Placing a dot on an image - onClick - javascript

A user will be able to click on 3 points on an image, and i want to display a BLACK dot at those points. Then i will save these values in my database, and regenerate the image with those 3 points later on.
This is a 2 part question:
1.) In my code, i am not able to detect the onClick event when the image is clicked. Can someone look into this. Here's my code. JSFIDDLE
$(document).ready(function () {
$('body').click(function (ev) {
alert("d");
mouseX = ev.pageX;
mouseY = ev.pageY
alert(mouseX + ' ' + mouseY);
var color = '#000000';
var size = '1px';
$("body").append(
$('<div></div>')
.css('position', 'absolute')
.css('top', mouseY + 'px')
.css('left', mouseX + 'px')
.css('width', size)
.css('height', size)
.css('background-color', color));
});
});
HTML
<body background="http://www.craigjoneswildlifephotography.co.uk/blog/wp-content/uploads/2010/07/CMJ57311.jpg">
</body>
2.) Say that i have the X and Y coordinates of the points, and how can i regenerate the image with those points ?

Just use document instead of body (your body element has a calculated height of 0, but document is always the full size of the window):
http://jsfiddle.net/TrueBlueAussie/95vczfve/5/
$(document).ready(function () {
$(document).click(function (ev) {
mouseX = ev.pageX;
mouseY = ev.pageY
console.log(mouseX + ' ' + mouseY);
var color = '#000000';
var size = '1px';
$("body").append(
$('<div></div>')
.css('position', 'absolute')
.css('top', mouseY + 'px')
.css('left', mouseX + 'px')
.css('width', size)
.css('height', size)
.css('background-color', color));
});
});
As a side note: Your original JSFiddle is also a great example of why you should not connect delegated events to body instead of document. The body element can be styled out of existence (also document exists before the DOM is even loaded) :)
Or, as Brian provided, a reduced version http://jsfiddle.net/BrianDillingham/95vczfve/7/:
$(document).ready(function(){
$(document).click(function (ev) {
$("body").append(
$('<div></div>').css({
position: 'absolute',
top: ev.pageY + 'px',
left: ev.pageX + 'px',
width: '10px',
height: '10px',
background: '#000000'
})
);
});
});
And Brian's final update with limit of 3 dots: http://jsfiddle.net/BrianDillingham/95vczfve/8/

Your body has 0 height because it has 0 content.
Try adding this to your CSS:
html, body { height: 100%; margin: 0; }
Or try adding some content.
jsFiddle
On a side tip, a lot of things about your jQuery can be made cleaner/easier:
$(document).ready(function(){
// here I asign the event dynamically, not needed for 'body' as such tag should always be present,
// but something you should look into
// see also: http://api.jquery.com/on/
$(document).on('click', 'body', function(e) {
mouseX = e.pageX;
mouseY = e.pageY
// simply press F12 to look at your browsers console and see the results
console.log('Mouse Position:\t' + mouseX + '|' + mouseY);
// no need in JS to write var for every variable declartion,
// just seperate with a comma
var color = '#000000',
size = '5px'; // changed size to 5px from 1 just to make it easier to see what's going on for you
// No need to use $("body") since this event takes place on the body tag
// $(this), in an event, always equals the selector the event is tied to
$(this).append(
// making an element with jquery is simple
// no need to insert whole tag, all you need is tag name and a closer
// like so
$('<div />')
// easily tie all css together
.css({
// also, in jquery CSS, any css variable with a '-'
// can be renamed when assigning
// simply remove the '-' and capitilize the first letter of the second word
// like so, here in 'background-color'
backgroundColor: color,
height: size,
left: mouseX + 'px',
position: 'absolute',
top: mouseY + 'px',
width: size
})
);
})
});

Regarding part 2 of your question, my first thought is to include query params in the image URL, so that instead of http://www.example.com/thingies/someimage.jpg you get something like http://www.example.com/thingies/someimage.jpg?x0=10&y0=25&x1=30&y1=5. From there you would simply check if that string has query params with names matching what you're looking for (x0, y0, x1, etc...) and place points according to those.
Alternatively, you could also store the parameters in the URL for that web page, but that might lead to noisy URLs depending on what you're doing.
This depends on the server storing the coordinates, though.
My second thought is Local Storage, would store the points with the client, but that means that the points are not necessarily sent to the server, and are being read only from the client's browser. It also depends on the browser supporting that, and allowing that. Of course, since 3 coordinates is a rather small set of data, it could be stored in a browser cookie.

Related

Run casper.evaluate() in included / external script

Introduction
I am using casperJS together with grunt-casper plugin for automating Tests for our new GUI Framework and just have a question about running jQuery / JS Code in the casper.evaluate() function to point out elements for capturing them.
First steps creating functionality
At first i build the tests a described in the casperJS HowTo like this:
casper.test.begin('LOGIN FORM TEST', function(test) {
casper.start('http://www.sample.org');
casper.waitForSelector("form.login-box",
function success() {
casper.test.assertElementCount('form.login-box > .well', 3, 'WORKS');
},
function fail() {
/* Create overlay over malicious element */
casper.evaluate(function () {
/* Get boundaries of malicous element */
var buffer = 6;
var height = $(selector).height() + buffer + "px";
var width = $(selector).width() + "px";
var position = $(selector).offset();
var posX = position.left + "px";
var posY = position.top + buffer + "px";
/* Add a overlay which matches the element and overlays it */
$("body").append("<div id='errormarker'></div>");
$("#errormarker")
.css({
'opacity': 0.4,
'position': 'absolute',
'top': posY,
'left': posX,
'height': height,
'width': width,
'background-color': '#f00',
'z-index': 5000
});
});
casper.test.fail('NOT COOL');
}, 200);
casper.capture('image.png');
casper.run(function() {
test.done();});
});
This worked fine, at first i created a DIV which has the measurements and position of the malicious element. Could be verified on the screenshot.
Second step make it a general UtilFunction
But as i have a lot of tests which need this functionality for taking a screenshot when a test fails, i assumed to create a Utils.js, include it to the script and call the function with parameters whenever i need it so i created this:
Gruntfile (because i use grunt-casper the include of the script is here, its just a simple include nothing specific)
casper: {
MyTest: {
options: {
includes: ['tests/testutils/Testutils.js']
Testutils.js
/**
* Constructor of TestingUtils
* #constructor
*/
function Testutils() {}
/**
* Function for creating a Screenshot with a marked malicious element for logging erroneous created objects
* #param selector CSS selector of the element
* #param pathForScreenshot the path where the screenshots are stored
* #param casper the casper test object
* #param screenshotName the name of the Screenshot which has to be created
*/
Testutils.prototype.createErrorScreenshot = function (selector, pathForScreenshot, casper, screenshotName) {
/* Set thin border around malicous element */
casper.evaluate(function () {
/* Get boundaries of malicous element */
var buffer = 6;
var height = $(selector).height() + buffer + "px";
var width = $(selector).width() + "px";
var position = $(selector).offset();
var posX = position.left + "px";
var posY = position.top + buffer + "px";
/* Add a overlay which matches the element and overlays it */
$("body").append("<div id='errormarker'></div>");
$("#errormarker")
.css({
'opacity': 0.4,
'position': 'absolute',
'top': posY,
'left': posX,
'height': height,
'width': width,
'background-color': '#f00',
'z-index': 5000
});
});
/* screenshot the whole screen with marker element */
casper.capture(pathForScreenshot + screenshotName);
/* Cleanup the content from marker */
casper.evaluate(function () {
$('#errormarker').remove();
});
/* Create specific screenshot of the element */
casper.captureSelector(pathForScreenshot + screenshotName, selector);
};
Calling the Function in Test.js
casper.test.begin('LOGIN FORM TEST', function(test) {
casper.start('http://www.sample.org');
casper.waitForSelector("form.login-box",
function success() {
casper.test.assertElementCount('form.login-box > .well', 3, 'WORKS');
},
function fail() {
/* THIS HERE IS NEW */
var testutils = new Testutils();
actUtils.createErrorScreenshot('form.login-box > .well > .form-group:nth-child(1)', tempCaptureFolder, casper, 'image.png');
});
casper.test.fail('NOT COOL');
}, 200);
casper.capture('image.png');
casper.run(function() {
test.done();});
});
Problem now
The casper specific functions (casper.capture) work in the included js file, BUT casper.evaluate is not run....never, i debugged and logged this but i cannot use this functionality here.
So my question is, what can i do here? I need to use jQuery functionality here and especially evaluate for marking the DOM content before screenshotting it.
I think it has to do with the following mechanism how evaluate works:
http://docs.casperjs.org/en/1.1-beta2/_images/evaluate-diagram.png
I would be very very glad if someone can help me here.
Next steps
I now went on and no errors are provided. Another problem occurred and i am wondering what happens here.
But now magically casper.evaluate is entered, but i got errors that the parameters
var height = $(selector).height() + buffer + "px";
var width = $(selector).width() + "px";
var position = $(selector).offset();
var posX = position.left + "px";
var posY = position.top + buffer + "px";
could not be initialised, o.e. the $(selector) returned NULL, so i tried to get the HTML context and when i got the DOM with jQuery i got the following output:
<html><head></head><body></body></html>
so the content is empty.
SSL Problem?
Now i know the problem with SSL and Casper and as i said when i ran the casper.evaluate in the function calling script it worked fine because i set the params
args: ['--ssl-protocol=any', '--ignore-ssl-errors=true', '--web-security=no']
in GRUNT configuration.
Wrong page?
Now i thought that i am on the wrong website so i got the URL from casper.getCurrentUrl() and it is the the correct URL, so i took a capture inside of the evaluate() function, and the screenshot was correct too what proved that i am on the correct page.
But as i said the gotten HTML Content is empty, so what can i do here?
I think it must be a small problem, maybe with the sandboxed content, i do not have a concrete idea here.

in gamequery I am trying to move a selected object with mousetracker by clicking on the object, and dragging it

I know I can use mousedown selection for it, but I am wanting the clicked on sprite to follow my mouse, there is a mousetracker function of sorts mentioned in the api; but unfortunately there are no examples of this other than stating that it allows mouse detection.
//add mousedown events for yarnballs.
$(".gQ_sprite").mousedown(function() {
clickedDivId = $(this).attr('id');
if(clickedDivId.charAt(8) == "-")
{
currentClickedDivId = clickedDivId
$(document).mousemove(function(e){
spriteXPosition = e.pageX
spriteYPosition = e.pageY
});
}
});
I have the location of the mouse selected, just not sure how to get the selected sprite to follow it.
any help would be greatly appreciated.
What Mati said is correct: $.gQ.mouseTracker allows you to access the mouse's state outside of an event handler. The example he gives is correct but it can't be used to move a gQ object (sprite, tile-map or group) around because you'r not allowed to use the .css() function for those. Doing so will break collision detection.
If what you want is to move a gQ object you should do this instead :
$('#' + currentClickedDivId).xy($.gQ.mouseTracker.x, $.gQ.mouseTracker.y);
But since this should be done in a periodical callback, the smoothness of the dragging will depend on the refresh rate.
If you want to use event handlers instead you could modify you code to look like this (without using the mouseTracker):
var clickedDiv;
var clickedDivOffset = {x:0, y:0};
$(".gQ_sprite").mousedown(function(e) {
clickedDiv = $(this);
clickedDivOffset = {
x: e.pageX - clickedDiv.x() - $().playground().offset().left,
y: e.pageY - clickedDiv.y() - $().playground().offset().top
};
});
$(".gQ_sprite").mouseup(function() {
clickedDiv = false;
});
$().playground().mousemove(function(e) {
if(clickedDiv){
clickedDiv.xy(
e.pageX - clickedDivOffset.x,
e.pageY - clickedDivOffset.y,
);
}
});
This will implement a drag-n-drop effect. If you want the clicked element to stick to the mouse you will have to slightly adapt the code but the basics will remain the same.
According to the documentation:
If the mouse tracker is enabled you can check the state of the mouse at anytime by looking into the object $.gQ.mouseTracker where x and y contain the position of the mouse and 1, 2 and 3 a boolean value where true means that the first, second or thrid button is pressed.
Observe the output of:
$("#playground").playground({ refreshRate: 60, mouseTracker: true });
$.playground().startGame();
$.playground().registerCallback(function(){
console.log( $.gQ.mouseTracker );
}, 1000);
To make those divs actually follow the cursor, you have to use .css()
$('#' + currentClickedDivId).css({
top: $.gQ.mouseTracker.y + 'px',
left: $.gQ.mouseTracker.x + 'px'
});

Apply jQuery events to all class elements?

I have the following code which will allowed a user running iOS to move a <div> with the class .drag around on the page. This works fine when there is one istance of .drag, but fails to work when there are two instances of it. Is it possible to have the code find all of the <div>'s, then allow them to be draggable?
var drag = $(".drag")[0];
xPos = drag.offsetWidth / 2;
yPos = drag.offsetHeight / 2;
drag.addEventListener("touchmove", function() {
event.preventDefault();
$(this).css({
'left' : event.targetTouches[0].pageX - xPos + 'px',
'top' : event.targetTouches[0].pageY - yPos + 'px'
});
});
When you use $(selector)[0], you get the first DOM element that matches the selector. Use .each() instead to add the event listener to all elements that match the selector:
$(".drag").each(function () {
var drag = this;
xPos = drag.offsetWidth / 2;
yPos = drag.offsetHeight / 2;
drag.addEventListener("touchmove", function() {
event.preventDefault();
$(this).css({
'left' : event.targetTouches[0].pageX - xPos + 'px',
'top' : event.targetTouches[0].pageY - yPos + 'px'
});
});
});​
Yes, it's possible. But you are using a jQuery selector (which can select and return multiple elements) and then immediately unwrapping it to return the first element. You can modify your code to use jQuery functions throughout and avoid this.
// an array of all elements with class "drag"
// each element is wrapped
var drag = $(".drag");
// selects all matching elements, but then references
// the first raw DOM element in the array
var drag = $(".drag")[0];
Another way of looking at it:
var matches = $(".drag");
// each() executes a function for each matched element
matches.each(function () {
var drag = this; // raw dom element
// or, wrap to get jQuery object
// var drag = $(this);
});​
As I mentioned, you can also use jQuery functions throughout your code. Two quick examples I see are the x/y coordinate calculation and the event binding.
First, you declare that you want only the first element by using [0].
Second, you should use jQuery's on() method. Here's how I see you function:
var drag = $(".drag");
drag.on("touchmove", function(event) {
xPos = $(this).offsetWidth / 2;
yPos = $(this).offsetHeight / 2;
event.preventDefault(); // preventDefault is IE-specific, is it?
$(this).css({
'left' : event.targetTouches[0].pageX - xPos + 'px',
'top' : event.targetTouches[0].pageY - yPos + 'px'
});
});
This is probably obvious to most experienced devs, but could be helpful to some junior devs who like myself have had trouble getting jQuery to apply to multiple elements.
Today I learned that you have to make sure you’re loading your script outside the div itself.
I was mistakenly loading the script inside the first element, and wondering why the jQuery function wasn’t applying to the other div farther down the page.
Screenshot showing < script > inside parent < div >
^ I was doing it wrong

Locating DOM element by absolute coordinates

Is there a simple way to locate all DOM elements that "cover" (that is, have within its boundaries) a pixel with X/Y coordinate pair?
You can have a look at document.elementFromPoint though I don't know which browsers support it.
Firefox and Chrome do. It is also in the MSDN, but I am not so familiar with this documentation so I don't know in which IE version it is included.
Update:
To find all elements that are somehow at this position, you could make the assumption that also all elements of the parent are at this position. Of course this does not work with absolute positioned elements.
elementFromPoint will only give you the most front element. To really find the others you would have to set the display of the front most element to none and then run the function again. But the user would probably notice this. You'd have to try.
I couldn't stop myself to jump on Felix Kling's answer:
var $info = $('<div>', {
css: {
position: 'fixed',
top: '0px',
left: '0px',
opacity: 0.77,
width: '200px',
height: '200px',
backgroundColor: '#B4DA55',
border: '2px solid black'
}
}).prependTo(document.body);
$(window).bind('mousemove', function(e) {
var ele = document.elementFromPoint(e.pageX, e.pageY);
ele && $info.html('NodeType: ' + ele.nodeType + '<br>nodeName: ' + ele.nodeName + '<br>Content: ' + ele.textContent.slice(0,20));
});
updated: background-color !
This does the job (fiddle):
$(document).click(function(e) {
var hitElements = getHitElements(e);
});
var getHitElements = function(e) {
var x = e.pageX;
var y = e.pageY;
var hitElements = [];
$(':visible').each(function() {
var offset = $(this).offset();
if (offset.left < x && (offset.left + $(this).outerWidth() > x) && (offset.top < y && (offset.top + $(this).outerHeight() > y))) {
hitElements.push($(this));
}
});
return hitElements;
}​
When using :visible, you should be aware of this:
Elements with visibility: hidden or opacity: 0 are considered visible,
since they still consume space in the layout. During animations that
hide an element, the element is considered to be visible until the end
of the animation. During animations to show an element, the element is
considered to be visible at the start at the animation.
So, based on your need, you would want to exclude the visibility:hidden and opacity:0 elements.

unable to get tooltip to work when usingjQuery load() content

I am having problem getting my tooltip to work when using the jQuery load() function. The tooltip works fine if i don't use load() to load external dynamic data.
I googled and found the i may need to use live(), but I can't figure how to get it to work. Any suggestion?
thank you!!
Here is my scripts:
function loadEMERContent(uid) {
$("#ActionEWPNBook").load("ajaxLoadDATA.cfm?uid="+uid, null, showLoading);
$("#EWPNBookloading").html('<img src="/masterIncludes/images/ajaxLoading.gif" alt="loading" align="center" />');
}
function showLoading() {
$("#EWPNBookloading").html('');
}
function simple_tooltip(target_items, name){
$(target_items).each(function(i){
$("body").append("<div class='"+name+"' id='"+name+i+"'><p style='padding:5px;'>"+$(this).attr('title')+"</p></div>");
var my_tooltip = $("#"+name+i);
$(this).removeAttr("title").mouseover(function(){
my_tooltip.css({opacity:0.8, display:"none"}).stop().fadeIn(400);
}).mousemove(function(kmouse){
my_tooltip.css({left:kmouse.pageX+15, top:kmouse.pageY+15});
}).mouseout(function(){
my_tooltip.stop().fadeOut(400);
});
});
}
Here is my ajaxLoadDATA.cfm: it returns an unorder list
<li><span title="dynamic title here" class="tipthis">date</span></li>
In your callback function, you need to run the tooltip code against the new items, like this:
function showLoading(data) { //data = the response text, passed from `.load()`
$("#EWPNBookloading").html('');
var items = //get items here, something like $('.giveMeATooltip', data);
var name = //set name, not sure what you're using for this
simple_tooltip(items, name);
}
One side tip, if you change this line:
$("body").append("<div class='"+name+"' id='"+name+i+"'><p style='padding:5px;'>"+$(this).attr('title')+"</p></div>");
To something like this:
$("body").append(
$("<div></div>", { 'class': name, 'id': name + i }).append(
$("<p style='padding:5px;'></p>").text($(this).attr('title'))
)
);
Your tooltip generation will be much faster due to how jQuery can cache document fragments for reuse.
I use a modified version of this tooltip. This version uses .live so loaded content will automatically have tooltip functionality. All you need to do is:
Add this script to your main page (adding it as an external file is perferred)
You need to ensure that the elements that need a tooltip have a class="tipthis" and that the tooltip contents are within the title attribute. Also, the tooltip can contain HTML (e.g. <h1>Tooltip</h1>Hello,<br>World).
You will also need some basic CSS:
#tooltip { background: #f7f5d1; color: #333; padding: 5px; width: 300px; }
Here is the script (using live and it requires jQuery version 1.4+)
/* Tooltip script */
this.tooltip = function(){
// Defaults
var tooltipSpeed = 300; // fadein speed in milliseconds
var xOffset = 20; // Don't use negative values here
var yOffset = 20;
$('.tipthis').live('mouseover',function(e) {
this.t = this.title;
this.title = '';
$('<div></div>', {
id : 'tooltip',
css: {
display : 'none',
position: 'absolute',
zIndex : 1000,
top : (e.pageY - xOffset) + 'px',
left : (e.pageX + yOffset) + 'px'
}
})
.html( this.t )
.appendTo('body');
$('#tooltip').fadeIn(tooltipSpeed);
})
.live('mouseout',function(){
this.title = this.t;
$('#tooltip').remove();
})
.live('mousemove',function(e){
$("#tooltip").css({
top : (e.pageY - xOffset) + 'px',
left: (e.pageX + yOffset) + 'px'
});
})
}
$(document).ready(function(){ tooltip(); });
Here is some sample HTML:
Hover over me!

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