blockly/core/renderers/common/renderer.js

/**
 * @license
 * Copyright 2019 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Base renderer.
 */
'use strict';

/**
 * Base renderer.
 * @class
 */
goog.module('Blockly.blockRendering.Renderer');

const Connection = goog.require('Blockly.Connection');
const ConstantProvider = goog.require('Blockly.blockRendering.ConstantProvider');
/* eslint-disable-next-line no-unused-vars */
const Debug = goog.requireType('Blockly.blockRendering.Debug');
const Drawer = goog.require('Blockly.blockRendering.Drawer');
const InsertionMarkerManager = goog.require('Blockly.InsertionMarkerManager');
/* eslint-disable-next-line no-unused-vars */
const IRegistrable = goog.require('Blockly.IRegistrable');
/* eslint-disable-next-line no-unused-vars */
const IPathObject = goog.requireType('Blockly.blockRendering.IPathObject');
const MarkerSvg = goog.require('Blockly.blockRendering.MarkerSvg');
const PathObject = goog.require('Blockly.blockRendering.PathObject');
/* eslint-disable-next-line no-unused-vars */
const RenderedConnection = goog.requireType('Blockly.RenderedConnection');
const RenderInfo = goog.require('Blockly.blockRendering.RenderInfo');
/* eslint-disable-next-line no-unused-vars */
const Theme = goog.requireType('Blockly.Theme');
/* eslint-disable-next-line no-unused-vars */
const WorkspaceSvg = goog.requireType('Blockly.WorkspaceSvg');
const debug = goog.require('Blockly.blockRendering.debug');
const object = goog.require('Blockly.utils.object');
/* eslint-disable-next-line no-unused-vars */
const {Block} = goog.requireType('Blockly.Block');
/* eslint-disable-next-line no-unused-vars */
const {BlockSvg} = goog.requireType('Blockly.BlockSvg');
const {ConnectionType} = goog.require('Blockly.ConnectionType');
/* eslint-disable-next-line no-unused-vars */
const {Marker} = goog.requireType('Blockly.Marker');


/**
 * The base class for a block renderer.
 * @param {string} name The renderer name.
 * @package
 * @constructor
 * @implements {IRegistrable}
 * @alias Blockly.blockRendering.Renderer
 */
const Renderer = function(name) {
  /**
   * The renderer name.
   * @type {string}
   * @package
   */
  this.name = name;

  /**
   * The renderer's constant provider.
   * @type {ConstantProvider}
   * @private
   */
  this.constants_ = null;

  /**
   * Rendering constant overrides, passed in through options.
   * @type {?Object}
   * @package
   */
  this.overrides = null;
};

/**
 * Gets the class name that identifies this renderer.
 * @return {string} The CSS class name.
 * @package
 */
Renderer.prototype.getClassName = function() {
  return this.name + '-renderer';
};

/**
 * Initialize the renderer.
 * @param {!Theme} theme The workspace theme object.
 * @param {Object=} opt_rendererOverrides Rendering constant overrides.
 * @package
 */
Renderer.prototype.init = function(theme, opt_rendererOverrides) {
  this.constants_ = this.makeConstants_();
  if (opt_rendererOverrides) {
    this.overrides = opt_rendererOverrides;
    object.mixin(this.constants_, opt_rendererOverrides);
  }
  this.constants_.setTheme(theme);
  this.constants_.init();
};

/**
 * Create any DOM elements that this renderer needs.
 * @param {!SVGElement} svg The root of the workspace's SVG.
 * @param {!Theme} theme The workspace theme object.
 * @package
 */
Renderer.prototype.createDom = function(svg, theme) {
  this.constants_.createDom(
      svg, this.name + '-' + theme.name,
      '.' + this.getClassName() + '.' + theme.getClassName());
};

/**
 * Refresh the renderer after a theme change.
 * @param {!SVGElement} svg The root of the workspace's SVG.
 * @param {!Theme} theme The workspace theme object.
 * @package
 */
Renderer.prototype.refreshDom = function(svg, theme) {
  const previousConstants = this.getConstants();
  previousConstants.dispose();
  this.constants_ = this.makeConstants_();
  if (this.overrides) {
    object.mixin(this.constants_, this.overrides);
  }
  // Ensure the constant provider's random identifier does not change.
  this.constants_.randomIdentifier = previousConstants.randomIdentifier;
  this.constants_.setTheme(theme);
  this.constants_.init();
  this.createDom(svg, theme);
};

/**
 * Dispose of this renderer.
 * Delete all DOM elements that this renderer and its constants created.
 * @package
 */
Renderer.prototype.dispose = function() {
  if (this.constants_) {
    this.constants_.dispose();
  }
};

/**
 * Create a new instance of the renderer's constant provider.
 * @return {!ConstantProvider} The constant provider.
 * @protected
 */
Renderer.prototype.makeConstants_ = function() {
  return new ConstantProvider();
};

/**
 * Create a new instance of the renderer's render info object.
 * @param {!BlockSvg} block The block to measure.
 * @return {!RenderInfo} The render info object.
 * @protected
 */
Renderer.prototype.makeRenderInfo_ = function(block) {
  return new RenderInfo(this, block);
};

/**
 * Create a new instance of the renderer's drawer.
 * @param {!BlockSvg} block The block to render.
 * @param {!RenderInfo} info An object containing all
 *   information needed to render this block.
 * @return {!Drawer} The drawer.
 * @protected
 */
Renderer.prototype.makeDrawer_ = function(block, info) {
  return new Drawer(block, info);
};

/**
 * Create a new instance of the renderer's debugger.
 * @return {!Debug} The renderer debugger.
 * @suppress {strictModuleDepCheck} Debug renderer only included in playground.
 * @protected
 */
Renderer.prototype.makeDebugger_ = function() {
  const Debug = goog.module.get('Blockly.blockRendering.Debug');
  if (!Debug) {
    throw Error('Missing require for Blockly.blockRendering.Debug');
  }
  return new Debug(this.getConstants());
};

/**
 * Create a new instance of the renderer's marker drawer.
 * @param {!WorkspaceSvg} workspace The workspace the marker belongs to.
 * @param {!Marker} marker The marker.
 * @return {!MarkerSvg} The object in charge of drawing
 *     the marker.
 * @package
 */
Renderer.prototype.makeMarkerDrawer = function(workspace, marker) {
  return new MarkerSvg(workspace, this.getConstants(), marker);
};

/**
 * Create a new instance of a renderer path object.
 * @param {!SVGElement} root The root SVG element.
 * @param {!Theme.BlockStyle} style The style object to use for
 *     colouring.
 * @return {!IPathObject} The renderer path object.
 * @package
 */
Renderer.prototype.makePathObject = function(root, style) {
  return new PathObject(
      root, style, /** @type {!ConstantProvider} */ (this.constants_));
};

/**
 * Get the current renderer's constant provider.  We assume that when this is
 * called, the renderer has already been initialized.
 * @return {!ConstantProvider} The constant provider.
 * @package
 */
Renderer.prototype.getConstants = function() {
  return /** @type {!ConstantProvider} */ (this.constants_);
};

/**
 * Determine whether or not to highlight a connection.
 * @param {Connection} _conn The connection to determine whether or not
 *     to highlight.
 * @return {boolean} True if we should highlight the connection.
 * @package
 */
Renderer.prototype.shouldHighlightConnection = function(_conn) {
  return true;
};

/**
 * Checks if an orphaned block can connect to the "end" of the topBlock's
 * block-clump. If the clump is a row the end is the last input. If the clump
 * is a stack, the end is the last next connection. If the clump is neither,
 * then this returns false.
 * @param {!BlockSvg} topBlock The top block of the block clump we want to try
 *     and connect to.
 * @param {!BlockSvg} orphanBlock The orphan block that wants to find
 *     a home.
 * @param {number} localType The type of the connection being dragged.
 * @return {boolean} Whether there is a home for the orphan or not.
 * @package
 */
Renderer.prototype.orphanCanConnectAtEnd = function(
    topBlock, orphanBlock, localType) {
  const orphanConnection =
      (localType === ConnectionType.OUTPUT_VALUE ?
           orphanBlock.outputConnection :
           orphanBlock.previousConnection);
  return !!Connection.getConnectionForOrphanedConnection(
      /** @type {!Block} **/ (topBlock),
      /** @type {!Connection} **/ (orphanConnection));
};

/**
 * Chooses a connection preview method based on the available connection, the
 * current dragged connection, and the block being dragged.
 * @param {!RenderedConnection} closest The available connection.
 * @param {!RenderedConnection} local The connection currently being
 *     dragged.
 * @param {!BlockSvg} topBlock The block currently being dragged.
 * @return {!InsertionMarkerManager.PREVIEW_TYPE} The preview type
 *     to display.
 * @package
 */
Renderer.prototype.getConnectionPreviewMethod = function(
    closest, local, topBlock) {
  if (local.type === ConnectionType.OUTPUT_VALUE ||
      local.type === ConnectionType.PREVIOUS_STATEMENT) {
    if (!closest.isConnected() ||
        this.orphanCanConnectAtEnd(
            topBlock,
            /** @type {!BlockSvg} */ (closest.targetBlock()), local.type)) {
      return InsertionMarkerManager.PREVIEW_TYPE.INSERTION_MARKER;
    }
    return InsertionMarkerManager.PREVIEW_TYPE.REPLACEMENT_FADE;
  }

  return InsertionMarkerManager.PREVIEW_TYPE.INSERTION_MARKER;
};

/**
 * Render the block.
 * @param {!BlockSvg} block The block to render.
 * @package
 */
Renderer.prototype.render = function(block) {
  if (debug.isDebuggerEnabled() && !block.renderingDebugger) {
    block.renderingDebugger = this.makeDebugger_();
  }
  const info = this.makeRenderInfo_(block);
  info.measure();
  this.makeDrawer_(block, info).draw();
};

exports = Renderer;