Add Zlib encoding

core/decoders/zlib.js

@@ -0,0 +1,51 @@
+/*
+ * noVNC: HTML5 VNC client
+ * Copyright (C) 2024 The noVNC Authors
+ * Licensed under MPL 2.0 (see LICENSE.txt)
+ *
+ * See README.md for usage and integration instructions.
+ *
+ */
+
+import Inflator from "../inflator.js";
+
+export default class ZlibDecoder {
+    constructor() {
+        this._zlib = new Inflator();
+        this._length = 0;
+    }
+
+    decodeRect(x, y, width, height, sock, display, depth) {
+        if ((width === 0) || (height === 0)) {
+            return true;
+        }
+
+        if (this._length === 0) {
+            if (sock.rQwait("ZLIB", 4)) {
+                return false;
+            }
+
+            this._length = sock.rQshift32();
+        }
+
+        if (sock.rQwait("ZLIB", this._length)) {
+            return false;
+        }
+
+        let data = new Uint8Array(sock.rQshiftBytes(this._length, false));
+        this._length = 0;
+
+        this._zlib.setInput(data);
+        data = this._zlib.inflate(width * height * 4);
+        this._zlib.setInput(null);
+
+        // Max sure the image is fully opaque
+        for (let i = 0; i < width * height; i++) {
+            data[i * 4 + 3] = 255;
+        }
+
+        display.blitImage(x, y, width, height, data, 0);
+
+        return true;
+    }
+}

core/encodings.js

@@ -11,6 +11,7 @@ export const encodings = {
     encodingCopyRect: 1,
     encodingRRE: 2,
     encodingHextile: 5,
+    encodingZlib: 6,
     encodingTight: 7,
     encodingZRLE: 16,
     encodingTightPNG: -260,
@@ -40,6 +41,7 @@ export function encodingName(num) {
         case encodings.encodingCopyRect: return "CopyRect";
         case encodings.encodingRRE:      return "RRE";
         case encodings.encodingHextile:  return "Hextile";
+        case encodings.encodingZlib:     return "Zlib";
         case encodings.encodingTight:    return "Tight";
         case encodings.encodingZRLE:     return "ZRLE";
         case encodings.encodingTightPNG: return "TightPNG";

core/rfb.js

@@ -31,6 +31,7 @@ import RawDecoder from "./decoders/raw.js";
 import CopyRectDecoder from "./decoders/copyrect.js";
 import RREDecoder from "./decoders/rre.js";
 import HextileDecoder from "./decoders/hextile.js";
+import ZlibDecoder from './decoders/zlib.js';
 import TightDecoder from "./decoders/tight.js";
 import TightPNGDecoder from "./decoders/tightpng.js";
 import ZRLEDecoder from "./decoders/zrle.js";
@@ -244,6 +245,7 @@ export default class RFB extends EventTargetMixin {
         this._decoders[encodings.encodingCopyRect] = new CopyRectDecoder();
         this._decoders[encodings.encodingRRE] = new RREDecoder();
         this._decoders[encodings.encodingHextile] = new HextileDecoder();
+        this._decoders[encodings.encodingZlib] = new ZlibDecoder();
         this._decoders[encodings.encodingTight] = new TightDecoder();
         this._decoders[encodings.encodingTightPNG] = new TightPNGDecoder();
         this._decoders[encodings.encodingZRLE] = new ZRLEDecoder();
@@ -2121,6 +2123,7 @@ export default class RFB extends EventTargetMixin {
             encs.push(encodings.encodingJPEG);
             encs.push(encodings.encodingHextile);
             encs.push(encodings.encodingRRE);
+            encs.push(encodings.encodingZlib);
         }
         encs.push(encodings.encodingRaw);