hummus-recipe
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A powerful PDF tool for NodeJS based on HummusJS
397 lines (361 loc) • 12.8 kB
JavaScript
const muhammara = require('muhammara');
const fs = require('fs');
this.knownColors = { // knownColors.colorspace.colorName = value
rgb: {
red : 'ff0000',
green : '00ff00',
blue : '0000ff',
},
cmyk: {
cyan : 'ff000000',
magenta: '00ff0000',
yellow : '0000ff00',
black : '000000ff'
},
gray: {
white : 'ff',
black : '00'
},
separation : { // meant for printing, so using cmyk values initially
cyan : 'ff000000',
magenta: '00ff0000',
yellow : '0000ff00',
black : '000000ff',
nans : '%,35,6,0' // a great PDF collaborator!
}
};
/**
* Associate color values to names
*
* The colorspace parameter is optional. When it is missing, the colorspace
* is automatically determined by the given color value. Note that the special
* PDF color space called 'separation' may also be used. The color value is then
* treated as the alternative color when the named 'separation' color is unavailable.
*
* If the 'name' parameter is '!load', the second parameter is the name of a JSON
* formatted file containing a formatted list of defined colors associated with the
* color spaces rgb, cmyk, gray, or separation (think PANTONE color definitions).
* This file will be merged with existing set of known colors. The color values
* must be specified as hex values.
*
* For example,
* {
* 'rgb': {'purple':'ff00ff', 'red':'#ff0000'},
* 'cmyk': {'cyan':'ff000000', 'magenta':'%0,100,0,0'},
* 'gray': {'grey':'#33'}
* }
*
* @name chroma
* @function
* @memberof Recipe
* @param {string} name - the name to be associated to given color value, or '!load'
* @param {string|number[]} value - the color value (HexColor, DecimalColor, or PercentColor), or name of '!load' file
* @param {string} colorspace - one of the followning: 'rgb', 'cmyk', 'gray', 'separation';
*/
exports.chroma = function chroma(name, value, colorspace='') {
if (name) {
if (name === '!load') {
let newColors = JSON.parse(fs.readFileSync(value));
// Add new colors to existing colorspaces
for (let cs in newColors) {
if (this.knownColors[cs]) {
Object.assign(this.knownColors[cs], newColors[cs]);
} else {
throw new Error(`Unrecognized colorspace: ${cs}`);
}
}
} else {
if (Array.isArray(value)) {
value = arrayToHex(value);
} else if (value.startsWith('%')) {
value = percentToHex(value.replace('%', ''));
} else {
value = value.replace('#', '');
}
// Only deal with valid hex codes from the
// device colorspaces gray, rgb, and cmyk.
if (![2,6,8].includes(value.toString().length)) {
throw new Error('Color value has incorrect size for gray, rgb, or cmyk colorspaces');
}
// Determine colorspace by length of given input
// value when colorspace not provided in call.
if (colorspace === '') {
const colorSpaces = {2:'gray', 6:'rgb', 8:'cmyk'};
colorspace = colorSpaces[`${value.length}`];
} else if (!['rgb','cmyk','gray','separation'].includes(colorspace)) {
throw new Error(`Unknown colorspace: ${colorspace}.`);
}
if (colorspace) {
this.knownColors[colorspace][name] = value;
}
}
}
return this;
};
function createColorSpaces(self, colorName, color) {
const deviceCS = {1:'DeviceGray', 3:'DeviceRGB', 4:'DeviceCMYK'};
const altCS = deviceCS[`${color.length}`];
this.colorSpaces = this.colorSpaces || {};
this.colorSpaces[altCS] = this.colorSpaces[altCS] || {};
let colorSpaceID = this.colorSpaces[altCS][colorName];
if (!colorSpaceID) {
const transformFunction = tintTransform(self, color);
self.pauseContext();
const objCxt = self.writer.getObjectsContext();
colorSpaceID = objCxt.startNewIndirectObject();
objCxt
.startArray()
.writeName('Separation')
.writeName(colorName)
.writeName(altCS)
.writeIndirectObjectReference(transformFunction)
.endArray(muhammara.eTokenSeparatorEndLine)
.endIndirectObject();
self.resumeContext();
this.colorSpaces[altCS][colorName] = colorSpaceID;
}
return colorSpaceID;
}
function tintTransform(self, color) {
const rangeCount = color.length;
self.pauseContext();
const objCxt = self.writer.getObjectsContext();
const tintFuncID = objCxt.startNewIndirectObject();
const dict = objCxt.startDictionary();
dict
.writeKey('FunctionType')
.writeNumberValue(2)
.writeKey('Domain');
objCxt
.startArray()
.writeNumber(0.0)
.writeNumber(1.0)
.endArray();
dict.writeKey('Range');
objCxt.startArray();
for (let index = 0; index < rangeCount; index++) {
objCxt.writeNumber(0.0).writeNumber(1.0);
}
objCxt.endArray();
dict.writeKey('N');
dict.writeNumberValue(1);
dict.writeKey('C0');
objCxt.startArray();
for (let index = 0; index < rangeCount; index++) {
objCxt.writeNumber(0.0);
}
objCxt.endArray();
dict.writeKey('C1');
objCxt.startArray();
for (let index = 0; index < rangeCount; index++) {
objCxt.writeNumber(color[index]);
}
objCxt.endArray();
objCxt.endDictionary(dict);
objCxt.endIndirectObject();
self.resumeContext();
return tintFuncID;
}
exports._createExtGStates = function _createExtGStates(value) {
this.extGStates = this.extGStates || {};
if (this.extGStates[value]) {
return this.extGStates[value];
}
const write = (key, value) => {
this.pauseContext();
const objCxt = this.writer.getObjectsContext();
const gsId = objCxt.startNewIndirectObject();
const dict = objCxt.startDictionary();
dict.writeKey('type');
dict.writeNameValue('ExtGState');
dict.writeKey(key);
objCxt.writeNumber(value);
objCxt.endLine();
objCxt.endDictionary(dict);
objCxt.endIndirectObject(); // new here [seh]
this.resumeContext();
return gsId;
};
this.extGStates[value] = {
stroke: write('CA', value),
fill: write('ca', value)
};
return this.extGStates[value];
};
function _defaultColor(colorspace='rgb') {
let defaultColor;
switch (colorspace) {
case 'cmyk':
defaultColor = 'FF000000';
break;
case 'gray':
defaultColor = '00';
break;
case 'rgb':
default:
defaultColor = '1777d1';
break;
}
return defaultColor;
}
/**
* Convert given color code int color model object
*
* ColorModel consists of: {
* color: number,
* colorspace: string {'rgb', 'cmyk', 'gray'},
* (colorspace == 'rgb') r, g, b
* (colorspace == 'cmyk') c, m, y, k
* (colorspace == 'gray') gray
* }
*
* where r,g,b,c,m,y,k,gray are all numbers between 0 and 1
*
* @param {string} code the color encoding as HexColor
* @param {string} colorspace the name of the colorspace of given color code
* @param {string} colorName the name to be associated with given color code
* @returns {any} the color model
*/
function toColorModel(self, code, colorspace, colorName) {
const cmodel = {};
let color = hexToArray(code);
cmodel.color = parseInt(code, 16);
// The initial decider of color space is length of given 'code'.
switch (color.length) {
default:
color = hexToArray(_defaultColor('rgb'));
// purposely want to fall through to 'rgb' case below.
case 3:
cmodel.colorspace = 'rgb';
cmodel.r = color[0];
cmodel.g = color[1];
cmodel.b = color[2];
break;
case 4:
cmodel.colorspace = 'cmyk';
cmodel.c = color[0];
cmodel.m = color[1];
cmodel.y = color[2];
cmodel.k = color[3];
break;
case 1:
cmodel.colorspace = 'gray';
cmodel.gray = color[0];
break;
}
// When creating a separation color space,
// use the colorspace from above as the
// alternative color transformation when
// the named color is unavailable.
if (colorspace === 'separation' && colorName !== '') {
cmodel.colorspace = colorspace;
cmodel.colorName = colorName;
cmodel.colorspaceId = createColorSpaces(self, colorName, color);
}
return cmodel;
}
/**
* Convert percentage string into hex string (x / 100 * 255)
*
* @param {string} code numbers separated by commas with values ranging between 0-100.
* @returns {string} massaged hexadecimal string that can be used as input to hexToArray.
*/
function percentToHex(code) {
return arrayToHex(code.split(',').map( x => Math.round(x * 2.55)) );
}
/**
* Transform color code into numeric value or colorModel
*
* @param code color specification in form of HexColor (string, begins with '#'),
* DecimalColor (1, 3, or 4 element array with values between 0-255),
* PercentColor (string, begins with '%' followed by values separated
* by commas with values between 0-100)
*/
exports._transformColor = function _transformColor(code = '', opt = {}) {
this.knownColors = this.knownColors || {};
let colorspace = opt.colorspace || 'rgb';
let wantColorModel = opt.wantColorModel || false;
let colorName = opt.colorName || '';
let defaultColor = _defaultColor(colorspace);
let transformation;
if (Array.isArray(code)) {
code = arrayToHex(code);
} else if (code.startsWith('#')){
code = code.replace('#', '');
} else if (code.startsWith('%')) {
code = percentToHex(code.replace('%', ''));
} else if (code !== '') {
let color = this.knownColors[colorspace][code]; // assuming code is a color name
if (!color) {
color = '';
code = defaultColor;
} else {
colorName = code;
// The following handles known colors in hex form,
// with or without initial '#' and percent form.
if (color.startsWith('#')) {
code = color.replace('#','');
} else if (color.startsWith('%')) {
code = percentToHex(color.replace('%', ''));
} else {
code = color;
}
}
}
// When colorspace is not explicitly given,
// use size of value to determine colorspace.
if (!opt.colorspace) {
colorspace = {2:'gray', 6:'rgb', 8:'cmyk'}[`${code.length}`] || 'rgb';
defaultColor = _defaultColor(colorspace);
}
// Suppply default color:
// when colorspace is given and given color code does not have appropriate length, or
// when colorspace is missing, verify allowable hex value sizes for rgb, cmyk, or gray.
if ( ['rgb','cmyk','gray'].includes(colorspace) && code.length != defaultColor.length ||
! [2,6,8].includes(code.toString().length)) {
code = defaultColor;
}
if (wantColorModel) {
transformation = toColorModel(this, code, colorspace, colorName);
if ( colorName && !this.knownColors[colorspace][colorName]) {
this.chroma(colorName, code, colorspace);
}
} else {
transformation = parseInt(`0x${code.toUpperCase()}`, 16);
}
return transformation;
};
function arrayToHex(color = []) {
let code = '';
color.forEach((item) => {
let hex = item.toString(16);
hex = (hex.length == 1) ? '0' + hex : hex;
code += hex;
});
return code;
}
function hexToArray(hex) {
const result = /^#?([a-f\d]{2})([a-f\d]{2})?([a-f\d]{2})?([a-f\d]{2})?$/i.exec(hex);
return result
.reduce((array, item, index) => {
if (index >= 1 && index <= (hex.length / 2)) {
array.push(parseInt(item, 16) / 255);
}
return array;
}, []);
}
exports._colorNumberToRGB = (bigint) => {
if (!bigint) {
return {
r: 0,
g: 0,
b: 0
};
} else {
return {
r: (bigint >> 16) & 255,
g: (bigint >> 8) & 255,
b: bigint & 255
};
}
};