Improve rendering speed.

core/block.js

@@ -512,6 +512,17 @@ Blockly.Block.prototype.setEditable = function(editable) {
   }
 };
 
+/**
+ * Set whether the connections are hidden (not tracked in a database) or not.
+ * @param {boolean} hidden True if connections are hidden.
+ */
+Blockly.Block.prototype.setConnectionsHidden = function(hidden) {
+  var myConnections = this.getConnections_(true);
+  for (var i = 0, connection; connection = myConnections[i]; i++) {
+    connection.setHidden(hidden);
+  }
+};
+
 /**
  * Set the URL of this block's help page.
  * @param {string|Function} url URL string for block help, or function that

core/connection.js

@@ -40,9 +40,10 @@ Blockly.Connection = function(source, type) {
   this.type = type;
   this.x_ = 0;
   this.y_ = 0;
-  this.inDB_ = false;
   // Shortcut for the databases for this connection's workspace.
-  this.dbList_ = this.sourceBlock_.workspace.connectionDBList;
+  this.dbList_ = source.workspace.connectionDBList;
+  this.hidden_ = !this.dbList_;
+  this.inDB_ = false;
 };
 
 /**
@@ -54,7 +55,6 @@ Blockly.Connection.prototype.dispose = function() {
   }
   if (this.inDB_) {
     this.dbList_[this.type].removeConnection_(this);
-    this.inDB_ = false;
   }
   if (Blockly.highlightedConnection_ == this) {
     Blockly.highlightedConnection_ = null;
@@ -322,7 +322,7 @@ Blockly.Connection.prototype.moveTo = function(x, y) {
   this.x_ = x;
   this.y_ = y;
   // Insert it into its new location in the database.
-  if (this.dbList_) {
+  if (!this.hidden_) {
     this.dbList_[this.type].addConnection_(this);
   }
 };
@@ -336,6 +336,19 @@ Blockly.Connection.prototype.moveBy = function(dx, dy) {
   this.moveTo(this.x_ + dx, this.y_ + dy);
 };
 
+/**
+ * Set whether this connections is hidden (not tracked in a database) or not.
+ * @param {boolean} hidden True if connection is hidden.
+ */
+Blockly.Connection.prototype.setHidden = function(hidden) {
+  this.hidden_ = hidden;
+  if (hidden && this.inDB_) {
+    this.dbList_[this.type].removeConnection_(this);
+  } else if (!hidden && !this.inDB_) {
+    this.dbList_[this.type].addConnection_(this);
+  }
+};
+
 /**
  * Add highlighting around this connection.
  */
@@ -653,7 +666,7 @@ Blockly.Connection.prototype.hideAll = function() {
  * @return {!Array.<!Blockly.Block>} List of blocks to render.
  */
 Blockly.Connection.prototype.unhideAll = function() {
-  if (!this.inDB_) {
+  if (!this.hidden_) {
     this.dbList_[this.type].addConnection_(this);
   }
   // All blocks that need unhiding must be unhidden before any rendering takes

core/xml.js

@@ -248,11 +248,15 @@ Blockly.Xml.domToBlock = function(workspace, xmlBlock, opt_reuseBlock) {
     var blocks = topBlock.getDescendants();
     // Render each block.
     for (var i = blocks.length - 1; i >= 0; i--) {
+      blocks[i].setConnectionsHidden(true);
       blocks[i].initSvg();
     }
     for (var i = blocks.length - 1; i >= 0; i--) {
       blocks[i].render(false);
     }
+    for (var i = blocks.length - 1; i >= 0; i--) {
+      blocks[i].setConnectionsHidden(false);
+    }
     topBlock.updateDisabled();
     // Fire an event to allow scrollbars to resize.
     Blockly.fireUiEvent(window, 'resize');

tests/playground.html

@@ -439,7 +439,7 @@ h1 {
   <p>
     Stress test:
     <input type="button" value="Airstrike!" onclick="airstrike(100)">
-    <input type="button" value="Spaghetti!" onclick="spaghetti(6)">
+    <input type="button" value="Spaghetti!" onclick="spaghetti(8)">
   </p>
 
   <!-- Realtime setup buttons. -->