I want to get color of a x y pixel with javascript/jquery, so googled and found that it could be done with canvas.
var canvas = $("<canvas>"); //Create the canvas element
//Create a layer which overlaps the whole window
canvas.css({ position: "fixed", top: "0", left: "0",
width: "100%", height: "100%", "z-index": 9001
});
//Add an event listener to the canvas element
canvas.click(function (ev) {
var x = ev.pageX, y = ev.pageY;
var canvas = this.getContext("2d");
canvas.drawWindow(window, x, y, 1, 1, "transparent");
var data = canvas.getImageData(0, 0, 1, 1).data;
var hex = rgb2hex(data[0], data[1], data[2]);
alert(hex);
$(this).remove();
});
but its not working (drawWindow in firefox not working, not working in chrome too).
any ideas ?
drawWindow is a custom JavaScript implementation. You have to include it before you can use it.
If you are referring to the native method drawWindow(), it cannot be used in a web content that's why it won't work.
Related
i use zoomtopoint and zoom to object. but not working with background.
I want to zoom in on the object and the background. How can i ?
Example :
object size : 100x100 not zoom.
after zoom object size :100x100
after zoom and The grid remained the same.
zoom event
document.addEventListener('wheel', function(event) {
var evt = window.event || event;
var delta = evt.detail? evt.detail*(-120) : evt.wheelDelta;
var curZoom = canvas.getZoom();
var newZoom = curZoom + delta / 4000;
var x = event.offsetX;
var y = event.offsetY;
canvas.zoomToPoint({ x: x, y: y }, newZoom);
if(event != null)event.preventDefault();
return false;
canvas.calcOffset();
}, false);
grid code:
canvas.setBackgroundColor({source: src, repeat: 'repeat'}, canvas.renderAll.bind(canvas), function () {
canvas.renderAll();
proceed();
});
EDİT
#canvas-background { display: inline-block; position: absolute; top: 0; right: 0; }
but i dont use css.
Background image
Thank you
Sorry, i cant speak english well.
Relevant code is below (and the rest is in the JSFiddle), note the canvas size and CSS container trick used to allow zooming out.
Example : object size : 100x100 not zoom.
after zoom object size :100x100
after zoom and The grid is no longer the same.
fabric.Image.fromURL('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADIAAAAyCAIAAACRXR/mAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAASdEVYdFNvZnR3YXJlAEdyZWVuc2hvdF5VCAUAAADLSURBVFhH7ZnBCoMwEET9/68URBHSNj0UolFoI+aQickKlT05jz0MGQIPkb2kadu3ta42ff/MTtLRazct55bajOMjO0lHr920vnWMMTGV0GuphVALoRaiqNV1dq4TLsdUIrTe+z0fw+ndmEo0w/D61AmXYyqh1179WjGVuNLyl0eohVALuZ8Wtzwgt9zyiNxSC6EWQi1EUYtbHpBbbnlEbqmFUAuhFqKoxS0PyC23PCK31EKohVAL0dXK3vLSOX0TnKZ1z8fw/3uiW37L27QIZwrV4gAAAABJRU5ErkJggg==', function(img) {
var patternSourceCanvas = new fabric.StaticCanvas();
patternSourceCanvas.add(img);
var pattern = new fabric.Pattern({
source: function() {
patternSourceCanvas.setDimensions({
width: img.getWidth(),
height: img.getHeight()
});
return patternSourceCanvas.getElement();
},
repeat: 'repeat'
});
var background = new fabric.Rect({
width: canvas.getWidth(),
height: canvas.getHeight(),
fill: pattern,
selectable: false
});
canvas.add(background, rectangle);
canvas.renderAll();
});
Here's a working JSFiddle, https://jsfiddle.net/rekrah/86t2b8bs/.
Hope this helps.
UPDATE:
#forguta also wanted to ensure objects didn't go behind the background when sendToBack() was run. Made "repeated" background image into one image so setBackgroundImage() could be used (image size only increased to 64K and I'm sure could be compressed further).
Simpler code:
canvas.setBackgroundImage('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAACcQAAAnECAIAAAChEWJqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH4QMDDwYflNda9wAAIABJREFUeNrs2TGO67qWhlHSotSFm7z5z+4NoQsoXJbFs8HObYoGbJxmslYk4JfgD053/u9///............', canvas.renderAll.bind(canvas), {
// Needed to position backgroundImage at 0/0
originX: 'left',
originY: 'top'
});
Here's an updated working JSFiddle, https://jsfiddle.net/rekrah/u0srdsdr/.
Hello I use fabricjs to play with the html canvas.
I create the canvas and i add group of objects on it.
On a group of objects, I need to keep fixed width & height for some objects while I scale the object.
I use the 'object:scaling' event to get the active object when it changes size, I read each object of the group and I assign element[i].set({'radius':5}) on the group objects that I want to be unchanged.
But the result is that , all the group object to resize.
I show you the snippet of the object:scaling event :
canvas.on('object:scaling',function(e){
var activeObject1 = e.target;
var elements = e.target._objects;
var count_elements = elements.length;
for(var i = 0; i < count_elements; i++) {
var type = elements[i].typeCircle;
if(type == "parts"){
//elements[i].set({"radius":8,"fill":"#abcde2","stroke":"#367827"});
//elements[i].set('radius',8);
/*elements[i].setWidth(16);
elements[i].setHeight(16);
elements[i].currentWidth = 16;
elements[i].currentHeight = 16;
elements[i].scaleX = 1;
elements[i].scaleY = 1;
console.log(elements[i]);
canvas.renderAll();*/
}
}
});
What should I write into the for loop to keep fixed size on some objects?
everything that I used above, they don't work except for the "fill":"#abcde2","stroke":"#367827"
If anyone has faced something similar on fabricjs, please let me know .
You must use setScaleX() and setScaleY() methods.
Here is an example...
var Rect = new fabric.Rect({
width: 200,
height: 200,
top: 100,
left: 100,
fill: 'rgba(255,0,0,0.5)',
stroke: '#000',
strokeWidth: 1,
});
var Circle = new fabric.Circle({
left: 100,
top: 100,
fill: '#FF00FF',
stroke: 'red',
radius: 100,
opacity: 1,
});
var Group = new fabric.Group([Rect, Circle])
canvas.add(Group)
canvas.on({
'object:scaling': onChange
})
function onChange(obj) {
var circle = obj.target.item(1),
group = obj.target,
scaleX = circle.width / group.getWidth(),
scaleY = circle.height / group.getHeight();
circle.setScaleX(scaleX);
circle.setScaleY(scaleY);
}
JSFIDDLE
Using fabricjs2 to stop scaling of a text item I have modified Rafik Avtoyan's function to work well. I have locked Y scaling for my group so you will have to add this if required.
function handleScalingEvent(obj) {
var text = obj.target.item(1),
group = obj.target,
scaleX = group.width / (group.width * group.scaleX);
text.set('scaleX', scaleX);
}
Best way to make the objects the same size is to divide desired width by object width. For example, if you want all added objects to be 256px the code will look this way:
function selectImage(imagePath){
fabric.Image.fromURL(imagePath, function(oImg) {
canvas.add(oImg);
let zoom = 256 / oImg.width;
oImg.set({ scaleX: zoom, scaleY: zoom, });
oImg.center();
});
}
In the case when the image will be 64px it will scale it by 4 to 256px and in case the image is 512px it will scale it by 0.5 which will make the image smaller to 256px.
Having trouble getting the modified rotational angle of fabic.js object retaliative to is original angle/position.
I'm using .getAngle(), If the object is rotated more than 360 degrees or rotated back and forth I'm having trouble converting this back to an angle in degrees relative to it original position/rotation.
var canvas = new fabric.Canvas('canvas');
//global canvas setting
canvas.selection = false;
canvas.setDimensions({
width: 500,
height: 310
});
//Canvas Objets
// create a rectangle with angle=45
var rect = new fabric.Rect({
left: 100,
top: 100,
fill: 'red',
width: 40,
height: 40,
lockUniScaling: true,
centeredRotation: true
});
canvas.add(rect);
//Object modification event
canvas.on('object:modified', function(e) {
var activeObject = e.target;
document.getElementById('result').value = activeObject.getAngle();
});
I've setup a fiddle showing the default output http://jsfiddle.net/1db5g7us/
I'm assuming in need to do some calculation on the result, but can't figure out what.
Just solved this one, all i needed to do was use the modulus operator to get the rotation relative to its original position rather than the total rotated angle.
activeObject = activeObject%360;
update the fiddle: http://jsfiddle.net/1db5g7us/
Being new to Javascript, my understanding of this is a bit shaky. I've read a few articles and SO posts and learned quite a bit, but I'm having issues implementing some code. I'm using the KineticJS library to implement some canvas functions. I was working with a fiddle and was able to get an image to resize with the mouse control, however, when I put the code into a prototype function, resizing no longer works.
Canvas.prototype.addImg = function(){
var self = this;
var image;
var imageObj = new Image();
imageObj.onload = function() {
image = new Kinetic.Image({
x: 200,
y: 50,
image: imageObj,
width: 106,
height: 118,
draggable: false
});
self.backgroundLayer.add(image);
self.stage.add(self.backgroundLayer);
};
imageObj.src = 'http://www.html5canvastutorials.com/demos/assets/yoda.jpg';
var circle1 = new Kinetic.Circle({
x: 150,
y: 150,
radius: 10,
fill: 'red',
stroke: 'black',
strokeWidth: 4,
draggable: false
});
circle1.isResizing = false;
circle1.on("click", function (e) {
// toggle resizing true/false
var isResizing = !this.isResizing;
this.setDraggable(isResizing);
self.backgroundLayer.setDraggable(!isResizing);
this.setFill((isResizing ? "green" : "red"));
this.isResizing = isResizing;
self.backgroundLayer.draw();
});
circle1.on("dragmove", function () {
if (this.isResizing) {
var pos = this.getPosition();
var x = pos.x;
var y = pos.y;
var rectX = image.getX();
var rectY = image.getY();
image.setSize(x - rectX, y - rectY);
self.backgroundLayer.draw();
}
});
self.backgroundLayer.add(circle1);
self.backgroundLayer.draw();
}
I am assuming the problem lies within the use of this in the function, but I'm not sure how to fix the problem. Could somebody tell me what the problem is and how I would fix this?
I can see a problem with the line that is setting the size of image:
image.setSize(x - rectX, y - rectY);
For example if x is 100 and rectX is 200, you end up with a width of '-100', which is not legal.
In the fiddle you provided, when I use constant values, the image re-sizes perfectly:
rect.setSize(200, 200);
Modified fiddle.
The solution I've come upon, is that it is not an issue of this, but the setSize() method. For some reason or another, it is not working in my local application. When I replace this for setWidth() and setHeight(), everything works the way that it should.
Im running into this strange problem..! I've a kineticJS text element and I'm converting it into image.. Here is the Code
var simpleText = new Kinetic.Text({
x: 50,
y: 50,
text: $("#text").val(),
fontSize: $("#fontSize").val(),
fontFamily: $("#fontName").val(),
fill: $("#fontColor").val(),
});
var twidth = simpleText.getWidth();
var theight = simpleText.getHeight();
simpleText.toImage({
width:twidth,
height:theight,
callback: function(img){
var textImg = new Kinetic.Image({
image: img,
x: 0,
y: 0,
width: twidth,
height: theight,
name: 'image',
stroke: 'red',
strokeWidth: 2,
strokeEnabled: false
});
addElement(textImg, textImg.getWidth(), textImg.getHeight());
}
});
So the problem exist here..!
var twidth = simpleText.getWidth();
var theight = simpleText.getHeight();
If I just put the width and height in numeric form, everything works fine and text is converted, something like this
var twidth = 500;
var theight = 100;
But if I use simpleText.getWidth() and simpleText.getHeight(), nothing happens, the image is created but it doesn't have that TEXT. As I saw in documentation, width and height are optional params for toImage(), so I removed now, but now its show this error..
Uncaught TypeError: Cannot read property 'bufferCanvas' of undefined
kinetic.js:28 Kinetic.Node.toDataURL kinetic.js:28
Kinetic.Node.toImage kinetic.js:28 add_text canvas.js:83 (anonymous
function) canvas.js:352 f.event.dispatch jquery.min.js:3 h.handle.i
any idea whats wrong with my code?
I am not shure is it bug or feature. But problem is: picture are taken from rectangle with this coordinates: {x:0 y:0}; width and height - what you insert as toImage params. (twidth, theight)
But text has coords {x : 50, y : 50}. So it is outside of "picture" rectagle above.
As you say if yor increase width and height:
var twidth = 500;
var theight = 100;
Everything is fine and you will see text, but image will be big with empty space.
So... just insert "x" and "y" params to toImage function:
simpleText.toImage({
width:twidth,
height:theight,
x : 50,
y : 50,
callback: function(img){
$('body').append($(img));
}
});
example: http://jsfiddle.net/lavrton/hgax2/