Always outputs XYZ format, doing the conversion from RGB internally if necessary

Author: imbcmdth

README.md

@@ -1,6 +1,6 @@
 # HDR
 
-A minimal streaming HDR image (ie. Radiance .pic format) library for node.js.
+A very minimal streaming HDR image (ie. Radiance .pic format) library for node.js. Always outputs XYZ color space regardless of the format of the HDR file.
 
 ## Contents
 
@@ -43,7 +43,7 @@ hdrloader.on('load', function() {
 	//-- this.width    - image width in pixels
 	//-- this.height   - image height in pixels
 	//-- this.data     - Float32Array of pixel colors with length = width*height*3
-	//--                 in non-planar [R, G, B, R, G, B, ...] pixel layout
+	//--                 in non-planar [X, Y, Z, X, Y, Z, ...] pixel layout
 });
 
 //-- Start piping in image data from filesystem/http request/ect.:
@@ -55,7 +55,10 @@ This library does the minimum required to read HDR files. It is up to the consum
 
 ## Versions
 
-* [v0.5.0](https://github.com/imbcmdth/hdr/archive/v1.0.0.zip) Initial public release
+* [v0.6.0](https://github.com/imbcmdth/hdr/archive/v0.6.0.zip) Output is now always in XYZ color format (doing the conversion automatically if the HDR file is in RGB format) and broke out color handling and pixel format into their own repositories/packages
+* [v0.5.1](https://github.com/imbcmdth/hdr/archive/v0.5.1.zip) Made internal functions more easily extensible
+* [v0.5.0](https://github.com/imbcmdth/hdr/archive/v0.5.0.zip) Initial public release
+
 
 ## License - MIT
 

lib/color.js

@@ -1,24 +1,31 @@
 'use strict';
 
-var stream = require('stream'),
-    util = require('util'),
-    colorUtil = require('./color');
+var stream = require('stream');
+var util = require('util');
+var floatUtils = require('mmme-encoding');
+var xyzUtils = require('xyz-utils');
 
 module.exports = HDRLoader;
 
-var MINLEN = 8,
-    MAXLEN = 0x7fff,
-    HEADER_REGEX = /([\#\?]+)?([^=\n\r]+)?=?([^=\n\r]*)?([\n\r]+)/gi,
-    DIMENSION_REGEX = /([+\-])([XY])\s(\d+)\s([+\-])([XY])\s(\d+)/i,
-    HEADER_PREFIXES = {
-    	'#?': 'FILETYPE',
-    	'#': 'COMMENT',
-    	'undefined': 'HEADER'
-    },
-    R = 0,
-    G = 1,
-    B = 2,
-    E = 3;
+var MINLEN = 8;
+var MAXLEN = 0x7fff;
+var HEADER_REGEX = /([\#\?]+)?([^=\n\r]+)?=?([^=\n\r]*)?([\n\r]+)/gi;
+var DIMENSION_REGEX = /^([+\-])([XY])\s(\d+)\s([+\-])([XY])\s(\d+)/i;
+var HEADER_PREFIXES = {
+	'#?': 'FILETYPE',
+	'#': 'COMMENT',
+	'undefined': 'HEADER'
+};
+var DEFAULT_HEADERS = {
+	'EXPOSURE': 1,
+	'COLORCORR': [1, 1, 1],
+	'PIXASPECT': 1,
+	'PRIMARIES': [0.640, 0.330, 0.290, 0.600, 0.150, 0.060, 0.333, 0.333]
+};
+var X = 0;
+var Y = 1;
+var Z = 2;
+var E = 3;
 
 function HDRLoader (options) {
 	if (!options) options = {};
@@ -37,6 +44,9 @@ function HDRLoader (options) {
 	this._error = false;
 	this._row_major = true;
 	this._scanlineSize = -1;
+	this._isRGBE = true;
+	this._hasExposure = false;
+	this._exposureVals = [1, 1, 1];
 }
 
 util.inherits(HDRLoader, stream.Writable);
@@ -100,17 +110,18 @@ HDRLoader.prototype._readScanline = function (chunk) {
 	var firstPixel = [],
 	    scanline;
 
-	firstPixel[R] = chunk.readUInt8(R);
-	firstPixel[G] = chunk.readUInt8(G);
-	firstPixel[B] = chunk.readUInt8(B);
+	firstPixel[X] = chunk.readUInt8(X);
+	firstPixel[Y] = chunk.readUInt8(Y);
+	firstPixel[Z] = chunk.readUInt8(Z);
 	firstPixel[E] = chunk.readUInt8(E);
 
 	if (this._isOldRLE(firstPixel)) {
 		scanline = this._readOldRLE(chunk);
 	} else {
-		if ((firstPixel[B] << 8 | firstPixel[E]) !== this._getScanlinePixels()) {
+		if ((firstPixel[Z] << 8 | firstPixel[E]) !== this._getScanlinePixels()) {
 			this._lastChunk = null;
 			this.data = null;
+			console.log(this, chunk)
 			this._error = true;
 			this.emit('error');
 			return;
@@ -123,14 +134,24 @@ HDRLoader.prototype._readScanline = function (chunk) {
 }
 
 HDRLoader.prototype._processScanline = function (scanline) {
+	var tempValues;
+	var tempFloats;
+	var tempXYZ;
+
 	if (this._row_major) {
 		for (var i = this._start_x; i !== this._end_x; i += this._inc_x) {
-			this._writePixel(i, this._current_y, colorUtil.toFloats.apply(null, scanline.shift()));
+			tempValues = scanline.shift();
+			tempFloats = floatUtils.toFloats(tempValues[0], tempValues[1], tempValues[2], tempValues[3]);
+			tempXYZ = this._processPixel(tempFloats);
+			this._writePixel(i, this._current_y, tempXYZ);
 		}
 		this._current_y += this._inc_y;
 	} else {
 		for (var i = this._start_y; i !== this._end_y; i += this._inc_y) {
-			this._writePixel(this._current_x, i, colorUtil.toFloats.apply(null, scanline.shift()));
+			tempValues = scanline.shift();
+			tempFloats = floatUtils.toFloats(tempValues[0], tempValues[1], tempValues[2], tempValues[3]);
+			tempXYZ = this._processPixel(tempFloats);
+			this._writePixel(this._current_x, i, tempXYZ);
 		}
 		this._current_x += this._inc_x;
 	}
@@ -145,19 +166,19 @@ HDRLoader.prototype._readOldRLE = function (chunk) {
 
 	while (len > 0) {
 		scanline[writePos] = [];
-		scanline[writePos][R] = chunk.readUInt8(offset++);
-		scanline[writePos][G] = chunk.readUInt8(offset++);
-		scanline[writePos][B] = chunk.readUInt8(offset++);
+		scanline[writePos][X] = chunk.readUInt8(offset++);
+		scanline[writePos][Y] = chunk.readUInt8(offset++);
+		scanline[writePos][Z] = chunk.readUInt8(offset++);
 		scanline[writePos][E] = chunk.readUInt8(offset++);
 
-		if (scanline[writePos][R] === 1
-			&& scanline[writePos][G] === 1
-			&& scanline[writePos][B] === 1) {
+		if (scanline[writePos][X] === 1
+			&& scanline[writePos][Y] === 1
+			&& scanline[writePos][Z] === 1) {
 			for (i = scanline[writePos][E] << rshift; i > 0; i--) {
 				scanline[writePos] = [];
-				scanline[writePos][R] = scanline[writePos - 1][R];
-				scanline[writePos][G] = scanline[writePos - 1][G];
-				scanline[writePos][B] = scanline[writePos - 1][B];
+				scanline[writePos][X] = scanline[writePos - 1][X];
+				scanline[writePos][Y] = scanline[writePos - 1][Y];
+				scanline[writePos][X] = scanline[writePos - 1][Z];
 				scanline[writePos][E] = scanline[writePos - 1][E];
 				writePos++;
 				len--;
@@ -214,12 +235,32 @@ HDRLoader.prototype._trimRemainingBuffer = function (chunk, consumed) {
 	this._lastChunk = chunk.slice(consumed);
 }
 
+HDRLoader.prototype._processPixel = function (pixelData) {
+	var XYZ = pixelData;
+
+	// First adjust the pixel data according to exposure settings
+	pixelData[0] /= this._exposureVals[0];
+	pixelData[1] /= this._exposureVals[1];
+	pixelData[2] /= this._exposureVals[2];
+
+	// If the pixel format is RGB we convert to XYZ because of the high
+	// likelyhood that any further HDR processing will be done in XYZ
+	// or a similar color space and XYZ offers the best intermediate for
+	// conversion between colorspaces
+	if (this._isRGBE) {
+		// TODO:  Use white point for conversion if supplied in headers
+		XYZ = xyzUtils.fromRGB(pixelData);
+	}
+
+	return XYZ;
+}
+
 HDRLoader.prototype._writePixel = function (x, y, pixelData) {
 	var offset = (x + y * this.width) * 3;
 
-	this.data[offset++] = pixelData[R];
-	this.data[offset++] = pixelData[G];
-	this.data[offset++] = pixelData[B];
+	this.data[offset++] = pixelData[X];
+	this.data[offset++] = pixelData[Y];
+	this.data[offset++] = pixelData[Z];
 }
 
 HDRLoader.prototype._readHeader = function (chunk) {
@@ -242,6 +283,20 @@ HDRLoader.prototype._readHeader = function (chunk) {
 			}
 
 			this._headerFinished = true;
+
+			if (this._hasExposure) {
+				if (this.headers['EXPOSURE']) {
+					var t = this.headers['EXPOSURE'];
+					this._exposureVals = [t, t, t];
+				}
+				if (this.headers['COLORCORR']) {
+					var t = this.headers['COLORCORR'];
+					this._exposureVals[0] *= t[0];
+					this._exposureVals[1] *= t[1];
+					this._exposureVals[2] *= t[2];
+				}
+			}
+
 			break;
 		} else {
 			switch (HEADER_PREFIXES[String(headerData[1])]) {
@@ -267,19 +322,34 @@ HDRLoader.prototype._readHeader = function (chunk) {
 	this._trimRemainingBuffer(chunk, sliceOffset);
 }
 
+// We only attempt to parse the most common headers
 HDRLoader.prototype._processHeader = function (headerName, headerValue) {
 	switch (headerName.toUpperCase()) {
 		case 'EXPOSURE':
+			this._hasExposure = true;
 		case 'PIXASPECT':
 			var val = parseFloat(headerValue);
 			return this.headers[headerName] ? this.headers[headerName] * val : val;
 		case 'PRIMARIES':
 			var vals = headerValue.split(/\s+/);
 			return vals.map(parseFloat);
 		case 'COLORCORR':
+			this._hasExposure = true;
 			var vals = headerValue.split(/\s+/);
 			vals = vals.map(parseFloat);
 			return this.headers[headerName] ? this.headers[headerName].map(mults(vals)) : vals;
+		case 'FORMAT':
+			if (headerValue === '32-bit_rle_rgbe') {
+				this._isRGBE = true;
+				return 'RGBE';
+			} else if (headerValue === '32-bit_rle_xyze') {
+				this._isRGBE = false;
+				return 'XYZE';
+			} else {
+				// Must be a parse error
+				this._error = true;
+				this.emit('error');
+			}
 		default:
 			return headerValue;
 	}
@@ -290,9 +360,9 @@ HDRLoader.prototype._isOldRLE = function (pixel) {
 
 	if (len < MINLEN || len > MAXLEN) return true;
 
-	if (pixel[R] !== 2) return true;
+	if (pixel[X] !== 2) return true;
 
-	if (pixel[G] !== 2 || pixel[B] & 128) return true;
+	if (pixel[Y] !== 2 || pixel[Z] & 128) return true;
 
 	return false;
 }
@@ -378,4 +448,4 @@ function mults (m) {
 	return function (v, i) {
 		return m[i] * v;
 	};
-}
+}

lib/hdr-load.js

@@ -1,3 +1,4 @@
 module.exports = {
-	loader: require('./hdr-load.js')
-}
+	loader: require('./hdr-load.js'),
+	utils: require('mmme-encoding')
+}

lib/hdr.js

@@ -1,7 +1,7 @@
 {
   "name": "hdr",
   "description": "Module for reading HDR image files",
-  "version": "0.5.1",
+  "version": "0.6.0",
   "homepage": "https://github.com/imbcmdth/hdr",
   "repository": {
     "type": "git",
@@ -22,11 +22,15 @@
     "xyze"
   ],
   "main": "./lib/hdr",
+  "dependencies": {
+    "mmme-encoding": "0.1.0",
+    "xyz-utils": "0.1.0"
+  },
   "devDependencies": {
     "mocha": "1.8.1"
   },
   "scripts": {
     "test": "./node_modules/mocha/bin/mocha test"
   },
   "license": "MIT"
-}
+}