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Load(string,int,int,int,RasterSizeFlags,CodecsLoadByteOrder,int,int) Method

Summary

Loads an image file to the desired width, height, and bits per pixel, resizing as it loads.

Syntax
C#
VB
Objective-C
C++
Public Overloads Function Load( _ 
   ByVal fileName As String, _ 
   ByVal width As Integer, _ 
   ByVal height As Integer, _ 
   ByVal bitsPerPixel As Integer, _ 
   ByVal flags As RasterSizeFlags, _ 
   ByVal order As CodecsLoadByteOrder, _ 
   ByVal firstPage As Integer, _ 
   ByVal lastPage As Integer _ 
) As RasterImage 
- (nullable LTRasterImage *)loadFile:(NSString *)file  
                               width:(NSInteger)width  
                              height:(NSInteger)height  
                        bitsPerPixel:(NSInteger)bitsPerPixel  
                               flags:(LTRasterSizeFlags)flags  
                               order:(LTCodecsLoadByteOrder)order  
                           firstPage:(NSInteger)firstPage  
                            lastPage:(NSInteger)lastPage  
                               error:(NSError **)error 

Parameters

fileName
A String containing the name of the image file to load.

width
New width of the image in pixels.

height
New height of the image in pixels.

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.

flags
Flag that indicates the type of resizing to use. Possible values are:

Value Meaning
RasterSizeFlagsRasterSizeFlags.None Normal resizing
RasterSizeFlagsRasterSizeFlags.Resample Linear interpolation resizing
RasterSizeFlagsRasterSizeFlags.Bicubic Bicubic interpolation resizing
RasterSizeFlagsRasterSizeFlags.FavorBlack Not supported

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.

Return Value

The RasterImage object that this method loads.

Remarks

This method resizes a file as it loads, to the desired width, height, and bits per pixel. Note that the original file is not completely loaded into memory. This method is ideal for sampling large images (i.e. generating a thumbnail) without the memory overhead of loading the large file itself.

The file can be in any supported image file format and bits per pixel, whether compressed or uncompressed.

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, and 48 and 64-bit color images is only available in the Document/Medical Imaging editions.

For supported formats, refer to Summary of All Supported 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.

Example

This example will load the last page of an image from file in a specified size.

C#
VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Svg; 
using LeadtoolsExamples.Common; 
 
public void LoadResize2Example() 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
 
   string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Eye.gif"); 
   string destFileName = Path.Combine(LEAD_VARS.ImagesDir, "LoadResize2.bmp"); 
 
   CodecsImageInfo info = codecs.GetInformation(srcFileName, true); 
 
   // Get the page number to load 
   int pageNumber = info.TotalPages; 
 
   // We want to load the image as 320/200 
   int width = 320; 
   int height = 200; 
 
   // Load the last page in the specified size 
   RasterImage image = codecs.Load( 
      srcFileName, 
      width, 
      height, 
      0, 
      RasterSizeFlags.Resample, 
      CodecsLoadByteOrder.BgrOrGray, 
      pageNumber, 
      pageNumber); 
 
   Debug.Assert(image.Width == width); 
   Debug.Assert(image.Height == height); 
 
   // Save this image back to disk 
   codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24); 
   image.Dispose(); 
 
   // Clean up 
   codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
Imports Leadtools.Drawing 
Imports Leadtools.Svg 
 
Public Sub LoadResize2Example() 
   Dim codecs As RasterCodecs = New RasterCodecs() 
 
   Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Eye.gif") 
   Dim destFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LoadResize2.bmp") 
 
   Dim info As CodecsImageInfo = codecs.GetInformation(srcFileName, True) 
 
   ' Get the page number to load 
   Dim pageNumber As Integer = info.TotalPages 
 
   ' We want to load the image as 320/200 
   Dim width As Integer = 320 
   Dim height As Integer = 200 
 
   ' Load the last page in the specified size 
   Dim image As RasterImage = codecs.Load(srcFileName, width, height, 0, RasterSizeFlags.Resample, CodecsLoadByteOrder.BgrOrGray, pageNumber, pageNumber) 
 
   Debug.Assert(image.Width = width) 
   Debug.Assert(image.Height = height) 
 
   ' Save this image back to disk 
   codecs.Save(image, destFileName, RasterImageFormat.Bmp, 24) 
   image.Dispose() 
 
   ' Clean up 
   codecs.Dispose() 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class 

Requirements

Target Platforms

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Leadtools.Codecs Assembly