mirror of
https://github.com/scratchfoundation/scratch-blocks.git
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273 lines
9.7 KiB
JavaScript
273 lines
9.7 KiB
JavaScript
/**
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* @license
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* Visual Blocks Editor
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*
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* Copyright 2016 Google Inc.
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* https://developers.google.com/blockly/
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @fileoverview A class that manages a surface for dragging blocks. When a
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* block drag is started, we move the block (and children) to a separate dom
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* element that we move around using translate3d. At the end of the drag, the
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* blocks are put back in into the svg they came from. This helps performance by
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* avoiding repainting the entire svg on every mouse move while dragging blocks.
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* @author picklesrus
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*/
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'use strict';
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goog.provide('Blockly.BlockDragSurfaceSvg');
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goog.require('Blockly.utils');
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goog.require('goog.asserts');
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goog.require('goog.math.Coordinate');
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/**
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* Class for a drag surface for the currently dragged block. This is a separate
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* SVG that contains only the currently moving block, or nothing.
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* @param {!Element} container Containing element.
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* @constructor
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*/
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Blockly.BlockDragSurfaceSvg = function(container) {
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/**
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* @type {!Element}
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* @private
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*/
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this.container_ = container;
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this.createDom();
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};
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/**
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* The SVG drag surface. Set once by Blockly.BlockDragSurfaceSvg.createDom.
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* @type {Element}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.SVG_ = null;
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/**
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* This is where blocks live while they are being dragged if the drag surface
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* is enabled.
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* @type {Element}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.dragGroup_ = null;
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/**
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* Containing HTML element; parent of the workspace and the drag surface.
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* @type {Element}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.container_ = null;
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/**
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* Cached value for the scale of the drag surface.
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* Used to set/get the correct translation during and after a drag.
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* @type {number}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.scale_ = 1;
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/**
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* Cached value for the translation of the drag surface.
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* This translation is in pixel units, because the scale is applied to the
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* drag group rather than the top-level SVG.
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* @type {goog.math.Coordinate}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.surfaceXY_ = null;
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/**
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* ID for the drag shadow filter, set in createDom.
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* @type {string}
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.dragShadowFilterId_ = '';
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/**
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* Standard deviation for gaussian blur on drag shadow, in px.
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* @type {number}
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* @const
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*/
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Blockly.BlockDragSurfaceSvg.SHADOW_STD_DEVIATION = 6;
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/**
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* Create the drag surface and inject it into the container.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.createDom = function() {
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if (this.SVG_) {
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return; // Already created.
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}
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this.SVG_ = Blockly.utils.createSvgElement('svg', {
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'xmlns': Blockly.SVG_NS,
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'xmlns:html': Blockly.HTML_NS,
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'xmlns:xlink': 'http://www.w3.org/1999/xlink',
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'version': '1.1',
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'class': 'blocklyBlockDragSurface'
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}, this.container_);
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var defs = Blockly.utils.createSvgElement('defs', {}, this.SVG_);
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this.dragShadowFilterId_ = this.createDropShadowDom_(defs);
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this.dragGroup_ = Blockly.utils.createSvgElement('g', {}, this.SVG_);
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this.dragGroup_.setAttribute('filter', 'url(#' + this.dragShadowFilterId_ + ')');
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};
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/**
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* Scratch-specific: Create the SVG def for the drop shadow.
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* @param {Element} defs Defs element to insert the shadow filter definition
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* @return {string} ID for the filter element
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*/
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Blockly.BlockDragSurfaceSvg.prototype.createDropShadowDom_ = function(defs) {
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var rnd = String(Math.random()).substring(2);
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// Adjust these width/height, x/y properties to prevent the shadow from clipping
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var dragShadowFilter = Blockly.utils.createSvgElement('filter',
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{'id': 'blocklyDragShadowFilter' + rnd, 'height': '140%', 'width': '140%', y: '-20%', x: '-20%'}, defs);
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Blockly.utils.createSvgElement('feGaussianBlur',
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{'in': 'SourceAlpha', 'stdDeviation': Blockly.BlockDragSurfaceSvg.SHADOW_STD_DEVIATION}, dragShadowFilter);
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var componentTransfer = Blockly.utils.createSvgElement('feComponentTransfer',
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{'result': 'offsetBlur'}, dragShadowFilter);
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// Shadow opacity is specified in the adjustable colour library,
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// since the darkness of the shadow largely depends on the workspace colour.
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Blockly.utils.createSvgElement('feFuncA',
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{'type': 'linear', 'slope': Blockly.Colours.dragShadowOpacity}, componentTransfer);
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Blockly.utils.createSvgElement('feComposite',
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{'in': 'SourceGraphic', 'in2': 'offsetBlur', 'operator': 'over'}, dragShadowFilter);
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return dragShadowFilter.id;
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};
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/**
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* Set the SVG blocks on the drag surface's group and show the surface.
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* Only one block group should be on the drag surface at a time.
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* @param {!Element} blocks Block or group of blocks to place on the drag
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* surface.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.setBlocksAndShow = function(blocks) {
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goog.asserts.assert(this.dragGroup_.childNodes.length == 0,
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'Already dragging a block.');
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// appendChild removes the blocks from the previous parent
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this.dragGroup_.appendChild(blocks);
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this.SVG_.style.display = 'block';
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this.surfaceXY_ = new goog.math.Coordinate(0, 0);
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// This allows blocks to be dragged outside of the blockly svg space.
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// This should be reset to hidden at the end of the block drag.
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// Note that this behavior is different from blockly where block disappear
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// "under" the blockly area.
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var injectionDiv = document.getElementsByClassName('injectionDiv')[0];
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injectionDiv.style.overflow = 'visible';
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};
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/**
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* Translate and scale the entire drag surface group to the given position, to
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* keep in sync with the workspace.
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* @param {number} x X translation in workspace coordinates.
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* @param {number} y Y translation in workspace coordinates.
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* @param {number} scale Scale of the group.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.translateAndScaleGroup = function(x, y, scale) {
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this.scale_ = scale;
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// This is a work-around to prevent a the blocks from rendering
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// fuzzy while they are being dragged on the drag surface.
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x = x.toFixed(0);
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y = y.toFixed(0);
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this.dragGroup_.setAttribute('transform', 'translate('+ x + ','+ y + ')' +
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' scale(' + scale + ')');
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};
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/**
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* Translate the drag surface's SVG based on its internal state.
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* @private
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*/
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Blockly.BlockDragSurfaceSvg.prototype.translateSurfaceInternal_ = function() {
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var x = this.surfaceXY_.x;
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var y = this.surfaceXY_.y;
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// This is a work-around to prevent a the blocks from rendering
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// fuzzy while they are being dragged on the drag surface.
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x = x.toFixed(0);
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y = y.toFixed(0);
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this.SVG_.style.display = 'block';
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Blockly.utils.setCssTransform(this.SVG_,
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'translate3d(' + x + 'px, ' + y + 'px, 0px)');
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};
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/**
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* Translate the entire drag surface during a drag.
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* We translate the drag surface instead of the blocks inside the surface
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* so that the browser avoids repainting the SVG.
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* Because of this, the drag coordinates must be adjusted by scale.
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* @param {number} x X translation for the entire surface.
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* @param {number} y Y translation for the entire surface.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.translateSurface = function(x, y) {
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this.surfaceXY_ = new goog.math.Coordinate(x * this.scale_, y * this.scale_);
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this.translateSurfaceInternal_();
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};
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/**
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* Reports the surface translation in scaled workspace coordinates.
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* Use this when finishing a drag to return blocks to the correct position.
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* @return {!goog.math.Coordinate} Current translation of the surface.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.getSurfaceTranslation = function() {
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var xy = Blockly.utils.getRelativeXY(this.SVG_);
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return new goog.math.Coordinate(xy.x / this.scale_, xy.y / this.scale_);
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};
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/**
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* Provide a reference to the drag group (primarily for
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* BlockSvg.getRelativeToSurfaceXY).
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* @return {Element} Drag surface group element.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.getGroup = function() {
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return this.dragGroup_;
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};
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/**
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* Get the current blocks on the drag surface, if any (primarily
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* for BlockSvg.getRelativeToSurfaceXY).
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* @return {!Element|undefined} Drag surface block DOM element, or undefined
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* if no blocks exist.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.getCurrentBlock = function() {
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return this.dragGroup_.firstChild;
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};
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/**
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* Clear the group and hide the surface; move the blocks off onto the provided
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* element.
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* If the block is being deleted it doesn't need to go back to the original
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* surface, since it would be removed immediately during dispose.
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* @param {Element} opt_newSurface Surface the dragging blocks should be moved
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* to, or null if the blocks should be removed from this surface without
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* being moved to a different surface.
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*/
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Blockly.BlockDragSurfaceSvg.prototype.clearAndHide = function(opt_newSurface) {
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if (opt_newSurface) {
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// appendChild removes the node from this.dragGroup_
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opt_newSurface.appendChild(this.getCurrentBlock());
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} else {
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this.dragGroup_.removeChild(this.getCurrentBlock());
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}
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this.SVG_.style.display = 'none';
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goog.asserts.assert(this.dragGroup_.childNodes.length == 0,
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'Drag group was not cleared.');
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this.surfaceXY_ = null;
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// Reset the overflow property back to hidden so that nothing appears outside
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// of the blockly area.
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// Note that this behavior is different from blockly. See note in
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// setBlocksAndShow.
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var injectionDiv = document.getElementsByClassName('injectionDiv')[0];
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injectionDiv.style.overflow = 'hidden';
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};
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