I'm experimenting with HTML5 games and found 'Crafty' API to make HTML5 Games
I looked up the documentation but my sprite's won't show up.
The path to the spritesheet is correct and so are the coordinations, so i should miss something.
Anyone have an idea?
This is my code now, when i open the page i have a blue screen. (Crafty.background)
Crafty.scene('Scene1', function() {
Crafty.background('rgb(150,215,255)');
Crafty.sprite('img/sprites.png',
{introbanner: [0, 0, 100, 100]});
var banner = Crafty.e('2D, DOM, introbanner');
banner.x = 20;
banner.y = 20;
});
Here are 3 things you can try:
Ensure your HTML is loaded from a web server. Locally loaded files have security restrictions when loading in a browser. If you see file: in your address bar, move your files onto a server and try again using http:
Try the full path to your image like so:
Crafty.sprite('http://www.domain.com/img/sprites.png',
Open up the developer console and see if the image is even being requested by your browser.
Related
StageWebView Flash's White when Displayed
So I've been working on a project using Adobe Animate to create a universal Air application that can be ported to multiple platforms i.e. Mac, Windows, and iOS.
It uses StageWebView to display videos embedded on HTML pages that have their own custom html5 video player and everything works well except for one simple but annoying thing.
Whenever I display a Stage Web View you'll see a flash of white before the page displays.
Now I originally thought this was an issue with checking for a URL load completion or a poorly formatted HTML document but that doesn't seem to be the case.
What I did notice after several attempts of trying to remove the issue is that it did go away if I used the embedded Air WebKit opposed to using the native WebKit from the desktop device.
(Code Below) Causes white flash on load:
var webView:StageWebView = new StageWebView(true);
(Code Below) This gets rid of the issue but my HTML tags like video and progress are not supported by the embedded WebKit and no longer function properly.
var webView:StageWebView = new StageWebView();
Information from about the setting from Adobe:
useNative:Boolean (default = false) — When useNative is false, a version of WebKit embedded within AIR is used as the source of the
StageWebView created. When useNative is true, then AIR will use the
the system's default web engine. Mobile platforms only support using
the system web engine, so useNative is ignored on mobile platforms.
The frustrating thing is that I've set a listener to check for load completion and that doesn't get rid of the issue. So as a workaround I've hidden the displayed StageWebView off the screen and then moved it's location to where I want it to be after a delay which is not great.
Other attempts to display it small as a pixel resize it in place cause the issue still.
/* Check for Stage Web View Errors */
webView.addEventListener(ErrorEvent.ERROR, onError);
function onError(e:ErrorEvent):void {
trace("Stage Web View error: " + e);
}
/* Function to not show Stage Web View until loaded. */
function onCompleteHandler(e:Event):void {
webView.assignFocus();
// Delay the Stage Web View to fix white flash issue.
setTimeout(callWebView,500);
webView.removeEventListener(Event.COMPLETE,onCompleteHandler);
}
/* Multi-Function Stage Web View Loader, Just add file path string to call */
function webviewFilePath(path:String):void {
webView.stage = this.stage;
// Prep filepath
filePath = new File(new File(path).nativePath).url;
// Load file path
webView.loadURL(filePath);
// Add listener for Complete URL Load then Show
webView.addEventListener(Event.COMPLETE,onCompleteHandler);
}
/* Function to call Stage Web View independantly so it can be delayed with a timer */
function callWebView() {
webView.viewPort = new Rectangle(posX(viewX), posY(viewY), viewWidth, viewHeight);
}
Any hints or tips on how I can alleviate or fix the issue would be great.
Of course if Adobe just actually updated the embedded Air WebKit that would probably fix the whole issue in the first place but I doubt that's happening anytime soon.
Partial Fix
So the issue still exists when I initially load up the Stage Web View but I've managed to minimize its appearance during app use.
One major part of the issue was how I reset the StageWebView in preparation for a new page I wanted to load or when I wanted to close the view.
I went a little overboard on resetting StageWebView because audio in StageWebView has been known to continue playing even when it's hidden.
/* Function to Reset Stage Web View */
function resetWebView():void {
webView.loadString("<!DOCTYPE HTML><html><body></body></html>");
//webView.viewPort = new Rectangle(0, 0, 0, 0);
webView.stage = null;
//webView.viewPort = null;
}
I realized I could just simply hide the StageWebView and load up a blank page while it was hidden from view to stop any audio playing. That was easy enough to accomplish with a simple string loaded into it.
Although from time to time I'll still see that white flash it's occurrence is minimal.
private var webView : StageWebView;
webView = new StageWebView( true );
webView.stage = this.stage;
webView.viewPort = new Rectangle( 0, 0, 1024, 768 );
I'm facing a CORS issue that is driving me insane. Allow me to share an example URL:
http://www.jungledragon.com/image/19905/mature_female_eastern_forktail.html/zoom
As the issue can only be reproduced once per page, here is a list of other images:
http://www.jungledragon.com/all/recent
From that overview, you can open any photo page. Next, from that photo page click the image once more to launch it fullscreen, as that is where the issue lies.
Now allow me to explain the setup, and the problem. The site itself is hosted on a Linux server within my control. The site is at www.jungledragon.com. The images, however, are stored at Amazon S3, where the image bucket has an alias of media.jungledragon.com.
The basic situation is simple:
<div id="slideshow-image-container">
<div class="slideshow-image-wrapper">
<img src="http://media.jungledragon.com/images/1755/19907_large.jpg?AWSAccessKeyId=05GMT0V3GWVNE7GGM1R2&Expires=1409788810&Signature=QH26XDrVuhyr1Qimd7IOBsnui5s%3D" id="19907" class="img-slideshow img-sec wide" data-constrained="true" data-maxheight="2056" crossorigin="anonymous">
</div>
</div>
As you can see, I'm just using the normal 'html' way of loading an image. The image URL is signed and can time out, but that shouldn't be relevant. It is my understanding that CORS does not apply to this situation, since loading images from an external domain this way has been supported for decades. The image is not loaded using javascript, after all.
Just to be sure though, the crossorigin attribute is set in HTML. Furthermore, as a way of testing, I have set a very liberal CORS policy on the image bucket:
<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
<CORSRule>
<AllowedOrigin>*</AllowedOrigin>
<AllowedMethod>GET</AllowedMethod>
<MaxAgeSeconds>3000</MaxAgeSeconds>
<AllowedHeader>Authorization</AllowedHeader>
</CORSRule>
<CORSRule>
<AllowedOrigin>*</AllowedOrigin>
<AllowedMethod>PUT</AllowedMethod>
<MaxAgeSeconds>3000</MaxAgeSeconds>
<AllowedHeader>Content-Type</AllowedHeader>
<AllowedHeader>x-amz-acl</AllowedHeader>
<AllowedHeader>origin</AllowedHeader>
</CORSRule>
</CORSConfiguration>
Now, the situation gets a bit more complicated. The fullscreen image viewer is supposed to get a background color that is the dominant/average color of the actual image on screen. That color is calculated using canvas, yet it is only calculated once. The first time it is calculated for that image, the result is communicated to the back-end using an ajax call and then stored forever. Subsequent visits to the image will not run the calculation logic again, it will simply set the background color of the body element and all is good.
Here is the logic that does the calculation:
<script>
$( document ).ready(function() {
<?php if (!$bigimage['dominantcolor']) { ?>
$('#<?= $bigimage['image_id'] ?>').load(function(){
var rgb = getAverageRGB(document.getElementById('<?= $bigimage['image_id'] ?>'));
document.body.style.backgroundColor = 'rgb('+rgb.r+','+rgb.g+','+rgb.b+')';
if (rgb!==false) {
$.get(basepath + "image/<?= $bigimage['image_id'] ?>/setcolor/" + rgb.r + "-" + rgb.g + "-" + rgb.b);
}
});
<?php } ?>
});
Yes, I'm mixing in back-end code with front-end code. The above code says that if we do not yet know the dominant color in the scene, calculate it. The load function is used because at document ready, the actual image from the normal html may not have been loaded completely. Next, if the dominant color is not known yet, and the image is loaded, we trigger the function that calculates the dominant color. Here it is:
function getAverageRGB(imgEl) {
var blockSize = 5, // only visit every 5 pixels
defaultRGB = {r:0,g:0,b:0}, // for non-supporting envs
canvas = document.createElement('canvas'),
context = canvas.getContext && canvas.getContext('2d'),
data, width, height,
i = -4,
length,
rgb = {r:0,g:0,b:0},
count = 0;
if (!context) {
return defaultRGB;
}
height = canvas.height = imgEl.naturalHeight || imgEl.offsetHeight || imgEl.height;
width = canvas.width = imgEl.naturalWidth || imgEl.offsetWidth || imgEl.width;
imgEl.crossOrigin = "anonymous";
context.drawImage(imgEl, 0, 0);
try {
data = context.getImageData(0, 0, width, height);
} catch(e) {
/* security error, img on diff domain */
return false;
}
length = data.data.length;
while ( (i += blockSize * 4) < length ) {
++count;
rgb.r += data.data[i];
rgb.g += data.data[i+1];
rgb.b += data.data[i+2];
}
// ~~ used to floor values
rgb.r = ~~(rgb.r/count);
rgb.g = ~~(rgb.g/count);
rgb.b = ~~(rgb.b/count);
return rgb;
}
The following line is CORS-relevant:
data = context.getImageData(0, 0, width, height);
Although I believe I have set up CORS correctly, I can live with this code failing in some browsers. It seems to work fine in Firefox and IE11, for example. If it fails, I would expect it to fail calculating the dominant color. However, something far worse is happening in highly specific cases: the image is not shown alltogether.
My thinking is that my 'classic' loading of the image via img src tags should have nothing to do with this script working or failing, in all cases at least the image should just load, irrespective of the canvas trick.
Here are the situations I discovered where the image does not load alltogether, which I consider a major issue:
On iOS7 on iPhone 5, the first load works fine. The calculation may fail but the image loads. Refreshing the page often breaks the image. 3rd and 4th tries then continue to succeed, and so on.
Worse, at work in Chrome 36 the image does not load alltogether. I say at work, since at home it is not an issue. Possibly a proxy makes the difference. I can refresh all I want, for images that do not have the calculation ran yet, it keeps failing.
The natural thing to do then is to debug it using Chrome's inspector. Guess what? With the inspector open, it always succeeds. The image will always load and the CORS request headers and responses look perfectly fine. This leaves me with virtually no way to debug this. I can tell though that when opening the inspector when the image does not load does give me the "CORS error" in the console, from the previous request I made. Refreshing with the inspector open will then make that go away.
From reading other questions I've learned that cache may be an influence, yet more likely the issue lies in the origin header not sent by the browser. I believe the issue may be in that direction, yet I fail to understand this:
How it influences my "normal" loading of the image using img tags
How it is only an issue behind a proxy (supposedly) in Chrome, and only when the inspector windows is closed
How it works so unreliably and inconsistently in Safari on iOS
As said, I can live with only some browsers succeeding with the canvas part, but I can't live with the image not being normally loaded in any case. That part should just work.
I realize the situation is incredibly hard for you to debug, but I hope my explanation triggers some much-needed help.
Update: I've discovered that when I remove crossorigin="anonymous" from the img tag, the image will load correctly in the specific scenarios I mentioned. However, the consequence of that move is that the color calculation will no longer work in Chrome, not at home and not at work. It continues to work in Firefox though. I'm investigating what to do next.
I managed to solve the issue myself. I still cannot fully explain cause and effect here, but this is what I did:
I removed crossorigin="anonymous" from the html's img element. This will at least make sure that the image is always loaded.
The color calculation part I solved by basically rewriting its logic:
var imgSrc = $('#<?= $bigimage['image_id'] ?>').attr('src');
var cacheBurstPrefix = imgSrc.indexOf("?") > -1 ? '&' : '?';
imgSrc += cacheBurstPrefix + 'ts=' + new Date().getTime();
var imagePreloader = new Image();
imagePreloader.crossOrigin = "Anonymous";
imagePreloader.src = imgSrc;
$(imagePreloader).imagesLoaded(function() {
var rgb = getAverageRGB(imagePreloader);
document.body.style.backgroundColor = 'rgb('+rgb.r+','+rgb.g+','+rgb.b+')';
if (rgb!==false) {
$.get(basepath + "image/<?= $bigimage['image_id'] ?>/setcolor/" + rgb.r + "-" + rgb.g + "-" + rgb.b);
}
});
Instead of reusing the img element from the html, I'm creating a new in-memory image element. Using a cache bursting technique I'm making sure it is freshly loaded. Next, I'm using imagesLoaded (a 3rd party plugin) to detect the event of this in-memory image being loaded, which is far more reliable than jQuery's load() event.
I've tested extensively and can confirm that in no case does normal image loading ever break again. It works in every browser and proxy situation. As an added bonus, the color calculation part now seems to work in far more browsers, including several mobile browsers.
Although I am still not confident on the root cause, after much frustration I'm very happy with the new situation.
I am trying to use stackBlur (http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html) to blur entire image with stackBlurImage( 'srcimg', 'canvas', 10, false );. But neither it's working on local system nor on internet. Could someone please suggest me correct way of doing it?
Here is my jsFiddle - http://jsfiddle.net/yesprasoon/3KxrW/
Or please let me know any other way of blurring the image. CSS transition is not working in Phonegap for Android webkit.
UPDATE
Image was not getting blurred due to some '..because the canvas has been tainted by cross-origin data' error. I was testing it as local file in Chrome. Script runs fine with chrome:localhost/IE9/FF.
The reason is that you are not allowed to access and modify an image (with a canvas), unless it is hosted on the same server as your webpage.
See here for more details.
If the image is hosted alongside the webpage, then there is no problem using the code you provided (e.g. stackBlurImage("srcimg", "canvas", 5, false);).
See, also, this short demo.
Our web app is built entirely in JS.
To make it snappy we cache resources (models) between page views and reload the resource when you view a page.
Our flow is like this:
The user is in ViewA
The user switches to ViewB
We use the cached resource to render ViewB
We start a fetch for resource
When the resource is fetched we render again
This has a nasty drawback of causing <img> tags to flicker, ever if they are the same.
The problem is that Backbone.js, which we use, doesn't tell us if anything changed when fetching a collection, just that it was fetched.
Here's a quick demo of what I mean: http://jsfiddle.net/p7DdG/
It only happens in webkit and with <img> tags, not with background images as you can see.
We think it's kinda ugly to use background-image instead of a proper img tag.
Is there any solution to this?
The problem is gone in Chrome 19, problem solved :)
Not knowing exactly how the URL of each image is being built I'm not certain this will work, but could you check the src attribute of each image tag against the one you are replacing it with before doing the replace?
e.g.
var newImageSrc = "http://www.google.com/intl/en_com/images/srpr/logo3w.png";
if (newImageSrc != $("img").attr("src")) {
$('img').replaceWith('<img src="'+newImageSrc +'">');
}
Alternatively - load the image offscreen, and attach an event handler to the onload event of the image, which moves the image to the current image's parent tag, and remove the old one.
e.g.
var oldImage = $("#oldImageId");
var newImageSrc = "http://www.google.com/intl/en_com/images/srpr/logo3w.png";
var newImage = new Image();
$(newImage).load(function (event) {
$(oldImage).parent().append(newImage);
$(oldImage).detach();
});
$(newImage).attr("src", newImageSrc);
I ran into the same problem and noticed that sometimes images do flicker and sometimes don't. Even in latest Chrome (v33 as of now).
For posterity, flickering happens with uncached images.
In my case, Cache-Control: public, max-age=31536000 totally eliminated it.
I am pre-loading some images and then using them in a lightbox. The problem I have is that although the images are loading, they aren't being displayed by the browser.
This issue is specific to Chrome. It has persisted through Chrome 8 - 10, and I've been trying on and off to fix it all this time and have got nowhere.
I have read these similar questions,
Chrome not displaying images though assets are being delivered to browser
2 Minor Crossbrowser CSS Issues. Background images not displaying in Google Chrome?
JavaScript preloaded images are getting reloaded
Which all detail similar behaviour but in Chrome for Mac. Whereas this is happening in Windows.
All other browsers seem to be fine.
If you have Firefox and Chrome open, load the page in Firefox, and then in Chrome, the images appear.
Once you have manually loaded the images, using the Webkit webdev toolbar thingy, they always show up
All the links the images and such are fine and working
Clearing everything from Chrome doesn't seem to make any difference (cache, history, etc)
If anyone has any ideas it would be fantastically helpfull, as I'm literally all out of options here.
PS, Apologies if there are late replies, I'm off on holiday for a week tomorrow! :D
Update
Here is the javascript function which is preloading the images.
var preloaded = new Array();
function preload_images() {
for (var i = 0; i < arguments.length; i++){
document.write('<');
document.write('img src=\"'+arguments[i]+'\" style=\"display:none;\">');
};
};
Update
I'm still having issues with this, and I've removed the whole preloading images function. Perhaps delivering a style sheet via document.write() isn't the best way?
Chrome might not be preloading them as it's writing to the DOM with no display, so it might be intelligent enough to realise it doesn't need to be rendered. Try this instead:
var preloaded = new Array();
function preload_images(){
for (var x = 0; x < preload_images.arguments.length; x++)
{
preloaded[x] = new Image();
preloaded[x].src = preload_images.arguments[x];
}
}
The Javascript Image object has a lot of useful functions as well you might find useful:
http://www.javascriptkit.com/jsref/image.shtml
onabort()
Code is executed when user aborts the
downloading of the image.
onerror()
Code is executed when an error occurs
with the loading of the image (ie: not
found). Example(s)
onload()
Code is executed when the image
successfully and completely downloads.
And then you also have the complete property which true/false tells you if the image has fully (pre)loaded.
It turns out that Chrome takes into account the HTTP Caching and discards any preloaded images immediately after preload if the Caching is incorrectly set to expire.
In my case I am generating the images dynamically and by default the response was sent to the browser with immediate expiration.
To fix it I had to set the following below:
Response.Cache.SetExpires(DateTime.Now.AddYears(1));
Response.Cache.SetCacheability(HttpCacheability.Public);
return File(jpegStream, "image/jpeg");