scratch-blocks/core/field_label_serializable.js
2018-04-17 14:15:18 -07:00

125 lines
4.3 KiB
JavaScript

/**
* @license
* Visual Blocks Editor
*
* Copyright 2017 Google Inc.
* https://developers.google.com/blockly/
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @fileoverview Serialized label field. Behaves like a normal label but is
* always serialized to XML. It may only be edited programmatically.
* @author fenichel@google.com (Rachel Fenichel)
*/
'use strict';
goog.provide('Blockly.FieldLabelSerializable');
goog.require('Blockly.FieldLabel');
/**
* Class for a variable getter field.
* @param {string} text The initial content of the field.
* @param {string} opt_class Optional CSS class for the field's text.
* @extends {Blockly.FieldLabel}
* @constructor
*
*/
Blockly.FieldLabelSerializable = function(text, opt_class) {
Blockly.FieldLabelSerializable.superClass_.constructor.call(this, text,
opt_class);
// Used in base field rendering, but we don't need it.
this.arrowWidth_ = 0;
};
goog.inherits(Blockly.FieldLabelSerializable, Blockly.FieldLabel);
/**
* Construct a FieldLabelSerializable from a JSON arg object,
* dereferencing any string table references.
* @param {!Object} options A JSON object with options (text, and class).
* @returns {!Blockly.FieldLabelSerializable} The new field instance.
* @package
* @nocollapse
*/
Blockly.FieldLabelSerializable.fromJson = function(options) {
var text = Blockly.utils.replaceMessageReferences(options['text']);
return new Blockly.FieldLabelSerializable(text, options['class']);
};
/**
* Editable fields usually show some sort of UI for the user to change them.
* This field should be serialized, but only edited programmatically.
* @type {boolean}
* @public
*/
Blockly.FieldLabelSerializable.prototype.EDITABLE = false;
/**
* Serializable fields are saved by the XML renderer, non-serializable fields
* are not. This field should be serialized, but only edited programmatically.
* @type {boolean}
* @public
*/
Blockly.FieldLabelSerializable.prototype.SERIALIZABLE = true;
/**
* Updates the width of the field. This calls getCachedWidth which won't cache
* the approximated width on IE/Edge when `getComputedTextLength` fails. Once
* it eventually does succeed, the result will be cached.
**/
Blockly.FieldLabelSerializable.prototype.updateWidth = function() {
// Set width of the field.
// Unlike the base Field class, this doesn't add space to editable fields.
this.size_.width = Blockly.Field.getCachedWidth(this.textElement_);
};
/**
* Draws the border with the correct width.
* Saves the computed width in a property.
* @private
*/
Blockly.FieldLabelSerializable.prototype.render_ = function() {
if (this.visible_ && this.textElement_) {
// Replace the text.
goog.dom.removeChildren(/** @type {!Element} */ (this.textElement_));
var textNode = document.createTextNode(this.getDisplayText_());
this.textElement_.appendChild(textNode);
this.updateWidth();
// Update text centering, based on newly calculated width.
var centerTextX = this.size_.width / 2;
// If half the text length is not at least center of
// visible field (FIELD_WIDTH), center it there instead.
var minOffset = Blockly.BlockSvg.FIELD_WIDTH / 2;
if (this.sourceBlock_.RTL) {
// X position starts at the left edge of the block, in both RTL and LTR.
// First offset by the width of the block to move to the right edge,
// and then subtract to move to the same position as LTR.
var minCenter = this.size_.width - minOffset;
centerTextX = Math.min(minCenter, centerTextX);
} else {
// (width / 2) should exceed Blockly.BlockSvg.FIELD_WIDTH / 2
// if the text is longer.
centerTextX = Math.max(minOffset, centerTextX);
}
// Apply new text element x position.
this.textElement_.setAttribute('x', centerTextX);
}
};
Blockly.Field.register(
'field_label_serializable', Blockly.FieldLabelSerializable);