Refactor print preview web ui

chrome/browser/resources/print_preview/data/measurement_system.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+cr.define('print_preview', function() {
+  'use strict';
+
+  /**
+   * Measurement system of the print preview. Used to parse and serialize point
+   * measurements into the system's local units (e.g. millimeters, inches).
+   * @param {string} thousandsDelimeter Delimeter between thousands digits.
+   * @param {string} decimalDelimeter Delimeter between integers and decimals.
+   * @param {print_preview.MeasurementSystem.UnitType} unitType Measurement unit
+   *     type of the system.
+   * @constructor
+   */
+  function MeasurementSystem(thousandsDelimeter, decimalDelimeter, unitType) {
+    this.thousandsDelimeter_ = thousandsDelimeter || ',';
+    this.decimalDelimeter_ = decimalDelimeter || '.';
+    this.unitType_ = unitType;
+  };
+
+  /**
+   * Parses |numberFormat| and extracts the symbols used for the thousands point
+   * and decimal point.
+   * @param {string} numberFormat The formatted version of the number 12345678.
+   * @return {!Array.<string>} The extracted symbols in the order
+   *     [thousandsSymbol, decimalSymbol]. For example,
+   *     parseNumberFormat("123,456.78") returns [",", "."].
+   */
+  MeasurementSystem.parseNumberFormat = function(numberFormat) {
+    if (!numberFormat) {
+      return [',', '.'];
+    }
+    var regex = /^(\d+)(\W?)(\d+)(\W?)(\d+)$/;
+    var matches = numberFormat.match(regex) || ['', '', ',', '', '.'];
+    return [matches[2], matches[4]];
+  };
+
+  /**
+   * Enumeration of measurement unit types.
+   * @enum {number}
+   */
+  MeasurementSystem.UnitType = {
+    METRIC: 0, // millimeters
+    IMPERIAL: 1 // inches
+  };
+
+  /**
+   * Maximum resolution of local unit values.
+   * @type {Object.<print_preview.MeasurementSystem.UnitType, number>}
+   * @private
+   */
+  MeasurementSystem.Precision_ = {};
+  MeasurementSystem.Precision_[MeasurementSystem.UnitType.METRIC] = 0.5;
+  MeasurementSystem.Precision_[MeasurementSystem.UnitType.IMPERIAL] = 0.01;
+
+  /**
+   * Maximum number of decimal places to keep for local unit.
+   * @type {Object.<print_preview.MeasurementSystem.UnitType, number>}
+   * @private
+   */
+  MeasurementSystem.DecimalPlaces_ = {};
+  MeasurementSystem.DecimalPlaces_[MeasurementSystem.UnitType.METRIC] = 1;
+  MeasurementSystem.DecimalPlaces_[MeasurementSystem.UnitType.IMPERIAL] = 2;
+
+  /**
+   * Number of points per inch.
+   * @type {number}
+   * @const
+   * @private
+   */
+  MeasurementSystem.PTS_PER_INCH_ = 72.0;
+
+  /**
+   * Number of points per millimeter.
+   * @type {number}
+   * @const
+   * @private
+   */
+  MeasurementSystem.PTS_PER_MM_ = MeasurementSystem.PTS_PER_INCH_ / 25.4;
+
+  MeasurementSystem.prototype = {
+    /** @return {string} The unit type symbol of the measurement system. */
+    get unitSymbol() {
+      if (this.unitType_ == MeasurementSystem.UnitType.METRIC) {
+        return 'mm';
+      } else if (this.unitType_ == MeasurementSystem.UnitType.IMPERIAL) {
+        return '"';
+      } else {
+        throw Error('Unit type not supported: ' + this.unitType_);
+      }
+    },
+
+    /**
+     * @return {string} The thousands delimeter character of the measurement
+     *     system.
+     */
+    get thousandsDelimeter() {
+      return this.thousandsDelimeter_;
+    },
+
+    /**
+     * @return {string} The decimal delimeter character of the measurement
+     *     system.
+     */
+    get decimalDelimeter() {
+      return this.decimalDelimeter_;
+    },
+
+    setSystem: function(thousandsDelimeter, decimalDelimeter, unitType) {
+      this.thousandsDelimeter_ = thousandsDelimeter;
+      this.decimalDelimeter_ = decimalDelimeter;
+      this.unitType_ = unitType;
+    },
+
+    /**
+     * Rounds a value in the local system's units to the appropriate precision.
+     * @param {number} value Value to round.
+     * @return {number} Rounded value.
+     */
+    roundValue: function(value) {
+      var precision = MeasurementSystem.Precision_[this.unitType_];
+      var roundedValue = Math.round(value / precision) * precision;
+      // Truncate
+      return roundedValue.toFixed(
+          MeasurementSystem.DecimalPlaces_[this.unitType_]);
+    },
+
+    /**
+     * @param {number} pts Value in points to convert to local units.
+     * @return {number} Value in local units.
+     */
+    convertFromPoints: function(pts) {
+      if (this.unitType_ == MeasurementSystem.UnitType.METRIC) {
+        return pts / MeasurementSystem.PTS_PER_MM_;
+      } else {
+        return pts / MeasurementSystem.PTS_PER_INCH_;
+      }
+    },
+
+    /**
+     * @param {number} Value in local units to convert to points.
+     * @return {number} Value in points.
+     */
+    convertToPoints: function(localUnits) {
+      if (this.unitType_ == MeasurementSystem.UnitType.METRIC) {
+        return localUnits * MeasurementSystem.PTS_PER_MM_;
+      } else {
+        return localUnits * MeasurementSystem.PTS_PER_INCH_;
+      }
+    }
+  };
+
+  // Export
+  return {
+    MeasurementSystem: MeasurementSystem
+  };
+});