javascript - Problems with asynchrony of loading images (using a canvas and timer) -


enter link description herei have seen derivatives of question ask here not think addresses problem.

i have canvas object , refreshing need be. many frames second.

to these new frames call web api within recurring timer latest time stamp of image on server , if different loads hidden canvas object data.

when loaded 'refreshes' visible canvas.

on observation have seen images can load out of sync. have tested order images sent server , have tested order images 'grabbed' server , displayed in client browser.

how can ensure initial image has finished loading before loading or skipping next image?

should use queue of canvas images , 'read' top 1? cause memory spike have read using queue in javascript can cause memory leak?

thanks

this javascript code:

i have misnised not inclduing html5 , error handling.

if not enough post rest...

<script type="text/javascript">     var j1 = new jpegimage();      j1.onload = function () {         var d1 = ctx1.getimagedata(0, 0, 360, 238);         j1.copytoimagedata(d1);         //brightenandcontrastimage(d1, contrastby, brightenby);         csingle.putimagedata(d1, 0, 0)     };      var tmrfeeder;     function startfeedup() {         try {             var throttled = _.delay(startnonhtml5feed, 100);         }         catch (err) {             document.getelementbyid("divmode2").innerhtml = err;         }     }       function startnonhtml5feed() {         jquery(function ($) {             jquery.support.cors = true;             $.ajax({                 crossdomain: true,                 type: "post",                 url: "feed.aspx/getnextframes",                 data: json.stringify({                     alias: alias,                     guidlogon: guidlogon                 }),                 timeout: 10000,                 contenttype: "application/json; charset=utf-8",                 datatype: "json",                 success: function (msg) {                     var ts1 = msg.d['ts1'];                                 if (ts1 == "") {                         ts1 = "0";                     }                      if (t1 != ts1) {                         t1 = ts1;                         j1.load('/cloud/livexp.ashx?alias=' + alias + '&camindex=0&guid=' + ts1);                     }                 });         });         var throttled = _.delay(startnonhtml5feed, 100);     } </script>


Comments

Post a Comment

Popular posts from this blog

javascript - Jquery show_hide, what to add in order to make the page scroll to the bottom of the hidden field once button is clicked -

i have button on website when clicked, reveals map. button can seen when page first loads up, when clicked, section holding map slides open , goes out of screen since page loads @ top (normal). want page scroll down bottom of div select when button pushed, if map out of screen. if page scrolled down, , clicks show map button, don't want page jump bottom of map. i tried figure out myself, no luck. seasoned jquery coders able give me guidance? many thanks! map = mapdiv.gmap3("get"); infobox = new infobox({ pixeloffset: new google.maps.size(-220, -310), closeboxurl: '', enableeventpropagation: true }); mapdiv.delegate('.infobox .close','click',function () { infobox.close(); }); jquery(".slidingdiv").hide(); jquery(".show_hide").show(); jquery('.show_hide').click(function(){ lastcenter=map.getcenter(); jquery(".slidingdiv&quo
Read more

javascript - Highcharts multi-color line -

Image
i looking create highchart multi-colored line. if goes down under value, become red, , when comes on value, become green . here picture example: or maybe highcharts have other charts models differentiate high or low level color? you can achieve coloring using lineargradient coloring: color: { lineargradient: { x1: 0, x2: 0, y1: 0, y2: 1 }, stops: [ [0, 'red'], [0.25, 'yellow'], [0.50, 'green'], [0.75, 'yellow'], [1, 'red'] ] } here 0 in stops relates minimum value of series , 1 maximum value, , in between percentages between values. if find percentages according values prior creating chart use correct stops values make relate specific values in data (at least approximately). see this jsfiddle example .
Read more

javascript - Enter key does not work in search box -

tried search guys sorry. input in search box doesnt work (or search) when hit enter when user clicks search button. doing wrong? here code. thanks. <script type="text/javascript"> $(document).ready(function() { $("#submit").click(function() { var url = "http://asla.org/awardssearch.html"; url += "?s=" + $('#googlecse').val(); window.location = url; }); $('#googlecse').keydown(function(event) { if (event.keycode == '13') { $("#submit").click(); } else { //do nothing :) } }); }); </script> <form class="navbar-form navbar-right" role="search"> <div class="search"> <input id="googlecse" type="text" onblur="if(this.value=='')this.value=this.defaultvalue;" onfocus="if(this.value==this.defaultvalue)t
Read more