Is there a way one could zoom and pan on a canvas using KineticJS? I found this library kineticjs-viewport, but just wondering if there is any other way of achieving this because this library seems to be using so many extra libraries and am not sure which ones are absolutely necessary to get the job done.
Alternatively, I am even open to the idea of drawing a rectangle around the region of interest and zooming into that one particular area. Any ideas on how to achieve this? A JSFiddle example would be awesome!
You can simply add .setDraggable("draggable") to a layer and you will be able to drag it as long as there is an object under the cursor. You could add a large, transparent rect to make everything draggable. The zoom can be achieved by setting the scale of the layer. In this example I'm controlling it though the mousewheel, but it's simply a function where you pass the amount you want to zoom (positive to zoom in, negative to zoom out). Here is the code:
var stage = new Kinetic.Stage({
container: "canvas",
width: 500,
height: 500
});
var draggableLayer = new Kinetic.Layer();
draggableLayer.setDraggable("draggable");
//a large transparent background to make everything draggable
var background = new Kinetic.Rect({
x: -1000,
y: -1000,
width: 2000,
height: 2000,
fill: "#000000",
opacity: 0
});
draggableLayer.add(background);
//don't mind this, just to create fake elements
var addCircle = function(x, y, r){
draggableLayer.add(new Kinetic.Circle({
x: x*700,
y: y*700,
radius: r*20,
fill: "rgb("+ parseInt(255*r) +",0,0)"
})
);
}
var circles = 300
while (circles) {
addCircle(Math.random(),Math.random(), Math.random())
circles--;
}
var zoom = function(e) {
var zoomAmount = e.wheelDeltaY*0.001;
draggableLayer.setScale(draggableLayer.getScale().x+zoomAmount)
draggableLayer.draw();
}
document.addEventListener("mousewheel", zoom, false)
stage.add(draggableLayer)
http://jsfiddle.net/zAUYd/
Here's a very quick and simple implementation of zooming and panning a layer. If you had more layers which would need to pan and zoom at the same time, I would suggest grouping them and then applying the on("click")s to that group to get the same effect.
http://jsfiddle.net/renyn/56/
If it's not obvious, the light blue squares in the top left are clicked to zoom in and out, and the pink squares in the bottom left are clicked to pan left and right.
Edit: As a note, this could of course be changed to support "mousedown" or other events, and I don't see why the transformations couldn't be implemented as Kinetic.Animations to make them smoother.
this is what i have done so far.. hope it will help you.
http://jsfiddle.net/v1r00z/ZJE7w/
I actually wrote kineticjs-viewport. I'm happy to hear you were interested in it.
It is actually intended for more than merely dragging. It also allows zooming and performance-focused clipping. The things outside of the clip region aren't rendered at all, so you can have great rendering performance even if you have an enormous layer with a ton of objects.
That's the use case I had. For example, a large RTS map which you view via a smaller viewport region -- think Starcraft.
I hope this helps.
As I was working with Kinetic today I found a SO question that might interest you.
I know it would be better as a comment, but I don't have enough rep for that, anyway, I hope that helps.
These answers seems not to work with the KineticJS 5.1.0. These do not work mainly for the signature change of the scale function:
stage.setScale(newscale); --> stage.setScale({x:newscale,y:newscale});
However, the following solution seems to work with the KineticJS 5.1.0:
JSFiddle: http://jsfiddle.net/rpaul/ckwu7u86/3/
Unfortunately, setting state or layer draggable prevents objects not draggable.
Duopixel's zooming solution is good, but I would rather set it for stage level, not layer level.
Her is my solution
var stage = new Kinetic.Stage({
container : 'container',
width: $("#container").width(),
height: $("#container").height(),
});
var layer = new Kinetic.Layer();
//layer.setDraggable("draggable");
var center = { x:stage.getWidth() / 2, y: stage.getHeight() / 2};
var circle = new Kinetic.Circle({
x: center.x-100,
y: center.y,
radius: 50,
fill: 'green',
draggable: true
});
layer.add(circle);
layer.add(circle.clone({x: center.x+100}));
// zoom by scrollong
document.getElementById("container").addEventListener("mousewheel", function(e) {
var zoomAmount = e.wheelDeltaY*0.0001;
stage.setScale(stage.getScale().x+zoomAmount)
stage.draw();
e.preventDefault();
}, false)
// pan by mouse dragging on stage
stage.on("dragstart dragmove", function(e) {window.draggingNode = true;});
stage.on("dragend", function(e) { window.draggingNode = false;});
$("#container").on("mousedown", function(e) {
if (window.draggingNode) return false;
if (e.which==1) {
window.draggingStart = {x: e.pageX, y: e.pageY, stageX: stage.getX(), stageY: stage.getY()};
window.draggingStage = true;
}
});
$("#container").on("mousemove", function(e) {
if (window.draggingNode || !window.draggingStage) return false;
stage.setX(window.draggingStart.stageX+(e.pageX-window.draggingStart.x));
stage.setY(window.draggingStart.stageY+(e.pageY-window.draggingStart.y));
stage.draw();
});
$("#container").on("mouseup", function(e) { window.draggingStage = false } );
stage.add(layer);
http://jsfiddle.net/bighostkim/jsqJ2/
Related
The game I'm creating doesn't require any physics, however you are able to interact when hovering over/clicking on the sprite by using sprite.setInteractive({cursor: "pointer"});, sprite.on('pointermove', function(activePointer) {...}); and similar. However I noticed two issues with that:
The sprite has some area which are transparent. The interactive functions will still trigger when clicking on those transparent areas, which is unideal.
When playing a sprite animation, the interactive area doesn't seem to entirely (at all?) change, thus if the sprite ends on a frame bigger than the previous, there end up being small areas I can't interact with.
One option I thought of was to create a polygon over my sprite, which covers the area I want to be interactive. However before I do that, I simply wanted to ask if there are simpler ways to fix these issues.
Was trying to find an answer for this myself just now..
Think Make Pixel Perfect is what you're looking for.
this.add.sprite(x, y, key).setInteractive(this.input.makePixelPerfect());
https://newdocs.phaser.io/docs/3.54.0/focus/Phaser.Input.InputPlugin-makePixelPerfect
This might not be the best solution, but I would solve this problem like this. (If I don't want to use physics, and if it doesn't impact the performance too much)
I would check in the event-handler, if at the mouse-position the pixel is transparent or so, this is more exact and less work, than using bounding-boxes.
You would have to do some minor calculations, but it should work well.
btw.: if the origin is not 0, you would would have to compensate in the calculations for this. (in this example, the origin offset is implemented)
Here is a demo, for the click event:
let Scene = {
preload ()
{
this.load.spritesheet('brawler', 'https://labs.phaser.io/assets/animations/brawler48x48.png', { frameWidth: 48, frameHeight: 48 });
},
create ()
{
// Animation set
this.anims.create({
key: 'walk',
frames: this.anims.generateFrameNumbers('brawler', { frames: [ 0, 1, 2, 3 ] }),
frameRate: 8,
repeat: -1
});
// create sprite
const cody = this.add.sprite(200, 100).setOrigin(0);
cody.play('walk');
cody.setInteractive();
// just info text
this.mytext = this.add.text(10, 10, 'Click the Sprite, or close to it ...', { fontFamily: 'Arial' });
// event to watch
cody.on('pointerdown', function (pointer) {
// calculate x,y position of the sprite to check
let x = (pointer.x - cody.x) / (cody.displayWidth / cody.width)
let y = (pointer.y - cody.y) / (cody.displayHeight / cody.height);
// just checking if the properties are set
if(cody.anims && cody.anims.currentFrame){
let currentFrame = cody.anims.currentFrame;
let pixelColor = this.textures.getPixel(x, y, currentFrame.textureKey, currentFrame.textureFrame);
// alpha > 0 a visible pixel of the sprite, is clicked
if(pixelColor.a > 0) {
this.mytext.text = 'Hit';
} else {
this.mytext.text = 'No Hit';
}
// just reset the textmessage
setTimeout(_ => this.mytext.text = 'Click the Sprite, or close to it ...' , 1000);
}
}, this);
}
};
const config = {
type: Phaser.AUTO,
width: 400,
height: 200,
scene: Scene
};
const game = new Phaser.Game(config);
<script src="https://cdn.jsdelivr.net/npm/phaser#3.55.2/dist/phaser.js"></script>
I'm pretty much new to canvas. What I'm trying to make is that I can write text in canvas using input and can be able to resize it by dragging it's corners. Also I should be able to drag text position within the canvas.
Following is the screen shot of what I want!
Canvas is raster, not vector. By simply drawing and resizing text you would expect it to get blurry or pixelated. And redrawing the whole canvas each time user moves the cursor while resizing will not result in the best performance. Consider using svg instead. In case you do need canvas and don't want to implement all the functions yourself, you can use the paperjs library.
http://paperjs.org/reference/pointtext/
As #hirasawa-yui mentioned, you can use Paper.js to greatly facilitate the implementation of what you want in a canvas.
Here is a simplified sketch showing a possible implementation of dragging/resizing interactions.
// create item
var item = new PointText({
content: 'Custom text content',
point: view.center,
justification: 'center',
fontSize: 30,
selected: true
});
// init variables so they can be shared by event handlers
var resizeVector;
var moving;
// on mouse down...
function onMouseDown(event) {
// ...do a hit test on item bounds with a small tolerance for better UX
var cornerHit = item.hitTest(event.point, {
bounds: true,
tolerance: 5
});
// if a hit is detected on one of the corners...
if (cornerHit && ['top-left', 'top-right', 'bottom-left', 'bottom-right'].indexOf(cornerHit.name) >= 0) {
// ...store current vector from item center to point
resizeVector = event.point - item.bounds.center;
// ...else if hit is detected inside item...
} else if (item.hitTest(event.point, { fill: true })) {
// ...store moving state
moving = true;
}
}
// on mouse drag...
function onMouseDrag(event) {
// ...if a corner was previously hit...
if (resizeVector) {
// ...calculate new vector from item center to point
var newVector = event.point - item.bounds.center;
// scale item so current mouse position is corner position
item.scale(newVector / resizeVector);
// store vector for next event
resizeVector = newVector;
// ...if item fill was previously hit...
} else {
// ...move item
item.position += event.delta;
}
}
// on mouse up...
function onMouseUp(event) {
// ... reset state
resizeVector = null;
moving = null;
}
// draw instructions
new PointText({
content: 'Drag rectangle to move, drag corners to resize.',
point: view.center + [0, -50],
justification: 'center'
});
I am trying to do an application with canvas and which have multiple objects with events binded to them like, mouse down and mouse up e.t.c.,
I am using kinetic js.
Well My doubt is if I have to draw two circles on canvas using kinetic js. I can use objects directly. But if I have to place 500 circles in the division, Its too difficult to have 500 circle objects to create manually. So, is there any other alternative to implement this one?
I use these events for every circle object I use
var circle = new Kinetic.Circle({
x: 100,
y: 100,
radius: 5,
fill: 'red',
stroke: 'black',
strokeWidth: 1
});
circle.setAttr('fact','Kinetic JS is Awesome')
circle.on('mouseover', function() {
document.body.style.cursor = 'pointer'
});
circle.on('mouseout', function() {
document.body.style.cursor = 'default'
});
circle.on('mousedown', function() {
var fill = this.getFill() == 'red' ? '#00d00f' : 'red';
this.setFill(fill);
alert(this.getAttr('fact'));// I do some stuff here
layer.draw();
});
I recommend also that you check the tutorials of KineticJS, this one is about a stress test: 1000 shapes + their respective tooltips.
http://www.html5canvastutorials.com/labs/html5-canvas-10000-shape-stress-test-with-kineticjs
PS: You just have to copy paste the code and update the KineticJS version here.
I need some assistance changing the opacity of a shape using KineticJS (5.0.0.).
In an mouse event, I want to change the opacity of the shape, which triggered the event. Whenever the shape is hovered, it gets visible ( opacity 1.0 ) and when it's left, it becomes invisible ( opacity 0.0 ). It works fine, whenever I redraw the whole Layer of the specified shape.
The point is, I can't redraw the whole Layer because it takes to much time ( ~300 shapes ). For that reason I changed some code, to just draw the shape.
jsFiddle:
http://jsfiddle.net/p39uH/2/ ( see lines 25 and 30 of HTML )
var stage = new Kinetic.Stage({
container: 'container',
width: 578,
height: 200
});
var layer = new Kinetic.Layer();
var pentagon = new Kinetic.RegularPolygon({
x: stage.width()/2,
y: stage.height()/2,
sides: 5,
radius: 70,
fill: 'red',
stroke: 'black',
strokeWidth: 4,
opacity: 0.1
});
pentagon.on('mouseover', function() {
this.opacity(0.3);
this.draw(); // instead of layer.draw();
});
pentagon.on('mouseout', function() {
this.opacity(0.0);
this.draw(); // instead of layer.draw();
});
// add the shape to the layer
layer.add(pentagon);
// add the layer to the stage
stage.add(layer);
( Code is based on this: http://www.html5canvastutorials.com/kineticjs/html5-canvas-set-alpha-with-kineticjs/ )
Even though I set the opacity of the shape to 0.0 when left, it's still visible as you can see. Every time it is hovered, it becomes more and more visible ( I guess the shape gets redrawn ).
Is there any way to (re)draw the shape with an opacity of 0.0 WITHOUT drawing the whole stage and/or layer ?
Thanks in advance.
Yes, a quick look indicates node.draw() might be broken in 5.0.1.
Workarounds:
Drop back to version 4.4.0
Use layer.drawScene() which saves redraw time by not redrawing the hit-canvas.
I am animating a circle using Raphael. When the circle is large I get artifacts around the circle when its moving. It seems to be something of a clipping / redraw region issue and wondered if there was a work around?
It seems to be OK in firefox (if a little jerky) and appears very reliably in Chrome. It also is exacerbated by using opacity on the fill property i.e. rgba(255,0,0,0.7)
Here is a jsFiddle showing the issue. Just click around the paper on the right to move the circle.
Code:
var discattr = {
fill: "#666",
stroke: "none",
width: 35
};
var paper = Raphael("svgcontainer", 400, 400);
circle = paper.circle(150, 150, discattr.width, discattr.width).attr({
stroke: "none",
fill: "rgba(255,0,0,0.7)"
});
var coords = []
var animateCircle = function(coords) {
if (!coords.length) return;
var nextCoords = coords.shift()
var move = Raphael.animation(nextCoords, 500, "linear", function() {animateCircle(coords)});
circle.animate(move);
}
$("#svgcontainer").on("mouseup", function(e) {
coords.push({cx: e.pageX, cy: e.pageY})
animateCircle(coords);
});
Buffering is a technique used to prevent animation artifacts (tearing, as JamWaffles points out). If you look at the answer to this Stack Overflow question you'll find information about an SVG setting to turn on buffering, but so far it doesn't appear to be supported by major browsers.