I am able to get the intersects from my click event when I use the window object to acquire height and width, but getting the intersects position on a canvas that's dynamically sized is proving much harder. I'm not certain of the formula I would need to use to calculate the vector.x and vector.y values with a div that isn't always the same size.
The canvas is the size of a div that always has a width: height ratio of 4:3 and resizes to fit in the window and is always positioned in the center of the window.
If I resize the window to be 4:3 then the following code works perfectly:
mouse.x = (ecx/div_width) *2 -1;
mouse.y= -(ecy/div_height) *2 + 1;
when I resize the window, whichever dimension is larger than the size of the canvas has the incorrect value. I've linked an image to roughly describe how the problem presents itself
Image of horizontal dimension issue
I initially thought that the matches would be as simple as dividing the difference between the the sizes of the window and the canvas by
My question is, how would I acquire the correct values to pass to the vector object for it's x and y attributes? (using Vector3 and Raycaster)
here is the function I'm using to try and get the object(s) being clicked:
function getClicked(event){
event.preventDefault();
var ecx = event.clientX;
var ecy = event.clientY;
//elem is the div containing the canvas
//the canvas is not the same size as the window
var elem_w = elem.innerWidth();
var elem_h = elem.innerHeight();
//most examples suggest using the window height and width
//to get the position of the mouse in the scene.
//since the scene isn't the same size as the window, that doesn't work
var ww = window.innerWidth;
var wh = window.innerHeight;
mouse.x = (ecx/ww) *2 -1;
mouse.y= -(ecy/wh) *2 + 1;
var objlist = []
rc.setFromCamera(mouse, camera);
var intersects = rc.intersectObjects(scene.children, true);
for (var i=0;i<names_to_spin.length;i++){
var obj = intersects[i];
objlist.push(obj);
}
//ideally, this should return a list of the objects under the cursor
return objlist;
}
I have an array of canvas objects that draw correctly. i have three problems:
Offset. I have tested the code below in JS fiddle and it works, but when i export it my web page, the variables get skewed. The detection happens, but not in the right place. the page width is set in CSS, and the actual canvas area is centered using a margin:0 auto call, however it is smaller than the page width.
<canvas id="canvas" width="780" height="690" style="position:absolute;"></canvas>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var $canvas = $("#canvas");
var canvasOffset = $canvas.offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var scrollX = $canvas.scrollLeft();
var scrollY = $canvas.scrollTop();
var $results = $("#results");
// define the polygon items
var polyArray = new Array (6);
polyArray [0] =[{x:50,y:236}, {x:200,y:115}, {x:350,y:50}, {x:350,y:300}, {x:232,y:325}, {x:75,y:300}];
polyArray [1] =[{x:350,y:55}, {x:350,y:300}, {x:510,y:300}, {x:510,y:205}, {x:578,y:172}, {x:690,y:96}, {x:650,y:17}];
polyArray [2] =[{x:510,y:300}, {x:510,y:200}, {x:715,y:113}, {x:780,y:200}, {x:780,y:485}, {x:625,y:468}, {x:605,y:456}, {x:605,y:428}];
polyArray [3] =[{x:0,y:446}, {x:284,y:320}, {x:255,y:540}, {x:240,y:566}, {x:73,y:600}, {x:0,y:565}];
polyArray [4] =[{x:355,y:305}, {x:510,y:305}, {x:604,y:423}, {x:604,y:460}, {x:628,y:484}, {x:610,y:513}, {x:587,y:468}, {x:537,y:426}, {x:500,y:400}, {x:447,y:424}, {x:312,y:365}, {x:307,y:314 }];
polyArray [5] =[{x:350,y:425}, {x:415,y:421}, {x:455,y:434}, {x:495,y:411}, {x:550,y:444}, {x:618,y:590}, {x:570,y:616}, {x:359,y:597}, {x:333,y:522}];
// call the function to draw all the objects in the array
define(polyArray);
// call through the array to draw the objects
function define(polygon) {
ctx.beginPath();
for (var i = 0; i < polygon.length; i++) {
ctx.moveTo(polygon[i][0].x, polygon[i][0].y);
for (var j = 1; j < polygon[i].length; j++) {
ctx.lineTo(polygon[i][j].x, polygon[i][j].y);
}
ctx.fill();
}
ctx.closePath();
}
function hitTest(polygon) {
// redefine the polygon
define(polygon);
// ask isPointInPath to hit test the mouse position
// against the current path
return (ctx.isPointInPath(mouseX, mouseY));
}
function handleMouseMove(e) {
e.preventDefault();
mouseX = parseInt(e.clientX - offsetX);
mouseY = parseInt(e.clientY - offsetY);
// check if the mouse is inside the polygon
var isInside = hitTest(polyArray);
if (isInside) {
canvas.style.cursor = 'pointer';
$results.text("Mouse is inside the area);
} else {
canvas.style.cursor = 'default';
$results.text("Outside");
}
}
$("#canvas").mousemove(function (e) {
handleMouseMove(e);
});
Detecting which object has been hovered over. What needs to happen is on hover of one the array shapes should effect some CSS/JS. How can i assign an ID variable and detect it?
when i bring responsive design into the equation i'm a bit stuck for how to incorporate this offset and the poly co-ords to scale appropriately.
Any point in the right direction would be greatly appreciated.
Question#1: Getting accurate mouse position after the canvas has moved
Whenever you move your canvas (fex: margin: 0 auto), you must recalculate your offsetX and offsetY values:
If you manually change the canvas element's CSS (fex: canvas.style.margin='50px' inside javascript), then you must also manually call reOffset().
// cache the canvas's offset positions since the
// offset positions are used often
var offsetX,offsetY;
// call this once at the beginning of your app
// and whenever you change the canvas's position on the page
// (eg call when you change margins, scroll, etc)
function reOffset(){
var BB=canvas.getBoundingClientRect();
offsetX=BB.left;
offsetY=BB.top;
}
// have the browser auto-reset offsetX & offsetX when
// the viewport scrolls or resizes
window.onscroll=function(e){ reOffset(); }
window.onresize=function(e){ reOffset(); }
Question#2 Detecting hovers & blurs over your polygons
Your hitTest function will test if the mouse is currently inside a specified polygon. So inside handleMousemove you could call hitText for each of the polygons inside your polyArray.
Keep a flag variable indicating the index# of the last polygon the mouse was inside (or -1 to indicate the mouse was outside all polygons. When your flag variable value changes, you know there has been either a hover-event or a blur-event. Compare the last and current flag variables to determine which polygon is now hovered or blurred.
Question#3 Incorporating a responsive design
Mouse coordinates reported by the browser into e.clientX and e.clientY are always in unscaled values relative to the browser viewport.
So if you:
Click the mouse and use e.clientX/e.clientY to determine the mouse is at [100,100],
Scale your canvas: context.scale(2,2),
And reclick without moving the mouse from its original [100,100] position,
Then:
Using e.clientX/e.clientY to detect the mouse coordinates will still report the position as [100,100] even if the canvas has been scaled and the mouse is at [200,200] relative to the scaled canvas.
The fix:
You must scale the browser's reported mouse position to match the scaling factor of the canvas:
// Determine how much you want to scale the canvas
var scaleFactor=2.00;
// scale the canvas
context.scale(scaleFactor,scaleFactor);
// also scale the mouse position reported by the browser
mouseX=parseInt(e.clientX-offsetX)*scaleFactor;
mouseY=parseInt(e.clientY-offsetY)*scaleFactor;
I want find top position of rotated div from element, I can able find top position of element but I want top(Y pos) position from left(x) position.
I am used this
var degree = degree;
if (degree < 0) {
var sign = -1;
} else {
var sign = 1;
}
var numY = Math.abs(myElem.position().top + sign * ((myElem.outerHeight() / 2) - Math.sin(degree)));
var numX = 0
var bottom = myElem.position().top + myElem.outerHeight(true);
y = numY;
Thanks in Advance
Slope:20 deg, height: 20px,width:400px, left 150px i want find top position
I want to re arrange dragged items after rotation for that I am finding top position.
Please find the jsbin link drop weights into plank.
I think it makes more sense to add the draggable image into the rotated div and to let everything rotate together, rather than worrying about the position of the draggable image. Here is a jsfiddle with your code updated (I only implemented dropping on the right side): http://jsfiddle.net/brendaz/17wwtffz/
drop:
// ...
var offset = ui.draggable.offset();
var rotateOffset = $('.rotatableAra').offset();
// Take the weight out of it's parent div and add it to the rotatable area
ui.draggable.remove();
ui.draggable.addClass("dropped");
ui.draggable.addClass("rightPlankDropped");
$('.rotatableAra').append(ui.draggable);
ui.draggable.css("top", ($('.rightPlank').position().top- ui.draggable.height()).toString() + "px");
ui.draggable.css("left", (offset.left - rotateOffset.left).toString() + "px");
rightArray[ind] = $textval * pos;
// ...
I'm working on an page that contains a rectangular inner-block inside a container. The inner-block can be dragged and also be scaled when you scroll the mouse.
[ See my JSFiddle. ]
The center of the screen is the origin point of the zoom transformation, so when the inner-block is centered in the page it appears to simply scale, but when you drag the inner-block about the center origin point, it will scale appropriately around or away from the center point of the screen. I marked the center screen point with a small red dot in the JSFiddle so its easier to see.
As the inner-block is dragged around I recalculate the top/left coords of it, and also the difference between that position and the center of the page in order to get the transformation-origin adjustment coords.
PROBLEM: It works fine when the inner-block is scale-factor 1, but if you zoom and then drag the object, it unexpectedly jumps position and doesn't zoom back correctly. Are you able to see what I am doing wrong, or what I would need to add to prevent the unexpected behavior? Thanks in advance!
//Get center of the page "origin"
var originX = $('.block').width()/2;
var originY = $('.block').height()/2;
//Get center point of the inner-block
var blockRX = $('.inner-block').width()/2;
var blockRY = $('.inner-block').height()/2;
//Set position of the inner-block to match center origin initially
$(".inner-block").css({top: originY-blockRY, left: originX-blockRX});
$(".inner-block").draggable();
//Initial Scale 1:1
var scale_system = 1;
//Get Top/Left coords of inner-block
var blockTop = $('.inner-block').offset().top;
var blockLeft = $('.inner-block').offset().left;
//Calculate diff between center of page and Top/Left of inner-block
var xCalc = (originX-blockLeft);
var yCalc = (originY-blockTop);
//Set origin of transformations as center of page (in relation to Top/Left)
//Using the just calculated values
$(".inner-block").css({"-webkit-transform-origin": xCalc+"px "+yCalc+"px"});
//Zoom settings
var maxScale = 4;
var minScale = 1;
var zoomScale = .07;
//Drag Actions
$(function() {
var isDragging = false;
//Perform calculations as drag occurs
$(".inner-block").mousedown(function() {
$('.inner-block').mousemove(function(e) {
isDragging = true;
$(window).unbind("mousemove");
//Get New Top/Left of inner-block as it drags
blockTop = $('.inner-block').offset().top;
blockLeft = $('.inner-block').offset().left;
console.log("BlockTopLeft "+blockLeft+" "+blockTop);
//Calculate new diff between Top/Left and Origin
xCalc = (originX-blockLeft);
yCalc = (originY-blockTop);
console.log("Origin Distance "+xCalc+" "+yCalc);
})
})
.mouseup(function() {
var wasDragging = isDragging;
isDragging = false;
$(window).unbind("mousemove");
if (wasDragging) {
//Update origin position in relation to Top/Left of inner-block
$(".inner-block").css({"-webkit-transform-origin": xCalc+"px "+yCalc+"px"});
}
});
});
//Perform scroll function below on mousewheel
$('.block').bind('mousewheel', function (event) {
scroll(event);
});
function scroll(event) {
event.preventDefault();
var newScale = ((event.originalEvent.wheelDelta / 120 > 0) ?
(scale_system * (1.0 + zoomScale)) :
(scale_system * (1.0 - zoomScale)));
scale_system = ((newScale > maxScale) ?
(maxScale) :
(((newScale < minScale)?
(minScale):
(newScale)))
);
//Update Top/Left position of the inner-block
blockTop = $('.inner-block').offset().top;
blockLeft = $('.inner-block').offset().left;
console.log("BlockTopLeft "+blockLeft+" "+blockTop);
//Update X/Y radius to block center
blockRX = ($('.inner-block').width()/2)*scale_system;
blockRY = ($('.inner-block').height()/2)*scale_system;
console.log("BlockRXY "+blockRX+" "+blockRY);
//Recalculate the diff between T/L and origin
console.log("Origin "+originX+" "+originY);
xCalc = (originX-blockLeft);
yCalc = (originY-blockTop);
console.log("Origin - TL "+xCalc+" "+yCalc);
$(".inner-block").css({"-webkit-transform": "scale(" + scale_system + ")"});
}
I think I have found the answer to my own question. After much Googling it appears there are problems with jQuery when trying to perform CSS transformations paired with dragging. There is an extensive issue page on jQuery's development ticket page highlighting the problem and many examples, and they have decided not to address the problem. I'm going to explore other options.
Cannot figure this out, how to find the translated position of the background relative to the canvas. I have the characters coordinates, and I have the coordinates from a mouse click within the canvas, but can't figure out how to find the offset.
In the canvas, when I click somewhere, I get an (x,y) value from (0,0) - (650,575), the size of the window, no matter where my character is. If the character is at (2000, 1500) on the canvas, my click/touch input will always send the character up and left towards 0,0 on the background coordinate.
At first I thought I should subtract the player X position from the max width, then add an offset half the width of the screen, and do the same for the Y position, but that didn't work.
Then I tried subtracting half the width/height of the screen from the current player x,y values but that doesn't work.
Anyone point me in the right direction, it seems elementary but I can't figure it out it's been years since math class???? Thanks
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 650;
canvas.height = 575;
var WIDTH=5000; //level width
var HEIGHT=3750; //level height
ctx.translate(-WIDTH*.5,-HEIGHT*.5); //starts in center of background
Where my player begins on load:
hero.x = WIDTH*.5+325; //offset half canvas width
hero.y = HEIGHT*.5+275; //offset half canvas height
For the Background:
ctx.drawImage(bgImage, BGsrcX , BGsrcY, 1250 , 938 ,-150, -150, BGdestW, BGdestH); `//image is stretched to 5000x3750`
This is the mouse input I'm using
if(navigator.userAgent.match(/(iPhone)|(iPod)|(iPad)/i)){
document.addEventListener('touchstart', function(e) {
if(e.touches.length == 1){ // Only deal with one finger
var touch = e.touches[0]; // Get the information for finger #1
var x = touch.pageX - canvas.offsetLeft;
var y = touch.pageY - canvas.offsetTop;
//clickEvent(x,y); //call your function to manage tweets
}
},false);
}
else{
document.addEventListener('mousedown',function(e) {
var x = e.pageX - canvas.offsetLeft;
var y = e.pageY - canvas.offsetTop;
console.log(x+":"+y);
clickEvent(x,y); //call your function to manage tweets
},false);
}
For the keyboard input to actually pan the background:
if(16 in keysDown && 38 in keysDown && hero.y > 200) {ctx.translate(0,12); }
Don't work with half-translated and non-translated coordinates, translate your mouse click coordinates AND your canvas coordinates.
Then you can just use simple subtraction to find the offset, and to find the distance, you you use the distance formula.