Merge pull request #2 from npalomba/master

Added eraser tool

.gitignore

@@ -2,3 +2,4 @@ _ext
 routes
 build
 node_modules
+.idea

README.md

@@ -21,9 +21,9 @@ Suggestions / Planned features:
 
 - Selections 
     - New selection tool 
-    - New canvas layer above the drawing layer 
+    - New currentLayer.canvas layer above the drawing layer 
     - Move when click and drag 
-    - Merge with canvas when click outside 
+    - Merge with currentLayer.canvas when click outside 
 
 - Copy/paste 
     - Add as selection 
@@ -35,7 +35,7 @@ Suggestions / Planned features:
 
 - Palette option remove unused colors 
 - Pixel Grid 
-    - Another canvas 
+    - Another currentLayer.canvas 
     - Must be rescaled each zoom 
 
 - Possibly add collaborate function using together.js 

css/pixel-editor.scss

@@ -35,7 +35,7 @@ svg {
   outline: 0 !important;
 }
 
-#pixel-canvas {
+.drawingCanvas {
   cursor: url('/pixel-art-where-to-start/pencil-tool-cursor.png');
 
   border: solid 1px #fff;
@@ -49,11 +49,20 @@ svg {
   -ms-interpolation-mode:nearest-neighbor;   /* IE8+           */
   width: 400px;
   height: 400px;
-  display: none;
   position: fixed;
+  display:none;
   box-shadow: 0px 0px 10px 0px rgba(0, 0, 0, 0.64);
 }
 
+#checkerboard {
+  z-index:1;
+}
+
+#pixel-canvas {
+  z-index:2;
+  background:transparent;
+}
+
 #eyedropper-preview {
   position: absolute;
   width: 45px;
@@ -83,7 +92,6 @@ svg {
 }
 
 #canvas-view {
-  background: color(indent-dark);
   bottom: 0px;
   left: 64px;
   right: 48px;
@@ -414,19 +422,23 @@ svg {
 }
 
 #tools-menu li button#pencil-bigger-button,
-#tools-menu li button#zoom-in-button {
+#tools-menu li button#zoom-in-button,
+#tools-menu li button#eraser-bigger-button{
   left: 0;
 }
 
 #tools-menu li button#pencil-smaller-button,
-#tools-menu li button#zoom-out-button {
+#tools-menu li button#zoom-out-button,
+#tools-menu li button#eraser-smaller-button{
   right: 0;
 }
 
 #tools-menu li.selected button#pencil-bigger-button,
 #tools-menu li.selected button#pencil-smaller-button,
 #tools-menu li.selected button#zoom-in-button,
-#tools-menu li.selected button#zoom-out-button {
+#tools-menu li.selected button#zoom-out-button,
+#tools-menu li.selected button#eraser-bigger-button,
+#tools-menu li.selected button#eraser-smaller-button{
   display: block;
 }
 

js/_addColorButton.js

@@ -52,6 +52,7 @@ on('click', 'add-color-button', function(){
   
   //show color picker
   addedColor.firstElementChild.jscolor.show();
+  console.log("showing picker");
   
   //hide edit button
   addedColor.lastChild.classList.add('hidden');

js/_canvas.js

@@ -0,0 +1,48 @@
+/** Handler class for a single canvas (a single layer)
+ *
+ * @param width Canvas width
+ * @param height Canvas height
+ * @param canvas HTML canvas element
+ */
+function Canvas(width, height, canvas) {
+    this.canvasSize = [width, height],
+    this.canvas = canvas,
+    this.context = this.canvas.getContext("2d"),
+    // Initializes the canvas
+    this.initialize = function() {
+        var maxHorizontalZoom = Math.floor(window.innerWidth/this.canvasSize[0]*0.75);
+        var maxVerticalZoom = Math.floor(window.innerHeight/this.canvasSize[1]*0.75);
+
+        zoom = Math.min(maxHorizontalZoom,maxVerticalZoom);
+        if (zoom < 1) zoom = 1;
+
+        //resize canvas
+        this.canvas.width = this.canvasSize[0];
+        this.canvas.height = this.canvasSize[1];
+        this.canvas.style.width = (this.canvas.width*zoom)+'px';
+        this.canvas.style.height = (this.canvas.height*zoom)+'px';
+
+        //unhide canvas
+        this.canvas.style.display = 'block';
+
+        //center canvas in window
+        this.canvas.style.left = 64+canvasView.clientWidth/2-(this.canvasSize[0]*zoom/2)+'px';
+        this.canvas.style.top = 48+canvasView.clientHeight/2-(this.canvasSize[1]*zoom/2)+'px';
+    },
+    // Resizes canvas
+    this.resize = function() {
+        let newWidth = (this.canvas.width * zoom) + 'px';
+        let newHeight = (this.canvas.height *zoom)+ 'px';
+
+        this.canvas.style.width = newWidth;
+        this.canvas.style.height = newHeight;
+    },
+    // Copies the otherCanvas' position and size
+    this.copyData = function(otherCanvas) {
+        this.canvas.style.width = otherCanvas.canvas.style.width;
+        this.canvas.style.height = otherCanvas.canvas.style.height;
+
+        this.canvas.style.left = otherCanvas.canvas.style.left;
+        this.canvas.style.top = otherCanvas.canvas.style.top;
+    }
+}

js/_changeZoom.js

@@ -1,6 +1,5 @@
 
-function changeZoom (direction, cursorLocation) {
+function changeZoom (layer, direction, cursorLocation) {
-
 	var oldWidth = canvasSize[0] * zoom;
 	var oldHeight = canvasSize[1] * zoom;
 	var newWidth, newHeight;
@@ -13,7 +12,7 @@ function changeZoom (direction, cursorLocation) {
 		newHeight = canvasSize[1] * zoom;
 		
 		//adjust canvas position
-		setCanvasOffset(canvas.offsetLeft + (oldWidth - newWidth) *cursorLocation[0]/oldWidth, canvas.offsetTop + (oldHeight - newHeight) *cursorLocation[1]/oldWidth)
+		setCanvasOffset(layer.canvas, layer.canvas.offsetLeft + (oldWidth - newWidth) *cursorLocation[0]/oldWidth, layer.canvas.offsetTop + (oldHeight - newHeight) *cursorLocation[1]/oldWidth)
 	}
 	//if you want to zoom in
 	else if (direction == 'in' && zoom + Math.ceil(zoom/10) < window.innerHeight/4){
@@ -22,12 +21,11 @@ function changeZoom (direction, cursorLocation) {
 		newHeight = canvasSize[1] * zoom;
 		
 		//adjust canvas position
-		setCanvasOffset(canvas.offsetLeft - Math.round((newWidth - oldWidth)*cursorLocation[0]/oldWidth), canvas.offsetTop - Math.round((newHeight - oldHeight)*cursorLocation[1]/oldHeight))
+		setCanvasOffset(layer.canvas, layer.canvas.offsetLeft - Math.round((newWidth - oldWidth)*cursorLocation[0]/oldWidth), layer.canvas.offsetTop - Math.round((newHeight - oldHeight)*cursorLocation[1]/oldHeight))
 	}
 	
 	//resize canvas
-	canvas.style.width = (canvas.width*zoom)+'px';
+	layer.resize();
-	canvas.style.height = (canvas.height*zoom)+'px';
 
 	// adjust brush size
 	updateCursor();

js/_checkerboard.js

@@ -0,0 +1,59 @@
+// This script contains all the functions used to manage the checkboard
+
+// Setting current colour (each square has a different colour
+var currentColor = firstCheckerBoardColor;
+// Saving number of squares filled until now
+var nSquaresFilled = 0;
+
+function fillCheckerboard() {
+    // Getting checkerboard context
+    var context = checkerBoard.context;
+
+    // Cycling through the canvas (using it as a matrix)
+    for (var i=0; i<canvasSize[0] / checkerBoardSquareSize; i++) {
+        nSquaresFilled = 0;
+
+        for (var j=0; j<canvasSize[1] / checkerBoardSquareSize; j++) {
+            var rectX;
+            var rectY;
+
+            // Managing the not perfect squares (the ones at the sides if the canvas' sizes are not powers of checkerBoardSquareSize
+            if (i * checkerBoardSquareSize < canvasSize[0]) {
+                rectX = i * checkerBoardSquareSize;
+            }
+            else {
+                rectX = canvasSize[0];
+            }
+
+            if (j * checkerBoardSquareSize < canvasSize[1]) {
+                rectY = j * checkerBoardSquareSize;
+            }
+            else {
+                rectY = canvasSize[1];
+            }
+
+            // Selecting the colour
+            context.fillStyle = currentColor;
+            context.fillRect(rectX, rectY, checkerBoardSquareSize, checkerBoardSquareSize);
+
+            // Changing colour
+            changeCheckerboardColor();
+
+            nSquaresFilled++;
+        }
+
+        // If the number of filled squares was even, I change colour for the next column
+        if ((nSquaresFilled % 2) == 0) {
+            changeCheckerboardColor();
+        }
+    }
+}
+
+// Simply switches the checkerboard colour
+function changeCheckerboardColor(isVertical) {
+    if (currentColor == firstCheckerBoardColor) {
+        currentColor = secondCheckerBoardColor;
+    } else if (currentColor == secondCheckerBoardColor) {
+        currentColor = firstCheckerBoardColor;
+    }
+}

js/_clickedColor.js

@@ -9,7 +9,7 @@ function clickedColor (e){
       if (selectedColor) selectedColor.classList.remove("selected");
 
     	//set current color
-    	context.fillStyle = this.style.backgroundColor;
+    	currentLayer.context.fillStyle = this.style.backgroundColor;
     	
     	//make color selected
     	e.target.parentElement.classList.add('selected');

js/_colorChanged.js

@@ -24,9 +24,6 @@ on('input', 'jscolor-hex-input', function (e) {
 //changes all of one color to another after being changed from color picker
 function colorChanged(e) {
   console.log('colorChanged()');
-  
-
-  
 	//get colors
 	var newColor = hexToRgb(e.target.value);
 	var oldColor = e.target.oldColor;

js/_createColorPalette.js

@@ -36,10 +36,10 @@ function createColorPalette(selectedPalette, fillBackground) {
 	
 	//fill bg with lightest color
 	if (fillBackground) {
-		context.fillStyle = lightestColor;
+		currentLayer.context.fillStyle = lightestColor;
-		context.fillRect(0, 0, canvasSize[0], canvasSize[1]);
+		currentLayer.context.fillRect(0, 0, canvasSize[0], canvasSize[1]);
 	}
 	
 	//set as current color
-	context.fillStyle = darkestColor;
+	currentLayer.context.fillStyle = darkestColor;
 }

js/_deleteColor.js

@@ -73,7 +73,7 @@ function deleteColor (color) {
     
     //set current color TO LIGHTEST COLOR
     lightestColor[1].parentElement.classList.add('selected');
-    context.fillStyle = '#'+lightestColor[1].jscolor.toString();
+    currentLayer.context.fillStyle = '#'+lightestColor[1].jscolor.toString();
   }
   
   //delete the element

js/_drawLine.js

@@ -6,11 +6,17 @@ function line(x0,y0,x1,y1) {
 	var sx = (x0 < x1 ? 1 : -1);
 	var sy = (y0 < y1 ? 1 : -1);
 	var err = dx-dy;
-	var breaker = 0;
 
 	while (true) {
 	    //set pixel
-		context.fillRect(x0-Math.floor(brushSize/2), y0-Math.floor(brushSize/2), brushSize, brushSize);
+		// If the current tool is the brush
+		if (currentTool == 'pencil') {
+			// I fill the rect
+			currentLayer.context.fillRect(x0-Math.floor(brushSize/2), y0-Math.floor(brushSize/2), brushSize, brushSize);
+		} else if (currentTool == 'eraser') {
+			// In case I'm using the eraser I must clear the rect
+            currentLayer.context.clearRect(x0-Math.floor(eraserSize/2), y0-Math.floor(eraserSize/2), eraserSize, eraserSize);
+		}
 		
 		//if we've reached the end goal, exit the loop
 		if ((x0==x1) && (y0==y1)) break;

js/_fill.js

@@ -6,6 +6,12 @@ function fill(cursorLocation) {
       tempImage.data[pixelPos] = fillColor.r;
       tempImage.data[pixelPos + 1] = fillColor.g;
       tempImage.data[pixelPos + 2] = fillColor.b;
+      tempImage.data[pixelPos + 3] = 255;
+	  /*
+  	tempImage.data[pixelPos] = fillColor.r;
+  	tempImage.data[pixelPos + 1] = fillColor.g;
+  	tempImage.data[pixelPos + 2] = fillColor.b;
+  	*/
   }
   
   //change x y to color value passed from the function and use that as the original color 
@@ -25,7 +31,7 @@ function fill(cursorLocation) {
 	//console.log('filling at '+ Math.floor(cursorLocation[0]/zoom) + ','+ Math.floor(cursorLocation[1]/zoom));
 
 	//temporary image holds the data while we change it
-	var tempImage = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+	var tempImage = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
 
 	//this is an array that holds all of the pixels at the top of the cluster
 	var topmostPixelsArray = [[Math.floor(cursorLocation[0]/zoom), Math.floor(cursorLocation[1]/zoom)]];
@@ -38,7 +44,7 @@ function fill(cursorLocation) {
 	var clusterColor = [tempImage.data[startingPosition],tempImage.data[startingPosition+1],tempImage.data[startingPosition+2]];
 
 	//the new color to fill with
-	var fillColor = hexToRgb(context.fillStyle);
+	var fillColor = hexToRgb(currentLayer.context.fillStyle);
 
 	//if you try to fill with the same color that's already there, exit the function
 	if (clusterColor[0] == fillColor.r &&
@@ -48,7 +54,6 @@ function fill(cursorLocation) {
 
 	//loop until there are no more values left in this array
 	while (topmostPixelsArray.length) {
-		
 		var reachLeft, reachRight;
 
 		//move the most recent pixel from the array and set it as our current working pixels
@@ -63,7 +68,6 @@ function fill(cursorLocation) {
 		//each pixel has 4 values, rgba
 		var pixelPos = (y * canvasSize[0] + x) * 4;
 
-		
 		//move up in the image until you reach the top or the pixel you hit was not the right color
 		while (y-- >= 0 && matchStartColor(tempImage, pixelPos, clusterColor)) {
 			pixelPos -= canvasSize[0] * 4;
@@ -74,7 +78,6 @@ function fill(cursorLocation) {
 		reachRight = false;
 		while (y++ < canvasSize[1] - 1 && matchStartColor(tempImage, pixelPos, clusterColor)) {
 			colorPixel(tempImage, pixelPos, fillColor);
-
 			if (x > 0) {
 				if (matchStartColor(tempImage, pixelPos - 4, clusterColor)) {
 					if (!reachLeft) {
@@ -102,6 +105,6 @@ function fill(cursorLocation) {
 			pixelPos += canvasSize[0] * 4;
 		}
 	}
-	context.putImageData(tempImage, 0, 0);
+    currentLayer.context.putImageData(tempImage, 0, 0);
 	//console.log('done filling')
 }

js/_history.js

@@ -5,19 +5,19 @@ const undoLogStyle = 'background: #87ff1c; color: black; padding: 5px;';
 
 //prototype for undoing canvas changes
 function HistoryStateEditCanvas () {
-  this.canvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+  this.canvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
   
   this.undo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     this.canvas = currentCanvas;
     redoStates.push(this);
   }
   
   this.redo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     this.canvas = currentCanvas;
     undoStates.push(this);
@@ -48,11 +48,11 @@ function HistoryStateAddColor (colorValue) {
 //prototype for undoing deleted colors
 function HistoryStateDeleteColor (colorValue) {
   this.colorValue = colorValue;
-  this.canvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+  this.canvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
   
   this.undo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     addColor(this.colorValue);
     
@@ -61,8 +61,8 @@ function HistoryStateDeleteColor (colorValue) {
   }
   
   this.redo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     deleteColor(this.colorValue);
   
@@ -78,11 +78,11 @@ function HistoryStateDeleteColor (colorValue) {
 function HistoryStateEditColor (newColorValue, oldColorValue) {
   this.newColorValue = newColorValue;
   this.oldColorValue = oldColorValue;
-  this.canvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+  this.canvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
   
   this.undo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     //find new color in palette and change it back to old color
     var colors = document.getElementsByClassName('color-button');
@@ -99,8 +99,8 @@ function HistoryStateEditColor (newColorValue, oldColorValue) {
   }
   
   this.redo = function () {
-    var currentCanvas = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+    var currentCanvas = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
-    context.putImageData(this.canvas, 0, 0);
+    currentLayer.context.putImageData(this.canvas, 0, 0);
     
     //find old color in palette and change it back to new color
     var colors = document.getElementsByClassName('color-button');

js/_hotkeyListener.js

@@ -33,6 +33,11 @@ function KeyPress(e) {
 		case 53:
 		  changeTool('zoom');
 		  break;
+		 // eraser -6, r
+	     case 54: case 82:
+	         console.log("Pressed r");
+            changeTool('eraser');
+	     	break;
 		//Z
 		case 90:
 		  console.log('PRESSED Z ', keyboardEvent.ctrlKey)

js/_jscolor.js

@@ -547,7 +547,7 @@ var jsc = {
 				//console.log(e.target,'=====================================')
 				//if they clicked on the delete button [lospec]
 				if (e.target.className == 'delete-color-button') {
-				  //saveHistoryState({type: 'deletecolor', colorValue: jsc.picker.owner.toString(), canvas: context.getImageData(0, 0, canvasSize[0], canvasSize[1])});
+				  //saveHistoryState({type: 'deletecolor', colorValue: jsc.picker.owner.toString(), canvas: canvas.context.getImageData(0, 0, canvasSize[0], canvasSize[1])});
 				  new HistoryStateDeleteColor(jsc.picker.owner.toString());
 				  
 				  deleteColor(jsc.picker.owner.styleElement);

js/_loadImage.js

@@ -15,10 +15,10 @@ document.getElementById('open-image-browse-holder').addEventListener('change', f
 					newPixel(this.width, this.height, []);
 					
 					//draw the image onto the canvas
-					context.drawImage(img, 0, 0);
+					currentLayer.context.drawImage(img, 0, 0);
 					
 					var colorPalette = {};
-					var imagePixelData = context.getImageData(0,0,this.width, this.height).data;
+					var imagePixelData = currentLayer.context.getImageData(0,0,this.width, this.height).data;
 					
 					var imagePixelDataLength = imagePixelData.length;
 					

js/_mouseEvents.js

@@ -17,7 +17,7 @@ window.addEventListener("mousedown", function (mouseEvent) {
 			currentTool = 'pan';
 		else if (mouseEvent.altKey) 
 			currentTool = 'eyedropper';
-		else if (mouseEvent.target == canvas && currentTool == 'pencil')
+		else if (mouseEvent.target == currentLayer.canvas && (currentTool == 'pencil' || currentTool == 'eraser'))
 		    new HistoryStateEditCanvas();
 		    //saveHistoryState({type: 'canvas', canvas: context.getImageData(0, 0, canvasSize[0], canvasSize[1])});
 		
@@ -29,8 +29,12 @@ window.addEventListener("mousedown", function (mouseEvent) {
 		currentTool = 'resize-brush';
 		prevBrushSize = brushSize;
 	}
+	else if (currentTool == 'eraser' && mouseEvent.which == 3) {
+	    currentTool = 'resize-eraser';
+	    prevEraserSize = eraserSize;
+    }
 	
-	if (currentTool == 'eyedropper' && mouseEvent.target == canvas)
+	if (currentTool == 'eyedropper' && mouseEvent.target == currentLayer.canvas)
 	    eyedropperPreview.style.display = 'block';
 	
 	return false;
@@ -45,7 +49,7 @@ window.addEventListener("mouseup", function (mouseEvent) {
 	
 	if (!documentCreated || dialogueOpen) return;
 	
-	if (currentTool == 'eyedropper' && mouseEvent.target == canvas) {
+	if (currentTool == 'eyedropper' && mouseEvent.target == currentLayer.canvas) {
 		var cursorLocation = getCursorPosition(mouseEvent);
 		var selectedColor = context.getImageData(Math.floor(cursorLocation[0]/zoom),Math.floor(cursorLocation[1]/zoom),1,1);
 		var newColor = rgbToHex(selectedColor.data[0],selectedColor.data[1],selectedColor.data[2]);
@@ -77,10 +81,10 @@ window.addEventListener("mouseup", function (mouseEvent) {
 		
 		
 	}
-	else if (currentTool == 'fill' && mouseEvent.target == canvas) {
+	else if (currentTool == 'fill' && mouseEvent.target == currentLayer.canvas) {
 	  console.log('filling')
 	  //if you clicked on anything but the canvas, do nothing
-		if (!mouseEvent.target == canvas) return;
+		if (!mouseEvent.target == currentLayer.canvas) return;
 		
 		//get cursor postion
 		var cursorLocation = getCursorPosition(mouseEvent);
@@ -92,9 +96,20 @@ window.addEventListener("mouseup", function (mouseEvent) {
     //fill starting at the location
 		fill(cursorLocation);
 	}
-	else if (currentTool == 'zoom' && mouseEvent.target == canvas) {
+	else if (currentTool == 'zoom' && mouseEvent.target == canvasView) {
-		if (mouseEvent.which == 1) changeZoom('in', getCursorPosition(mouseEvent));
+		let mode;
-		else if (mouseEvent.which == 3) changeZoom('out', getCursorPosition(mouseEvent))
+		if (mouseEvent.which == 1){
+			mode = "in";
+        }
+		else if (mouseEvent.which == 3){
+			mode = "out";
+        }
+
+        changeZoom(layers[0], mode, getCursorPosition(mouseEvent));
+
+        for (let i=1; i<layers.length; i++) {
+			layers[i].copyData(layers[0]);
+        }
 	}
 
 	dragging = false;
@@ -120,18 +135,18 @@ function draw (mouseEvent) {
 	if (currentTool == 'pencil') {
 	
 		//move the brush preview
-		brushPreview.style.left = cursorLocation[0] + canvas.offsetLeft - brushSize * zoom / 2 + 'px';
+		brushPreview.style.left = cursorLocation[0] + currentLayer.canvas.offsetLeft - brushSize * zoom / 2 + 'px';
-		brushPreview.style.top = cursorLocation[1] + canvas.offsetTop - brushSize * zoom / 2 + 'px';
+		brushPreview.style.top = cursorLocation[1] + currentLayer.canvas.offsetTop - brushSize * zoom / 2 + 'px';
 		
 		//hide brush preview outside of canvas / canvas view
-		if (mouseEvent.target == canvas || mouseEvent.target == canvasView)
+		if (mouseEvent.target == currentLayer.canvas || mouseEvent.target == canvasView)
 		  brushPreview.style.visibility = 'visible';
 		else
 		  brushPreview.style.visibility = 'hidden';
 
 		//draw line to current pixel
 		if (dragging) {
-			if (mouseEvent.target == canvas || mouseEvent.target == canvasView) {
+			if (mouseEvent.target == currentLayer.canvas || mouseEvent.target == canvasView) {
 				line(Math.floor(lastPos[0]/zoom),Math.floor(lastPos[1]/zoom),Math.floor(cursorLocation[0]/zoom),Math.floor(cursorLocation[1]/zoom));
 				lastPos = cursorLocation;
 			}
@@ -145,33 +160,42 @@ function draw (mouseEvent) {
 		if (colorLightness>127) brushPreview.classList.remove('dark');
 		else brushPreview.classList.add('dark');
 	}
-	else if (currentTool == 'pan' && dragging) {
+	// Decided to write a different implementation in case of differences between the brush and the eraser tool
+	else if (currentTool == 'eraser') {
+	    // Uses the same preview as the brush
+        //move the brush preview
+        brushPreview.style.left = cursorLocation[0] + canvas.offsetLeft - eraserSize * zoom / 2 + 'px';
+        brushPreview.style.top = cursorLocation[1] + canvas.offsetTop - eraserSize * zoom / 2 + 'px';
 
+        //hide brush preview outside of canvas / canvas view
+        if (mouseEvent.target == currentLayer.canvas || mouseEvent.target == canvasView)
+            brushPreview.style.visibility = 'visible';
+        else
+            brushPreview.style.visibility = 'hidden';
 
-		setCanvasOffset(canvas.offsetLeft + (cursorLocation[0] - lastPos[0]), canvas.offsetTop + (cursorLocation[1] - lastPos[1]))
+        //draw line to current pixel
-		/*
+        if (dragging) {
-		if 	(
+            if (mouseEvent.target == currentLayer.canvas || mouseEvent.target == canvasView) {
-			//right
+                line(Math.floor(lastPos[0]/zoom),Math.floor(lastPos[1]/zoom),Math.floor(cursorLocation[0]/zoom),Math.floor(cursorLocation[1]/zoom));
-			canvas.offsetLeft + (cursorLocation[0] - lastPos[0]) < window.innerWidth - canvasSize[0]*zoom*0.25 - 48 &&
+                lastPos = cursorLocation;
-			//left
-			canvas.offsetLeft + (cursorLocation[0] - lastPos[0]) > -canvasSize[0]*zoom*0.75 + 64) 
-				canvas.style.left = canvas.offsetLeft + (cursorLocation[0] - lastPos[0]) +'px';
-			
-		if (
-			//bottom
-			canvas.offsetTop + (cursorLocation[1] - lastPos[1]) < window.innerHeight-canvasSize[1]*zoom*0.25 &&
-			//top
-			canvas.offsetTop + (cursorLocation[1] - lastPos[1]) > -canvasSize[0]*zoom*0.75 + 48) 
-				canvas.style.top = canvas.offsetTop + (cursorLocation[1] - lastPos[1]) +'px';
-    	*/
             }
-    else if (currentTool == 'eyedropper' && dragging && mouseEvent.target == canvas) {
+        }
+	}
+	else if (currentTool == 'pan' && dragging) {
+	    // Setting first layer position
+        setCanvasOffset(layers[0].canvas, layers[0].canvas.offsetLeft + (cursorLocation[0] - lastPos[0]), layers[0].canvas.offsetTop + (cursorLocation[1] - lastPos[1]));
+		// Copying that position to the other layers
+        for (let i=1; i<layers.length; i++) {
+            layers[i].copyData(layers[0]);
+        }
+    }
+    else if (currentTool == 'eyedropper' && dragging && mouseEvent.target == currentLayer.canvas) {
         var selectedColor = context.getImageData(Math.floor(cursorLocation[0]/zoom),Math.floor(cursorLocation[1]/zoom),1,1).data;
         eyedropperPreview.style.borderColor = '#'+rgbToHex(selectedColor[0],selectedColor[1],selectedColor[2]);
         eyedropperPreview.style.display = 'block';
        
-        eyedropperPreview.style.left = cursorLocation[0] + canvas.offsetLeft - 30 + 'px';
+        eyedropperPreview.style.left = cursorLocation[0] + currentLayer.canvas.offsetLeft - 30 + 'px';
-        eyedropperPreview.style.top = cursorLocation[1] + canvas.offsetTop - 30 + 'px';
+        eyedropperPreview.style.top = cursorLocation[1] + currentLayer.canvas.offsetTop - 30 + 'px';
         
         var colorLightness = Math.max(selectedColor[0],selectedColor[1],selectedColor[2]);
         
@@ -180,7 +204,6 @@ function draw (mouseEvent) {
 		else eyedropperPreview.classList.add('dark');
     }
     else if (currentTool == 'resize-brush' && dragging) {
-       
         //get new brush size based on x distance from original clicking location
         var distanceFromClick = cursorLocation[0] - lastPos[0];
         //var roundingAmount = 20 - Math.round(distanceFromClick/10);
@@ -192,8 +215,25 @@ function draw (mouseEvent) {
         brushSize = Math.max(1,newBrushSize);
 
         //fix offset so the cursor stays centered
-		brushPreview.style.left = lastPos[0] + canvas.offsetLeft - brushSize * zoom / 2 + 'px';
+        brushPreview.style.left = lastPos[0] + currentLayer.canvas.offsetLeft - brushSize * zoom / 2 + 'px';
-		brushPreview.style.top = lastPos[1] + canvas.offsetTop - brushSize * zoom / 2 + 'px';
+        brushPreview.style.top = lastPos[1] + currentLayer.canvas.offsetTop - brushSize * zoom / 2 + 'px';
+
+        updateCursor();
+    }
+    else if (currentTool == 'resize-eraser' && dragging) {
+        //get new brush size based on x distance from original clicking location
+        var distanceFromClick = cursorLocation[0] - lastPos[0];
+        //var roundingAmount = 20 - Math.round(distanceFromClick/10);
+        //this doesnt work in reverse...  because... it's not basing it off of the brush size which it should be
+        var eraserSizeChange = Math.round(distanceFromClick/10);
+        var newEraserSizeChange = prevEraserSize + eraserSizeChange;
+
+        //set the brush to the new size as long as its bigger than 1
+        eraserSize = Math.max(1,newEraserSizeChange);
+
+        //fix offset so the cursor stays centered
+        brushPreview.style.left = lastPos[0] + currentLayer.canvas.offsetLeft - eraserSize * zoom / 2 + 'px';
+        brushPreview.style.top = lastPos[1] + currentLayer.canvas.offsetTop - eraserSize * zoom / 2 + 'px';
 
         updateCursor();
     }
@@ -203,8 +243,21 @@ function draw (mouseEvent) {
 canvasView.addEventListener("wheel", function(mouseEvent){
 	
 	if (currentTool == 'zoom' || mouseEvent.altKey) {
-		if (mouseEvent.deltaY < 0) changeZoom('in', getCursorPosition(mouseEvent));
+		let mode;
-		else if (mouseEvent.deltaY > 0) changeZoom('out', getCursorPosition(mouseEvent))
+		if (mouseEvent.deltaY < 0){
+			mode = 'in';
+        }
+		else if (mouseEvent.deltaY > 0) {
+			mode = 'out';
+        }
+
+        // Changing zoom and position of the first layer
+        changeZoom(layers[0], mode, getCursorPosition(mouseEvent))
+
+        for (let i=1; i<layers.length; i++) {
+			// Copying first layer's data into the other layers
+            layers[i].copyData(layers[0]);
+		}
 	}
 		
 });

js/_newPixel.js

@@ -1,26 +1,15 @@
 
 function newPixel (width, height, palette) {
+    currentLayer = new Canvas(width, height, canvas);
+    currentLayer.initialize();
 
-	canvasSize = [width,height];
+    checkerBoard = new Canvas(width, height, checkerBoardCanvas);
+    checkerBoard.initialize();
 
-	var maxHorizontalZoom = Math.floor(window.innerWidth/canvasSize[0]*0.75);
+	canvasSize = currentLayer.canvasSize;
-	var maxVerticalZoom = Math.floor(window.innerHeight/canvasSize[1]*0.75);
 
-	zoom = Math.min(maxHorizontalZoom,maxVerticalZoom);
+	layers.push(currentLayer);
-	if (zoom < 1) zoom = 1;
+	layers.push(checkerBoard);
-	
-	//resize canvas
-	canvas.width = canvasSize[0];
-	canvas.height = canvasSize[1];
-	canvas.style.width = (canvas.width*zoom)+'px';
-	canvas.style.height = (canvas.height*zoom)+'px';
-	
-	//unhide canvas
-	canvas.style.display = 'block';
-	
-	//center canvas in window
-	canvas.style.left = 64+canvasView.clientWidth/2-(canvasSize[0]*zoom/2)+'px';
-	canvas.style.top = 48+canvasView.clientHeight/2-(canvasSize[1]*zoom/2)+'px';
 
 	//remove current palette
 	colors = document.getElementsByClassName('color-button');
@@ -56,13 +45,16 @@ function newPixel (width, height, palette) {
 	  addColor(defaultBackgroundColor);
     
     //fill background of canvas with bg color
-		context.fillStyle = '#'+defaultBackgroundColor;
+		fillCheckerboard();
-		context.fillRect(0, 0, canvasSize[0], canvasSize[1]);
+		/*
+		currentLayer.context.fillStyle = '#'+defaultBackgroundColor;
+		currentLayer.context.fillRect(0, 0, canvasSize[0], canvasSize[1]);
 		
 		console.log('#'+defaultBackgroundColor)
+		*/
 		
 		//set current drawing color as foreground color
-		context.fillStyle = '#'+defaultForegroundColor;
+		currentLayer.context.fillStyle = '#'+defaultForegroundColor;
 		selectedPalette = 'none';
 	}
 		

js/_replaceAllOfColor.js

@@ -7,7 +7,7 @@ function replaceAllOfColor (oldColor, newColor) {
   if (typeof newColor === 'string') newColor = hexToRgb(newColor);
     
   //create temporary image from canvas to search through
-	var tempImage = context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
+	var tempImage = currentLayer.context.getImageData(0, 0, canvasSize[0], canvasSize[1]);
 	
 	//loop through all pixels
 	for (var i=0;i<tempImage.data.length;i+=4) {
@@ -21,5 +21,5 @@ function replaceAllOfColor (oldColor, newColor) {
 	}
 	
 	//put temp image back onto canvas
-	context.putImageData(tempImage,0,0);
+	currentLayer.context.putImageData(tempImage,0,0);
 }

js/_setCanvasOffset.js

@@ -1,8 +1,7 @@
-function setCanvasOffset (offsetLeft, offsetTop) {
+function setCanvasOffset (canvas, offsetLeft, offsetTop) {
-		
 		//horizontal offset
 		var minXOffset = -canvasSize[0]*zoom+ 164;
-		var maxXOffset = window.innerWidth - 148
+		var maxXOffset = window.innerWidth - 148;
 		
 		if 	(offsetLeft < minXOffset)
 			canvas.style.left = minXOffset +'px';

js/_toolButtons.js

@@ -10,11 +10,28 @@ on('click',"pencil-bigger-button", function(){
 }, false);
 
 //pencil smaller
-on('click',"pencil-smaller-button", function(e){
+on('click',"pencil-smaller-button", function(){
     if(brushSize > 1) brushSize--;
     updateCursor();
 }, false);
 
+//eraser
+on('click',"eraser-button", function(){
+    changeTool('eraser');
+}, false);
+
+//eraser bigger
+on('click',"eraser-bigger-button", function(){
+    eraserSize++;
+    updateCursor();
+}, false);
+
+//eraser smaller
+on('click',"eraser-smaller-button", function(e){
+    if(eraserSize > 1) eraserSize--;
+    updateCursor();
+}, false);
+
 //fill
 on('click',"fill-button", function(){
     changeTool('fill');
@@ -38,10 +55,18 @@ on('click',"zoom-button", function(){
 //zoom in button
 on('click',"zoom-in-button", function(){
 	//changeZoom('in',[window.innerWidth/2-canvas.offsetLeft,window.innerHeight/2-canvas.offsetTop]);
-	changeZoom('in',[canvasSize[0]*zoom/2,canvasSize[1]*zoom/2]); 
+    changeZoom(layers[0],'in', [canvasSize[0] * zoom / 2, canvasSize[1] * zoom / 2]);
+
+    for (let i=1; i<layers.length; i++) {
+        layers[i].copyData(layers[0]);
+    }
 }, false);
 
 //zoom out button
 on('click',"zoom-out-button", function(){
-	changeZoom('out',[canvasSize[0]*zoom/2,canvasSize[1]*zoom/2]); 
+    changeZoom(layers[0],'out',[canvasSize[0]*zoom/2,canvasSize[1]*zoom/2]);
+
+    for (let i=1; i<layers.length; i++) {
+        layers[i].copyData(layers[0]);
+    }
 }, false);

js/_updateCursor.js

@@ -6,6 +6,11 @@ function updateCursor () {
 		brushPreview.style.display = 'block';
 		brushPreview.style.width = brushSize * zoom + 'px';
 		brushPreview.style.height = brushSize * zoom + 'px';
+	} else if (currentTool == 'eraser' || currentTool == 'resize-eraser') {
+        canvasView.style.cursor = 'crosshair';
+        brushPreview.style.display = 'block';
+        brushPreview.style.width = eraserSize * zoom + 'px';
+        brushPreview.style.height = eraserSize * zoom + 'px';
 	} else
 		brushPreview.style.display = 'none';
 	
@@ -26,7 +31,6 @@ function updateCursor () {
 	if (currentTool == 'zoom') 
 		canvasView.style.cursor = "url('/pixel-editor/zoom-in.png'), auto";
 		
-	if (currentTool == 'resize-brush') 
+	if (currentTool == 'resize-brush' || currentTool == 'resize-eraser')
 		canvasView.style.cursor = 'default';
-
 }

js/_variables.js

@@ -2,15 +2,25 @@
 var canvasSize,zoom;
 var dragging = false;
 var lastPos = [0,0];
-var canvasPosition;
 var currentTool = 'pencil';
 var currentToolTemp = 'pencil';
 var brushSize = 1;
+var eraserSize = 1;
 var prevBrushSize = 1;
-var menuOpen = false;
+var prevEraserSize = 1;
 var dialogueOpen = false;
 var documentCreated = false;
 
+// Checkerboard management
+// Checkerboard color 1
+var firstCheckerBoardColor = 'rgba(179, 173, 182, 1)';
+// Checkerboard color 2
+var secondCheckerBoardColor = 'rgba(204, 200, 206, 1)';
+// Square size for the checkerboard
+var checkerBoardSquareSize = 16;
+// Checkerboard canvas
+var checkerBoardCanvas = document.getElementById("checkerboard");
+
 //common elements
 var brushPreview = document.getElementById("brush-preview");
 var eyedropperPreview = document.getElementById("eyedropper-preview");
@@ -19,7 +29,12 @@ var colors = document.getElementsByClassName("color-button");
 var colorsMenu = document.getElementById("colors-menu");
 var popUpContainer = document.getElementById("pop-up-container");
 
-//html canvas
+// main canvas
 var canvas = document.getElementById("pixel-canvas");
 var context = canvas.getContext("2d");
 
+// Layers
+var layers = [];
+// Currently selected layer
+var currentLayer;
+

js/pixel-editor.js

@@ -41,6 +41,8 @@
 //=include _history.js 
 //=include _deleteColor.js 
 //=include _replaceAllOfColor.js
+//=include _checkerboard.js
+//=include _canvas.js
 
 
 /**load file**/

package.json

@@ -16,9 +16,9 @@
     "gulp-include": "^2.3.1",
     "handlebars-helper-svg": "git+https://bitbucket.org/skeddles/npm-handlebars-helper-svg-lospec-open-source.git",
     "hbs": "^4.0.3",
-    "opn": "^6.0.0",
-    "sass": "^1.17.3",
     "hbs-register-helpers": "git+https://skeddles@bitbucket.org/skeddles/hbs-register-helpers.git",
-    "hbs-register-partials": "git+https://skeddles@bitbucket.org/skeddles/hbs-register-partials.git"
+    "hbs-register-partials": "git+https://skeddles@bitbucket.org/skeddles/hbs-register-partials.git",
+    "opn": "^6.0.0",
+    "sass": "^1.17.3"
   }
 }

views/pixel-editor.hbs

@@ -33,6 +33,7 @@
         <img src="/pixel-editor/pan-held.png" />
         <img src="/pixel-editor/pencil.png" />
         <img src="/pixel-editor/zoom-in.png" />
+        <img src = "/pixel-editor/eraser.png"/>
     </div>
     <ul id="main-menu">
         <li class="logo">Lospec Pixel Editor</li>
@@ -77,6 +78,11 @@
             <button title="Zoom In" id="zoom-in-button" class="tools-menu-sub-button">{{svg "plus.svg" width="12" height="12"}}</button>
             <button title="Zoom Out" id="zoom-out-button" class="tools-menu-sub-button">{{svg "minus.svg" width="12" height="12"}}</button>
         </li>
+        <li class = "expanded">
+            <button title="Eraser tool (R)" id="eraser-button">{{svg "eraser.svg" width="32" height="32"}}</button>
+            <button title="Increase Eraser Size" id="eraser-bigger-button" class="tools-menu-sub-button">{{svg "plus.svg" width="12" height="12"}}</button>
+            <button title="Decrease Eraser Size" id="eraser-smaller-button" class="tools-menu-sub-button">{{svg "minus.svg" width="12" height="12"}}</button>
+        </li>
     </ul>
 
     <ul id="colors-menu">
@@ -92,7 +98,8 @@
     <div id="brush-preview"></div>
 
     <div id="canvas-view">
-        <canvas id="pixel-canvas"></canvas>
+        <canvas id="pixel-canvas" class = "drawingCanvas"></canvas>
+        <canvas id="checkerboard" class = "drawingCanvas"></canvas>
     </div>
     <div id="canvas-view-shadow"></div>
 
@@ -103,8 +110,6 @@
       <canvas id="load-palette-canvas-holder"></canvas>
     </div>
 
-
-    
     <div class="jscolor-picker-bottom">
       <span>#</span><input type="text" id="jscolor-hex-input"/>
       <div id="duplicate-color-warning" title="Color is a duplicate of another in palette">{{svg "warning.svg" width="14" height="12" }}</div>