I currently have some javascript that receives an image from a variable and loads it into the canvas. The canvas is inside a div in order to use kineticjs. I'm loading a regular hexagon with the following code:
function MakeShape()
{
var stage = new Kinetic.Stage({
container: 'container',
width: 490,
height: 225
});
var polyLayer = new Kinetic.Layer();
var hexagon = new Kinetic.RegularPolygon({
x: stage.width()/2,
y: stage.height()/2,
sides: 6,
radius: 70,
fill: 'red',
offset: {
x: 100,
y: 0
},
draggable: true
});
polyLayer.add(hexagon);
stage.add(polyLayer);
}
However, when loading, the layer receives the background of the canvas, when I want the shape to be above the image. Do I have to draw the image onto the layer as well as the shape? How am I supposed to do this when the image is loaded before the shape? Thanks.
I'm not sure what you mean by "javascript receives an image from a variable and loads it into the Canvas". I'm guessing that your Canvas element's is assigned a background-image==that image.
Anyway, new Kinetic.Stage plus new Kinetic.Layer will create a new canvas that covers the container element. So any image you put in your Div and Canvas will be overlaid by the new Canvas that KineticJS creates.
Bottom line...Yes, draw the image onto the layer (using new Kinetic.Image) and eliminate your Canvas element with the image.
Good luck with your project!
[ Added Example code ]
var stage = new Kinetic.Stage({
container: 'container',
width: 490,
height: 225
});
var polyLayer = new Kinetic.Layer();
stage.add(polyLayer);
var hexagon,image1;
var img=new Image();
img.onload=start;
img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/nightscape.jpg";
function start(){
// add the image first
// It's z-index will be lower then the hexagon's z-index
// so the hexagon will be drawn over the image
image1=new Kinetic.Image({
x:0,
y:0,
image:img,
});
polyLayer.add(image1);
hexagon = new Kinetic.RegularPolygon({
x: stage.width()/2,
y: stage.height()/2,
sides: 6,
radius: 70,
fill: 'red',
offset: {
x: 100,
y: 0
},
draggable: true
});
polyLayer.add(hexagon);
polyLayer.draw();
}
body{padding:20px;}
#container{
border:solid 1px #ccc;
margin-top: 10px;
width:490px;
height:225px;
}
<script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v5.1.0.min.js"></script>
<h4>Background image with draggable hex on top.</h4>
<div id="container"></div>
Related
I'm just starting out the KineticJS library and been playing about with it creating shapes etc.. However, I'm struggling to create a custom circle with my own image in it. I have tried using the fillPattern but it doesn't scale/centre correctly at all. Am I meant to use my own circle image or a rectangle image and then let KineticJS take care of things?
Just to give a bit of background: What I want is 3 balls bouncing in and then settling in place.
Any advice is welcome.
Sorted it... needed the offset values
var ball = new Image();
ball.src = 'ball2.jpg';
ball.height = 230;
ball.width = 230;
var stage = new Kinetic.Stage({
container: 'container',
width: 1000,
height: 1000
});
var circle = new Kinetic.Circle({
x: 300,
y: 300,
radius: 115,
fillPatternImage: ball,
fillPatternOffset :{
x: -115,
y: -115
}
});
var layer = new Kinetic.Layer();
// add the shape to the layer
layer.add(circle);
// add the layer to the stage
stage.add(layer);
ball.onload = function () {
stage.draw();
}
I have an image and I need to extract and create another kinetic image from it (without modifying the original image).
The extracted image will be a rectangle, and I have the coordinates of its 4 points.
I checked on http://kineticjs.com/docs/Kinetic.Image.html if there is any function that enables to do that but didn't find anything.
I tried with the crop method:
var newImage = new Image();
newImage.onload = function () {
var roikImage = new Kinetic.Image({
x: 10,
y: 100,
image: this,
width:100,
heigth:100,
crop: {
x:0 , y:0 , width:100, heigth:100
}
});
//Here I add the image to the layer, and draw the stage
};
newImage.src= 'src/of/my/image';
but I got a small portion of the image. I couldn't figure out how to do to crop the image using the coordinates of the 4 points of the rectangle.
Any ideas?
If I understand correctly, than you are on the right track by using crop.
You can grab the image of another Kinetic Image by using the .getImage() function and then you can use the crop attribute or setCrop() and getCrop() methods to achieve what you want.
var imageObj = new Image();
imageObj.onload = function () {
var yoda = new Kinetic.Image({
x: 100,
y: 50,
image: imageObj,
width: 106,
height: 118
});
// add the shape to the layer
layer.add(yoda);
var newImage = new Kinetic.Image({
x: 300,
y: 50,
width: 100,
height: 100,
image: yoda.getImage(), //get the original image from yoda
crop: {
x:0 , y:0 , width:100, height:100
}
});
layer.add(newImage);
// add the layer to the stage
stage.add(layer);
};
imageObj.src = 'http://www.html5canvastutorials.com/demos/assets/yoda.jpg';
Change the x,y values inside crop to choose where you want to start the crop, and then set the width and height to the dimensions you would your crop size to be starting at the x,y point of the image. x:0, y:0 is the top left corner of the image.
jsfiddle
I have two layers generally representing a large background and some content on top of it.
I have made the background draggable but when dragged, it covers the content of the other layer.
Is it possible to keep it in the background while dragging it?
I have tried binding the drag events with .moveToBottom() for the background group (later added to backgroundLayer) like that:
groupBackground.on('dragstart',function(){
groupBackground.moveToBottom();
});
groupBackground.on('dragmove',function(){
groupBackground.moveToBottom();
});
groupBackground.on('dragend',function(){
groupBackground.moveToBottom();
});
but to no result.
You can “draw under” by using the canvas “.globalCompositeOperation”
This will allow your user to drag the background under the foreground.
And you can apply it to KineticJs like this:
layer.getContext().globalCompositeOperation = "destination-over";
Here is code and a Fiddle: http://jsfiddle.net/m1erickson/2GFSE/
var stage = new Kinetic.Stage({
container: 'container',
width: 578,
height: 200
});
var layer = new Kinetic.Layer();
stage.add(layer);
var background = new Kinetic.Rect({
x: stage.getWidth() / 2,
y: stage.getHeight() / 2,
width: 250,
height: 250,
fill: 'black',
stroke: 'black',
strokeWidth: 4,
draggable: true
});
var foreground = new Kinetic.Ellipse({
x: stage.getWidth() / 3,
y: stage.getHeight() / 3,
radius: {
x: 50,
y: 30
},
fill: 'red',
stroke: 'black',
strokeWidth: 4
});
// add the background and foreground to the layer
layer.add(foreground);
layer.draw();
layer.getContext().globalCompositeOperation = "destination-over";
layer.add(background);
layer.draw();
After updating KineticJS from v4.0.5 to v4.3.1, I can no longer fill a Polygon with an Image using this method:
polygon.setFill({
image: imageObj
});
I end up with a black background. Is there another way around this?
Attempt: I tried poly.setFillPattern(image)
jsfiddle: http://jsfiddle.net/eeSSN/
Remove "fill" config in Kinetic.Polygon.
You created thingImage but never used it.
You can use "setFillPatternImage"
You have to call stage.draw inside iamge.onload
Code:
var stage = new Kinetic.Stage({
container: 'canvas',
width: 600,
height: 600
});
var layer = new Kinetic.Layer();
// Outline
var poly = new Kinetic.Polygon({
points: [0, 0, 400, 0, 400, 400, 0, 400],
//fill: 'red',
stroke: '#000',
strokeWidth: 0,
name: 'poly',
draggable: false
});
var imageObj = new Image();
imageObj.src = 'http://www.html5canvastutorials.com/demos/assets/darth-vader.jpg';
imageObj.onload = function() {
poly.setFillPatternImage(imageObj);
stage.draw();
}
layer.add(poly);
stage.add(layer);
http://jsfiddle.net/lavrton/eeSSN/1/
What I want do is dynamically create a shape on mousedown, and then immediately have it (the shape) follow the mouse cursor until mouseup sets it in place.
Here is what I have so far and it's not working for me.
addNegativeButton.on('mousedown', function(){
var userPos = stage.getUserPosition();
shapesLayer.add(new Kinetic.Image({
image: imageObj,
x: userPos.x,
y: userPos.y,
height: 25,
width: 25,
rotation: 1,
draggable: true,
offset: 12
}));
var last = shapesLayer.getChildren()[shapesLayer.getChildren().length -1];
stage.on("mouseup", function(){
last.setAbsolutePosition(stage.getUserPosition());
stage.off("mouseup");
});
To reiterate:
What I have is an 'addNegativeButton' which when clicked creates a shape.
But I want it to follow the mouse cursor until the click is released.
http://jsfiddle.net/CPrEe/37/
Any suggestions?
Turns out its rather simple ;)
After you add the element/shape, all you have to do is use the simulate function to simulate mouse down and it drags....
var stage = new Kinetic.Stage({
container: 'container',
width: 578,
height: 200
});
var layer = new Kinetic.Layer();
var rect = new Kinetic.Rect({
x: 20,
y: 20,
width: 100,
height: 50,
fill: 'green',
stroke: 'black',
strokeWidth: 4
});
//What I really want here is to start dragging the circle until the
//user releases the mouse, which would then place the circle.
rect.on('mousedown', function(evt) {
var userPos = stage.getUserPosition();
var latestElement = new Kinetic.Circle({
x: userPos.x,
y: userPos.y,
radius: 20,
fill: 'red',
stroke: 'black',
strokeWidth: 4,
draggable: true
})
layer.add(latestElement);
// Here's the bit you want. After adding the circle (with draggable:true) simulate the mousedown event on it which will initiate the drag
latestElement.simulate('mousedown');
layer.draw();
});
layer.add(rect);
stage.add(layer);
http://jsfiddle.net/CPrEe/38/
http://kineticjs.com/docs/symbols/Kinetic.Node.php#simulate