RgbImage

RgbImage Class

The RgbImage class represents an RGB, BGR, RGBA or BGRA image with support for both managed and unmanaged memory. It provides methods for memory management, cropping, and aspect ratio adjustment.

Table of Contents

• Overview
• Constructors
• Properties
• Methods
• Usage Examples

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Overview

The RgbImage class is designed to handle RGB format images with efficient memory allocation. It supports both managed and unmanaged memory modes.

Features:

• Supports RGB, BGR, RGBA or BGRA formats.
• Handles both managed (byte[]) and unmanaged (IntPtr) memory.
• Provides methods for cropping and aspect ratio adjustment without any copy.
• Implements IDisposable for proper memory management.
• Unmanaged memory is freed on disposal only if the memory is allocated by this class(owns).

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Constructors

Constructor	Description
RgbImage(ImageFormat format, int width, int height)	Allocates unmanaged memory for the image, size depending on format.
RgbImage(ImageFormat format, int width, int height, int stride, byte[] data)	Creates an image from an existing byte array without allocating new memory.
RgbImage(ImageFormat format, int width, int height, byte[] data)	Assumes default stride((w3) or (w4)) and uses an existing byte array.
RgbImage(ImageFormat format, int width, int height, int stride, IntPtr imageBytes)	References an existing unmanaged memory block.

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Properties

Property	Type	Description
Format	ImageFormat	The image format (RGB, BGR, RGBA or BGRA).
Width	int	The image width in pixels.
Height	int	The image height in pixels.
Stride	int	The number of bytes per row.
IsManaged	bool	Indicates if memory is managed (true) or unmanaged (false).
NativeBytes	IntPtr	Pointer to unmanaged image data (if applicable).
ManagedBytes	byte[]	Managed image data (if applicable).
dataOffset	int	Offset within the data buffer.
dataLength	int	Length of the image data in bytes.

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Methods

Method	Return Type	Description
Crop(int top, int bottom, int left, int right)	RgbImage	Creates a cropped shallow copy of the image.
ChangeAspectRatio(int targetWidth, int targetHeight)	RgbImage	Adjusts the aspect ratio of the image by cropping.
GetBytes()	byte[]	Returns the image data as a byte array.
CopyTo(MemoryStream stream)	void	Copies image data to a memory stream.
Dispose()	void	Releases unmanaged memory.

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Usage Examples

Creating a New Image

RgbImage img = new RgbImage(ImageFormat.Rgb, 1920, 1080);

Creating an Image from Managed Memory

byte[] data = new byte[800 * 600 * 3]; // RGB format
RgbImage img = new RgbImage(ImageFormat.Rgb, 800, 600, data);

Cropping an Image

RgbImage cropped = img.Crop(10, 10, 20, 20);

Adjusting Aspect Ratio

RgbImage adjusted = img.ChangeAspectRatio(16, 9);

Releasing Resources

img.Dispose();

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This documentation provides a structured overview of the RgbImage class and its functionalities.