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Fix the interface of JpegStream/JpxStream/Jbig2Stream to agree with the other DecodeStreams

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The interface of all of the "image" streams look kind of weird, and I'm actually a bit surprised that there hasn't been any errors because of it.
For example: None of them actually implement `readBlock` methods, and it seems more luck that anything else that we're not calling `getBytes()` (without providing a length) for those streams, since that would trigger a code-path in `getBytes` that assumes `readBlock` to exist.

To address this long-standing issue, the `ensureBuffer` methods are thus renamed to `readBlock`. Furthermore, the new `ensureBuffer` methods are now no-ops.
Finally, this patch also replaces `var` with `let` in a number of places.
This commit is contained in:
Jonas Jenwald 2017-10-26 13:15:57 +02:00
parent 36593d6bbc
commit de5297b9ea
3 changed files with 68 additions and 56 deletions
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29
src/core/jbig2_stream.js
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@ -22,7 +22,7 @@ import { shadow } from '../shared/util';
* For JBIG2's we use a library to decode these images and
* the stream behaves like all the other DecodeStreams.
*/
var Jbig2Stream = (function Jbig2StreamClosure() {
let Jbig2Stream = (function Jbig2StreamClosure() {
function Jbig2Stream(stream, maybeLength, dict, params) {
this.stream = stream;
this.maybeLength = maybeLength;
@ -36,36 +36,39 @@ var Jbig2Stream = (function Jbig2StreamClosure() {
Object.defineProperty(Jbig2Stream.prototype, 'bytes', {
get() {
// If this.maybeLength is null, we'll get the entire stream.
// If `this.maybeLength` is null, we'll get the entire stream.
return shadow(this, 'bytes', this.stream.getBytes(this.maybeLength));
},
configurable: true,
});
Jbig2Stream.prototype.ensureBuffer = function(req) {
if (this.bufferLength) {
Jbig2Stream.prototype.ensureBuffer = function(requested) {
// No-op, since `this.readBlock` will always parse the entire image and
// directly insert all of its data into `this.buffer`.
};
Jbig2Stream.prototype.readBlock = function() {
if (this.eof) {
return;
}
let jbig2Image = new Jbig2Image();
var jbig2Image = new Jbig2Image();
var chunks = [];
let chunks = [];
if (isDict(this.params)) {
var globalsStream = this.params.get('JBIG2Globals');
let globalsStream = this.params.get('JBIG2Globals');
if (isStream(globalsStream)) {
var globals = globalsStream.getBytes();
let globals = globalsStream.getBytes();
chunks.push({ data: globals, start: 0, end: globals.length, });
}
}
chunks.push({ data: this.bytes, start: 0, end: this.bytes.length, });
var data = jbig2Image.parseChunks(chunks);
var dataLength = data.length;
let data = jbig2Image.parseChunks(chunks);
let dataLength = data.length;
// JBIG2 had black as 1 and white as 0, inverting the colors
for (var i = 0; i < dataLength; i++) {
for (let i = 0; i < dataLength; i++) {
data[i] ^= 0xFF;
}
this.buffer = data;
this.bufferLength = dataLength;
this.eof = true;

43
src/core/jpeg_stream.js
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@ -21,15 +21,15 @@ import { JpegImage } from './jpg';
/**
* Depending on the type of JPEG a JpegStream is handled in different ways. For
* JPEG's that are supported natively such as DeviceGray and DeviceRGB the image
* data is stored and then loaded by the browser. For unsupported JPEG's we use
* data is stored and then loaded by the browser. For unsupported JPEG's we use
* a library to decode these images and the stream behaves like all the other
* DecodeStreams.
*/
var JpegStream = (function JpegStreamClosure() {
let JpegStream = (function JpegStreamClosure() {
function JpegStream(stream, maybeLength, dict, params) {
// Some images may contain 'junk' before the SOI (start-of-image) marker.
// Note: this seems to mainly affect inline images.
var ch;
let ch;
while ((ch = stream.getByte()) !== -1) {
if (ch === 0xFF) { // Find the first byte of the SOI marker (0xFFD8).
stream.skip(-1); // Reset the stream position to the SOI.
@ -48,27 +48,32 @@ var JpegStream = (function JpegStreamClosure() {
Object.defineProperty(JpegStream.prototype, 'bytes', {
get: function JpegStream_bytes() {
// If this.maybeLength is null, we'll get the entire stream.
// If `this.maybeLength` is null, we'll get the entire stream.
return shadow(this, 'bytes', this.stream.getBytes(this.maybeLength));
},
configurable: true,
});
JpegStream.prototype.ensureBuffer = function JpegStream_ensureBuffer(req) {
if (this.bufferLength) {
JpegStream.prototype.ensureBuffer = function(requested) {
// No-op, since `this.readBlock` will always parse the entire image and
// directly insert all of its data into `this.buffer`.
};
JpegStream.prototype.readBlock = function() {
if (this.eof) {
return;
}
var jpegImage = new JpegImage();
let jpegImage = new JpegImage();
// Checking if values need to be transformed before conversion.
var decodeArr = this.dict.getArray('Decode', 'D');
let decodeArr = this.dict.getArray('Decode', 'D');
if (this.forceRGB && Array.isArray(decodeArr)) {
var bitsPerComponent = this.dict.get('BitsPerComponent') || 8;
var decodeArrLength = decodeArr.length;
var transform = new Int32Array(decodeArrLength);
var transformNeeded = false;
var maxValue = (1 << bitsPerComponent) - 1;
for (var i = 0; i < decodeArrLength; i += 2) {
let bitsPerComponent = this.dict.get('BitsPerComponent') || 8;
let decodeArrLength = decodeArr.length;
let transform = new Int32Array(decodeArrLength);
let transformNeeded = false;
let maxValue = (1 << bitsPerComponent) - 1;
for (let i = 0; i < decodeArrLength; i += 2) {
transform[i] = ((decodeArr[i + 1] - decodeArr[i]) * 256) | 0;
transform[i + 1] = (decodeArr[i] * maxValue) | 0;
if (transform[i] !== 256 || transform[i + 1] !== 0) {
@ -81,26 +86,26 @@ var JpegStream = (function JpegStreamClosure() {
}
// Fetching the 'ColorTransform' entry, if it exists.
if (isDict(this.params)) {
var colorTransform = this.params.get('ColorTransform');
let colorTransform = this.params.get('ColorTransform');
if (Number.isInteger(colorTransform)) {
jpegImage.colorTransform = colorTransform;
}
}
jpegImage.parse(this.bytes);
var data = jpegImage.getData(this.drawWidth, this.drawHeight,
let data = jpegImage.getData(this.drawWidth, this.drawHeight,
this.forceRGB);
this.buffer = data;
this.bufferLength = data.length;
this.eof = true;
};
JpegStream.prototype.getBytes = function JpegStream_getBytes(length) {
this.ensureBuffer();
JpegStream.prototype.getBytes = function(length) {
this.readBlock();
return this.buffer;
};
JpegStream.prototype.getIR = function JpegStream_getIR(forceDataSchema) {
JpegStream.prototype.getIR = function(forceDataSchema = false) {
return createObjectURL(this.bytes, 'image/jpeg', forceDataSchema);
};

52
src/core/jpx_stream.js
View File

@ -21,7 +21,7 @@ import { shadow } from '../shared/util';
* For JPEG 2000's we use a library to decode these images and
* the stream behaves like all the other DecodeStreams.
*/
var JpxStream = (function JpxStreamClosure() {
let JpxStream = (function JpxStreamClosure() {
function JpxStream(stream, maybeLength, dict, params) {
this.stream = stream;
this.maybeLength = maybeLength;
@ -35,44 +35,48 @@ var JpxStream = (function JpxStreamClosure() {
Object.defineProperty(JpxStream.prototype, 'bytes', {
get: function JpxStream_bytes() {
// If this.maybeLength is null, we'll get the entire stream.
// If `this.maybeLength` is null, we'll get the entire stream.
return shadow(this, 'bytes', this.stream.getBytes(this.maybeLength));
},
configurable: true,
});
JpxStream.prototype.ensureBuffer = function JpxStream_ensureBuffer(req) {
if (this.bufferLength) {
JpxStream.prototype.ensureBuffer = function(requested) {
// No-op, since `this.readBlock` will always parse the entire image and
// directly insert all of its data into `this.buffer`.
};
JpxStream.prototype.readBlock = function() {
if (this.eof) {
return;
}
var jpxImage = new JpxImage();
let jpxImage = new JpxImage();
jpxImage.parse(this.bytes);
var width = jpxImage.width;
var height = jpxImage.height;
var componentsCount = jpxImage.componentsCount;
var tileCount = jpxImage.tiles.length;
let width = jpxImage.width;
let height = jpxImage.height;
let componentsCount = jpxImage.componentsCount;
let tileCount = jpxImage.tiles.length;
if (tileCount === 1) {
this.buffer = jpxImage.tiles[0].items;
} else {
var data = new Uint8ClampedArray(width * height * componentsCount);
let data = new Uint8ClampedArray(width * height * componentsCount);
for (var k = 0; k < tileCount; k++) {
var tileComponents = jpxImage.tiles[k];
var tileWidth = tileComponents.width;
var tileHeight = tileComponents.height;
var tileLeft = tileComponents.left;
var tileTop = tileComponents.top;
for (let k = 0; k < tileCount; k++) {
let tileComponents = jpxImage.tiles[k];
let tileWidth = tileComponents.width;
let tileHeight = tileComponents.height;
let tileLeft = tileComponents.left;
let tileTop = tileComponents.top;
var src = tileComponents.items;
var srcPosition = 0;
var dataPosition = (width * tileTop + tileLeft) * componentsCount;
var imgRowSize = width * componentsCount;
var tileRowSize = tileWidth * componentsCount;
let src = tileComponents.items;
let srcPosition = 0;
let dataPosition = (width * tileTop + tileLeft) * componentsCount;
let imgRowSize = width * componentsCount;
let tileRowSize = tileWidth * componentsCount;
for (var j = 0; j < tileHeight; j++) {
var rowBytes = src.subarray(srcPosition, srcPosition + tileRowSize);
for (let j = 0; j < tileHeight; j++) {
let rowBytes = src.subarray(srcPosition, srcPosition + tileRowSize);
data.set(rowBytes, dataPosition);
srcPosition += tileRowSize;
dataPosition += imgRowSize;