noVNC/core/decoders/tight.js
Pierre Ossman 6a19390baa Switch to RGBx pixel format
This is what the browser wants so it avoids having to spend time
converting everything. Unfortunately it usually means the server instead
needs to convert it for us, but we assume it has more power than we do.
2020-06-08 07:57:17 +02:00

324 lines
9.6 KiB
JavaScript

/*
* noVNC: HTML5 VNC client
* Copyright (C) 2019 The noVNC Authors
* (c) 2012 Michael Tinglof, Joe Balaz, Les Piech (Mercuri.ca)
* Licensed under MPL 2.0 (see LICENSE.txt)
*
* See README.md for usage and integration instructions.
*
*/
import * as Log from '../util/logging.js';
import Inflator from "../inflator.js";
export default class TightDecoder {
constructor() {
this._ctl = null;
this._filter = null;
this._numColors = 0;
this._palette = new Uint8Array(1024); // 256 * 4 (max palette size * max bytes-per-pixel)
this._len = 0;
this._zlibs = [];
for (let i = 0; i < 4; i++) {
this._zlibs[i] = new Inflator();
}
}
decodeRect(x, y, width, height, sock, display, depth) {
if (this._ctl === null) {
if (sock.rQwait("TIGHT compression-control", 1)) {
return false;
}
this._ctl = sock.rQshift8();
// Reset streams if the server requests it
for (let i = 0; i < 4; i++) {
if ((this._ctl >> i) & 1) {
this._zlibs[i].reset();
Log.Info("Reset zlib stream " + i);
}
}
// Figure out filter
this._ctl = this._ctl >> 4;
}
let ret;
if (this._ctl === 0x08) {
ret = this._fillRect(x, y, width, height,
sock, display, depth);
} else if (this._ctl === 0x09) {
ret = this._jpegRect(x, y, width, height,
sock, display, depth);
} else if (this._ctl === 0x0A) {
ret = this._pngRect(x, y, width, height,
sock, display, depth);
} else if ((this._ctl & 0x08) == 0) {
ret = this._basicRect(this._ctl, x, y, width, height,
sock, display, depth);
} else {
throw new Error("Illegal tight compression received (ctl: " +
this._ctl + ")");
}
if (ret) {
this._ctl = null;
}
return ret;
}
_fillRect(x, y, width, height, sock, display, depth) {
if (sock.rQwait("TIGHT", 3)) {
return false;
}
const rQi = sock.rQi;
const rQ = sock.rQ;
display.fillRect(x, y, width, height,
[rQ[rQi], rQ[rQi + 1], rQ[rQi + 2]], false);
sock.rQskipBytes(3);
return true;
}
_jpegRect(x, y, width, height, sock, display, depth) {
let data = this._readData(sock);
if (data === null) {
return false;
}
display.imageRect(x, y, width, height, "image/jpeg", data);
return true;
}
_pngRect(x, y, width, height, sock, display, depth) {
throw new Error("PNG received in standard Tight rect");
}
_basicRect(ctl, x, y, width, height, sock, display, depth) {
if (this._filter === null) {
if (ctl & 0x4) {
if (sock.rQwait("TIGHT", 1)) {
return false;
}
this._filter = sock.rQshift8();
} else {
// Implicit CopyFilter
this._filter = 0;
}
}
let streamId = ctl & 0x3;
let ret;
switch (this._filter) {
case 0: // CopyFilter
ret = this._copyFilter(streamId, x, y, width, height,
sock, display, depth);
break;
case 1: // PaletteFilter
ret = this._paletteFilter(streamId, x, y, width, height,
sock, display, depth);
break;
case 2: // GradientFilter
ret = this._gradientFilter(streamId, x, y, width, height,
sock, display, depth);
break;
default:
throw new Error("Illegal tight filter received (ctl: " +
this._filter + ")");
}
if (ret) {
this._filter = null;
}
return ret;
}
_copyFilter(streamId, x, y, width, height, sock, display, depth) {
const uncompressedSize = width * height * 3;
let data;
if (uncompressedSize < 12) {
if (sock.rQwait("TIGHT", uncompressedSize)) {
return false;
}
data = sock.rQshiftBytes(uncompressedSize);
} else {
data = this._readData(sock);
if (data === null) {
return false;
}
this._zlibs[streamId].setInput(data);
data = this._zlibs[streamId].inflate(uncompressedSize);
this._zlibs[streamId].setInput(null);
}
let rgbx = new Uint8Array(width * height * 4);
for (let i = 0, j = 0; i < width * height * 4; i += 4, j += 3) {
rgbx[i] = data[j];
rgbx[i + 1] = data[j + 1];
rgbx[i + 2] = data[j + 2];
rgbx[i + 3] = 255; // Alpha
}
display.blitImage(x, y, width, height, rgbx, 0, false);
return true;
}
_paletteFilter(streamId, x, y, width, height, sock, display, depth) {
if (this._numColors === 0) {
if (sock.rQwait("TIGHT palette", 1)) {
return false;
}
const numColors = sock.rQpeek8() + 1;
const paletteSize = numColors * 3;
if (sock.rQwait("TIGHT palette", 1 + paletteSize)) {
return false;
}
this._numColors = numColors;
sock.rQskipBytes(1);
sock.rQshiftTo(this._palette, paletteSize);
}
const bpp = (this._numColors <= 2) ? 1 : 8;
const rowSize = Math.floor((width * bpp + 7) / 8);
const uncompressedSize = rowSize * height;
let data;
if (uncompressedSize < 12) {
if (sock.rQwait("TIGHT", uncompressedSize)) {
return false;
}
data = sock.rQshiftBytes(uncompressedSize);
} else {
data = this._readData(sock);
if (data === null) {
return false;
}
this._zlibs[streamId].setInput(data);
data = this._zlibs[streamId].inflate(uncompressedSize);
this._zlibs[streamId].setInput(null);
}
// Convert indexed (palette based) image data to RGB
if (this._numColors == 2) {
this._monoRect(x, y, width, height, data, this._palette, display);
} else {
this._paletteRect(x, y, width, height, data, this._palette, display);
}
this._numColors = 0;
return true;
}
_monoRect(x, y, width, height, data, palette, display) {
// Convert indexed (palette based) image data to RGB
// TODO: reduce number of calculations inside loop
const dest = this._getScratchBuffer(width * height * 4);
const w = Math.floor((width + 7) / 8);
const w1 = Math.floor(width / 8);
for (let y = 0; y < height; y++) {
let dp, sp, x;
for (x = 0; x < w1; x++) {
for (let b = 7; b >= 0; b--) {
dp = (y * width + x * 8 + 7 - b) * 4;
sp = (data[y * w + x] >> b & 1) * 3;
dest[dp] = palette[sp];
dest[dp + 1] = palette[sp + 1];
dest[dp + 2] = palette[sp + 2];
dest[dp + 3] = 255;
}
}
for (let b = 7; b >= 8 - width % 8; b--) {
dp = (y * width + x * 8 + 7 - b) * 4;
sp = (data[y * w + x] >> b & 1) * 3;
dest[dp] = palette[sp];
dest[dp + 1] = palette[sp + 1];
dest[dp + 2] = palette[sp + 2];
dest[dp + 3] = 255;
}
}
display.blitImage(x, y, width, height, dest, 0, false);
}
_paletteRect(x, y, width, height, data, palette, display) {
// Convert indexed (palette based) image data to RGB
const dest = this._getScratchBuffer(width * height * 4);
const total = width * height * 4;
for (let i = 0, j = 0; i < total; i += 4, j++) {
const sp = data[j] * 3;
dest[i] = palette[sp];
dest[i + 1] = palette[sp + 1];
dest[i + 2] = palette[sp + 2];
dest[i + 3] = 255;
}
display.blitImage(x, y, width, height, dest, 0, false);
}
_gradientFilter(streamId, x, y, width, height, sock, display, depth) {
throw new Error("Gradient filter not implemented");
}
_readData(sock) {
if (this._len === 0) {
if (sock.rQwait("TIGHT", 3)) {
return null;
}
let byte;
byte = sock.rQshift8();
this._len = byte & 0x7f;
if (byte & 0x80) {
byte = sock.rQshift8();
this._len |= (byte & 0x7f) << 7;
if (byte & 0x80) {
byte = sock.rQshift8();
this._len |= byte << 14;
}
}
}
if (sock.rQwait("TIGHT", this._len)) {
return null;
}
let data = sock.rQshiftBytes(this._len);
this._len = 0;
return data;
}
_getScratchBuffer(size) {
if (!this._scratchBuffer || (this._scratchBuffer.length < size)) {
this._scratchBuffer = new Uint8Array(size);
}
return this._scratchBuffer;
}
}