Support for Arabic/Hebrew/Persian languages.

lib/ace/bidihandler.js

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+/* ***** BEGIN LICENSE BLOCK *****
+ * Distributed under the BSD license:
+ *
+ * Copyright (c) 2010, Ajax.org B.V.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of Ajax.org B.V. nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL AJAX.ORG B.V. BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+define(function(require, exports, module) {
+"use strict";
+
+var bidiUtil = require("./lib/bidiutil");
+var lang = require("./lib/lang");
+var useragent = require("./lib/useragent");
+
+/**
+ * This object is used to ensure Bi-Directional support (for languages with text flowing from right to left, like Arabic or Hebrew)
+ * including correct caret positioning, text selection mouse and keyboard arrows functioning
+ * @class BidiHandler
+ **/
+
+/**
+ * Creates a new `BidiHandler` object
+ * @param {EditSession} session The session to use
+ *
+ * @constructor
+ **/
+var BidiHandler = function(session) {
+    this.session = session;
+    this.bidiMap = {};
+    /* current screen row */
+    this.currentRow = null;
+    this.bidiUtil = bidiUtil;
+    /* Arabic/Hebrew character width differs from regular character width */
+    this.charWidths = [];
+    this.EOL;
+    this.showInvisibles;
+    this.isRtlDir = false;
+    this.line = "";
+    this.wrapIndent = 0;
+    /* font face has been set to Courier to ensure monospaced Bidi characters in Chrome/Opera */
+    this.isCourierFont = false;
+    this.isLastRow = false;
+    this.EOF = "\xB6";
+};
+
+(function() {
+    /**
+     * Returns 'true' if row contains Bidi characters, in such case
+     * creates Bidi map to be used in operations related to selection
+     * (keyboard arrays, mouse click, select)
+     * @param {Number} the screen row to be checked
+     * @param {Number} the document row to be checked [optional]
+     * @param {Number} the wrapped screen line index [ optional]
+     **/
+	this.isBidiRow = function(screenRow, docRow, splitIndex) {
+		if (screenRow !== this.currentRow) {
+			this.currentRow = screenRow;
+			this.updateRowLine(docRow, splitIndex);
+			this.updateBidiMap();
+		}
+		return this.bidiMap.bidiLevels;
+	};
+
+	this.hasBidiCharacters = function(str) {
+		return /[\u0591-\u06ff\ufb1d-\ufefc]/.test(str);
+	};
+
+	this.getDocumentRow = function() {
+		var docRow = 0;
+		var rowCache = this.session.$screenRowCache;
+		if (rowCache.length) {
+			var index = this.session.$getRowCacheIndex(rowCache, this.currentRow);
+			if (index >= 0)
+				docRow = this.session.$docRowCache[index];
+		}
+
+		return docRow;
+	};
+
+	this.getSplitIndex = function() {
+		var splitIndex = 0;
+		var rowCache = this.session.$screenRowCache;
+		if (rowCache.length) {
+			var currentIndex, prevIndex = this.session.$getRowCacheIndex(rowCache, this.currentRow);
+			while (this.currentRow - splitIndex > 0) {
+				currentIndex = this.session.$getRowCacheIndex(rowCache, this.currentRow - splitIndex - 1);
+				if (currentIndex !== prevIndex)
+					break;
+
+				prevIndex = currentIndex;
+				splitIndex++;
+			}
+		}
+
+		return splitIndex;
+	};
+
+	this.updateRowLine = function(docRow, splitIndex) {
+		if (docRow === undefined)
+			docRow = this.getDocumentRow();
+
+		this.wrapIndent = 0;
+		this.isLastRow = (docRow === this.session.getLength() - 1);
+		this.line = this.session.getLine(docRow);
+		if (this.session.$useWrapMode) {
+			var splits = this.session.$wrapData[docRow];
+			if (splits) {
+				if (splitIndex === undefined)
+					splitIndex = this.getSplitIndex();
+
+				if(splitIndex > 0 && splits.length) {
+					this.wrapIndent = splits.indent;
+					this.line = (splitIndex < splits.length) ?
+						this.line.substring(splits[splitIndex - 1], splits[splits.length - 1]) :
+							this.line.substring(splits[splits.length - 1]);
+				} else {
+					this.line = this.line.substring(0, splits[splitIndex]);
+				}
+			}
+		}
+
+		/* replace tab and wide characters by commensurate spaces */
+		var session = this.session, shift = 0, size;
+		this.line = this.line.replace(/\t|[\u1100-\u2029, \u202F-\uFFE6]/g, function(ch, i){
+			if (ch === '\t' || session.isFullWidth(ch.charCodeAt(0))) {
+				size = (ch === '\t') ? session.getScreenTabSize(i + shift) : 2;
+				shift += size - 1;
+				return lang.stringRepeat(bidiUtil.DOT, size);		
+			}
+			return ch;
+		});
+	};
+
+	this.updateBidiMap = function() {
+		var textCharTypes = [], endOfLine = this.isLastRow ? this.EOF : this.EOL;
+		var line = this.line + (this.showInvisibles ? endOfLine : bidiUtil.DOT);
+		if (bidiUtil.hasBidiCharacters(line, textCharTypes)) {
+			this.bidiMap = bidiUtil.doBidiReorder(line, textCharTypes, this.isRtlDir);
+		} else {
+			this.bidiMap = {};
+		}
+	};
+
+    /**
+     * Resets stored info related to current screen row
+     **/
+	this.markAsDirty = function() {	
+		this.currentRow = null;
+	};
+
+    /**
+     * Updates array of character widths
+     * @param {Object} font metrics
+     *
+     **/
+	this.updateCharacterWidths = function($fontMetrics) {
+		var _regularCharWidth = $fontMetrics.$measureCharWidth('a'), _bidiCharWidth = $fontMetrics.$measureCharWidth('\u05d4');
+		/* on some Windows7 OS not 'Monaco' but 'Courier' family is true monospaced font for Bidi characters in Chrome based browsers */
+		if (!useragent.isMac && useragent.isChrome && (_bidiCharWidth !== $fontMetrics.$measureCharWidth('\u05d5'))) {
+			this.isCourierFont = true;
+			$fontMetrics.$main.style.fontFamily = "Courier";
+			_regularCharWidth = $fontMetrics.$measureCharWidth('a');
+			_bidiCharWidth = $fontMetrics.$measureCharWidth('\u05d4');
+			$fontMetrics.$main.style.fontFamily = "inherit";			
+		}
+
+		this.charWidths[bidiUtil.L] = this.charWidths[bidiUtil.EN] = this.charWidths[bidiUtil.ON_R] = _regularCharWidth;
+		this.charWidths[bidiUtil.R] = this.charWidths[bidiUtil.AN] = _bidiCharWidth;
+		this.charWidths[bidiUtil.R_H] = useragent.isChrome ? _bidiCharWidth : _bidiCharWidth * 0.45;
+		this.charWidths[bidiUtil.B] = 0;
+
+		if (this.currentRow !== null) {
+			this.updateBidiMap();
+		}   	
+	};
+
+	this.isCourierFontFace = function() {
+		return this.isCourierFont;
+	};
+
+	this.getShowInvisibles = function() {
+		return this.showInvisibles;
+	};
+
+	this.setShowInvisibles = function(showInvisibles) {
+		this.showInvisibles = showInvisibles;
+		if (this.currentRow !== null) {
+			this.updateBidiMap();
+		}
+	};
+
+	this.setEolChar = function(eolChar) {
+		this.EOL = eolChar; 
+	};
+
+	this.setTextDir = function(isRtlDir) {
+		this.isRtlDir = isRtlDir; 
+	};
+
+    /**
+     * Returns offset of character at position defined by column.
+     * @param {Number} the screen column position
+     *
+     * @return {int} horizontal pixel offset of given screen column
+     **/
+	this.getPosLeft = function(col) {
+		col -= this.wrapIndent;
+		var visualIdx = bidiUtil.getVisualFromLogicalIdx(col > 0 ? col - 1 : 0, this.bidiMap),
+			levels = this.bidiMap.bidiLevels, left = 0;
+
+		if (col === 0 && levels[visualIdx] % 2 !== 0)
+			visualIdx++;
+
+		for (var i = 0; i < visualIdx; i++) {
+			left += this.charWidths[levels[i]];
+		}
+
+		if (col !== 0 && levels[visualIdx] % 2 === 0)
+			left += this.charWidths[levels[visualIdx]];
+
+		if (this.wrapIndent)
+			left += this.wrapIndent * this.charWidths[bidiUtil.L];
+
+		return left;
+	};
+
+    /**
+     * Returns 'selections' - array of objects defining set of selection rectangles
+     * @param {Number} the start column position
+     * @param {Number} the end column position
+     *
+     * @return {Array of Objects} Each object contains 'left' and 'width' values defining selection rectangle.
+     **/
+	this.getSelections = function(startCol, endCol) {
+		var map = this.bidiMap, levels = map.bidiLevels, level, offset = this.wrapIndent * this.charWidths[bidiUtil.L], selections = [],
+			selColMin = Math.min(startCol, endCol) - this.wrapIndent, selColMax = Math.max(startCol, endCol) - this.wrapIndent,
+				isSelected = false, isSelectedPrev = false, selectionStart = 0;
+
+		for (var logIdx, visIdx = 0; visIdx < levels.length; visIdx++) {
+			logIdx = map.logicalFromVisual[visIdx];
+			level = levels[visIdx];
+			isSelected = (logIdx >= selColMin) && (logIdx < selColMax);
+			if (isSelected && !isSelectedPrev) {
+				selectionStart = offset;
+			} else if (!isSelected && isSelectedPrev) {
+				selections.push({left: selectionStart, width: offset - selectionStart});
+			}
+			offset += this.charWidths[level];
+			isSelectedPrev = isSelected;
+		}
+
+		if (isSelected && (visIdx === levels.length)) {
+			selections.push({left: selectionStart, width: offset - selectionStart});
+		}
+
+		return selections;			
+	};
+
+    /**
+     * Converts character coordinates on the screen to respective document column number
+     * @param {int} character horizontal offset
+     *
+     * @return {Number} screen column number corresponding to given pixel offset
+     **/
+	this.offsetToCol = function(posX) {
+		var logicalIdx = 0, posX = Math.max(posX, 0),
+			offset = 0, visualIdx = 0, levels = this.bidiMap.bidiLevels,
+				charWidth = this.charWidths[levels[visualIdx]];
+
+		if (this.wrapIndent) {
+			posX -= this.wrapIndent * this.charWidths[bidiUtil.L];
+		}
+
+		while(posX > offset + charWidth/2) {
+			offset += charWidth;
+			if(visualIdx === levels.length - 1) {
+				/* quit when we on the right of the last character, flag this by charWidth = 0 */
+				charWidth = 0;
+				break;
+			}
+			charWidth = this.charWidths[levels[++visualIdx]];
+		}
+
+		if (visualIdx > 0 && (levels[visualIdx - 1] % 2 !== 0) && (levels[visualIdx] % 2 === 0)){
+		/* Bidi character on the left and None Bidi character on the right */
+			if(posX < offset)
+				visualIdx--;
+			logicalIdx = this.bidiMap.logicalFromVisual[visualIdx];
+
+		} else if (visualIdx > 0 && (levels[visualIdx - 1] % 2 === 0) && (levels[visualIdx] % 2 !== 0)){
+		/* None Bidi character on the left and Bidi character on the right */
+			logicalIdx = 1 + ((posX > offset) ? this.bidiMap.logicalFromVisual[visualIdx]
+					: this.bidiMap.logicalFromVisual[visualIdx - 1]);
+
+		} else if ((this.isRtlDir && visualIdx === levels.length - 1 && charWidth === 0 && (levels[visualIdx - 1] % 2 === 0))
+				|| (!this.isRtlDir && visualIdx === 0 && (levels[visualIdx] % 2 !== 0))){
+		/* To the right of last character, which is None Bidi, in RTL direction or */
+		/* to the left of first Bidi character, in LTR direction */
+			logicalIdx = 1 + this.bidiMap.logicalFromVisual[visualIdx];
+		} else {
+			/* Tweak visual position when Bidi character on the left in order to map it to corresponding logical position */
+			if (visualIdx > 0 && (levels[visualIdx - 1] % 2 !== 0) && charWidth !== 0)
+				visualIdx--;
+
+			/* Regular case */
+			logicalIdx = this.bidiMap.logicalFromVisual[visualIdx];
+		}
+
+		return (logicalIdx + this.wrapIndent);
+	};
+
+}).call(BidiHandler.prototype);
+
+exports.BidiHandler = BidiHandler;
+});