Register block dragger (#4796)

core/interfaces/i_block_dragger.js

@@ -0,0 +1,58 @@
+/**
+ * @license
+ * Copyright 2021 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview The interface for a block dragger.
+ * @author aschmiedt@google.com (Abby Schmiedt)
+ */
+
+'use strict';
+
+goog.provide('Blockly.IBlockDragger');
+
+goog.requireType('Blockly.BlockSvg');
+goog.requireType('Blockly.utils.Coordinate');
+
+
+/**
+ * A block dragger interface.
+ * @interface
+ */
+Blockly.IBlockDragger = function() {};
+
+/**
+ * Start dragging a block.  This includes moving it to the drag surface.
+ * @param {!Blockly.utils.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at mouse down, in pixel units.
+ * @param {boolean} healStack Whether or not to heal the stack after
+ *     disconnecting.
+ */
+Blockly.IBlockDragger.prototype.startBlockDrag;
+
+/**
+ * Execute a step of block dragging, based on the given event.  Update the
+ * display accordingly.
+ * @param {!Event} e The most recent move event.
+ * @param {!Blockly.utils.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at the start of the drag, in pixel units.
+ */
+Blockly.IBlockDragger.prototype.dragBlock;
+
+/**
+ * Finish a block drag and put the block back on the workspace.
+ * @param {!Event} e The mouseup/touchend event.
+ * @param {!Blockly.utils.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at the start of the drag, in pixel units.
+ */
+Blockly.IBlockDragger.prototype.endBlockDrag;
+
+/**
+ * Get a list of the insertion markers that currently exist.  Drags have 0, 1,
+ * or 2 insertion markers.
+ * @return {!Array.<!Blockly.BlockSvg>} A possibly empty list of insertion
+ *     marker blocks.
+ */
+Blockly.IBlockDragger.prototype.getInsertionMarkers;