units.js

/*globals $, svgedit*/
/*jslint vars: true, eqeq: true*/
/**
 * Package: svgedit.units
 *
 * Licensed under the MIT License
 *
 * Copyright(c) 2010 Alexis Deveria
 * Copyright(c) 2010 Jeff Schiller
 */

// Dependencies:
// 1) jQuery

(function() {'use strict';

if (!svgedit.units) {
	svgedit.units = {};
}

var NS = svgedit.NS;
var wAttrs = ['x', 'x1', 'cx', 'rx', 'width'];
var hAttrs = ['y', 'y1', 'cy', 'ry', 'height'];
var unitAttrs = ['r', 'radius'].concat(wAttrs, hAttrs);
// unused
var unitNumMap = {
	'%':  2,
	'em': 3,
	'ex': 4,
	'px': 5,
	'cm': 6,
	'mm': 7,
	'in': 8,
	'pt': 9,
	'pc': 10
};

// Container of elements.
var elementContainer_;

/**
 * Stores mapping of unit type to user coordinates.
 */
var typeMap_ = {};

/**
 * ElementContainer interface
 *
 * function getBaseUnit() - returns a string of the base unit type of the container ('em')
 * function getElement() - returns an element in the container given an id
 * function getHeight() - returns the container's height
 * function getWidth() - returns the container's width
 * function getRoundDigits() - returns the number of digits number should be rounded to
 */

/**
 * Function: svgedit.units.init()
 * Initializes this module.
 *
 * Parameters:
 * elementContainer - an object implementing the ElementContainer interface.
 */
svgedit.units.init = function(elementContainer) {
	elementContainer_ = elementContainer;

	// Get correct em/ex values by creating a temporary SVG.
	var svg = document.createElementNS(NS.SVG, 'svg');
	document.body.appendChild(svg);
	var rect = document.createElementNS(NS.SVG, 'rect');
	rect.setAttribute('width', '1em');
	rect.setAttribute('height', '1ex');
	rect.setAttribute('x', '1in');
	svg.appendChild(rect);
	var bb = rect.getBBox();
	document.body.removeChild(svg);

	var inch = bb.x;
	typeMap_ = {
		'em': bb.width,
		'ex': bb.height,
		'in': inch,
		'cm': inch / 2.54,
		'mm': inch / 25.4,
		'pt': inch / 72,
		'pc': inch / 6,
		'px': 1,
		'%': 0
	};
};

// Group: Unit conversion functions

// Function: svgedit.units.getTypeMap
// Returns the unit object with values for each unit
svgedit.units.getTypeMap = function() {
	return typeMap_;
};

// Function: svgedit.units.shortFloat
// Rounds a given value to a float with number of digits defined in save_options
//
// Parameters:
// val - The value as a String, Number or Array of two numbers to be rounded
//
// Returns:
// If a string/number was given, returns a Float. If an array, return a string
// with comma-seperated floats
svgedit.units.shortFloat = function(val) {
	var digits = elementContainer_.getRoundDigits();
	if (!isNaN(val)) {
		// Note that + converts to Number
		return +((+val).toFixed(digits));
	}
	if ($.isArray(val)) {
		return svgedit.units.shortFloat(val[0]) + ',' + svgedit.units.shortFloat(val[1]);
	}
	return parseFloat(val).toFixed(digits) - 0;
};

// Function: svgedit.units.convertUnit
// Converts the number to given unit or baseUnit
svgedit.units.convertUnit = function(val, unit) {
	unit = unit || elementContainer_.getBaseUnit();
//	baseVal.convertToSpecifiedUnits(unitNumMap[unit]);
//	var val = baseVal.valueInSpecifiedUnits;
//	baseVal.convertToSpecifiedUnits(1);
	return svgedit.units.shortFloat(val / typeMap_[unit]);
};

// Function: svgedit.units.setUnitAttr
// Sets an element's attribute based on the unit in its current value.
//
// Parameters:
// elem - DOM element to be changed
// attr - String with the name of the attribute associated with the value
// val - String with the attribute value to convert
svgedit.units.setUnitAttr = function(elem, attr, val) {
//	if (!isNaN(val)) {
		// New value is a number, so check currently used unit
//		var old_val = elem.getAttribute(attr);

		// Enable this for alternate mode
//		if (old_val !== null && (isNaN(old_val) || elementContainer_.getBaseUnit() !== 'px')) {
//			// Old value was a number, so get unit, then convert
//			var unit;
//			if (old_val.substr(-1) === '%') {
//				var res = getResolution();
//				unit = '%';
//				val *= 100;
//				if (wAttrs.indexOf(attr) >= 0) {
//					val = val / res.w;
//				} else if (hAttrs.indexOf(attr) >= 0) {
//					val = val / res.h;
//				} else {
//					return val / Math.sqrt((res.w*res.w) + (res.h*res.h))/Math.sqrt(2);
//				}
//			} else {
//				if (elementContainer_.getBaseUnit() !== 'px') {
//					unit = elementContainer_.getBaseUnit();
//				} else {
//					unit = old_val.substr(-2);
//				}
//				val = val / typeMap_[unit];
//			}
//
//		val += unit;
//		}
//	}
	elem.setAttribute(attr, val);
};

var attrsToConvert = {
	'line': ['x1', 'x2', 'y1', 'y2'],
	'circle': ['cx', 'cy', 'r'],
	'ellipse': ['cx', 'cy', 'rx', 'ry'],
	'foreignObject': ['x', 'y', 'width', 'height'],
	'rect': ['x', 'y', 'width', 'height'],
	'image': ['x', 'y', 'width', 'height'],
	'use': ['x', 'y', 'width', 'height'],
	'text': ['x', 'y']
};

// Function: svgedit.units.convertAttrs
// Converts all applicable attributes to the configured baseUnit
//
// Parameters:
// element - a DOM element whose attributes should be converted
svgedit.units.convertAttrs = function(element) {
	var elName = element.tagName;
	var unit = elementContainer_.getBaseUnit();
	var attrs = attrsToConvert[elName];
	if (!attrs) {return;}

	var len = attrs.length;
	var i;
	for (i = 0; i < len; i++) {
		var attr = attrs[i];
		var cur = element.getAttribute(attr);
		if (cur) {
			if (!isNaN(cur)) {
				element.setAttribute(attr, (cur / typeMap_[unit]) + unit);
			}
			// else {
				// Convert existing?
			// }
		}
	}
};

// Function: svgedit.units.convertToNum
// Converts given values to numbers. Attributes must be supplied in 
// case a percentage is given
//
// Parameters:
// attr - String with the name of the attribute associated with the value
// val - String with the attribute value to convert
svgedit.units.convertToNum = function(attr, val) {
	// Return a number if that's what it already is
	if (!isNaN(val)) {return val-0;}
	var num;
	if (val.substr(-1) === '%') {
		// Deal with percentage, depends on attribute
		num = val.substr(0, val.length-1)/100;
		var width = elementContainer_.getWidth();
		var height = elementContainer_.getHeight();

		if (wAttrs.indexOf(attr) >= 0) {
			return num * width;
		}
		if (hAttrs.indexOf(attr) >= 0) {
			return num * height;
		}
		return num * Math.sqrt((width*width) + (height*height))/Math.sqrt(2);
	}
	var unit = val.substr(-2);
	num = val.substr(0, val.length-2);
	// Note that this multiplication turns the string into a number
	return num * typeMap_[unit];
};

// Function: svgedit.units.isValidUnit
// Check if an attribute's value is in a valid format
//
// Parameters:
// attr - String with the name of the attribute associated with the value
// val - String with the attribute value to check
svgedit.units.isValidUnit = function(attr, val, selectedElement) {
	var valid = false;
	if (unitAttrs.indexOf(attr) >= 0) {
		// True if it's just a number
		if (!isNaN(val)) {
			valid = true;
		} else {
		// Not a number, check if it has a valid unit
			val = val.toLowerCase();
			$.each(typeMap_, function(unit) {
				if (valid) {return;}
				var re = new RegExp('^-?[\\d\\.]+' + unit + '$');
				if (re.test(val)) {valid = true;}
			});
		}
	} else if (attr == 'id') {
		// if we're trying to change the id, make sure it's not already present in the doc
		// and the id value is valid.

		var result = false;
		// because getElem() can throw an exception in the case of an invalid id
		// (according to http://www.w3.org/TR/xml-id/ IDs must be a NCName)
		// we wrap it in an exception and only return true if the ID was valid and
		// not already present
		try {
			var elem = elementContainer_.getElement(val);
			result = (elem == null || elem === selectedElement);
		} catch(e) {}
		return result;
	}
	valid = true;

	return valid;
};

}());