new Uint8Array(bytes);
return new Blob([bytes], { type: "image/gif" });
return new Blob([byte], { type: "image/gif" });
}
}
......
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/*
LZWEncoder.js
Authors
Kevin Weiner (original Java version - kweiner@fmsware.com)
Thibault Imbert (AS3 version - bytearray.org)
Johan Nordberg (JS version - code@johan-nordberg.com)
Acknowledgements
GIFCOMPR.C - GIF Image compression routines
Lempel-Ziv compression based on 'compress'. GIF modifications by
David Rowley (mgardi@watdcsu.waterloo.edu)
GIF Image compression - modified 'compress'
Based on: compress.c - File compression ala IEEE Computer, June 1984.
By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas)
Jim McKie (decvax!mcvax!jim)
Steve Davies (decvax!vax135!petsd!peora!srd)
Ken Turkowski (decvax!decwrl!turtlevax!ken)
James A. Woods (decvax!ihnp4!ames!jaw)
Joe Orost (decvax!vax135!petsd!joe)
*/
var EOF = -1;
var BITS = 12;
var HSIZE = 5003; // 80% occupancy
var masks = [
0x0000,
0x0001,
0x0003,
0x0007,
0x000f,
0x001f,
0x003f,
0x007f,
0x00ff,
0x01ff,
0x03ff,
0x07ff,
0x0fff,
0x1fff,
0x3fff,
0x7fff,
0xffff,
];
function LZWEncoder(width, height, pixels, colorDepth) {
var initCodeSize = Math.max(2, colorDepth);
var accum = new Uint8Array(256);
var htab = new Int32Array(HSIZE);
var codetab = new Int32Array(HSIZE);
var cur_accum,
cur_bits = 0;
var a_count;
var free_ent = 0; // first unused entry
var maxcode;
// block compression parameters -- after all codes are used up,
// and compression rate changes, start over.
var clear_flg = false;
// Algorithm: use open addressing double hashing (no chaining) on the
// prefix code / next character combination. We do a variant of Knuth's
// algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
// secondary probe. Here, the modular division first probe is gives way
// to a faster exclusive-or manipulation. Also do block compression with
// an adaptive reset, whereby the code table is cleared when the compression
// ratio decreases, but after the table fills. The variable-length output
// codes are re-sized at this point, and a special CLEAR code is generated
// for the decompressor. Late addition: construct the table according to
// file size for noticeable speed improvement on small files. Please direct
// questions about this implementation to ames!jaw.
var g_init_bits, ClearCode, EOFCode;
// Add a character to the end of the current packet, and if it is 254
// characters, flush the packet to disk.
function char_out(c, outs) {
accum[a_count++] = c;
if (a_count >= 254) flush_char(outs);
}
// Clear out the hash table
// table clear for block compress
function cl_block(outs) {
cl_hash(HSIZE);
free_ent = ClearCode + 2;
clear_flg = true;
output(ClearCode, outs);
}
// Reset code table
function cl_hash(hsize) {
for (var i = 0; i < hsize; ++i) htab[i] = -1;
}
function compress(init_bits, outs) {
var fcode, c, i, ent, disp, hsize_reg, hshift;
// Set up the globals: g_init_bits - initial number of bits
g_init_bits = init_bits;
// Set up the necessary values
clear_flg = false;
n_bits = g_init_bits;
maxcode = MAXCODE(n_bits);
ClearCode = 1 << (init_bits - 1);
EOFCode = ClearCode + 1;
free_ent = ClearCode + 2;
a_count = 0; // clear packet
ent = nextPixel();
hshift = 0;
for (fcode = HSIZE; fcode < 65536; fcode *= 2) ++hshift;
hshift = 8 - hshift; // set hash code range bound
hsize_reg = HSIZE;
cl_hash(hsize_reg); // clear hash table
output(ClearCode, outs);
outer_loop: while ((c = nextPixel()) != EOF) {
fcode = (c << BITS) + ent;
i = (c << hshift) ^ ent; // xor hashing
if (htab[i] === fcode) {
ent = codetab[i];
continue;
} else if (htab[i] >= 0) {
// non-empty slot
disp = hsize_reg - i; // secondary hash (after G. Knott)
if (i === 0) disp = 1;
do {
if ((i -= disp) < 0) i += hsize_reg;
if (htab[i] === fcode) {
ent = codetab[i];
continue outer_loop;
}
} while (htab[i] >= 0);
}
output(ent, outs);
ent = c;
if (free_ent < 1 << BITS) {
codetab[i] = free_ent++; // code -> hashtable
htab[i] = fcode;
} else {
cl_block(outs);
}
}
// Put out the final code.
output(ent, outs);
output(EOFCode, outs);
}
function encode(outs) {
outs.writeByte(initCodeSize); // write "initial code size" byte
remaining = width * height; // reset navigation variables
curPixel = 0;
compress(initCodeSize + 1, outs); // compress and write the pixel data
outs.writeByte(0); // write block terminator
}
// Flush the packet to disk, and reset the accumulator
function flush_char(outs) {
if (a_count > 0) {
outs.writeByte(a_count);
outs.writeBytes(accum, 0, a_count);
a_count = 0;
}
}
function MAXCODE(n_bits) {
return (1 << n_bits) - 1;
}
// Return the next pixel from the image
function nextPixel() {
if (remaining === 0) return EOF;
--remaining;
var pix = pixels[curPixel++];
return pix & 0xff;
}
function output(code, outs) {
cur_accum &= masks[cur_bits];
if (cur_bits > 0) cur_accum |= code << cur_bits;
else cur_accum = code;
cur_bits += n_bits;
while (cur_bits >= 8) {
char_out(cur_accum & 0xff, outs);
cur_accum >>= 8;
cur_bits -= 8;
}
// If the next entry is going to be too big for the code size,
// then increase it, if possible.
if (free_ent > maxcode || clear_flg) {
if (clear_flg) {
maxcode = MAXCODE((n_bits = g_init_bits));
clear_flg = false;
} else {
++n_bits;
if (n_bits == BITS) maxcode = 1 << BITS;
else maxcode = MAXCODE(n_bits);
}
}
if (code == EOFCode) {
// At EOF, write the rest of the buffer.
while (cur_bits > 0) {
char_out(cur_accum & 0xff, outs);
cur_accum >>= 8;
cur_bits -= 8;
}
flush_char(outs);
}
}
this.encode = encode;
}
module.exports = LZWEncoder;
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