ChangeViewPerspective Method

Summary

Rotates and flips the image data as necessary to achieve the desired view perspective.

Syntax

Objective-C

C++/CLI

Java

Python

public void ChangeViewPerspective( 
   RasterViewPerspective viewPerspective 
)

- (BOOL)changeViewPerspective:(LTRasterViewPerspective)viewPerspective error:(NSError **)error

public void changeViewPerspective( 
   RasterViewPerspective viewPerspective 
);

public: 
void ChangeViewPerspective(  
   RasterViewPerspective viewPerspective 
)

def ChangeViewPerspective(self,viewPerspective):

Parameters

viewPerspective
Desired view perspective.

Remarks

The ViewPerspective is the arrangement of pixels in the image. This method references image coordinates, which are often different from the display coordinates of an image.

Use this method to change the data and the ViewPerspective to simplify calculations that involve image coordinates. This method does not affect the image display. For more information, refer to Accounting for View Perspective.

The following values for viewPerspective are supported in (Document/Medical only) only:

Example

This example demonstrates the low-level methods for accessing 1-bit compressed image data. It demonstrates the ability to get and put rows, and the ability to process rows in buffer-to-buffer processing. The result of the function is an the first 50 lines are inverted.

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 GetRowCompressedExample() 
{ 
	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); 
 
	// This example does not work with rotated view perspectives. 
	if ((image.ViewPerspective != RasterViewPerspective.TopLeft) || (image.ViewPerspective != RasterViewPerspective.BottomLeft)) 
		image.ChangeViewPerspective(RasterViewPerspective.TopLeft); 
 
	// Adjust the YOffset if the view perspective is bottom left. 
	int nRow = 500; // first row to get. 
	int nYSize = 500; // number of rows to get. 
 
	if (image.ViewPerspective == RasterViewPerspective.BottomLeft) 
		nRow = image.Height - nRow - nYSize; 
 
	// Allocate the buffers. 
	byte[] pBuffer = new byte[Convert.ToInt32((((image.Width + 31) & ~(31)) / 8)) * nYSize]; // Buffer to hold the expanded row. 
	ushort[] pRunBuffer = new ushort[((image.Width + 3) * 2) * nYSize]; // Buffer to hold the compressed row. 
 
	if (image.IsGlobalMemory) 
		image.Access(); 
	// Get the top nRow lines. 
	image.GetRowCompressed(null, pRunBuffer, 0, nRow, nYSize); 
	// Expand the compressed data. 
	RasterRleCompressor.ExpandRows(pRunBuffer, pBuffer, 0, image.Width, nYSize); 
	// Invert the data. 
 
	for (int n = 0; n < (image.BytesPerLine * nYSize); n++) 
		pBuffer[n] ^= 0xff; 
 
 
	// Compress the inverted data. 
	RasterRleCompressor.CompressRows(pRunBuffer, pBuffer, 0, image.Width, nYSize); 
 
	// Put the inverted, compressed data back into the image. 
	image.SetRowCompressed(null, pRunBuffer, 0, nRow, nYSize); 
 
	if (image.IsGlobalMemory) 
		image.Release(); 
 
	codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1_getrowcompresed.BMP"), RasterImageFormat.Bmp, 0); 
 
	image.Dispose(); 
	codecs.Dispose(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}

Requirements

Target Platforms

Reference

RasterImage Class

RasterImage Members

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Help Version 22.0.2023.5.16

Leadtools Assembly

Introduction

Getting Started

Namespaces

Leadtools Namespace

Leadtools.ImageProcessing Namespace

Assemblies