Initial commit of 001code-html Scratch frontend project.

Includes scratch-gui, scratch-vm, scratch-blocks, scratch-render, scratch-l10n, and deployment config.

Co-authored-by: Cursor <cursoragent@cursor.com>

scratch-blocks/core/workspace_dragger.js

@@ -0,0 +1,132 @@
+/**
+ * @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 Methods for dragging a workspace visually.
+ * @author fenichel@google.com (Rachel Fenichel)
+ */
+'use strict';
+
+goog.provide('Blockly.WorkspaceDragger');
+
+goog.require('goog.math.Coordinate');
+goog.require('goog.asserts');
+
+
+/**
+ * Class for a workspace dragger.  It moves the workspace around when it is
+ * being dragged by a mouse or touch.
+ * Note that the workspace itself manages whether or not it has a drag surface
+ * and how to do translations based on that.  This simply passes the right
+ * commands based on events.
+ * @param {!Blockly.WorkspaceSvg} workspace The workspace to drag.
+ * @constructor
+ */
+Blockly.WorkspaceDragger = function(workspace) {
+  /**
+   * @type {!Blockly.WorkspaceSvg}
+   * @private
+   */
+  this.workspace_ = workspace;
+
+  /**
+   * The workspace's metrics object at the beginning of the drag.  Contains size
+   * and position metrics of a workspace.
+   * Coordinate system: pixel coordinates.
+   * @type {!Object}
+   * @private
+   */
+  this.startDragMetrics_ = workspace.getMetrics();
+
+  /**
+   * The scroll position of the workspace at the beginning of the drag.
+   * Coordinate system: pixel coordinates.
+   * @type {!goog.math.Coordinate}
+   * @private
+   */
+  this.startScrollXY_ = new goog.math.Coordinate(
+      workspace.scrollX, workspace.scrollY);
+};
+
+/**
+ * Sever all links from this object.
+ * @package
+ */
+Blockly.WorkspaceDragger.prototype.dispose = function() {
+  this.workspace_ = null;
+};
+
+/**
+ * Start dragging the workspace.
+ * @package
+ */
+Blockly.WorkspaceDragger.prototype.startDrag = function() {
+  if (Blockly.selected) {
+    Blockly.selected.unselect();
+  }
+  this.workspace_.setupDragSurface();
+};
+
+/**
+ * Finish dragging the workspace and put everything back where it belongs.
+ * @param {!goog.math.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at the start of the drag, in pixel coordinates.
+ * @package
+ */
+Blockly.WorkspaceDragger.prototype.endDrag = function(currentDragDeltaXY) {
+  // Make sure everything is up to date.
+  this.drag(currentDragDeltaXY);
+  this.workspace_.resetDragSurface();
+};
+
+/**
+ * Move the workspace based on the most recent mouse movements.
+ * @param {!goog.math.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at the start of the drag, in pixel coordinates.
+ * @package
+ */
+Blockly.WorkspaceDragger.prototype.drag = function(currentDragDeltaXY) {
+  var metrics = this.startDragMetrics_;
+  var newXY = goog.math.Coordinate.sum(this.startScrollXY_, currentDragDeltaXY);
+
+  // Bound the new XY based on workspace bounds.
+  var x = Math.min(newXY.x, -metrics.contentLeft);
+  var y = Math.min(newXY.y, -metrics.contentTop);
+  x = Math.max(x, metrics.viewWidth - metrics.contentLeft -
+               metrics.contentWidth);
+  y = Math.max(y, metrics.viewHeight - metrics.contentTop -
+               metrics.contentHeight);
+
+  x = -x - metrics.contentLeft;
+  y = -y - metrics.contentTop;
+
+  this.updateScroll_(x, y);
+};
+
+/**
+ * Move the scrollbars to drag the workspace.
+ * x and y are in pixels.
+ * @param {number} x The new x position to move the scrollbar to.
+ * @param {number} y The new y position to move the scrollbar to.
+ * @private
+ */
+Blockly.WorkspaceDragger.prototype.updateScroll_ = function(x, y) {
+  this.workspace_.scrollbar.set(x, y);
+};