Camera image orientation on iOS

Thank you a lot for you quick reply. After few hours trying and looking around, finnally I can read EXIF of a photo on iOS, actually it's JFIF as you said.

Allow me to write something here, hope it helps people who still can't get the orientation of the photos on iOS...

As first, you guys have to take a look at this: http://code.shichiseki.jp/as3/ExifInfo

And as Joe said above, On iOS, the datasource for the MediaPromise is not file-based, so the file URL is null. Instead, you have to read the image data into a ByteArray in order to access the raw image data. (To just display the image, you could use the Loader.loadMediaPromise() method, but that doesn't give you the EXIF data.)

Also:

It also wasn't hard to fix the jp.shichiseki library to ignore the JFIF marker. You just have to add the folowing to the ExifInfo class:

private const JFIF_MAKER:Array = [0xff, 0xe0]; //new marker type

        //Updated to skip JFIF marker
        private function validate(stream:ByteArray):Boolean {
            var app1DataSize:uint;
            // JPG format check
            if (!hasSoiMaker(stream) ) {
                return false;
            }
            if(hasJFIFMaker(stream)) //Skip the JFIF marker, if present. CWW
            {
                stream.position += 16;
            }
            else stream.position -=2; //Set position back to start of APP1 marker
           
            if ( !hasAPP1Maker(stream)) {
                return false;
            }
            // handle app1 data size
            app1DataSize = stream.readUnsignedShort();
            if (!hasExifHeader(stream)) {
                return false;
            }
            return true;
        }

        //New function to check for JFIF marker
        private function hasJFIFMaker(stream:ByteArray):Boolean {
            return compareStreamBytes(stream, JFIF_MAKER);
        }

Note that the library fails silently if it doesn't recognize the file format. That's why you get a null reference error. The library wasn't creating any of its usual objects. Another thing to be aware of is that not all devices on Android record the orientation. In my collection, only one of three did so.

Finally, below is my few lines of code:

var mediaPromise:MediaPromise; var dataSource:IDataInput; var loader:Loader = new Loader(); loader.contentLoaderInfo.addEventListener(Event.COMPLETE, loadComplete); addChild(loader); captureBtn.addEventListener(MouseEvent.CLICK, function(){           trace(CameraRoll.supportsBrowseForImage)           if(CameraRoll.supportsBrowseForImage){                     camRoll.browseForImage()           } }) function onSelected(e:MediaEvent){           mediaPromise = e.data;           dataSource = mediaPromise.open();           if( mediaPromise.isAsync )     {         trace( "Asynchronous media promise." );         var eventSource:IEventDispatcher = dataSource as IEventDispatcher;                    eventSource.addEventListener( Event.COMPLETE, onMediaLoaded );             }     else     {         trace( "Synchronous media promise." );         readMediaData();     }           //output.appendText("\n"+mediaPromise)           //output.appendText("\n"+mediaPromise.file)           //output.appendText("\n"+mediaPromise.file.url)           //trace(mediaPromise.file.url); } function onMediaLoaded( event:Event ):void {     trace("Media load complete");     readMediaData(); } function readMediaData():void {           // THIS PART IS READING JFIF DATA:           var data:ByteArray = new ByteArray();           dataSource.readBytes( data );           exif = new ExifInfo(data);           //output.text = displayIFD(exif.ifds.exif); // This stores some properties like resolutionX, resolutionY,.etc.           //output.text = displayIFD(exif.ifds.primary); // This one stores the orientation data.           output.text = getOrientation(exif.ifds.primary)     //do something with the data           loader.loadFilePromise(mediaPromise); } function displayIFD(ifd:IFD):String {           //trace(" --- " + ifd.level + " --- ");           var str:String = "";           for (var entry:String in ifd) {                     trace(entry + ": " + ifd[entry]);                     str += (entry + ": " + ifd[entry] + "\n")           }           return str; } function getOrientation(ifd:IFD):String{           var str:String = "";           for (var entry:String in ifd) {                     if(entry == "Orientation"){                               str = ifd[entry];                     }           }           switch(str){                     case "1": //normal                               str = "NORMAL";                     break;                     case "3": //rotated 180 degrees (upside down)                               str = "UPSIDE_DOWN";                     break;                     case "6": //rotated 90 degrees CW                               str = "ROTATED_LEFT"                     break;                     case "8": //rotated 90 degrees CCW                               str = "ROTATED_RIGHT"                     break;                     case "9": //unknown                               str = "UNKNOWN"                     break;           }           return str; } function onCancelled(e:Event){ }

Thank you a bunch, again, Joe!

Have a good day!

Thanks a lot for your answer.

I understand the concept of switching the APP marker to get data, but i already have trouble about accessing picture.

For exemple if i take the sample from ExifInfo AS3 Library (just the part about accessing the image), here is my test

private function mediaSelectHandler( event:MediaEvent ):void
{
        mediaPromise = event.data;
        trace(mediaPromise);
        trace(mediaPromise.file.url);

        /*
        this.exifLoader = new ExifLoader();
        this.exifLoader.addEventListener(Event.COMPLETE, completeHandler );
        this.exifLoader.load( new URLRequest( mediaPromise.file.url ) );

        */

}

When media is selected, when i trace mediaPromise, i get a media [mediaPromise object], but when i trace mediaPromise.file.url its null. In that way how can i get access to the file because since on iOS its null.

Is there any example/sample about this, because i really get the concept and the logic, but i have no idea how to get it.

Thank you again