Related
i want to retain drawn boxes and path once page is refreshed.
i'm using mxgraph https://jgraph.github.io/mxgraph/docs/manual.html
Question: once the drawing is done, if i do page refresh it should retain the same drawing by storing drawing data into localStorage.
NOTE: i want to get json object of drawn canvas, and re-construct it back from that object on page refresh.
Below video shows how to draw: https://drive.google.com/file/d/1McTMz3e8I_quOcLGt2CtaQhqif3R31qs/view
https://jgraph.github.io/mxgraph/javascript/examples/editors/images/
<!--
Copyright (c) 2006-2013, JGraph Ltd
Dynamic toolbar example for mxGraph. This example demonstrates changing the
state of the toolbar at runtime.
-->
<html>
<head>
<title>Toolbar example for mxGraph</title>
<!-- Sets the basepath for the library if not in same directory -->
<script type="text/javascript">
mxBasePath = 'https://jgraph.github.io/mxgraph/javascript/src';
</script>
<!-- Loads and initializes the library -->
<script type="text/javascript" src="https://jgraph.github.io/mxgraph/javascript/src/js/mxClient.js"></script>
<!-- Example code -->
<script type="text/javascript">
// Program starts here. Creates a sample graph in the
// DOM node with the specified ID. This function is invoked
// from the onLoad event handler of the document (see below).
function main()
{
// Checks if browser is supported
if (!mxClient.isBrowserSupported())
{
// Displays an error message if the browser is
// not supported.
mxUtils.error('Browser is not supported!', 200, false);
}
else
{
// Defines an icon for creating new connections in the connection handler.
// This will automatically disable the highlighting of the source vertex.
mxConnectionHandler.prototype.connectImage = new mxImage('images/connector.gif', 16, 16);
// Creates the div for the toolbar
var tbContainer = document.createElement('div');
tbContainer.style.position = 'absolute';
tbContainer.style.overflow = 'hidden';
tbContainer.style.padding = '2px';
tbContainer.style.left = '0px';
tbContainer.style.top = '0px';
tbContainer.style.width = '24px';
tbContainer.style.bottom = '0px';
document.body.appendChild(tbContainer);
// Creates new toolbar without event processing
var toolbar = new mxToolbar(tbContainer);
toolbar.enabled = false
// Creates the div for the graph
var container = document.createElement('div');
container.style.position = 'absolute';
container.style.overflow = 'hidden';
container.style.left = '24px';
container.style.top = '0px';
container.style.right = '0px';
container.style.bottom = '0px';
container.style.background = 'url("editors/images/grid.gif")';
document.body.appendChild(container);
// Workaround for Internet Explorer ignoring certain styles
if (mxClient.IS_QUIRKS)
{
document.body.style.overflow = 'hidden';
new mxDivResizer(tbContainer);
new mxDivResizer(container);
}
// Creates the model and the graph inside the container
// using the fastest rendering available on the browser
var model = new mxGraphModel();
var graph = new mxGraph(container, model);
// Enables new connections in the graph
graph.setConnectable(true);
graph.setMultigraph(false);
// Stops editing on enter or escape keypress
var keyHandler = new mxKeyHandler(graph);
var rubberband = new mxRubberband(graph);
var addVertex = function(icon, w, h, style)
{
var vertex = new mxCell(null, new mxGeometry(0, 0, w, h), style);
vertex.setVertex(true);
var img = addToolbarItem(graph, toolbar, vertex, icon);
img.enabled = true;
graph.getSelectionModel().addListener(mxEvent.CHANGE, function()
{
var tmp = graph.isSelectionEmpty();
mxUtils.setOpacity(img, (tmp) ? 100 : 20);
img.enabled = tmp;
});
};
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rectangle.gif', 100, 40, '');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rounded.gif', 100, 40, 'shape=rounded');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/ellipse.gif', 40, 40, 'shape=ellipse');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/rhombus.gif', 40, 40, 'shape=rhombus');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/triangle.gif', 40, 40, 'shape=triangle');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/cylinder.gif', 40, 40, 'shape=cylinder');
addVertex('https://jgraph.github.io/mxgraph/javascript/examples/editors/images/actor.gif', 30, 40, 'shape=actor');
}
}
function addToolbarItem(graph, toolbar, prototype, image)
{
// Function that is executed when the image is dropped on
// the graph. The cell argument points to the cell under
// the mousepointer if there is one.
var funct = function(graph, evt, cell, x, y)
{
graph.stopEditing(false);
var vertex = graph.getModel().cloneCell(prototype);
vertex.geometry.x = x;
vertex.geometry.y = y;
graph.addCell(vertex);
graph.setSelectionCell(vertex);
}
// Creates the image which is used as the drag icon (preview)
var img = toolbar.addMode(null, image, function(evt, cell)
{
var pt = this.graph.getPointForEvent(evt);
funct(graph, evt, cell, pt.x, pt.y);
});
// Disables dragging if element is disabled. This is a workaround
// for wrong event order in IE. Following is a dummy listener that
// is invoked as the last listener in IE.
mxEvent.addListener(img, 'mousedown', function(evt)
{
// do nothing
});
// This listener is always called first before any other listener
// in all browsers.
mxEvent.addListener(img, 'mousedown', function(evt)
{
if (img.enabled == false)
{
mxEvent.consume(evt);
}
});
mxUtils.makeDraggable(img, graph, funct);
return img;
}
</script>
</head>
<!-- Calls the main function after the page has loaded. Container is dynamically created. -->
<body onload="main();" >
</body>
</html>
This uses the XML encoding of mxgraph. You see this code in one of the examples of mxGraph. While it is not json, it is very easy to turn into json, and can be edited or saved as you wish. Now it it stored in localStorage as you asked.
Add the following lines at the end of your main function (after the last call to addVertex):
// read state on load
if(window.localStorage.graphState){
var doc = mxUtils.parseXml(window.localStorage.graphState);
var dec = new mxCodec(doc);
dec.decode(doc.documentElement, graph.getModel());
}
// save state on change
graph.getModel().addListener('change',function(){
var codec = new mxCodec();
window.localStorage.graphState = codec.encode(
graph.getModel()
).outerHTML;
});
Update using JSON
Update 2: Switched to my own custom html2json and json2html implementation to make the answer fully self-contained
If you do need a proper JSON object, you can convert from xml to json and back. Below you can see I stringify and parse the json object, this is only needed to save it in localStorage though.
First add these two functions to convert from html/xml to json and from json back to html/xml:
function html2json(html){
if(html.nodeType==3){
return {
"tagName":"#text",
"content":html.textContent
}
}
var element = {
"tagName":html.tagName
};
if(html.getAttributeNames().length>0){
element.attributes = html.getAttributeNames().reduce(
function(acc,at){acc[at]=html.getAttribute(at); return acc;},
{}
);
}
if(html.childNodes.length>0){
element.children = Array.from(html.childNodes)
.filter(
function(el){
return el.nodeType!=3
||el.textContent.trim().length>0
})
.map(function(el){return html2json(el);});
}
return element;
}
function json2html(json){
var xmlDoc = document.implementation.createDocument(null, json.tagName);
var addAttributes = function(jsonNode, node){
if(jsonNode.attributes){
Object.keys(jsonNode.attributes).map(
function(name){
node.setAttribute(name,jsonNode.attributes[name]);
}
);
}
}
var addChildren = function(jsonNode,node){
if(jsonNode.children){
jsonNode.children.map(
function(jsonChildNode){
json2htmlNode(jsonChildNode,node);
}
);
}
}
var json2htmlNode = function(jsonNode,parent){
if(jsonNode.tagName=="#text"){
return xmlDoc.createTextNode(jsonNode.content);
}
var node = xmlDoc.createElement(jsonNode.tagName);
addAttributes(jsonNode,node);
addChildren(jsonNode,node);
parent.appendChild(node);
}
addAttributes(json,xmlDoc.firstElementChild);
addChildren(json,xmlDoc.firstElementChild);
return xmlDoc;
}
Then change my JavaScript snippet from above like this to transform the xml into json and back:
// read state on load
if(window.localStorage.graphState){
var doc = json2html(JSON.parse(localStorage.graphState));
var dec = new mxCodec(doc);
dec.decode(doc.documentElement, graph.getModel());
}
// save state on change
graph.getModel().addListener('change',function(){
var codec = new mxCodec();
window.localStorage.graphState = JSON.stringify(html2json(codec.encode(
graph.getModel()
)));
});
We are building an image editor of sorts using Paper.js. We have a queue on the side of the Paper.js canvas that allows switching between images. Each time we switch between images, we want to flatten all the annotations (rasterize) onto the image just being edited.
Each time we switch images, this method is called, which rasterizes the current image and annotations to a data URL. (If we revisit this image, a raster from this data URL will be displayed.)
var flattenToDataUrl = function() {
layerAsRaster = paper.project.layers[0].rasterize(); // Layer to Paper.js Raster object
layerAsRaster.visible = false; // Attempt to set not visible
var dataString = layerAsRaster.toDataURL();
return dataString;
};
Then we end up calling this method, which changes out the image we're editing:
var setCanvasImage = function(imageObject) {
if(imageObject != null)
{
imageHeight = imageObject.height;
var imageWidth = imageObject.width;
// Set up HTMLImage
var imageElement = new Image(imageObject.width, imageObject.height);
if(_.has(imageObject, 'imageData')) { // Came as 64 bit data
imageElement.src = 'data:image/png;base64,' + imageObject.imageData;
} else if(_.has(imageObject, 'imageUrl')) { // Came as URL
imageElement.src = imageObject.imageUrl;
}
// Add image to Paper.js canvas
imageElement.onload = function(event) {
// Initialize Paper.js on the canvas
paper.setup(canvas);
raster = new paper.Raster(imageElement, new paper.Point(canvas.width / 2, canvas.height / 2));
setUpNotes();
selectedItems = new paper.Group(); // Since Paper.js has been setup we can now initialize this Group
registerCanvasEvents(); // Panning, zooming, moving selected items, deselecting all selected items
fitToPage();
};
}
};
So, this changes out the image, but when I move my mouse into the canvas after selecting a different image in the queue, it glitches to the image we were just on (with its annotations) until I do something like pan, zoom, etc. Then I see the image I selected and am truly working with.
Removing the flattenToDataUrl() functionality makes the queue work seamlessly. So it seems to me something is fishy there. We are generating a Paper.js Raster object in that method. Rasters seem to automatically add themselves. I attempt to curb this with a call to
layerAsRaster.visible = false;
but to no avail.
What is causing this glitchy behavior and how do I prevent it?
Update
For clarity (hopefully) and completeness, I've decided to post the whole PaperFunctions class we use in conjunction with React, which hosts our <canvas> element. There's a lot of code, and a lot of cleanup to do, especially in registerCanvasEvents(). Bear with this learning beginner. Also it's several hundred lines, so it may be helpful to paste it into your favorite editor. Entry points include setCanvas which is called in componentDidMount of the React class with the <canvas> element, and canvasSetImage which is called from the queue. I agree from bmacnaughton's answer that it's weird to call paper.setup(canvas) every time we load a new image. I'm currently investigating the right solution to this, the right place to put it. setCanvas seems logical but when I drag the image to move it in that setup, it leaves a trail of images in its wake. Anyway, here's PaperFunctions.js:
var JQueryMousewheel = require('jquery-mousewheel')($);
var SimplePanAndZoom = require('./SimplePanAndZoom.js');
var panAndZoom = new SimplePanAndZoom();
var selectedItems;
// We use selection here in two distinct ways.
// An item may be Paper.js selected but not in the selection group.
// This is because we want to show it is selectable.
// A blue bounding box indicates it is selectable.
// A green bounding box indicates it has actually been selected and added to selectedItems.
// Only things in selectedItems are actually operated on.
// So the event handlers in this method basically set up whether or not the item is in selectedItems (and therefore will be operated on for moving, resizing, deleting, etc.).
// That is, the event handlers here are concerned with displaying to the user the status of selection for the item - whether or not it will be operated on when events actually happen on the selectedItems Group.
var registerItemEvents = function(item) {
// Boolean flag for mouseup to know if was drag or click
var dragged;
// For tracking if dragging or clicking is happening
item.on('mousedown', function(e) {
dragged = false;
});
// On click toggle selection
item.on('mouseup', function(event) {
event.stopPropagation(); // Only for item applied to
event.preventDefault();
if(!dragged) {
var justAdded = addIfNotInSelectedItems(item);
if(!justAdded) { // Item was in selection group, remove it
item.remove();
paper.project.activeLayer.addChild(item);
this.selectedColor = paper.project.activeLayer.selectedColor;
//item.selected = false;
}
}
});
// Show as selectable even after has been deselected
item.on('mousemove', function(event) {
this.selected = true;
})
// If not selected, on mouse enter show that it is selectable
item.on('mouseenter', function(event) {
if(!this.selected) {
this.selected = true;
}
});
// If not selected, on mouse leave remove indicator that is selectable
item.on('mouseleave', function(event) {
var isInSelectedItems = selectedItems.getItem(item);
if(this.selected && isInSelectedItems == null) {
this.selected = false;
}
});
// On drag, move item
item.on('mousedrag', function(event) {
dragged = true;
// If user starts dragging automatically select the item
addIfNotInSelectedItems(item);
});
}
var addIfNotInSelectedItems = function(item) {
var isInSelectedItems = selectedItems.getItem(item);
if(isInSelectedItems == null) { // Item not currently in selection group, add it
selectedItems.addChild(item);
item.selectedColor = 'green';
item.selected = true;
return true; // Was added, return true
} else {
return false; // Already in, return false
}
}
var registerCanvasEvents = function() {
if(paper.view != null && canvas != null) {
// Zoom on mousewheel
$(canvas).mousewheel(function(event) {
event.preventDefault();
var mousePosition = new paper.Point(event.offsetX, event.offsetY);
var viewPosition = paper.view.viewToProject(mousePosition);
var returnedValues = panAndZoom.changeZoom(paper.view.zoom, (event.deltaY * -1), paper.view.center, viewPosition, 1.1);
var newZoom = returnedValues[0];
var offset = returnedValues[1];
paper.view.zoom = newZoom;
paper.view.center = paper.view.center.add(offset);
});
// For tracking if dragging or clicking is happening
var dragged;
paper.project.layers[0].on('mousedown', function(e) { // TODO should be layer 0 in long run?
dragged = false;
});
// Pan on mouse drag
/*paper.project.layers[0].on('mousedrag', function(event) { // TODO should be layer 0 in long run?
if(!event.event.ctrlKey && !event.event.altKey && !event.event.shiftKey) { // No keys (that we use) can be pushed
dragged = true; // We're panning, we don't wish to deselect all items as we would do with a click
paper.view.center = panAndZoom.changeCenter(paper.view.center, event.delta.x, event.delta.y, 0.7);
//event.preventDefault();
}
});*/
// Move selected items on mouse drag
selectedItems.on('mousedrag', function(event) {
event.stopPropagation(); // Don't propogate up or it will register as a pan event
event.preventDefault();
dragged = true; // We're panning, we don't wish to deselect all items as we would do with a click
this.translate(new paper.Point(event.delta.x, event.delta.y));
});
// If was a click and not a drag, deselect selected items
paper.project.layers[0].on('mouseup', function(event) {
if(!dragged) {
var removedItems = selectedItems.removeChildren(); // Remove from selection group, which also removes from display
paper.project.activeLayer.addChildren(removedItems); // Return to display
// Reset selection colors for showing selectable
for(var i =0; i < removedItems.length; i++) {
removedItems[i].selectedColor = paper.project.activeLayer.selectedColor;
removedItems[i].selected = false;
}
}
});
// Initial path object, will be reset for new paths after Alt is released
var path = newPath();
var paths = [];
paths.push(path);
// On mousedown add point to start from
paper.project.layers[0].on('mousedown', function(event) {
if(event.event.altKey && !event.event.ctrlKey) { // Alt key to add a path, but disallow attempting to add text at the same time
if(paths[paths.length-1].lastSegment == null) {
//path.add(event.point, event.point);
paths[paths.length-1].add(event.point, event.point);
} else {
//path.add(path.lastSegment.point, path.lastSegment.point);
paths[paths.length-1].add(paths[paths.length-1].lastSegment.point, paths[paths.length-1].lastSegment.point);
}
}
});
// On mousedrag add points to path
paper.project.layers[0].on('mousedrag', function(event) {
if(event.event.altKey && !event.event.ctrlKey) { // Alt key to add a path, but disallow attempting to add text at the same time
if(event.event.shiftKey) { // Use shift key for freeform
//path.add(event.point);
paths[paths.length-1].add(event.point);
} else { // Default of straight line added to path
//path.lastSegment.point = event.point;
paths[paths.length-1].lastSegment.point = event.point;
}
}
}.bind(this));
var tool = new paper.Tool();
var startDragPoint;
// Capture start of drag selection
paper.tool.onMouseDown = function(event) {
if((event.event.ctrlKey && event.event.shiftKey) || (event.event.ctrlKey && event.event.altKey)) {
startDragPoint = new paper.Point(event.point);
}
};
paper.tool.onMouseDrag = function(event) {
// Panning
if(!event.event.ctrlKey && !event.event.altKey && !event.event.shiftKey) { // No keys (that we use) can be pushed
dragged = true; // We're panning, we don't wish to deselect all items as we would do with a click
paper.view.center = panAndZoom.changeCenter(paper.view.center, event.delta.x, event.delta.y, 0.7);
//event.preventDefault();
}
// Show box indicating the area that has been selected
// For moving area and whiting out area
if((event.event.ctrlKey && event.event.shiftKey) || (event.event.ctrlKey && event.event.altKey)) {
dragged = true;
var showSelection = new paper.Path.Rectangle({
from: startDragPoint,
to: event.point,
strokeColor: 'red',
strokeWidth: 1
});
// Stop showing the selected area on drag (new one is created) and up because we're done
showSelection.removeOn({
drag: true,
up: true
});
}
};
// Capture start of drag selection
paper.tool.onMouseUp = function(event) {
if((event.event.ctrlKey && event.event.shiftKey) || (event.event.ctrlKey && event.event.altKey)) {
var endDragPoint = new paper.Point(event.point);
if(event.event.ctrlKey && event.event.shiftKey) { // Whiteout area
whiteoutArea(startDragPoint, endDragPoint);
} else if(event.event.ctrlKey && event.event.altKey) { // Move selected area
selectArea(startDragPoint, endDragPoint);
}
}
};
// Key events
paper.tool.onKeyUp = function(event) {
// Delete selected items on delete key
if(event.key == 'delete') {
selectedItems.removeChildren();
} else if (event.key == 'option') {
registerItemEvents(paths[paths.length-1]);
// Start a new path
paths.push(newPath());
}
}
}
}
// These variables are scoped so that all methods in PaperFunctions can access them
var canvas; // Set by setCanvas
var imageHeight; // Set by setCanvasImage
var raster;
var toolsSetup = false;
var setCanvas = function(canvasElement) {
canvas = canvasElement;
paper.setup(canvas);
};
var setCanvasImage = function(imageObject) {
if(imageObject != null)
{
imageHeight = imageObject.height;
var imageWidth = imageObject.width;
// Set up HTMLImage
var imageElement = new Image(imageObject.width, imageObject.height);
if(_.has(imageObject, 'imageData')) { // Came as 64 bit data
imageElement.src = 'data:image/png;base64,' + imageObject.imageData;
} else if(_.has(imageObject, 'imageUrl')) { // Came as URL
imageElement.src = imageObject.imageUrl;
}
// Add image to Paper.js canvas
imageElement.onload = function(event) {
//canvas.height = $(document).height()-3; // Set canvas height. Why do this here and not in the React component? Because we set the width here too, so we're keeping those together. Perhaps in the future this will be changed when we are responsive to window resizing.
//scalingFactor = canvas.height / imageObject.height; // Determine the ratio
//canvas.width = imageElement.width * scalingFactor; // Scale width based on height; canvas height has been set to the height of the document
// Initialize Paper.js on the canvas
paper.setup(canvas);
raster = new paper.Raster(imageElement, new paper.Point(canvas.width / 2, canvas.height / 2));
//setUpLineAndFreeFormDrawing(); // TODO once we cycle through images will we need to reset this for each new image or can we do this just once?
setUpNotes(); // TODO once we cycle through images will we need to reset this for each new image or can we do this just once?
selectedItems = new paper.Group(); // Since Paper.js has been setup we can now initialize this Group
registerCanvasEvents(); // Panning, zooming, moving selected items, deselecting all selected items
fitToPage();
};
}
};
var fitToPage = function() {
if(paper.view != null && canvas != null) {
// Fit image to page so whole thing is displayed
var scalingFactor = canvas.height / imageHeight; // Constant representation of the ratio of the canvas size to the image size
var zoomFactor = scalingFactor / paper.view.zoom; // Dynamic representation of the zoom needed to return to viewing the whole image in the canvas
// Reset the center point to the center of the canvas
var canvasCenter = new paper.Point(canvas.width/2, canvas.height/2);
paper.view.center = canvasCenter;
// Zoom to fit the whole image in the canvas
var returnedValues = panAndZoom.changeZoom(paper.view.zoom, -1, canvasCenter, canvasCenter, zoomFactor); // Always pass -1 as the delta, not entirely sure why
var newZoom = returnedValues[0];
var offset = returnedValues[1];
paper.view.zoom = newZoom;
paper.view.center = paper.view.center.add(offset);
}
};
var addImage = function(imageDataUrl) {
if(paper.view != null) {
var img = document.createElement("img");
img.src = imageDataUrl;
var presentMomentForId = new Date().getTime() + "-image"; // For purposes of having unique IDs
img.id = presentMomentForId;
img.hidden = true;
document.body.appendChild(img);
var raster = new paper.Raster(presentMomentForId);
registerItemEvents(raster);
}
};
var setUpLineAndFreeFormDrawing = function() {
if(paper.project != null) {
// Initial path object, will be reset for new paths after Alt is released
var path = newPath();
var paths = [];
paths.push(path);
// On mousedown add point to start from
paper.project.layers[0].on('mousedown', function(event) {
if(event.event.altKey && !event.event.ctrlKey) { // Alt key to add a path, but disallow attempting to add text at the same time
if(paths[paths.length-1].lastSegment == null) {
//path.add(event.point, event.point);
paths[paths.length-1].add(event.point, event.point);
} else {
//path.add(path.lastSegment.point, path.lastSegment.point);
paths[paths.length-1].add(paths[paths.length-1].lastSegment.point, paths[paths.length-1].lastSegment.point);
}
}
});
// On mousedrag add points to path
paper.project.layers[0].on('mousedrag', function(event) {
if(event.event.altKey && !event.event.ctrlKey) { // Alt key to add a path, but disallow attempting to add text at the same time
if(event.event.shiftKey) { // Use shift key for freeform
//path.add(event.point);
paths[paths.length-1].add(event.point);
} else { // Default of straight line added to path
//path.lastSegment.point = event.point;
paths[paths.length-1].lastSegment.point = event.point;
}
}
}.bind(this));
// Each time Alt comes up, start a new path
paper.tool.onKeyUp = function(event) {
if(event.key == "option") {
registerItemEvents(paths[paths.length-1]);
// Start a new path
paths.push(newPath());
}
};
}
};
// Establishes default line style
var newPath = function() {
var path = new paper.Path();
path.strokeColor = 'black';
path.strokeWidth = 10;
return path;
};
var note = "";
var setNote = function(newNote) {
note = newNote;
};
var setUpNotes = function() {
if(paper.project != null) {
paper.project.layers[0].on('mousedown', function(event) { // TODO should be layer 0 in long run?
if(event.event.ctrlKey && !event.event.altKey && !event.event.shiftKey) { // Only Ctrl key to add text
// Add text box
var textBox = new paper.PointText(event.point);
textBox.justification = 'left';
textBox.fillColor = 'black';
textBox.fontSize = 60;
textBox.content = note;
registerItemEvents(textBox);
}
});
}
};
var selectArea = function(startDragPoint, endDragPoint) {
var rasterTopLeftCorner = new paper.Point(raster.bounds.topLeft);
var adjustedStartDragPoint = new paper.Point(startDragPoint.x - rasterTopLeftCorner.x, startDragPoint.y - rasterTopLeftCorner.y);
var adjustedEndDragPoint = new paper.Point(endDragPoint.x - rasterTopLeftCorner.x, endDragPoint.y - rasterTopLeftCorner.y);
var boundingRectangleRasterCoordinates = new paper.Rectangle(adjustedStartDragPoint, adjustedEndDragPoint);
var boundingRectangleCanvasCoordinates = new paper.Rectangle(startDragPoint, endDragPoint);
var selectedArea = raster.getSubRaster(boundingRectangleRasterCoordinates);
var whitedOutSelection = new paper.Shape.Rectangle(boundingRectangleCanvasCoordinates);
whitedOutSelection.fillColor = 'white';
whitedOutSelection.insertAbove(raster); // Whiteout just above the image we're working with
registerItemEvents(selectedArea);
}
var whiteoutArea = function(startDragPoint, endDragPoint) {
var whitedOutSelection = new paper.Shape.Rectangle(startDragPoint, endDragPoint);
whitedOutSelection.fillColor = 'white';
whitedOutSelection.insertAbove(raster); // Whiteout just above the image we're working with
}
var flattenToDataUrl = function() {
layerAsRaster = paper.project.layers[0].rasterize(); // TODO should be layer 0 in long run? // Layer to Paper.js Raster object
layerAsRaster.visible = false;
var dataString = layerAsRaster.toDataURL();
return dataString;
};
module.exports = {
setCanvas: setCanvas,
setCanvasImage: setCanvasImage,
fitToPage: fitToPage,
addImage: addImage,
setNote: setNote,
flattenToDataUrl: flattenToDataUrl
};
Additionally, here's the SimplePanAndZoom.js file for clarity. It uses minimal Paper functions, it mainly just does calculations:
// Based on http://matthiasberth.com/articles/stable-zoom-and-pan-in-paperjs/
var SimplePanAndZoom = (function() {
function SimplePanAndZoom() { }
SimplePanAndZoom.prototype.changeZoom = function(oldZoom, delta, centerPoint, offsetPoint, zoomFactor) {
var newZoom = oldZoom;
if (delta < 0) {
newZoom = oldZoom * zoomFactor;
}
if (delta > 0) {
newZoom = oldZoom / zoomFactor;
}
// Zoom towards offsetPoint, not centerPoint (unless they're the same)
var a = null;
if(!centerPoint.equals(offsetPoint)) {
var scalingFactor = oldZoom / newZoom;
var difference = offsetPoint.subtract(centerPoint);
a = offsetPoint.subtract(difference.multiply(scalingFactor)).subtract(centerPoint);
}
return [newZoom, a];
};
SimplePanAndZoom.prototype.changeCenter = function(oldCenter, deltaX, deltaY, factor) {
var offset;
offset = new paper.Point(-deltaX, -deltaY);
offset = offset.multiply(factor);
return oldCenter.add(offset);
};
return SimplePanAndZoom;
})();
module.exports = SimplePanAndZoom;
Thanks.
I'm taking some guesses here but I'll address some problems in the code that will hopefully address the behavior you're seeing.
First, I presume paper.project.layers[0] is paper.project.activeLayer. Once that has been rasterized 1) the raster is added to the layer and setting visible = false does cause it to disappear when an update is done.
Second, when you invoke paper.setup(canvas) in imageElement.onload you create a new paper project. This project starts out as the active project and makes the previous project "disappear". So when you create a raster with raster = new paper.Raster(...) it goes into the new project, not the old project.
So now there is a hidden (.visible = false) raster in the old project (let's call it project1) and a new version of it in project2.
I'm not sure if this is the intended behavior or not, but when you invoke paper.setup(canvas) for what seems to be the second time then paper seems to notice that they both refer to the same canvas and keeps project1 and project2 in sync. So creating the second project clears the first project's children array. And adding new paper.Raster(...) ends up adding the raster to project1 and project2.
Now I can't tell what the next piece of the puzzle is. You'd need to add some information like 1) where the mouse event handlers are setup and what they are attached to, 2) what setUpNotes() does, 3) what registerCanvasEvents() does, and 4) what fitToPage does.
There are a few globals created, imageHeight and raster that probably aren't intentional. And it's not clear why you need to use new Image() at all - paper.Raster() accepts URLs, including data URLs.
I was surprised paper cleared the first project. It's curious.
Version 2:
Let me take a stab at structuring this using layers. I'd suggest you get rid of multiple projects because having mouse event handlers attached to multiple projects that share the same canvas adds too much complexity.
So, in your code initialization: paper.setup(canvas). Do this once and only once.
Setup the initial image in the single layer initially created by paper.
// this will be inserted into the current layer, project.activeLayer
var raster = new paper.Raster(imageURL, paper.view.bounds.center);
When the image in your queue changes do something like:
// make the existing image/layer invisible
paper.project.activeLayer.visible = false;
// add a new layer which is inserted in the project and activated
var layer = new paper.Layer();
// the new layer is activated, create a raster for the image
var raster = new paper.Raster(imageURL, paper.view.bounds.center);
// now do your normal logic for editing, zooming, etc.
It's really a bit more complicated than that because you have a queue of images and you only want to create a layer the first time you visit an image. You could initialize all the rasters at the outset, something like:
var imageURLs = ["url to image1", "url to image2", "etc"];
imageURLs.forEach(function(url) {
new paper.Layer();
paper.project.activeLayer.visible = false;
new paper.Raster(url, paper.view.bounds.center);
});
// make the first layer visible and activate it
paper.project.layers[0].visible = true;
paper.project.layers[0].activate();
The preceeding code gives you a parallel array to the images in your queue so switching images is straightforward - there is no checking to see if that image has been created or not:
function setImage(index) {
paper.project.activeLayer.visible = false;
paper.project.layers[index].activate();
paper.project.layers[index].visible = true;
}
Finally, I would make sure my mouse handling wasn't causing me problems. From the new code you posted it looks like each project had a global tool that handled 'mousedown', 'mousedrag', and 'mouseup' events, another set of handlers for activeLayer for 'mousedown', 'mousedrag', and 'mouseup' events, and also selectedItems has a handler for 'mousedrag'. I can't keep track of what all the different handlers are supposed to do across projects. I'm guessing that these are the root issue with the flickering you saw.
I would likely just use paper.view.on for 'mousedown', 'mousedrag', and 'mouseup' events. When I get an event I would check to see if anything on the layer was hit by using the following:
paper.project.activeLayer.hitTest(event.point);
Being able to set events on the view is new for paper but very useful. There may be a few other tweaks necessary to handle highlighting unselected items. A relatively straightforward way to handle that is to have a group of selected items and a group of unselected items:
unSelectedGroup.on('mouseenter', function() {
unSelectedGroup.selected = true;
});
unSelectedGroup.on('mouseleave', function() {
unSelectedGroup.selected = false;
});
These should be safe across layers when only one layer is visible at a time. I would set up these group handlers when setting up the images, whether all up front or on an as-needed basis. Alternatively, you could also add paper.view.on('mousemove', ...) and handle the 'mouseenter' and 'mouseleave' events yourself using hitTest as shown above, but either approach should work.
I think using a layer-based approach to your images will keep things in sync. There are enough problems with the project-based approach and many different mouse event handlers that you'll be on more stable ground regardless.
in a map I want when the user clicks inside the map to be able to draw with his mouse a scheme. For example it clicks and then circles an area just by moving his mouse. The problem is that when he circles the area, continues to draw at the current mouse position.
In other words I want the user to click for start drawing and click again to stop it.
I am using addEventListener and removeEventListener
I am trying to remove the events from the map but it does not work.
Any ideas?
Code:
map.addEventListener('click', goInter, false);
function goInter() {
map.addEventListener('mousemove', move, false);
map.addEventListener('click', close, false);
var pointList = [];
var first_element;
var trig = 0;
function move(e) {
map.dragging.disable();
pointList[pointList.length] = new L.LatLng(e.latlng.lat, e.latlng.lng);
first_element = pointList[0];
//ama to valw den doulebei tipota!!
//document.getElementById("elements").innerHTML = pointList[ii++];
if (pointList.length > 400){
pointList = [];
}
var line = new L.Polyline(pointList, {
color: 'red',
weight: 2,
opacity: 0.5,
});
map.addLayer(line);
if (trig == 1){
map.preventDefault();
alert("den einai 1");
return false;
}
};
function close(){
//map.removeEventListener ('mousemove', move, false);
var last_points = [first_element, pointList[pointList.length-1]];
var last_connection = new L.Polyline(last_points, {
color: 'blue',
weight: 1,
opacity: 0.9
});
map.addLayer(last_connection);
trig = 1;
map.preventDefault();
//map.removeLayer(line);
//map.fitBounds(line.getBounds());
};
};
I have a progress -> i changed the two click events to -> mouseup and mousedown respectively. That gives me a better interaction. when the user releases the button it stops drawing. However if you press it again it draws. ALSO uncomment first line of close() function
Using the Google Earth plugin, I want to be able to allow the user to select placemarks on the ground while the camera is moving, but am not sure how this is possible. It seems that when you call setAbstractView(), even with the flyToSpeed set to SPEED_TELEPORT, the Google Earth plugin ignores any mouse down events except for those to the GEGlobe.
Here's the code, altered slightly (from http://code.google.com/apis/ajax/playground/#draggable_placemark) to illustrate my issue:
var ge;
var placemark;
var dragInfo = null;
var la;
var lat = 37;
var lon = -122;
google.load("earth", "1");
function init() {
google.earth.createInstance('map3d', initCallback, failureCallback);
}
function tick() {
la.set(lat, lon,
0, // altitude
ge.ALTITUDE_RELATIVE_TO_GROUND,
0, // heading
0, // straight-down tilt
5000 // range (inverse of zoom)
);
ge.getView().setAbstractView(la);
lon = lon + 0.00000001;
}
function initCallback(instance) {
ge = instance;
ge.getWindow().setVisibility(true);
// add a navigation control
ge.getNavigationControl().setVisibility(ge.VISIBILITY_AUTO);
// add some layers
ge.getLayerRoot().enableLayerById(ge.LAYER_BORDERS, true);
ge.getLayerRoot().enableLayerById(ge.LAYER_ROADS, true);
// create the placemark
placemark = ge.createPlacemark('');
var point = ge.createPoint('');
point.setLatitude(lat);
point.setLongitude(lon);
placemark.setGeometry(point);
// add the placemark to the earth DOM
ge.getFeatures().appendChild(placemark);
// look at the placemark we created
la = ge.createLookAt('');
placemark.setName('Drag Me!');
ge.getOptions().setFlyToSpeed(ge.SPEED_TELEPORT);
tick();
// Comment this next line out and the drag works as expected.
google.earth.addEventListener(ge, "frameend", tick);
// listen for mousedown on the window (look specifically for point placemarks)
google.earth.addEventListener(ge.getWindow(), 'mousedown', function(event) {
console.log("target type = " + event.getTarget().getType());
if (event.getTarget().getType() == 'KmlPlacemark' &&
event.getTarget().getGeometry().getType() == 'KmlPoint') {
//event.preventDefault();
var placemark = event.getTarget();
dragInfo = {
placemark: event.getTarget(),
dragged: false
};
}
});
// listen for mousemove on the globe
google.earth.addEventListener(ge.getGlobe(), 'mousemove', function(event) {
if (dragInfo) {
event.preventDefault();
var point = dragInfo.placemark.getGeometry();
point.setLatitude(event.getLatitude());
point.setLongitude(event.getLongitude());
dragInfo.dragged = true;
}
});
// listen for mouseup on the window
google.earth.addEventListener(ge.getWindow(), 'mouseup', function(event) {
if (dragInfo) {
if (dragInfo.dragged) {
// if the placemark was dragged, prevent balloons from popping up
event.preventDefault();
}
dragInfo = null;
}
});
document.getElementById('installed-plugin-version').innerHTML =
ge.getPluginVersion().toString();
}
function failureCallback(errorCode) {
}
If you comment out line 56, where tick() is called at each frameend, everything works as in the unaltered code: you can successfully drag the place mark. But when line 56 is in, you can't. So the problem is really with setAbstractView keeping mousedown events from propagating to either the globe or whatever placemark or feature was being clicked.
Any ideas? Is there a workaround for this?
The issue isn't caused by the setAbstractView method, it is caused because of the repeated calls to the tick method via framend.
To explain, you have set up the tick method as an event handler for the frameend event.
Then the tick method updates the view immediately, triggering the frameend event, ad infinitum ...
This pattern causes an issue with the browser message loop, in effect it is blocking the other drag events. Think of it like a very tight loop that is causing a deadlock. To work it you can use setTimeout with a value of 0 to execute the code. This way the animation won't be processed until all other pending drag messages are processed.
The key part is a the modification to your tick() method.
function tick() {
// prevent deadlock
setTimeout(function () {
la.set(lat, lon, 0, ge.ALTITUDE_RELATIVE_TO_GROUND, 0, 0, 5000);
ge.getView().setAbstractView(la);
lon += 0.00001;
}, 0);
};
Here, I made a fully working example for you http://jsfiddle.net/fraser/JFLaT/
I tested it and it is working in Chrome, IE, Firefox on Windows 8 and Chrome, Safari, Firefox on OSX.
I am currently trying to learn Javascript and doing the following tutorial (http://www.sitepoint.com/creating-a-simple-windows-8-game-with-javascript-input-and-sound/) however I have run into an issue that I cannot get past.
I have created a canvas element, attached three listeners to the canvas to work with mouse clicks:
canvas.addEventListener("MSPointerUp", endAim, false);
canvas.addEventListener("MSPointerMove", adjustAim, false);
canvas.addEventListener("MSPointerDown", beginAim, false);
But my functions are never being called on PointerUp or Down or Move.
Below are the functions in question, also note that I have done "console.log" just to debug.. None of those are being even recorded to the console, which is why I am thinking that the events are not being triggered..
function beginAim(event){
console.log("Aim ahoy");
if (playerTurn == 1) {
if (!isAiming) {
aimStart = new createjs.Point(event.x, event.y);
isAiming = true;
}
}
}
function adjustAim(event){
console.log("adjustAim event called");
if (isAiming) {
var aimCurrent = new createjs.Point(event.x, event.y);
aimVector = calculateAim(aimStart, aimCurrent);
//ToDo: write text / show aim arror
console.log("Aiming... " + aimVector.x + "/" + aimVector.y);
}
}
function endAim(event){
if (isAiming) {
console.log("endAim Function called");
isAiming = false;
var aimCurrent = new createjs.Point(event.x, event.y);
aimVector = calculateAim(aimStart, aimCurrent);
playerFire = true;
}
}
function calculateAim(start, end){
var aim = new createjs.Point(
(end.x - start.x) / 80,
(end.y - start.y) / 80);
aim.x = Math.min(MAX_SHOT_POWER, aim.x);
aim.x = Math.max(0, aim.x);
aim.y = Math.max(-MAX_SHOT_POWER, aim.y);
aim.y = Math.min(0, aim.y);
return aim;
}
I knew this was going to be a simple issue.. The MSPointerUp /Down / Move are all for Windows8, this is why they never triggered.
I ended up switching to mousedown, mouseup, and mousemove to get the same results.
add to body or canvas to route touch events to JavaScript:
body, canvas {
-ms-user-select: none;
touch-action: none;
}
Then, you'll need to create a MSGesture object, set its target to canvas, also create a pointerdown listener:
var gesture = new MSGesture();
gesture.target = canvas;
canvas.addEventListener("pointerdown", beginAim, false)
in beginAim add a handler for pointerdown and add it to gesture like this:
if (event.type == "pointerdown") {
gesture.addPointer(e.pointerId);
return
}