Reconnect blocks after a ghost disappears.

core/block.js

@@ -637,6 +637,28 @@ Blockly.Block.prototype.setConnectionsHidden = function(hidden) {
   }
 };
 
+/**
+ * Find the connection on this block that corresponds to the given connection
+ * on the other block.
+ * Used to match connections between a block and its ghost.
+ * @param {!Blockly.Block} otherBlock The other block to match against.
+ * @param {!Blockly.Connection} conn The other connection to match.
+ * @return {Blockly.Connection} the matching connection on this block, or null.
+ */
+Blockly.Block.prototype.getMatchingConnection = function(otherBlock, conn) {
+  var connections = this.getConnections_(true);
+  var otherConnections = otherBlock.getConnections_(true);
+  if (connections.length != otherConnections.length) {
+    throw "Connection lists did not match in length.";
+  }
+  for (var i = 0; i < otherConnections.length; i++) {
+    if (otherConnections[i] == conn) {
+      return connections[i];
+    }
+  }
+  return null;
+};
+
 /**
  * Set the URL of this block's help page.
  * @param {string|Function} url URL string for block help, or function that
@@ -708,12 +730,14 @@ Blockly.Block.prototype.setColour = function(colour, colourSecondary, colourTert
   if (colourSecondary !== undefined) {
     this.colourSecondary_ = this.makeColour_(colourSecondary);
   } else {
-    this.colourSecondary_ = goog.color.darken(colour, 0.1);
+    this.colourSecondary_ = goog.color.darken(goog.color.hexToRgb(this.colour_),
+        0.1);
   }
   if (colourTertiary !== undefined) {
     this.colourTertiary_ = this.makeColour_(colourTertiary);
   } else {
-    this.colourTertiary_ = goog.color.darken(colour, 0.2);
+    this.colourTertiary_ = goog.color.darken(goog.color.hexToRgb(this.colour_),
+        0.2);
   }
   if (this.rendered) {
     this.updateColour();

core/block_render_svg_horizontal.js

@@ -358,7 +358,6 @@ Blockly.BlockSvg.prototype.renderDraw_ = function(metrics) {
   // Fetch the block's coordinates on the surface for use in anchoring
   // the connections.
   var connectionsXY = this.getRelativeToSurfaceXY();
-
   // Assemble the block's path.
   var steps = [];
 
@@ -377,7 +376,7 @@ Blockly.BlockSvg.prototype.renderDraw_ = function(metrics) {
   }
 
   // Position icon
-  if (!this.isGhost() && metrics.icon) {
+  if (metrics.icon) {
     var icon = metrics.icon.getSvgRoot();
     var iconSize = metrics.icon.getSize();
     // Icon's position is calculated relative to the "end" edge of the block.
@@ -394,6 +393,9 @@ Blockly.BlockSvg.prototype.renderDraw_ = function(metrics) {
         iconX = -metrics.width + Blockly.BlockSvg.SEP_SPACE_X / 1.5;
       }
     }
+    if (this.isGhost()) {
+      icon.setAttribute('display', 'none');
+    }
     icon.setAttribute('transform',
       'translate(' + iconX + ',' + iconY + ') ' + iconScale);
   }

core/block_svg.js

@@ -219,7 +219,9 @@ Blockly.BlockSvg.terminateDrag_ = function() {
     if (selected) {
       if (selected.ghostBlock_) {
         Blockly.Events.disable();
-        selected.ghostBlock_.unplug(true /* healStack */);
+        if (Blockly.localGhostConnection_) {
+          selected.disconnectGhost();
+        }
         selected.ghostBlock_.dispose();
         selected.ghostBlock_ = null;
         Blockly.Events.enable();
@@ -594,7 +596,6 @@ Blockly.BlockSvg.prototype.onMouseUp_ = function(e) {
     Blockly.fireUiEvent(window, 'resize');
   }
   if (Blockly.highlightedConnection_) {
-    Blockly.highlightedConnection_.unhighlight();
     Blockly.highlightedConnection_ = null;
   }
   Blockly.Css.setCursor(Blockly.Css.Cursor.OPEN);
@@ -814,50 +815,128 @@ Blockly.BlockSvg.prototype.onMouseMove_ = function(e) {
       }
     }
 
-    // Remove connection highlighting if needed.
-    if (Blockly.highlightedConnection_ &&
-        Blockly.highlightedConnection_ != closestConnection) {
-      if (this.ghostBlock_) {
-        // Don't fire events for ghost block creation or movement.
-        Blockly.Events.disable();
-        this.ghostBlock_.unplug(true /* healStack */);
-        this.ghostBlock_.dispose();
-        this.ghostBlock_ = null;
-        Blockly.Events.enable();
-      }
-      Blockly.highlightedConnection_.unhighlight();
-      Blockly.highlightedConnection_ = null;
-      Blockly.localConnection_ = null;
+    this.updatePreviews(closestConnection, localConnection, radiusConnection,
+        e, newXY.x - this.dragStartXY_.x, newXY.y - this.dragStartXY_.y);
+  }
+  // This event has been handled.  No need to bubble up to the document.
+  e.stopPropagation();
+};
+
+/**
+ * Preview the results of the drag if the mouse is released immediately.
+ * @param {Blockly.Connection} closestConnection The closest connection found
+ *    during the search
+ * @param {Blockly.Connection} localConnection The connection on the moving
+ *    block.
+ * @param {number} radiusConnection The distance between closestConnection and
+ *    localConnection.
+ * @param {!Event} e Mouse move event.
+ * @param {number} dx The x distance the block has moved onscreen up to this
+ *    point in the drag.
+ * @param {number} dy The y distance the block has moved onscreen up to this
+ *    point in the drag.
+ */
+Blockly.BlockSvg.prototype.updatePreviews = function(closestConnection,
+    localConnection, radiusConnection, e, dx, dy) {
+  // Don't fire events for ghost block creation or movement.
+  Blockly.Events.disable();
+  // Remove a ghost if needed.  For Scratch-Blockly we are using ghosts instead
+  // of highlighting the connection; for compatibility with Web Blockly the
+  // name "highlightedConnection" will still be used.
+  if (Blockly.highlightedConnection_ &&
+      Blockly.highlightedConnection_ != closestConnection) {
+    if (this.ghostBlock_ && Blockly.localGhostConnection_) {
+      this.disconnectGhost();
     }
-    // Add connection highlighting if needed.
-    if (closestConnection &&
-        closestConnection != Blockly.highlightedConnection_) {
-      closestConnection.highlight();
-      Blockly.highlightedConnection_ = closestConnection;
-      Blockly.localConnection_ = localConnection;
-      Blockly.Events.disable();
-      if (!this.ghostBlock_){
-        this.ghostBlock_ = this.workspace.newBlock(this.type);
-        this.ghostBlock_.setGhost(true);
-        this.ghostBlock_.moveConnections_(radiusConnection);
+    Blockly.highlightedConnection_ = null;
+    Blockly.localConnection_ = null;
+  }
+
+  // Add a ghost if needed.
+  if (closestConnection &&
+      closestConnection != Blockly.highlightedConnection_ &&
+      !closestConnection.sourceBlock_.isGhost()) {
+    Blockly.highlightedConnection_ = closestConnection;
+    Blockly.localConnection_ = localConnection;
+    if (!this.ghostBlock_){
+      this.ghostBlock_ = this.workspace.newBlock(this.type);
+      this.ghostBlock_.setGhost(true);
+      this.ghostBlock_.initSvg();
+    }
+
+    var ghostBlock = this.ghostBlock_;
+    var localGhostConnection = ghostBlock.getMatchingConnection(this,
+        localConnection);
+    if (localGhostConnection != Blockly.localGhostConnection_) {
+      ghostBlock.getSvgRoot().setAttribute('visibility', 'visible');
+      ghostBlock.rendered = true;
+      // Move the preview to the correct location before the existing block.
+      if (localGhostConnection.type == Blockly.NEXT_STATEMENT) {
+        var relativeXy = this.getRelativeToSurfaceXY();
+        var connectionOffsetX = (localConnection.x_ - (relativeXy.x - dx));
+        var connectionOffsetY = (localConnection.y_ - (relativeXy.y - dy));
+        var newX = closestConnection.x_ - connectionOffsetX;
+        var newY = closestConnection.y_ - connectionOffsetY;
+        var ghostPosition = ghostBlock.getRelativeToSurfaceXY();
+        ghostBlock.moveBy(newX - ghostPosition.x, newY - ghostPosition.y, true);
+
       }
-      if (Blockly.localConnection_ == this.previousConnection) {
-        // Setting the block to rendered will actually change the connection
-        // behaviour :/
-        this.ghostBlock_.rendered = true;
-        this.ghostBlock_.previousConnection.connect(closestConnection);
+      if (localGhostConnection.type == Blockly.PREVIOUS_STATEMENT &&
+          !ghostBlock.nextConnection) {
+        Blockly.bumpedConnection_ = closestConnection.targetConnection;
       }
-      this.ghostBlock_.render(true);
-      Blockly.Events.enable();
+      // Renders ghost.
+      localGhostConnection.connect(closestConnection);
+      // Render dragging block so it appears on top.
+      this.workspace.getCanvas().appendChild(this.getSvgRoot());
+      Blockly.localGhostConnection_ = localGhostConnection;
     }
-    // Provide visual indication of whether the block will be deleted if
-    // dropped here.
-    if (this.isDeletable()) {
-      this.workspace.isDeleteArea(e);
+  }
+  // Reenable events.
+  Blockly.Events.enable();
+
+  // Provide visual indication of whether the block will be deleted if
+  // dropped here.
+  if (this.isDeletable()) {
+    this.workspace.isDeleteArea(e);
+  }
+};
+
+/**
+ * Disconnect the current ghost block from the stack, and heal the stack to its
+ * previous state.
+ */
+Blockly.BlockSvg.prototype.disconnectGhost = function() {
+  // The ghost block is the first block in a stack, either because it doesn't
+  // have a previous connection or because the previous connection is not
+  // connection.  Unplug won't do anything in that case.  Instead, unplug the
+  // following block.
+  if (Blockly.localGhostConnection_ == this.ghostBlock_.nextConnection &&
+      (!this.ghostBlock_.previousConnection ||
+      !this.ghostBlock_.previousConnection.targetConnection)) {
+    Blockly.localGhostConnection_.targetBlock().unplug(false);
+  }
+  // Inside of a C-block, first statement connection.
+  else if (Blockly.localGhostConnection_.type == Blockly.NEXT_STATEMENT &&
+      Blockly.localGhostConnection_ != this.ghostBlock_.nextConnection) {
+    var innerConnection = Blockly.localGhostConnection_.targetConnection;
+    innerConnection.sourceBlock_.unplug(false);
+    var previousBlockNextConnection =
+      this.ghostBlock_.previousConnection.targetConnection;
+    this.ghostBlock_.unplug(true);
+    if (previousBlockNextConnection) {
+      previousBlockNextConnection.connect(innerConnection);
     }
   }
-  // This event has been handled.  No need to bubble up to the document.
-  e.stopPropagation();
+  else {
+    this.ghostBlock_.unplug(true /* healStack */);
+  }
+
+  if (Blockly.localGhostConnection_.targetConnection) {
+    throw 'LocalGhostConnection still connected at the end of disconnectGhost';
+  }
+  Blockly.localGhostConnection_ = null;
+  this.ghostBlock_.getSvgRoot().setAttribute('visibility', 'hidden');
 };
 
 /**

core/blockly.js

@@ -191,6 +191,22 @@ Blockly.highlightedConnection_ = null;
  */
 Blockly.localConnection_ = null;
 
+/**
+ * Connection on ghost block that matches Blockly.localConnecxtion_ on the
+ * dragged block.
+ * @type {Blockly.Connection}
+ * @private
+ */
+Blockly.localGhostConnection_ = null;
+
+/**
+ * Connection that was bumped out of the way by a ghost block, and may need
+ * to be put back as the drag continues.
+ * @type {Blockly.Connection}
+ * @private
+ */
+Blockly.bumpedConnection_ = null;
+
 /**
  * Number of pixels the mouse must move before a drag starts.
  */
@@ -199,7 +215,7 @@ Blockly.DRAG_RADIUS = 5;
 /**
  * Maximum misalignment between connections for them to snap together.
  */
-Blockly.SNAP_RADIUS = 20;
+Blockly.SNAP_RADIUS = 50;
 
 /**
  * Delay in ms between trigger and bumping unconnected block out of alignment.

core/connection.js

@@ -295,6 +295,14 @@ Blockly.Connection.prototype.dispose = function() {
   this.dbOpposite_ = null;
 };
 
+/**
+ * @return true if the connection is not connected or is connected to a ghost
+ *    block, false otherwise.
+ */
+Blockly.Connection.prototype.isConnectedToNonGhost = function() {
+  return this.targetConnection && !this.targetBlock().isGhost();
+};
+
 /**
  * Does the connection belong to a superior block (higher in the source stack)?
  * @return {boolean} True if connection faces down or right.
@@ -404,6 +412,21 @@ Blockly.Connection.prototype.isConnectionAllowed = function(candidate,
       this.sourceBlock_.getFirstStatementConnection();
 
   if (candidate.type == Blockly.PREVIOUS_STATEMENT) {
+    if (!firstStatementConnection || this != firstStatementConnection) {
+      if (this.targetConnection) {
+        return false;
+      }
+      if (candidate.targetConnection) {
+        // If the other side of this connection is the active ghost connection,
+        // we've obviously already decided that this is a good connection.
+        if (candidate.targetConnection == Blockly.localGhostConnection_) {
+          return true;
+        } else {
+          return false;
+        }
+      }
+    }
+
     // Scratch-specific behaviour:
     // If this is a c-shaped block, statement blocks cannot be connected
     // anywhere other than inside the first statement input.
@@ -416,32 +439,15 @@ Blockly.Connection.prototype.isConnectionAllowed = function(candidate,
         }
       }
       // The only other eligible connection of this type is the next connection
-      // when the candidate is not already connection (connecting at the start
+      // when the candidate is not already connected (connecting at the start
       // of the stack).
       else if (this == this.sourceBlock_.nextConnection &&
-          candidate.targetConnection) {
-        return false;
-      }
-    } else {
-      // Otherwise, don't offer to connect the bottom of a statement block to
-      // the top of a block that's already connected.  And don't connect the
-      // bottom of a statement block that's already connected.
-      if (this.targetConnection || candidate.targetConnection) {
+          candidate.isConnectedToNonGhost()) {
         return false;
       }
     }
   }
 
-  // Don't offer to connect the bottom of a statement block to one that's
-  // already connected.
-  // But the first statement input on c-block can connect to the start of a
-  // block in a stack.
-  if (candidate.type == Blockly.PREVIOUS_STATEMENT &&
-      this != this.sourceBlock_.getFirstStatementConnection() &&
-      (this.targetConnection || candidate.targetConnection)) {
-        return false;
-  }
-
   // Offering to connect the left (male) of a value block to an already
   // connected value pair is ok, we'll splice it in.
   // However, don't offer to splice into an unmovable block.
@@ -455,8 +461,7 @@ Blockly.Connection.prototype.isConnectionAllowed = function(candidate,
   // Don't let a block with no next connection bump other blocks out of the
   // stack.
   if (this.type == Blockly.PREVIOUS_STATEMENT &&
-      candidate.targetConnection &&
-      !this.sourceBlock_.nextConnection) {
+      candidate.isConnectedToNonGhost() && !this.sourceBlock_.nextConnection) {
     return false;
   }
 

tests/jsunit/connection_db_test.js

@@ -271,7 +271,8 @@ function helper_makeSourceBlock(sharedWorkspace) {
     movable_: true,
     isMovable: function() { return true; },
     isShadow: function() { return false; },
-    isGhost: function() { return false; }
+    isGhost: function() { return false; },
+    getFirstStatementConnection: function() { return null; }
   };
 }