Loading and displaying an image in WinRT (Windows Store) (Tutorial II)

Take the following steps to start a project and to add some code that will load and display an image in a Windows Store application using LEADTOOLS WinRT libraries.

  1. Start Visual Studio 2012
  2. Choose File --> New Project from the menu.
  3. In the New Project dialog box, choose JavaScript and Windows Store as the project template, and choose Blank App in the Templates List.
  4. Type the project name as Load And Display in the Project Name field, and then click OK. If desired, type a new location for your project or select a directory using the Browse button, and then click OK.

  5. In the Solution Explorer window, right-click on the References folder for the project and select Add Reference... from the context menu. Browse to the <LEADTOOLS_INSTALLDIR>\Bin\WinRT8_1\ folder (depending on your target platform), and select the following .WINMD files:

    • Leadtools.winmd
    • Leadtools.Kernel.winmd
    • Leadtools.Codecs.winmd
    • Leadtools.Codecs.Kernel.winmd
    • Leadtools.Codecs.Bmp.winmd
    • Leadtools.Codecs.Cmp.winmd
    • Leadtools.Codecs.Fax.winmd
    • Leadtools.Codecs.Gif.winmd
    • Leadtools.Codecs.J2k.winmd
    • Leadtools.Codecs.Png.winmd
    • Leadtools.Codecs.Tif.winmd
    • Leadtools.Dicom.winmd
    • Leadtools.Converters.winmd
    • Leadtools.ImageProcessing.Core
    • Leadtools.ImageProcessing.Utilities

    Click the Add button and then click OK to add the above references.

  6. Open the default.html file and copy the below html code into the editor:

     

     

<!DOCTYPE html> 
<html> 
   <head> 
      <meta charset="utf-8" /> 
      <title>Load And Display</title> 
 
      <!-- WinJS references --> 
      <link href="//Microsoft.WinJS.1.0/css/ui-dark.css" rel="stylesheet" /> 
      <script src="//Microsoft.WinJS.1.0/js/base.js"></script> 
      <script src="//Microsoft.WinJS.1.0/js/ui.js"></script> 
 
      <!-- LoadDisplay references --> 
      <link href="/css/default.css"rel="stylesheet"/> 
      <script src="/js/default.js" ></script> 
   </head>  
 
   <body> 
      <input id="btnLoad" type="button" value="Load" /> 
      <br /> 
      <div> 
         <canvas id="outputCanvas" /> 
      </div> 
   </body> 
</html>

  1. Change to default.js in the Solution Explorer and copy the following code into the file (overwrite all existing code):

// For an introduction to the Blank template, see the following documentation:  
// http://msdn.microsoft.com/en-us/library/windows/apps/hh758331.aspx   
                  
(function () { 
   "use strict"; 
                    
   WinJS.Binding.optimizeBindingReferences = true; 
                    
   var app = WinJS.Application; 
   var activation = Windows.ApplicationModel.Activation; 
                    
   app.onactivated = function (args) { 
      if (args.detail.kind === activation.ActivationKind.launch) { 
         if (args.detail.previousExecutionState !== activation.ApplicationExecutionState.terminated) { 
            // TODO: This application has been newly launched. Initialize  
            // your application here.  
            document.getElementById("btnLoadAndReadBarcodes").addEventListener("click", ReadBarcodes, false); 
            Leadtools.RasterSupport.initialize(); // replace this with RasterSupport.SetLicense when you have a valid runtime license.  
            _barcodeEngine = new Leadtools.Barcode.BarcodeEngine(); 
         } else { 
            // TODO: This application has been reactivated from suspension.  
            // Restore application state here.  
         } 
         args.setPromise(WinJS.UI.processAll()); 
      } 
   }; 
                  
   app.oncheckpoint = function (args) { 
      // TODO: This application is about to be suspended. Save any state  
      // that needs to persist across suspensions here. You might use the  
      // WinJS.Application.sessionState object, which is automatically  
      // saved and restored across suspension. If you need to complete an  
      // asynchronous operation before your application is suspended, call  
      // args.setPromise().  
   }; 
                    
   app.start(); 
                    
   function LoadImage() { 
      // Create a file picker object  
      var openPicker = new  Windows.Storage.Pickers.FileOpenPicker(); 
      openPicker.viewMode = Windows.Storage.Pickers.PickerViewMode.thumbnail; 
      openPicker.suggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.picturesLibrary; 
      openPicker.ViewMode = Windows.Storage.Pickers.PickerViewMode.List;  
                    
      //Add a few supported file types  
      openPicker.fileTypeFilter.append(".jpg"); 
      openPicker.fileTypeFilter.append(".jpeg"); 
      openPicker.fileTypeFilter.append(".jxr"); 
      openPicker.fileTypeFilter.append(".png"); 
      openPicker.fileTypeFilter.append(".bmp"); 
      openPicker.fileTypeFilter.append(".pcx"); 
      openPicker.fileTypeFilter.append(".tif"); 
      openPicker.fileTypeFilter.append(".tiff"); 
      openPicker.fileTypeFilter.append(".j2k"); 
      openPicker.fileTypeFilter.append(".jbg"); 
      openPicker.fileTypeFilter.append(".gif"); 
      openPicker.fileTypeFilter.append(".jls"); 
      openPicker.fileTypeFilter.append(".jb2"); 
      openPicker.fileTypeFilter.append(".psd"); 
      openPicker.fileTypeFilter.append(".dcm"); 
      openPicker.fileTypeFilter.append(".dic"); 
      openPicker.fileTypeFilter.append(".pdf"); 
                    
      // Open the picker for the user to pick a file  
      openPicker.pickSingleFileAsync().then(function (file) { 
         if (!file) { 
            // The picker was dismissed with no selected file  
            return; 
         } 
                             
         // Create a RasterCodecs object to load the file  
         var codecs = new  Leadtools.Codecs.RasterCodecs(); 
                             
         // Create a LEAD Stream for the file  
         var leadStream = Leadtools.LeadStreamFactory.create(file); 
                    
         // Load it  
         codecs.options.load.initAlpha = true; 
         codecs.loadAsync(leadStream, 32, Leadtools.Codecs.CodecsLoadByteOrder.bgr, 1, 1).then(function  (rasterImage) { 
            //Render it to our canvas  
            //Get the canvas' context  
            //Create ImageData with size equal to our raster image size  
            //Use RasterImageRenderer to render the raster image onto the image data  
                                
            //ImageContext  
            var imageCanvas = document.createElement("canvas"); 
            var imageContext = document.createElement("2d"); 
                                
            outputCanvas.width = outerWidth; 
            outputCanvas.height = outerHeight - outputCanvas.offsetTop; 
                   
            //Check if the image needs to be scaled  
            var fScale = 1.0; 
            if (rasterImage.width > outputCanvas.width ||   rasterImage.height > outputCanvas.height) { 
               var xScale = outputCanvas.width / rasterImage.width; 
               var yScale = outputCanvas.height / rasterImage.height; 
                   
               fScale = (xScale > yScale) ? yScale : xScale; 
            } 
                                
            outputContext.scale(fScale, fScale); 
            outputContext.drawImage(imageCanvas, 0, 0);   
            } 
         }, function (e) { 
            var msg = new Windows.UI.Popups.MessageDialog("Error loading image"); 
            msg.showAsync(); 
         }); 
      }); 
}})();

  1. Build, and Run the program to test it.
  2. Click the Load button, and select an image.
  3. NOTE: If you encounter an "Invalid File Format" or "Feature Not Supported" exception, please refer to the topic Invalid File Format/Feature Not Supported.
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