Advanced functionality for image encoding
In This Topic
SDK allows to edit an image, which is divided into tiles, without reencoding the whole image. This allows to edit very large images of unlimited size, which are consist from tiles and physically can not be loaded entirely into memory. Editing is implemented by changing the image tiles sequentially using an object, which implements the
IRasterGridEditor interface.
Objects implementing
IRasterGridEditor interface support the following methods:
IRasterGridEditor interface is implemented for TIFF (
TiffFile) and JPEG2000 (
Jpeg2000File) files.
The
DecoderBase class allows to get an instance that implements the
IRasterGridEditor interface using the
DecoderBase.GetRasterGridEditor method.
Here is C#/VB.NET code that demonstrates how to get an image tile, change it and save back to the file:
/// <summary>
/// Gets an image of first tile of TIFF page,
/// rotates the tile image 180 degrees,
/// sets changed tile image as new image of first tile,
/// saves changes to the source TIFF file.
/// </summary>
public static void ChangeTileOfTiffPage(string tiffFilename, int pageIndex)
{
using (System.IO.Stream stream = new System.IO.FileStream(
tiffFilename, System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite))
{
using (Vintasoft.Imaging.Codecs.Decoders.TiffDecoder decoder =
new Vintasoft.Imaging.Codecs.Decoders.TiffDecoder(stream))
{
// get raster grid editor
Vintasoft.Imaging.Codecs.ImageFiles.IRasterGridEditor rasterGridEditor = decoder.GetRasterGridEditor();
// get grid of raster regions
System.Drawing.Rectangle[] grid = rasterGridEditor.GetRasterEditorGrid(pageIndex);
if (grid == null || grid.Length == 0)
throw new System.Exception("Image tiles cannot be changed.");
// index of the region to change
int rectIndex = 0;
// get region to change
System.Drawing.Rectangle region = grid[rectIndex];
// image of changing region
Vintasoft.Imaging.VintasoftImage regionImage;
// create image renderer
using (Vintasoft.Imaging.ImageRendering.ImageRenderer renderer =
new Vintasoft.Imaging.ImageRendering.ImageRenderer(decoder, pageIndex))
{
// create region rendering task
Vintasoft.Imaging.ImageRendering.ImageRenderingTask renderingTask =
Vintasoft.Imaging.ImageRendering.ImageRenderingTask.CreateImageRegion(region);
// set to convert to the source format
renderingTask.ConvertDestImageToSourceFormat = true;
// get an image of first tile
regionImage = renderer.ExecuteRendering(renderingTask);
}
// rotate the tile image 180 degrees
regionImage.Flip(Vintasoft.Imaging.ImageProcessing.Transforms.ImageRotateFlipType.Rotate180FlipNone);
// set the tile image as new image of first tile
rasterGridEditor.SetImageRect(pageIndex, rectIndex, regionImage, null);
regionImage.Dispose();
// save changes to the source TIFF file
rasterGridEditor.SaveChanges(null);
}
}
''' <summary>
''' Gets an image of first tile of TIFF page,
''' rotates the tile image 180 degrees,
''' sets changed tile image as new image of first tile,
''' saves changes to the source TIFF file.
''' </summary>
Public Shared Sub ChangeTileOfTiffPage(tiffFilename As String, pageIndex As Integer)
Using stream As System.IO.Stream = New System.IO.FileStream(tiffFilename, System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite)
Using decoder As New Vintasoft.Imaging.Codecs.Decoders.TiffDecoder(stream)
' get raster grid editor
Dim rasterGridEditor As Vintasoft.Imaging.Codecs.ImageFiles.IRasterGridEditor = decoder.GetRasterGridEditor()
' get grid of raster regions
Dim grid As System.Drawing.Rectangle() = rasterGridEditor.GetRasterEditorGrid(pageIndex)
If grid Is Nothing OrElse grid.Length = 0 Then
Throw New System.Exception("Image tiles cannot be changed.")
End If
' index of the region to change
Dim rectIndex As Integer = 0
' get region to change
Dim region As System.Drawing.Rectangle = grid(rectIndex)
' image of changing region
Dim regionImage As Vintasoft.Imaging.VintasoftImage
' create image renderer
Using renderer As New Vintasoft.Imaging.ImageRendering.ImageRenderer(decoder, pageIndex)
' create region rendering task
Dim renderingTask As Vintasoft.Imaging.ImageRendering.ImageRenderingTask = Vintasoft.Imaging.ImageRendering.ImageRenderingTask.CreateImageRegion(region)
' set to convert to the source format
renderingTask.ConvertDestImageToSourceFormat = True
' get an image of first tile
regionImage = renderer.ExecuteRendering(renderingTask)
End Using
' rotate the tile image 180 degrees
regionImage.Flip(Vintasoft.Imaging.ImageProcessing.Transforms.ImageRotateFlipType.Rotate180FlipNone)
' set the tile image as new image of first tile
rasterGridEditor.SetImageRect(pageIndex, rectIndex, regionImage, Nothing)
regionImage.Dispose()
' save changes to the source TIFF file
rasterGridEditor.SaveChanges(Nothing)
End Using
End Using