LoadAsync(string,int,CodecsLoadByteOrder,int,int,object) Method (original) (raw)
Summary
Loads the specified image file using specific options asynchronously.
Syntax
C#
Objective-C
C++/CLI
Python
- (void)loadFileAsync:(NSString *)file
bitsPerPixel:(NSInteger)_bitsPerPixel_
order:(LTCodecsLoadByteOrder)_order_
firstPage:(NSInteger)_firstPage_
lastPage:(NSInteger)_lastPage_
completion:(void (^)(LTRasterImage * __nullable image, NSError * __nullable error))completion
Parameters
fileName
A String containing the name of the image file to load.
bitsPerPixel
Resulting image pixel depth. Valid values are:
| Value | Meaning |
|---|---|
| 0 | Keep the original file's pixel depth (Do not convert). |
| 1 to 8 | The specified bits per pixel in the resulting image. |
| 12 | 12 bits per pixel in the resulting image. |
| 16 | 16 bits per pixel in the resulting image. |
| 24 | 24 bits per pixel in the resulting image. |
| 32 | 32 bits per pixel in the resulting image. |
| 48 | 48 bits per pixel in the resulting image. |
| 64 | 64 bits per pixel in the resulting image. |
order
Color order for 16-bit, 24-bit, 32-bit, 48-bit, and 64-bit images. If the resulting image is less than 16 bits per pixel, this will have no effect since palletized images have no order. The following are valid values.
| Value | Meaning |
|---|---|
| CodecsLoadByteOrder.Rgb | Red, green, and blue color order in memory |
| CodecsLoadByteOrder.Bgr | Blue, green, and red color order in memory |
| CodecsLoadByteOrder.Gray | 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are only supported in the Document/Medical Imaging editions. |
| CodecsLoadByteOrder.RgbOrGray | Load the image as red, green, blue OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions |
| CodecsLoadByteOrder.BgrOrGray | Load the image as blue, green, red OR as a 12 or 16-bit grayscale image. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions |
| CodecsLoadByteOrder.Romm | ROMM order. ROMM only supports 24 and 48-bit images |
| CodecsLoadByteOrder.BgrOrGrayOrRomm | Load the image as red, green, blue OR as a 12 or 16-bit grayscale image OR as ROMM. 12 and 16-bit grayscale images are supported in the Document/Medical Imaging editions only. ROMM only supports 24 and 48-bit color images. |
firstPage
1-based index of the first page to load.
lastPage
The 1-based index of the last page to load. Must be greater than or equal to firstPage. You can pass -1 to load from firstPage to the last page in the file.
userState
A user-defined object that is passed to the method invoked when the asynchronous operation completes.
Return Value
The RasterImage object that this method loads. See remarks for the usage of this object.
Example
using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing;
using Leadtools.ImageProcessing.Color;
using Leadtools.Svg;
public void LoadAsyncFile2Example()
{
string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif");
RasterCodecs codecs = new RasterCodecs();
// Now load the first page of the image as 24 bits/pixel with order BGR asynchronously
codecs.LoadAsyncCompleted += new EventHandler<CodecsLoadAsyncCompletedEventArgs>(LoadAsyncFile2Example_LoadAsyncCompleted);
object rasterImageObject = codecs.LoadAsync(srcFileName, 24, CodecsLoadByteOrder.BgrOrGray, 1, 1, null);
// Notice that the returned rasterImageObject is a RasterImage with IsLoading set to true at this point
// The IsLoading will be false (and hence, the object will be usable) when the LoadAsyncCompleteted
// fires.
}
private void LoadAsyncFile2Example_LoadAsyncCompleted(object sender, CodecsLoadAsyncCompletedEventArgs e)
{
if (e.Cancelled)
{
Debug.WriteLine("User canceled");
}
else if (e.Error != null)
{
Debug.WriteLine("Error: " + e.Error.Message);
}
else
{
// Everything is OK, get the image
RasterImage image = e.Image;
Debug.WriteLine("Image at {0} loaded OK, size: {1} by {2}, order: {3}, bits/pixel: {4}", e.FileName, image.Width, image.Height, image.Order, image.BitsPerPixel);
image.Dispose();
}
// Unsubscribe to the event and dispose the RasterCodecs object
RasterCodecs codecs = sender as RasterCodecs;
codecs.LoadAsyncCompleted -= new EventHandler<CodecsLoadAsyncCompletedEventArgs>(LoadAsyncFile2Example_LoadAsyncCompleted);
codecs.Dispose();
}
static class LEAD_VARS
{
public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images";
}
Leadtools.Codecs Assembly
CompactFile(Stream,Stream,int,int,bool,int,int,bool,int,CodecsSavePageMode,bool,bool) Method
CompactFile(Stream,Stream,int,int,bool,long,int,bool,long,CodecsSavePageMode,bool,bool,bool) Method
CompactFile(string,string,int,int,bool,int,int,bool,int,CodecsSavePageMode,bool,bool) Method
CompactFile(string,string,int,int,bool,long,int,bool,long,CodecsSavePageMode,bool,bool,bool) Method