CompressRow(ushort[],byte[],long,int,int) Method

Summary

Performs buffer-to-buffer RLE compression of 1-bit image data.

Syntax

C++/CLI

Python

[CLSCompliantAttribute(false)] 
public static void CompressRow( 
   ushort[] runBuffer, 
   byte[] buffer, 
   long bufferOffset, 
   int column, 
   int width 
)

[CLSCompliantAttribute(false)] 
public: 
static void CompressRow(  
   array<ushort>^ runBuffer, 
   array<byte>^ buffer, 
   long bufferOffset, 
   int column, 
   int width 
)

def CompressRow(self,runBuffer,buffer,bufferOffset,column,width):

Parameters

runBuffer
The output buffer, which will be filled with 1-bit compressed image data.

buffer
The input buffer, which contains the 1-bit image data to be compressed.

bufferOffset
Zero-based index into buffer.

column
Column offset within the row to be processed. The method skips this many pixels before it begins processing.

width
The number of pixels to process.

Remarks

Use this method to process all or part of a single line of image data. This method is available in the Document/Medical Toolkits.

This function is useful for working with 1-bit images that are loaded in their compressed formats for faster loading and display. For more information, refer to Speeding Up 1-Bit Documents.

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Dicom; 
using Leadtools.Drawing; 
using Leadtools.Controls; 
using Leadtools.Svg; 
 
 
public void GetRowColumnCompressedExample() 
{ 
	RasterCodecs codecs = new RasterCodecs(); 
	// Load the bitmap, at 1 bit per pixel, compressed 
	codecs.Options.Load.Compressed = true; 
	RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "OCR1.TIF"), 1, Leadtools.Codecs.CodecsLoadByteOrder.Bgr, 1, 1); 
 
	int xOffset;   // Column offset of the rectangle to process. 
	int xSize;     // Pixel width of the rectangle to process. 
	int yOffset;   // Row offset of the rectangle to process. 
	int ySize;     // Pixel height of the rectangle to process. 
	int i, n;       // Counters. 
 
	byte[] buffer;      // Buffer to hold the expanded row. 
	ushort[] runBuffer; // Buffer to hold the compressed row. 
	byte[] workBuffer;  // Work buffer. 
 
	// This example does not work with rotated view perspectives. 
	if ((image.ViewPerspective != RasterViewPerspective.TopLeft) || (image.ViewPerspective != RasterViewPerspective.BottomLeft)) 
		image.ChangeViewPerspective(RasterViewPerspective.TopLeft); 
 
	// Specify a rectangle in the middle right part of the displayed image. 
	xOffset = image.Width / 3; 
	xSize = image.Width - xOffset; 
	yOffset = image.Height / 3; 
	ySize = image.Height / 3; 
	// Adjust the YOffset if the view perspective is bottom left. 
	if (image.ViewPerspective == RasterViewPerspective.BottomLeft) 
	{ 
		yOffset = image.Height - yOffset - ySize; 
	} 
 
	if (image.IsGlobalMemory) 
		image.Access(); 
	// Allocate the buffers. 
	buffer = new Byte[(xSize + 7) / 8]; 
	runBuffer = new ushort[(xSize + 3) * 2]; 
	workBuffer = new Byte[image.BytesPerLine]; 
	// Invert the colors of pixels in the left half of the rectangle. 
	// Notice that we get the whole rectangle, but process only half of it. 
	for (i = yOffset; i < (yOffset + ySize); i++) 
	{ 
		image.GetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize); 
		RasterRleCompressor.ExpandRow(runBuffer, buffer, 0, 0, xSize); 
		for (n = 0; n < (xSize / 16); n++) 
			buffer[n] ^= 0xFF; 
		RasterRleCompressor.CompressRow(runBuffer, buffer, 0, 0, xSize); 
		image.SetRowColumnCompressed(workBuffer, runBuffer, 0, i, xOffset, xSize); 
 
	} 
	if (image.IsGlobalMemory) 
		image.Release(); 
 
	codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrowcolcompresed.BMP"), RasterImageFormat.Bmp, 0); 
 
	image.Dispose(); 
	codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}

Requirements

Target Platforms

Reference

RasterRleCompressor Class

RasterRleCompressor Members

Overload List

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Help Version 22.0.2023.5.16

Leadtools Assembly

Introduction

Getting Started

Namespaces

Leadtools Namespace

Leadtools.ImageProcessing Namespace

Assemblies