Add RealVNC's JPEG encoding

Add support for RealVNC's JPEG encoding.

Add tests for JPEGDecoder. Fix the corner case of caching Huffman or quantization tables.

4 files changed, 434 insertions, 0 deletions

diff --git a/core/decoders/jpeg.js b/core/decoders/jpeg.js
new file mode 100644
index 0000000..e1f2bdf
--- /dev/null
+++ b/core/decoders/jpeg.js
@@ -0,0 +1,141 @@
+/*
+ * noVNC: HTML5 VNC client
+ * Copyright (C) 2019 The noVNC Authors
+ * Licensed under MPL 2.0 (see LICENSE.txt)
+ *
+ * See README.md for usage and integration instructions.
+ *
+ */
+
+export default class JPEGDecoder {
+    constructor() {
+        // RealVNC will reuse the quantization tables
+        // and Huffman tables, so we need to cache them.
+        this._quantTables = [];
+        this._huffmanTables = [];
+        this._cachedQuantTables = [];
+        this._cachedHuffmanTables = [];
+
+        this._jpegLength = 0;
+        this._segments = [];
+    }
+
+    decodeRect(x, y, width, height, sock, display, depth) {
+        // A rect of JPEG encodings is simply a JPEG file
+        if (!this._parseJPEG(sock.rQslice(0))) {
+            return false;
+        }
+        const data = sock.rQshiftBytes(this._jpegLength);
+        if (this._quantTables.length != 0 && this._huffmanTables.length != 0) {
+            // If there are quantization tables and Huffman tables in the JPEG
+            // image, we can directly render it.
+            display.imageRect(x, y, width, height, "image/jpeg", data);
+            return true;
+        } else {
+            // Otherwise we need to insert cached tables.
+            const sofIndex = this._segments.findIndex(
+                x => x[1] == 0xC0 || x[1] == 0xC2
+            );
+            if (sofIndex == -1) {
+                throw new Error("Illegal JPEG image without SOF");
+            }
+            let segments = this._segments.slice(0, sofIndex);
+            segments = segments.concat(this._quantTables.length ?
+                this._quantTables :
+                this._cachedQuantTables);
+            segments.push(this._segments[sofIndex]);
+            segments = segments.concat(this._huffmanTables.length ?
+                this._huffmanTables :
+                this._cachedHuffmanTables,
+                                       this._segments.slice(sofIndex + 1));
+            let length = 0;
+            for (let i = 0; i < segments.length; i++) {
+                length += segments[i].length;
+            }
+            const data = new Uint8Array(length);
+            length = 0;
+            for (let i = 0; i < segments.length; i++) {
+                data.set(segments[i], length);
+                length += segments[i].length;
+            }
+            display.imageRect(x, y, width, height, "image/jpeg", data);
+            return true;
+        }
+    }
+
+    _parseJPEG(buffer) {
+        if (this._quantTables.length != 0) {
+            this._cachedQuantTables = this._quantTables;
+        }
+        if (this._huffmanTables.length != 0) {
+            this._cachedHuffmanTables = this._huffmanTables;
+        }
+        this._quantTables = [];
+        this._huffmanTables = [];
+        this._segments = [];
+        let i = 0;
+        let bufferLength = buffer.length;
+        while (true) {
+            let j = i;
+            if (j + 2 > bufferLength) {
+                return false;
+            }
+            if (buffer[j] != 0xFF) {
+                throw new Error("Illegal JPEG marker received (byte: " +
+                                   buffer[j] + ")");
+            }
+            const type = buffer[j+1];
+            j += 2;
+            if (type == 0xD9) {
+                this._jpegLength = j;
+                this._segments.push(buffer.slice(i, j));
+                return true;
+            } else if (type == 0xDA) {
+                // start of scan
+                let hasFoundEndOfScan = false;
+                for (let k = j + 3; k + 1 < bufferLength; k++) {
+                    if (buffer[k] == 0xFF && buffer[k+1] != 0x00 &&
+                        !(buffer[k+1] >= 0xD0 && buffer[k+1] <= 0xD7)) {
+                        j = k;
+                        hasFoundEndOfScan = true;
+                        break;
+                    }
+                }
+                if (!hasFoundEndOfScan) {
+                    return false;
+                }
+                this._segments.push(buffer.slice(i, j));
+                i = j;
+                continue;
+            } else if (type >= 0xD0 && type < 0xD9 || type == 0x01) {
+                // No length after marker
+                this._segments.push(buffer.slice(i, j));
+                i = j;
+                continue;
+            }
+            if (j + 2 > bufferLength) {
+                return false;
+            }
+            const length = (buffer[j] << 8) + buffer[j+1] - 2;
+            if (length < 0) {
+                throw new Error("Illegal JPEG length received (length: " +
+                                   length + ")");
+            }
+            j += 2;
+            if (j + length > bufferLength) {
+                return false;
+            }
+            j += length;
+            const segment = buffer.slice(i, j);
+            if (type == 0xC4) {
+                // Huffman tables
+                this._huffmanTables.push(segment);
+            } else if (type == 0xDB) {
+                // Quantization tables
+                this._quantTables.push(segment);
+            }
+            this._segments.push(segment);
+            i = j;
+        }
+    }
+}
diff --git a/core/encodings.js b/core/encodings.js
index 51c0992..f16d033 100644
--- a/core/encodings.js
+++ b/core/encodings.js
@@ -13,6 +13,7 @@ export const encodings = {
     encodingHextile: 5,
     encodingTight: 7,
     encodingTightPNG: -260,
+    encodingJPEG: 21,
 
     pseudoEncodingQualityLevel9: -23,
     pseudoEncodingQualityLevel0: -32,
@@ -39,6 +40,7 @@ export function encodingName(num) {
         case encodings.encodingHextile:  return "Hextile";
         case encodings.encodingTight:    return "Tight";
         case encodings.encodingTightPNG: return "TightPNG";
+        case encodings.encodingJPEG:     return "JPEG";
         default:                         return "[unknown encoding " + num + "]";
     }
 }
diff --git a/core/rfb.js b/core/rfb.js
index bc52f4a..1583103 100644
--- a/core/rfb.js
+++ b/core/rfb.js
@@ -33,6 +33,7 @@ import HextileDecoder from "./decoders/hextile.js";
 import TightDecoder from "./decoders/tight.js";
 import TightPNGDecoder from "./decoders/tightpng.js";
 import ZRLEDecoder from "./decoders/zrle.js";
+import JPEGDecoder from "./decoders/jpeg.js";
 
 // How many seconds to wait for a disconnect to finish
 const DISCONNECT_TIMEOUT = 3;
@@ -220,6 +221,7 @@ export default class RFB extends EventTargetMixin {
         this._decoders[encodings.encodingTight] = new TightDecoder();
         this._decoders[encodings.encodingTightPNG] = new TightPNGDecoder();
         this._decoders[encodings.encodingZRLE] = new ZRLEDecoder();
+        this._decoders[encodings.encodingJPEG] = new JPEGDecoder();
 
         // NB: nothing that needs explicit teardown should be done
         // before this point, since this can throw an exception
@@ -1775,6 +1777,7 @@ export default class RFB extends EventTargetMixin {
             encs.push(encodings.encodingTight);
             encs.push(encodings.encodingTightPNG);
             encs.push(encodings.encodingZRLE);
+            encs.push(encodings.encodingJPEG);
             encs.push(encodings.encodingHextile);
             encs.push(encodings.encodingRRE);
         }
diff --git a/tests/test.jpeg.js b/tests/test.jpeg.js
new file mode 100644
index 0000000..6834f03
--- /dev/null
+++ b/tests/test.jpeg.js
@@ -0,0 +1,288 @@
+const expect = chai.expect;
+
+import Websock from '../core/websock.js';
+import Display from '../core/display.js';
+
+import JPEGDecoder from '../core/decoders/jpeg.js';
+
+import FakeWebSocket from './fake.websocket.js';
+
+function testDecodeRect(decoder, x, y, width, height, data, display, depth) {
+    let sock;
+
+    sock = new Websock;
+    sock.open("ws://example.com");
+
+    sock.on('message', () => {
+        decoder.decodeRect(x, y, width, height, sock, display, depth);
+    });
+
+    // Empty messages are filtered at multiple layers, so we need to
+    // do a direct call
+    if (data.length === 0) {
+        decoder.decodeRect(x, y, width, height, sock, display, depth);
+    } else {
+        sock._websocket._receiveData(new Uint8Array(data));
+    }
+
+    display.flip();
+}
+
+describe('JPEG Decoder', function () {
+    let decoder;
+    let display;
+
+    before(FakeWebSocket.replace);
+    after(FakeWebSocket.restore);
+
+    beforeEach(function () {
+        decoder = new JPEGDecoder();
+        display = new Display(document.createElement('canvas'));
+        display.resize(4, 4);
+    });
+
+    it('should handle JPEG rects', function (done) {
+        let data = [
+            // JPEG data
+            0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46,
+            0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x01, 0x2c,
+            0x01, 0x2c, 0x00, 0x42, 0xff, 0xdb, 0x00, 0x43,
+            0x00, 0x03, 0x02, 0x02, 0x03, 0x02, 0x02, 0x03,
+            0x03, 0x03, 0x03, 0x04, 0x03, 0x03, 0x04, 0x05,
+            0x08, 0x05, 0x05, 0x04, 0x04, 0x05, 0x0a, 0x07,
+            0x07, 0x06, 0x08, 0x0c, 0x0a, 0x0c, 0x0c, 0x0b,
+            0x0a, 0x0b, 0x0b, 0x0d, 0x0e, 0x12, 0x10, 0x0d,
+            0x0e, 0x11, 0x0e, 0x0b, 0x0b, 0x10, 0x16, 0x10,
+            0x11, 0x13, 0x14, 0x15, 0x15, 0x15, 0x0c, 0x0f,
+            0x17, 0x18, 0x16, 0x14, 0x18, 0x12, 0x14, 0x15,
+            0x14, 0xff, 0xdb, 0x00, 0x43, 0x01, 0x03, 0x04,
+            0x04, 0x05, 0x04, 0x05, 0x09, 0x05, 0x05, 0x09,
+            0x14, 0x0d, 0x0b, 0x0d, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0xff, 0xc0,
+            0x00, 0x11, 0x08, 0x00, 0x04, 0x00, 0x04, 0x03,
+            0x01, 0x11, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11,
+            0x01, 0xff, 0xc4, 0x00, 0x1f, 0x00, 0x00, 0x01,
+            0x05, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+            0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+            0x0a, 0x0b, 0xff, 0xc4, 0x00, 0xb5, 0x10, 0x00,
+            0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05,
+            0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7d, 0x01,
+            0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21,
+            0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22,
+            0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23,
+            0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24,
+            0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17,
+            0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29,
+            0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a,
+            0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
+            0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
+            0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
+            0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
+            0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
+            0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
+            0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8,
+            0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+            0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6,
+            0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5,
+            0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3,
+            0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1,
+            0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
+            0xfa, 0xff, 0xc4, 0x00, 0x1f, 0x01, 0x00, 0x03,
+            0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+            0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+            0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+            0x0a, 0x0b, 0xff, 0xc4, 0x00, 0xb5, 0x11, 0x00,
+            0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07,
+            0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77, 0x00,
+            0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31,
+            0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13,
+            0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1,
+            0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15,
+            0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1,
+            0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27,
+            0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39,
+            0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
+            0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+            0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
+            0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
+            0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88,
+            0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+            0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6,
+            0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5,
+            0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4,
+            0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3,
+            0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2,
+            0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
+            0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
+            0xfa, 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00,
+            0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00, 0xf9,
+            0xf7, 0xfb, 0x67, 0x56, 0xff, 0x00, 0x9f, 0xf8,
+            0x3f, 0xf0, 0x51, 0xa7, 0xff, 0x00, 0xf2, 0x3d,
+            0x7e, 0x6f, 0xfd, 0xab, 0x94, 0x7f, 0xd0, 0x9a,
+            0x8f, 0xfe, 0x0d, 0xc7, 0x7f, 0xf3, 0x61, 0xfd,
+            0xa7, 0xff, 0x00, 0x10, 0x77, 0x0d, 0xff, 0x00,
+            0x43, 0xec, 0xcf, 0xff, 0x00, 0x0b, 0xab, 0x1f,
+            0xff, 0xd9,
+        ];
+
+        testDecodeRect(decoder, 0, 0, 4, 4, data, display, 24);
+
+        let targetData = new Uint8Array([
+            0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255,
+            0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255,
+            0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255,
+            0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255
+        ]);
+
+        // Browsers have rounding errors, so we need an approximate
+        // comparing function
+        function almost(a, b) {
+            let diff = Math.abs(a - b);
+            return diff < 5;
+        }
+
+        display.onflush = () => {
+            expect(display).to.have.displayed(targetData, almost);
+            done();
+        };
+        display.flush();
+    });
+
+    it('should handle JPEG rects without Huffman and quantification tables', function (done) {
+        let data1 = [
+            // JPEG data
+            0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46,
+            0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x01, 0x2c,
+            0x01, 0x2c, 0x00, 0x42, 0xff, 0xdb, 0x00, 0x43,
+            0x00, 0x03, 0x02, 0x02, 0x03, 0x02, 0x02, 0x03,
+            0x03, 0x03, 0x03, 0x04, 0x03, 0x03, 0x04, 0x05,
+            0x08, 0x05, 0x05, 0x04, 0x04, 0x05, 0x0a, 0x07,
+            0x07, 0x06, 0x08, 0x0c, 0x0a, 0x0c, 0x0c, 0x0b,
+            0x0a, 0x0b, 0x0b, 0x0d, 0x0e, 0x12, 0x10, 0x0d,
+            0x0e, 0x11, 0x0e, 0x0b, 0x0b, 0x10, 0x16, 0x10,
+            0x11, 0x13, 0x14, 0x15, 0x15, 0x15, 0x0c, 0x0f,
+            0x17, 0x18, 0x16, 0x14, 0x18, 0x12, 0x14, 0x15,
+            0x14, 0xff, 0xdb, 0x00, 0x43, 0x01, 0x03, 0x04,
+            0x04, 0x05, 0x04, 0x05, 0x09, 0x05, 0x05, 0x09,
+            0x14, 0x0d, 0x0b, 0x0d, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0x14,
+            0x14, 0x14, 0x14, 0x14, 0x14, 0x14, 0xff, 0xc0,
+            0x00, 0x11, 0x08, 0x00, 0x04, 0x00, 0x04, 0x03,
+            0x01, 0x11, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11,
+            0x01, 0xff, 0xc4, 0x00, 0x1f, 0x00, 0x00, 0x01,
+            0x05, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+            0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+            0x0a, 0x0b, 0xff, 0xc4, 0x00, 0xb5, 0x10, 0x00,
+            0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05,
+            0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7d, 0x01,
+            0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21,
+            0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22,
+            0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23,
+            0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24,
+            0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17,
+            0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29,
+            0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a,
+            0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
+            0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,
+            0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
+            0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
+            0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
+            0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
+            0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8,
+            0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+            0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6,
+            0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5,
+            0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3,
+            0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1,
+            0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
+            0xfa, 0xff, 0xc4, 0x00, 0x1f, 0x01, 0x00, 0x03,
+            0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+            0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+            0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+            0x0a, 0x0b, 0xff, 0xc4, 0x00, 0xb5, 0x11, 0x00,
+            0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07,
+            0x05, 0x04, 0x04, 0x00, 0x01, 0x02, 0x77, 0x00,
+            0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31,
+            0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13,
+            0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1,
+            0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15,
+            0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1,
+            0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27,
+            0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39,
+            0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
+            0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
+            0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
+            0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
+            0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88,
+            0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+            0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6,
+            0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5,
+            0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4,
+            0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3,
+            0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2,
+            0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
+            0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
+            0xfa, 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00,
+            0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00, 0xf9,
+            0xf7, 0xfb, 0x67, 0x56, 0xff, 0x00, 0x9f, 0xf8,
+            0x3f, 0xf0, 0x51, 0xa7, 0xff, 0x00, 0xf2, 0x3d,
+            0x7e, 0x6f, 0xfd, 0xab, 0x94, 0x7f, 0xd0, 0x9a,
+            0x8f, 0xfe, 0x0d, 0xc7, 0x7f, 0xf3, 0x61, 0xfd,
+            0xa7, 0xff, 0x00, 0x10, 0x77, 0x0d, 0xff, 0x00,
+            0x43, 0xec, 0xcf, 0xff, 0x00, 0x0b, 0xab, 0x1f,
+            0xff, 0xd9,
+        ];
+
+        testDecodeRect(decoder, 0, 0, 4, 4, data1, display, 24);
+
+        let data2 = [
+            // JPEG data
+            0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46,
+            0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x01, 0x2c,
+            0x01, 0x2c, 0x00, 0x73, 0xff, 0xc0, 0x00, 0x11,
+            0x08, 0x00, 0x04, 0x00, 0x04, 0x03, 0x01, 0x11,
+            0x00, 0x02, 0x11, 0x01, 0x03, 0x11, 0x01, 0xff,
+            0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, 0x11,
+            0x03, 0x11, 0x00, 0x3f, 0x00, 0xf9, 0xf7, 0xfb,
+            0x67, 0x56, 0xff, 0x00, 0x9f, 0xf8, 0x3f, 0xf0,
+            0x51, 0xa7, 0xff, 0x00, 0xf2, 0x3d, 0x7e, 0x6f,
+            0xfd, 0xab, 0x94, 0x7f, 0xd0, 0x9a, 0x8f, 0xfe,
+            0x0d, 0xc7, 0x7f, 0xf3, 0x61, 0xfd, 0xa7, 0xff,
+            0x00, 0x10, 0x77, 0x0d, 0xff, 0x00, 0x43, 0xec,
+            0xcf, 0xff, 0x00, 0x0b, 0xab, 0x1f, 0xff, 0xd9,
+        ];
+
+        testDecodeRect(decoder, 0, 0, 4, 4, data2, display, 24);
+
+        let targetData = new Uint8Array([
+            0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255,
+            0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255,
+            0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255,
+            0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255, 0xff, 0x00, 0x00, 255
+        ]);
+
+        // Browsers have rounding errors, so we need an approximate
+        // comparing function
+        function almost(a, b) {
+            let diff = Math.abs(a - b);
+            return diff < 5;
+        }
+
+        display.onflush = () => {
+            expect(display).to.have.displayed(targetData, almost);
+            done();
+        };
+        display.flush();
+    });
+});