Part of my app contains functionality similar to google maps in that the user should be able to zoom in and out on an image within a container.
In the same way that google maps does I want the user to be able to scroll with the mousewheel and the pixel on the image to remain directly under the mousepointer at all times. So essentially the user will be zooming to wherever their mouse pointer is.
For the zooming/translating I am using css transforms like so:
visible
$('#image').css({
'-moz-transform': 'scale(' + ui.value + ') translate(' + self.zoomtrans.xNew + 'px, ' + self.zoomtrans.yNew + 'px)',
'-moz-transform-origin' : self.zoomtrans.xImage + 'px ' + self.zoomtrans.yImage + 'px',
'-webkit-transform': 'scale(' + ui.value + ') translate(' + self.zoomtrans.xNew + 'px, ' + self.zoomtrans.yNew + 'px)',
'-webkit-transform-origin' : self.zoomtrans.xImage + 'px ' + self.zoomtrans.yImage + 'px',
'-o-transform': 'scale(' + ui.value + ') translate(' + self.zoomtrans.xNew + 'px, ' + self.zoomtrans.yNew + 'px)',
'-o-transform-origin' : self.zoomtrans.xImage + 'px ' + self.zoomtrans.yImage + 'px',
'-ms-transform': 'scale(' + ui.value + ') translate(' + self.zoomtrans.xNew + 'px, ' + self.zoomtrans.yNew + 'px)',
'-ms-transform-origin' : self.zoomtrans.xImage + 'px ' + self.zoomtrans.yImage + 'px',
'transform': 'scale(' + ui.value + ') translate(' + self.zoomtrans.xNew + 'px, ' + self.zoomtrans.yNew + 'px)',
'transform-origin' : self.zoomtrans.xImage + 'px ' + self.zoomtrans.yImage + 'px'
});
I have managed to find various implementations of how to go about doing this however I am using a self rolled smooth scroll technique to interpolate the mouse events and provide momentum.
Trying to get the two to work correctly together is proving troublesome.
Rather than paste a whole load of code here I have created a jsFiddle that includes the mousewheel smoothscroll technique along with the zoom function that I have so far.
http://jsfiddle.net/gordyr/qGGwx/2/
This is essentially a fully functioning demo of this part of my app.
If you scroll the mousewheel you will see that the jqueryui slider interpolates and provides the momentum/deceleration correctly. However the zoom does not react correctly.
If you scroll your mousewheel only one point the zoom works perfectly but any further scrolls do not work. I assume this is because the scale of the image has now changed causing the calculations to be incorrect. I have attempted to compensate for this but have not had any luck so far.
So to summarise, I would like to modify the code in my jsFiddle so that the image zooms directly to the mousepointer at all times.
Huge thanks in advance to anyone willing to help.
You can do it more easily with css3 transitions.
Exemple: http://jsfiddle.net/BaliBalo/xn75a/
The main center-mouse algorithm is here:
//Center the image if it's smaller than the container
if(scale <= 1)
{
currentLocation.x = im.width() / 2;
currentLocation.y = im.height() / 2;
}
else
{
currentLocation.x += moveSmooth * (mouseLocation.x - currentLocation.x) / currentScale;
currentLocation.y += moveSmooth * (mouseLocation.y - currentLocation.y) / currentScale;
}
If you want to keep your already-existing code, I think you can do it approximatively the same: the trick to get the mouse position on the zoomed image when the image itself is zoomed by a css scale transform and using transform-origin is to substract the transform origin to your point then multiply by the factor and finally re-add the transform-origin.
You can also use translate as in this updated example: http://jsfiddle.net/BaliBalo/xn75a/15/
As you can see it even simplifies the formulas but don't forget to sub the center of the element to mouse point as a translation of {0, 0} will zoom on the middle of the image.
EDIT:
I stumbled on this answer of mine today and figured it wasn't really the behaviour you wanted. I didn't understand correctly the first time that you didn't want to center the point under the mouse but to keep it in the same spot. As I did it recently for a personnal project I tried to correct myself. So here is a more accurate answer :
http://jsfiddle.net/BaliBalo/7ozrc1cq/
The main part is now (if currentLocation is the top-left point of the image in the container) :
var factor = 1 - newScale / currentScale;
currentLocation.x += (mouseLocation.x - currentLocation.x) * factor;
currentLocation.y += (mouseLocation.y - currentLocation.y) * factor;
I also removed the CSS transition. I think the best way to achieve a smooth scrolling would be to use requestAnimationFrame to create an animation loop and instead of changing values directly in the zoom function, store values and animate towards them in the loop.
Related
I am making a website with a multipage google-doc-like user interface and want to allow the user to "zoom" or change the scale of everything on the page with "zoom in" and "zoom out" buttons. At first I tried to achieve this by styling everything using rem units and using this js:
$(document).ready(function() {
var fontSize = parseInt($("html").css("font-size"), 10);
$("#in").on("click", function() {
fontSize += 0.5;
$("html").css("font-size", fontSize + "px");
});
$("#out").on("click", function() {
fontSize -= 0.5;
$("html").css("font-size", fontSize + "px");
});
});
This works, but the problem is that there are many divs on the page (laid out in a single vertical column), so if you are scrolled in the middle of the page and then click the zoom function, causing them all to resize, it produces a scrolling effect as the divs get smaller or bigger and therefore get pushed further up or down on the page. This is disorienting if the content you were viewing before zooming is no longer on the page after the zoom. Here is a codepen demonstrating this.
Next, I tried zooming using the transform scale() css property and adjusting the transform-origin to be centered on the user's scroll position:
var zoom = 1;
$("#in").on("click", function () {
var x = window.innerWidth / 2;
var y = $(window).scrollTop() + $(window).height() / 2;
zoom += 0.2;
$(".container").css({
transformOrigin: x + "px " + y + "px",
transform: "scale(" + zoom + ")",
});
});
$("#out").on("click", function () {
var x = window.innerWidth / 2;
var y = $(window).scrollTop() + $(window).height() / 2;
zoom -= 0.2;
$(".container").css({
transformOrigin: x + "px " + y + "px",
transform: "scale(" + zoom + ")",
});
});
The problem with this is that portions of the pages get cut off when you zoom as the viewport doesn't expand to accommodate the scaled divs. Here is a codepen to demonstrate this approach.
I've searched extensively and can't seem to find a good solution to the problem. I have also considered using the "zoom" css function but from what I understand this is not supported and behaves differently in different browsers.
Any ideas would be much appreciated! Thanks
Experimenting with JQuery and HTML5 for a college assignment at the moment. I would like to update the css values of the div when the slider is moved.
HTML
Scale<input id="slider" type="range" name="points" min="1" max="10">
Currently this is my script:
$("#slider").change(function(){
size = $("#slider").val();
console.log("Size: " + size);
//Update the size of box while dragging
b1.css({
"-webkit-transform":"scaleX"+size/10,
"-webkit-transform":"scaleY"+size/10
});
});
It works however the values do not seem to be updating in my CSS and I am guessing it is because I am assigning them incorrectly.
Does anyone have a solution as to how I can fix the problem?
JSFiddle
http://jsfiddle.net/JQ7vD/
The main problem was that you forgot your parenthesis before and after the scale value. To make it scale both the X and Y, however, you need to combine the jQuery lines into one, i.e.
b1.css({
"-webkit-transform": "scaleX(" + size / 10 + ") scaleY(" + size / 10 + ")"
});
This is because if you have them in separate lines then the second one will always override the first because it does so in CSS. Take the following example
#image {
background:url('/exampleImage.jpg');
background:red;
}
The background would be red, not the image declared first. To support all browsers you need to include the browser prefixes in the jQuery as well
b1.css({
'-webkit-transform': 'scale3d(' + size/10 + ',' + size/10 + ',1)',
'-moz-transform': 'scale3d(' + size/10 + ',' + size/10 + '1)',
'-ms-transform': 'scale3d(' + size/10 + ',' + size/10 + ',1)',
'transform': 'scale3d(' + size/10 + ',' + size/10 + ',1)'
});
DEMO: http://jsfiddle.net/JQ7vD/4/
I am using javascript Gesture events to detect multitouch pan/scale/rotation applied to an element in a HTML document.
Visit this URL with an iPad:
http://www.merkwelt.com/people/stan/rotate_test/
You can touch the element with two finger and rotate it, but sometimes the rotation property goes go astray and my element flips around many full rotations.
Here is part of my code, I am really only taking the value directly from the event object:
...bind("gesturechange",function(e){
e.preventDefault();
curX = e.originalEvent.pageX - startX;
curY = e.originalEvent.pageY - startY;
node.style.webkitTransform = "rotate(" + (e.originalEvent.rotation) + "deg)" +
" scale(" + e.originalEvent.scale + ") translate3D(" + curX + "px, " + curY + "px, 0px)";
}...
What happens is that the value gets either 360 degrees added or subtracted, so I could monitor the value and react to sudden large changes, but this feels like a last resort.
Am I missing something obvious?
I found a solution.
In order to avoid sudden changes in the rotation that don't reflect real finger moves you need to test for that. I do that testing if the rotation changed more then 300 degrees in either direction, if it does then you need to add or subtract 360 depending on the direction. Not really intuitive, but it works.
Fixed page is here:
http://www.merkwelt.com/people/stan/rotate_test/index2.html
Here is the code
<script type="text/javascript">
var node;
var node_rotation=0;
var node_last_rotation=0;
$('.frame').bind("gesturestart",function(e){
e.preventDefault();
node=e.currentTarget;
startX=e.originalEvent.pageX;
startY=e.originalEvent.pageY;
node_rotation=e.originalEvent.rotation;
node_last_rotation=node_rotation;
}).bind("gesturechange",function(e){
e.preventDefault();
//whats the difference to the last given rotation?
var diff=(e.originalEvent.rotation-node_last_rotation)%360;
//test for the outliers and correct if needed
if( diff<-300)
{
diff+=360;
}
else if(diff>300)
{
diff-=360;
}
node_rotation+=diff;
node_last_rotation=e.originalEvent.rotation;
node.style.webkitTransform = "rotate(" + (node_rotation) + "deg)" +
" scale(" + (e.originalEvent.scale) +
") translate3D(" + (e.originalEvent.pageX - startX) + "px, " + (e.originalEvent.pageY - startY) + "px, 0px)";
}).bind("gestureend",function(e){
e.preventDefault();
});
</script>
when I try to animate the rotation of an image (with Raphael 2), which I have done before successfully with Raphael 1, nothing happens.
Animating another property such as height does work.
this.image.animate({rotation: this.angle + " " + this.centerY + " " + this.centerY}, this.animationTime, '<>');
Do you have an idea?
Thanks.
As I see on http://raphaeljs.com/reference.html element.animate does not have an rotation parameter(at least in version 2.0; maybe in earlier version it was there?).
You have to use
this.image.animate({transform:"r"+this.angle + "," + this.centerY + "," + this.centerY}, this.animationTime);
this.image.rotate(45);
I have noticed that the old way has been updated in 2.0.
I'm developing a jQuery plugin to make a block-level element rotatable with mouse. Now it works as expected in non-IE browsers, but have a strange behavior while rotating in Internet Explorer.
Demo is hosted at testerski.antaranian.me here, rotation plugin script is
$.fn.roll = function(angle){
var $this = this,
ie = !jQuery.support.leadingWhitespace;
if (ie) {
var cosAngle = parseFloat(parseFloat(Math.cos(angle.rad())).toFixed(8)),
sinAngle = parseFloat(parseFloat(Math.sin(angle.rad())).toFixed(8)),
tx = 0, ty = 0,
matrixFilter = '(M11=' + cosAngle + ', '
+ 'M12=' + -sinAngle + ', '
+ 'M21=' + sinAngle + ', '
+ 'M22=' + cosAngle + ','
+ 'sizingMethod=\'auto expand\')',
filter = 'progid:DXImageTransform.Microsoft.Matrix' + matrixFilter,
css = {
'-ms-filter': filter,
'filter': filter
};
debug.log(filter);
var matrix = $M([
[cosAngle, -sinAngle, tx],
[sinAngle, cosAngle, ty],
[0, 0, 1]
]);
debug.log(matrix);
$this.transformOrigin(matrix);
$this.fixIeBoundaryBug(matrix);
} else {
var css = {
'-webkit-transform': 'rotate(' + angle + 'deg)',
'-moz-transform': 'rotate(' + angle + 'deg)',
'-o-transform': 'rotate(' + angle + 'deg)'
};
}
$this.css(css);
return this;
};
I googled and found these two pages related to this subject
Grady's guide and Zoltan's guide
As I get there are some accounting needed related to Linear Algebra, but it's hard for me so if anyone have more simple tutorial, or knows the direct solution, please let me know.
Any help would be appreciated,
Antaranian.
IE's Transform Filter, unfortunately, doesn't have a concept of "transform-origin". the 'auto expand' sizingMethod will make the transformed object take the minimum amount of space possible, and you need to change it's positioning.
In cssSandpaper, I put another <div> tag around the transformed object and adjusted it's margin-left and margin-top. If you go to the cssSandpaper website and look through the code, you will see the exact formula (search for "setMatrixFilter" in cssSandpaper.js). You can hard code it into your library, or you can use cssSandpaper itself to do it (using the cssSandpaper.setTransform() method). Even though it may add a few KB to your code, I suggest this just in case I make improvements to the way I handle transforms in the future.
In any case, good luck!
Z.
Actually I've coded it according to my needs, here is the code, if anyone else is interested.
$.fn.ieRotate = function(alfa){
var self = this,
cosAlfa = Math.cos(alfa),
sinAlfa = Math.sin(alfa),
matrix = '(M11=' + cosAlfa + ', '
+ 'M12=' + -sinAlfa + ', '
+ 'M21=' + sinAlfa + ', '
+ 'M22=' + cosAlfa + ','
+ 'sizingMethod=\'auto expand\')',
// constructing the final filter string
filter = 'progid:DXImageTransform.Microsoft.Matrix' + matrix;
self.each(function(el){
var $this = $(el),
size = $this.data('size'),
pos = $this.data('pos');
$this.css({
'-ms-filter': filter,
'filter': filter,
// for IE9
'transform': 'rotate(' + angle + 'deg)'
});
// calculate the difference between element's expeced and the actual centers
var dLeft = ($this.width() - size.width) / 2,
dTop = ($this.height() - size.height) / 2;
$this.css({
top: pos.top -dTop,
left: pos.left - dLeft
});
});
return self;
};
Usage:
// caching the image object to a variable
$image = $('img#my-image');
// saving images non-rotated position and size data
$image.data('pos', {
top: $image.position().top,
left: $image.position().left
}).data('size', {
height: $image.height(),
width: $image.width()
});
// rotate image 1.2 radians
$image.ieRotate(1.2);
Thanks to #Zoltan Hawryluk, his code helped me during the development.
The position fix for IE can also be calculated analytically - see here