RetrieveDataFromImage Property

var  myMode;

CodecsOptionsExamples.prototype.RetrieveDataFromImageExample = function () {
   Tools.SetLicense();
   with (Leadtools) {
      with (Leadtools.Codecs) {
         
         var codecs = new RasterCodecs();
         Leadtools.RasterSupport.initialize();
         codecs.eventsDispatchMode = Leadtools.LeadEventsDispatchMode.useCoreDispatcher;
         var srcFileName = "Assets\\Image1.cmp";

         var blankFile = "Sample1_Blank.bmp";
         var defaultFile = "Sample1_Default.bmp";
         var invertedFile = "Sample1_Inverted.bmp";
         var image ;

         // Load the source image
         return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
            return codecs.loadAsync(LeadStreamFactory.create(loadFile))
         })
            .then(function (img) {
               image = img;

               // Subscribe to the SaveImage event
               codecs.addEventListener("saveimage", codecs_SaveImage);

               // First, set RetrieveDataFromImage to false and save
               // This should generate a blank image
               myMode = 0;
               codecs.options.save.retrieveDataFromImage = false;
               return Tools.AppLocalFolder().createFileAsync(blankFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {

               // Next, set RetrieveDataFromImage to true but do not
               // change the data, this should generate the correct image and is the equivalant
               // to calling Save without subscribing to SaveImage
               myMode = 1;
               codecs.options.save.retrieveDataFromImage = true;
               return Tools.AppLocalFolder().createFileAsync(defaultFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {

               // Finally, leave RetrieveDataFromImage as true but change the data by inverting
               // the scanlines, this should generate an inverted image
               myMode = 2;
               return Tools.AppLocalFolder().createFileAsync(invertedFile)
            })
            .then(function (saveFile) {
               return codecs.saveAsync(image, LeadStreamFactory.create(saveFile), RasterImageFormat.bmp, 24)
            })
            .then(function () {
               codecs.removeEventListener("saveimage", codecs_SaveImage);
               codecs.close();
            });
      }
   }
}


function codecs_SaveImage(e) {
   // This example works with 24 bpp images only
   console.assert(e.image.bitsPerPixel == 24, "e.image.bitsPerPixel == 24");

   switch (myMode) {
      case 0:
         // Do not do anything
         break;

      case 1:
         // Do not do anything
         break;

      case 2:
         // Invert the image data
         {
            var scanlineLength = e.image.bytesPerLine;
            var scanline = new Array(scanlineLength);

            // Loop through all the scanlines in the data
            for (var y = 0; y < e.lines; y++) {
               // Get this row
               e.buffer.getData(y * scanlineLength, scanline, 0, scanlineLength);

               // Process it by inverting every pixel data
               for (var x = 0; x < scanlineLength; x++) {
                  scanline[x] = Tools.ToByte(255 - scanline[x]);
               }

               // Copy it back to the event buffer
               e.buffer.setData(y * scanlineLength, scanline, 0, scanlineLength);
            }
         }
         break;
   }
}