PGENLib.HdrImage Class Reference

A High-Dynamic-Range 2D image. This class has 3 members:

Width	number (int) of columns in the 2D matrix of colors
Height	number (int) of rows in the 2D matrix of colors
Pixel	the 2D matrix (array of Color), represented as a 1D array

More...

Public Member Functions
	HdrImage (int WidthConstr, int HeightConstr, Color[]? pixels=null)
	Constructor, empty or with pixels. More...
bool	ValidCoord (int x, int y)
	Check that given coordinates have values between 0 and the number of rows / columns. More...
void	SetPixel (int x, int y, Color newCol)
	Sets the color of a pixel of given coordinates. More...
Color	GetPixel (int x, int y)
	Given a pair of coordinates, it returns the color of the corresponding pixel. More...
HdrImage	ReadPFMFile (Stream input)
	Function that reads a PFM file and writes the content to a new HDR image. More...
string	ReadLine (Stream input)
	Reads a line of a stream. More...
int[]	ParseImgSize (string str)
	Image size reading function. More...
int	ParseEndianness (string input)
	Reads the endianness and returns if it is little or big. More...
void	WritePFMFile (Stream output, Endianness endian)
	Function that writes a PFM file from an HDR image. More...
float	AverageLum (double delta=1e-10)
	Returns the average brightness of the image. The delta parameter is used to prevent numerical problems for underilluminated pixels. More...
void	NormalizeImage (float factor, float? luminosity=null)
	Calculate the average brightness of an image according to the axRi / <l> formula. More...
float	ClampFloat (float x)
	Maps a float from [0, + inf) to [0,1]. More...
void	ClampImage ()
	Apply correction for bright spots.
void	WriteLdrImage (String output, String format, float gamma=1.0f)
	Convert an HDR image to LDR format. Before calling this function, you should apply a tone-mapping algorithm to the image and be sure that the R, G, and B values of the colors in the image are all in the range [0, 1]. Use HdrImage.NormalizeImage and HdrImage.ClampImage to do this. More...

Static Public Member Functions
static float	ReadFloat (Stream input, Endianness end)
	Reads a 32-bit sequence from a stream and converts it to a floating-point number. More...

Public Attributes
int	Width
int	Height
Color[]	Pixels

Private Member Functions
int	PixelOffset (int x, int y)
	Given a pair of coordinates, it returns the position of the pixel in the storage vector. More...

Static Private Member Functions
static void	WriteFloat (Stream outputStream, float value, Endianness end)
	Method of writing a 32-bit floating-point number in binary. More...

Detailed Description

A High-Dynamic-Range 2D image. This class has 3 members:

Width	number (int) of columns in the 2D matrix of colors
Height	number (int) of rows in the 2D matrix of colors
Pixel	the 2D matrix (array of Color), represented as a 1D array

Constructor & Destructor Documentation

HdrImage()

PGENLib.HdrImage.HdrImage	(	int	WidthConstr,
		int	HeightConstr,
		Color?[]	pixels = null
	)

Constructor, empty or with pixels.

Parameters

WidthConstr
HeightConstr
pixels

Member Function Documentation

AverageLum()

float PGENLib.HdrImage.AverageLum

(

double

delta = 1e-10

)

Returns the average brightness of the image. The delta parameter is used to prevent numerical problems for underilluminated pixels.

Parameters

delta

Returns

ClampFloat()

float PGENLib.HdrImage.ClampFloat

(

float

x

)

Maps a float from [0, + inf) to [0,1].

Parameters

x

Returns

GetPixel()

Color PGENLib.HdrImage.GetPixel	(	int	x,
		int	y
	)

Given a pair of coordinates, it returns the color of the corresponding pixel.

Parameters

x	type int
y	type int

Returns

Pixel's Color in coordinates (x,y)

NormalizeImage()

void PGENLib.HdrImage.NormalizeImage	(	float	factor,
		float?	luminosity = null
	)

Calculate the average brightness of an image according to the axRi / <l> formula.

Parameters

factor
luminosity

ParseEndianness()

int PGENLib.HdrImage.ParseEndianness

(

string

input

)

Reads the endianness and returns if it is little or big.

Parameters

input

string

Returns

+1 if endianness=big or -1 if endianness=small

ParseImgSize()

int[] PGENLib.HdrImage.ParseImgSize

(

string

str

)

Image size reading function.

Parameters

str	input string

Returns

int[2] containing Width and Height

PixelOffset()

int PGENLib.HdrImage.PixelOffset ( int  x, int  y  )

private

Given a pair of coordinates, it returns the position of the pixel in the storage vector.

Parameters

x
y

Returns

the position in the 1D array of the specified pixel

ReadFloat()

static float PGENLib.HdrImage.ReadFloat ( Stream  input, Endianness  end  )

static

Reads a 32-bit sequence from a stream and converts it to a floating-point number.

Parameters

input	Stream
end	Endianness

Returns

float

ReadLine()

string PGENLib.HdrImage.ReadLine

(

Stream

input

)

Reads a line of a stream.

Parameters

input

type Stream

Returns

String containing the line of the input stream

ReadPFMFile()

HdrImage PGENLib.HdrImage.ReadPFMFile

(

Stream

input

)

Function that reads a PFM file and writes the content to a new HDR image.

Parameters

input

type Stream

Returns

a HdrImage object containing the image. If an error occurs, raise a InvalidPfmFileFormat exception.

SetPixel()

void PGENLib.HdrImage.SetPixel	(	int	x,
		int	y,
		Color	newCol
	)

Sets the color of a pixel of given coordinates.

Parameters

x	type int
y	type int
newCol	type Color

ValidCoord()

bool PGENLib.HdrImage.ValidCoord	(	int	x,
		int	y
	)

Check that given coordinates have values between 0 and the number of rows / columns.

Parameters

x
y

Returns

True if (x, y) are coordinates within the 2D matrix

WriteFloat()

static void PGENLib.HdrImage.WriteFloat ( Stream  outputStream, float  value, Endianness  end  )

staticprivate

Method of writing a 32-bit floating-point number in binary.

Parameters

outputStream
value
end

WriteLdrImage()

void PGENLib.HdrImage.WriteLdrImage	(	String	output,
		String	format,
		float	gamma = 1.0f
	)

Convert an HDR image to LDR format. Before calling this function, you should apply a tone-mapping algorithm to the image and be sure that the R, G, and B values of the colors in the image are all in the range [0, 1]. Use HdrImage.NormalizeImage and HdrImage.ClampImage to do this.

Parameters

output
format
gamma

WritePFMFile()

void PGENLib.HdrImage.WritePFMFile	(	Stream	output,
		Endianness	endian
	)

Function that writes a PFM file from an HDR image.

Parameters

output
endian

---

The documentation for this class was generated from the following file:

• /Users/fra/Documenti/Università/Magistrale/SNIF/PhotoGENius/PGENLib/HdrImage.cs