Loads the specified rectangle from the specified image stream using the specified options asynchronously.
public RasterImage LoadAsync(
Stream stream,
LeadRect tile,
int bitsPerPixel,
CodecsLoadByteOrder order,
int firstPage,
int lastPage,
object userState
)
Public Overloads Function LoadAsync( _
ByVal stream As Stream, _
ByVal tile As Leadtools.LeadRect, _
ByVal bitsPerPixel As Integer, _
ByVal order As Leadtools.Codecs.CodecsLoadByteOrder, _
ByVal firstPage As Integer, _
ByVal lastPage As Integer, _
ByVal userState As Object _
) As Leadtools.RasterImage
public Leadtools.RasterImage LoadAsync(
Stream stream,
Leadtools.LeadRect tile,
int bitsPerPixel,
Leadtools.Codecs.CodecsLoadByteOrder order,
int firstPage,
int lastPage,
object userState
)
- (void)loadStreamAsync:(LTLeadStream *)stream
tile:(LeadRect)tile
bitsPerPixel:(NSInteger)bitsPerPixel
order:(LTCodecsLoadByteOrder)order
firstPage:(NSInteger)firstPage
lastPage:(NSInteger)lastPage
completion:(void (^)(LTRasterImage * nullable image, NSError * nullable error))completion
public Object loadAsync(ILeadStream stream, LeadRect tile, int bitsPerPixel, CodecsLoadByteOrder order, int firstPage, int lastPage, Object userState)
function Leadtools.Codecs.RasterCodecs.LoadAsync(Stream,LeadRect,Int32,CodecsLoadByteOrder,Int32,Int32,Object)(
stream ,
tile ,
bitsPerPixel ,
order ,
firstPage ,
lastPage ,
userState
)
public:
Leadtools.RasterImage^ LoadAsync(
Stream^ stream,
Leadtools.LeadRect tile,
int bitsPerPixel,
Leadtools.Codecs.CodecsLoadByteOrder order,
int firstPage,
int lastPage,
Object^ userState
)
stream
A Stream containing the image data to load.
tile
A LeadRect describing the tile/area of the image to load.
bitsPerPixel
Resulting image pixel depth.
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.
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.
The RasterImage object that this method loads. See remarks for the usage of this object.
This method loads a section of an image file (any format). The section begins is defined by tile rectangle.
Valid values for the bitsPerPixel parameter 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. |
Valid values for the order parameter are:
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. |
LEADTOOLS will attempt to load corrupted files so you can see at least a portion of the image. For these images, the load methods succeed, but LoadStatus will return an error code.
Use the CodecsLoadOptions class to set up other load option parameters before calling this method.
Support for 12 and 16-bit grayscale images is only available in the Document/Medical Imaging editions.
For supported formats, refer to Summary of All Supported Image File Formats.
LEADTOOLS loads all PDF files as Raster PDF uncompressed RasterImageFormat.RasPdf, regardless of the compression and color space used when saving the file.
The RasterCodecs class supports loading image files asynchronously using the LoadAsync methods. When calling any of these methods, the caller thread will not be blocked and the method will return instantly with an instance of RasterImage that is in a loading status (RasterImage.IsLoading set to true). You should not use the other properties of this object while the object is in loading status.
When the RasterCodecs object finishes loading the image, the various properties of the RasterImage will be populated with the image information and data and the RasterImage.IsLoading property will be set to false.
Do not poll the RasterImage.IsLoading property to determine whether the image has finished loading. Instead, subscribe to the LoadAsyncCompleted event to get notification when the LoadAsync operation has completed and whether any errors occurred.
The LoadAsyncCompleted event data will also contain the same object returned from LoadAsync so you do not have to keep the original object in your application.
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