Add interpolation when using the pen tool quickly

js/drawingtools/BaseTool.js

@@ -55,4 +55,41 @@
 	ns.BaseTool.prototype.removeCanvasOverlays = function () {
 		$(".canvas-overlay").remove();
 	};
+
+	/**
+	 * Bresenham line algorihtm: Get an array of pixels from
+	 * start and end coordinates.
+	 *
+	 * http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
+	 * http://stackoverflow.com/questions/4672279/bresenham-algorithm-in-javascript
+	 *
+	 * @private
+	 */
+	ns.BaseTool.prototype.getLinePixels_ = function(x0, x1, y0, y1) {
+		
+		var pixels = [];
+		var dx = Math.abs(x1-x0);
+	   	var dy = Math.abs(y1-y0);
+	   	var sx = (x0 < x1) ? 1 : -1;
+	   	var sy = (y0 < y1) ? 1 : -1;
+	   	var err = dx-dy;
+
+	   	while(true){
+
+	    	// Do what you need to for this
+	    	pixels.push({"col": x0, "row": y0});
+
+		    if ((x0==x1) && (y0==y1)) break;
+		    var e2 = 2*err;
+		    if (e2>-dy){
+		    	err -= dy;
+		    	x0  += sx;
+		    }
+		    if (e2 < dx) {
+		    	err += dx;
+		    	y0  += sy;
+		    }
+	    }
+	    return pixels;
+     };
 })();

js/drawingtools/SimplePen.js

@@ -10,6 +10,9 @@
 		this.toolId = "tool-pen"
 	};
 
+	this.previousCol = null;
+	this.previousRow = null;
+
 	pskl.utils.inherit(ns.SimplePen, ns.BaseTool);
 	
 	/**
@@ -17,6 +20,9 @@
 	 */
 	ns.SimplePen.prototype.applyToolAt = function(col, row, frame, color, canvas, dpi) {
 		
+		this.previousCol = col;
+		this.previousRow = row;
+
 		// Change model:
 		var color = pskl.utils.normalizeColor(color);
 	    if (color != frame[col][row]) {
@@ -29,6 +35,21 @@
 	};
 
 	ns.SimplePen.prototype.moveToolAt = function(col, row, frame, color, canvas, dpi) {
-		this.applyToolAt(col, row, frame, color, canvas, dpi);
+		
+		if((Math.abs(col - this.previousCol) > 1) || (Math.abs(row - this.previousRow) > 1)) {
+			// The pen movement is too fast for the mousemove frequency, there is a gap between the
+			// current point and the previously drawn one.
+			// We fill the gap by calculating missing dots (simple linear interpolation) and draw them.
+			var interpolatedPixels = this.getLinePixels_(col, this.previousCol, row, this.previousRow);
+			for(var i=0, l=interpolatedPixels.length; i<l; i++) {
+				this.applyToolAt(interpolatedPixels[i].col, interpolatedPixels[i].row, frame, color, canvas, dpi);
+			}
+		}
+		else {
+			this.applyToolAt(col, row, frame, color, canvas, dpi);
+		}
+
+		this.previousCol = col;
+		this.previousRow = row;
 	};
 })();

js/drawingtools/Stroke.js

@@ -99,41 +99,4 @@
 		this.removeCanvasOverlays();
 	};
 
-	/**
-	 * Bresenham line algorihtm: Get an array of pixels from
-	 * start and end coordinates.
-	 *
-	 * http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
-	 * http://stackoverflow.com/questions/4672279/bresenham-algorithm-in-javascript
-	 *
-	 * @private
-	 */
-	ns.Stroke.prototype.getLinePixels_ = function(x0, x1, y0, y1) {
-		
-		var pixels = [];
-		var dx = Math.abs(x1-x0);
-	   	var dy = Math.abs(y1-y0);
-	   	var sx = (x0 < x1) ? 1 : -1;
-	   	var sy = (y0 < y1) ? 1 : -1;
-	   	var err = dx-dy;
-
-	   	while(true){
-
-	    	// Do what you need to for this
-	    	pixels.push({"col": x0, "row": y0});
-
-		    if ((x0==x1) && (y0==y1)) break;
-		    var e2 = 2*err;
-		    if (e2>-dy){
-		    	err -= dy;
-		    	x0  += sx;
-		    }
-		    if (e2 < dx) {
-		    	err += dx;
-		    	y0  += sy;
-		    }
-	    }
-	    return pixels;
-     };
-
 })();

js/piskel.js

@@ -11,18 +11,23 @@ $.namespace("pskl");
       DEFAULT_PEN_COLOR = '#000000',
       PISKEL_SERVICE_URL = 'http://2.piskel-app.appspot.com',
 
+      // Temporary zoom implementation to easily get bigger canvases to
+      // see how good perform critical algorithms on big canvas.
+      zoom = 1,
+
       // Configuration:
       // Canvas size in pixel size (not dpi related)
-      framePixelWidth = 32, 
-      framePixelHeight = 32,
+      framePixelWidth = 32 * zoom, 
+      framePixelHeight = 32 * zoom,
+
 
       // Scaling factors for a given frameSheet rendering:
       // Main drawing area:
-      drawingCanvasDpi = 20,
+      drawingCanvasDpi = Math.ceil(20/ zoom),
       // Canvas previous in the slideshow:
-      previewTileCanvasDpi = 4,
+      previewTileCanvasDpi = Math.ceil(4 / zoom),
       // Ainmated canvas preview:
-      previewAnimationCanvasDpi = 8,
+      previewAnimationCanvasDpi = Math.ceil(8 / zoom),
 
       // DOM references:
       drawingAreaContainer,
@@ -39,6 +44,7 @@ $.namespace("pskl");
       paletteColors = [],
       currentFrame = null;
       currentToolBehavior = null,
+      previousMousemoveTime = 0,
 
       //utility
       _normalizeColor = function (color) {
@@ -131,21 +137,22 @@ $.namespace("pskl");
     },
 
     removeMessage : function () {
-      var message = $("user-message");
-      if (message) {
-        message.parentNode.removeChild(message);  
+      var message = $("#user-message");
+      if (message.length) {
+        message.remove();
       }
     },
 
     persistToLocalStorageRequest: function() {
       // Persist to localStorage when drawing. We throttle localStorage accesses
       // for high frequency drawing (eg mousemove).
-      if(localStorageThrottler == null) {
-          localStorageThrottler = window.setTimeout(function() {
-            piskel.persistToLocalStorage();
-            localStorageThrottler = null;
-          }, 1000);
+      if(localStorageThrottler != null) {
+          window.clearTimeout(localStorageThrottler);
       }
+      localStorageThrottler = window.setTimeout(function() {
+        piskel.persistToLocalStorage();
+        localStorageThrottler = null;
+      }, 1000);
     },
 
     persistToLocalStorage: function() {
@@ -394,20 +401,25 @@ $.namespace("pskl");
     onCanvasMousemove : function (event) {
 
       //this.updateCursorInfo(event);
-      if (isClicked) {
-        var spriteCoordinate = this.getSpriteCoordinate(event);
-        currentToolBehavior.moveToolAt(
-            spriteCoordinate.col,
-            spriteCoordinate.row,
-            currentFrame,
-            penColor,
-            drawingAreaCanvas,
-            drawingCanvasDpi);
-        
-        // TODO(vincz): Find a way to move that to the model instead of being at the interaction level.
-        // Eg when drawing, it may make sense to have it here. However for a non drawing tool,
-        // you don't need to draw anything when mousemoving and you request useless localStorage.
-        piskel.persistToLocalStorageRequest();
+      var currentTime = new Date().getTime();
+      // Throttling of the mousemove event:
+      if ((currentTime - previousMousemoveTime) > 40 ) {
+        if (isClicked) {
+          var spriteCoordinate = this.getSpriteCoordinate(event);
+          currentToolBehavior.moveToolAt(
+              spriteCoordinate.col,
+              spriteCoordinate.row,
+              currentFrame,
+              penColor,
+              drawingAreaCanvas,
+              drawingCanvasDpi);
+          
+          // TODO(vincz): Find a way to move that to the model instead of being at the interaction level.
+          // Eg when drawing, it may make sense to have it here. However for a non drawing tool,
+          // you don't need to draw anything when mousemoving and you request useless localStorage.
+          piskel.persistToLocalStorageRequest();
+        }
+        previousMousemoveTime = currentTime;
       }
     },