Re: [flexcoders] Need Help - Loader changes the pixel value after loading as bitmap

[Alex Harui]

I’m missing what the other way of loading is and how you are getting its pixels.


On 8/27/12 3:15 AM, "RAJ" <raaj_...@yahoo.com> wrote:






Hi all ,

My aim is to load two images and compare its color information pixel by pixel. 
For this purpose i used "flash.display.Loader" class to load the images, and 
once load completes i'll typecast the loaded content to bitmap object 
(loaderObj.content as Bitmap). Finally i'll get the bitmapdata from the bitmap 
of both the images and compare the pixels.

Now the problem is the color information of the original image and the loaded 
bitmap is slightly different. For example the color value of pixels of the 
attached image image1.jpg is 0xDDDDDD for complete 1366x768. And for the same 
image when it is loaded as bitmap the color value of pixels are different from 
the original value (For some pixels only, not all pixels are different).

I've given the source code below.

Please can anyone help me out how to resolve this issue?

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009 
<http://ns.adobe.com/mxml/2009> "
                                                     
xmlns:s="library://ns.adobe.com/flex/spark"
                                                     
xmlns:mx="library://ns.adobe.com/flex/mx"
   ! ;                                                  width="1376" 
height="800"
                                                     showStatusBar="false">

         <fx:Declarations>
                    <!-- Place non-visual elements (e.g., services, value 
objects) here -->
          </fx:Declarations>

         <fx:Script>
                    <![CDATA[
                              private function loadBtn_ClickHandler():void{
                                        var file:File = new 
File(File.desktopDirectory.nativePath);
                                      &nbs! p; 
file.addEventListener(Event.SELECT, onFileSelectionHandler);
                                        file.browseForOpen("Open an image",[new 
FileFilter("Images", "*.jpg;*.gif;*.png;*.jpeg")]);
                              }

                             private function 
onFileSelectionHandler(ev:Event):void{
                                        var loadedFilePath:String = (ev.target 
as File).nativePath;
                                        loadImageAsBitmap(loadedFilePath);
                          !     }

                             /* Load image as bitmap using Loader */
                              private function 
loadImageAsBitmap(url:String):void 
<http://tech.groups.yahoo.com/group/flexcoders/String):void> {
                                        var loader:Loader = new Loader();
                 &! nbsp;                      // load content as bitmap
                                        
loader.contentLoaderInfo.addEventListener(Event.COMPLETE, 
onContentLoadComplete);
                                        
loader.contentLoaderInfo.addEventListener(IOErrorEvent.IO_ERROR, 
onContentLoadFail);
                              &nbs! p;         loader.load! (new URL 
Request(url));
                              }

                             private function 
onContentLoadComplete(ev:Event):void{
                                        var loaderInfo:LoaderInfo = ev.target 
as LoaderInfo;
                                        var bitmap:Bitmap = loaderInfo.content 
as Bitmap;
                         ! ;               printPixelValue(bitmap.bitmapData);
                                        container_ID.addChild(bitmap);
                              }

                             private function 
onContentLoadFail(ioe:IOErrorEvent):void{
                                        trace("Image Load Failed");
                              }

                             private function 
printPixelValue(bmData:BitmapData):void{
                                        var initPixelValue:Number = -1;
                                        //for (var countI:int = 0; countI < 
bmData.height; countI++) {
                        &nb! sp;               var countI:int = 1;
                                        for (var countJ:int = 0; countJ < 
bmData.width; countJ++) {
                                                  var pixelValue:Number = 
bmData.getPixel32(countJ, countI);
                                    ! ;          &! nbsp;&nb sp;  if(pixelValue 
!= initPixelValue){
                                                            initPixelValue = 
pixelValue;
                                                            // Print the pixel 
value only for one row
                          ! ;                                  trace("Pixel 
Value at " + countI + "x" + countJ + " is: " + pixelValue);
                                                  }
                                        }
                            &nbs! p;          ! trace(" Pixel Value at " + 
countI + "x" + countJ + " is: " + pixelValue);
                                        //}
                              }
                    ]]>
          </fx:Script>

          <s:Button id="loadBtn_ID" label="Load!" click="loadBtn_ClickHandler()"
                       &nb! sp;        x="5" y="5" height="20"/>
          <mx:UIComponent id="container_ID" x="5" y="30" width="1366" 
height="768"/>
</s:WindowedApplication>



Regards,
Rajkumar S





--
Alex Harui
Flex SDK Team
Adobe Systems, Inc.
http://blogs.adobe.com/aharui