rendering_engine::ImageData Class Reference

Represents raw 2D image data stored in memory. More...

#include <image_data.hpp>

Public Member Functions
	ImageData ()
	Constructs an empty image.
	ImageData (unsigned int width, unsigned int height)
	Constructs a blank image with specified dimensions.
	ImageData (std::string filepath)
	Loads image data from a file.
	ImageData (std::vector< uint8_t > const &fileBytes)
	Constructs an image by decoding raw file bytes.
	ImageData (unsigned int width, unsigned int height, std::vector< unsigned int > const &pixelsRGBA)
	Constructs image from raw RGBA pixel buffer.
	~ImageData ()
	Destructor that frees memory.
	ImageData (const ImageData &src)
	Copy constructor.
ImageData &	operator= (const ImageData &rhs)
	Copy assignment operator.
unsigned int	GetWidth () const
	Returns the image width.
unsigned int	GetHeight () const
	Returns the image height.
void	Fill (Color color)
	Fills the image with a solid color.
void	SetPixel (unsigned int x, unsigned int y, Color color)
	Sets the color of a specific pixel.
const Color	GetPixel (unsigned int x, unsigned int y) const
	Retrieves the color of a specific pixel.
std::vector< uint8_t >	GetImageDataRGBA () const
	Gets raw image data in RGBA format.
std::vector< uint8_t >	GetImageDataRGB () const
	Gets raw image data in RGB format.
size_t	GetSizeInBytes () const
	Gets the total size of the image in memory.
void	WriteJpegFile (char const *filename)
	Writes the image data to a JPEG file.
void	WritePngFile (char const *filename)
	Writes the image data to a PNG file.

Static Public Member Functions
static void	DrawImageOnImageAtPos (unsigned int const x, unsigned int const y, ImageData &toImage, ImageData &fromImage)
	Overlays one image on top of another at a given position.

Protected Member Functions
void	AllocateMemory (unsigned int width, unsigned int height)
	Allocates memory for internal pixel storage.
void	CleanAllocatedMemory ()
	Frees allocated memory.
void	LoadImageDataRGBA (std::vector< unsigned int > const &pixels)
	Loads image data from a 32-bit RGBA buffer.
void	LoadImageDataRGB (std::vector< unsigned int > const &pixels)
	Loads image data from a 24-bit RGB buffer.
bool	LoadTexturePngFile (char const *filename)
	Loads image from a PNG file.
bool	LoadTextureJpegFile (char const *filename)
	Loads image from a JPEG file.

Detailed Description

Represents raw 2D image data stored in memory.

Definition at line 72 of file image_data.hpp.

Constructor & Destructor Documentation

ImageData() [1/6]

rendering_engine::ImageData::ImageData

(

)

Constructs an empty image.

Definition at line 11 of file image_data.cpp.

    :
    ImageData::ImageData(0U, 0U)
{
}

ImageData() [2/6]

rendering_engine::ImageData::ImageData	(	unsigned int	width,
		unsigned int	height )

Constructs a blank image with specified dimensions.

Parameters

width	Image width in pixels
height	Image height in pixels

Definition at line 17 of file image_data.cpp.

    :
    mWidth( width ),
    mHeight( height )
{
    AllocateMemory( mWidth, mHeight );
}

ImageData() [3/6]

rendering_engine::ImageData::ImageData

(

std::string

filepath

)

Loads image data from a file.

Parameters

filepath

Path to the image file (JPG or PNG)

Definition at line 25 of file image_data.cpp.

    :
    ImageData::ImageData()
{
    auto const pathToTexture = boost::filesystem::path(filepath);
    if( boost::filesystem::exists(pathToTexture) && boost::filesystem::is_regular_file(pathToTexture) )
    {
        boost::filesystem::path const pathToTexture = boost::filesystem::path(filepath);
        
        size_t const dot = pathToTexture.string().find_last_of(".");
        std::string const fileExtension = pathToTexture.string().substr(dot + 1);
 
        if( std::string{ "jpg" } == fileExtension )
        {
            LoadTextureJpegFile(pathToTexture.string().c_str());
        }
        else
        {
            if( std::string{ "png" } == fileExtension )
            {
                LoadTexturePngFile(pathToTexture.string().c_str());
            }
            else
            {
                throw std::runtime_error("Unsupported texture file format!");
            }
        }
    }
    else
    {
        throw std::runtime_error("Path to texture file is incorrect.");
    }
}

ImageData() [4/6]

rendering_engine::ImageData::ImageData

(

std::vector< uint8_t > const &

fileBytes

)

Constructs an image by decoding raw file bytes.

This constructor allows loading an image from a memory buffer rather than a file on disk. The data is interpreted as either PNG or JPEG depending on format detection. Decoded pixel data is stored internally in 32-bit RGBA format.

Parameters

fileBytes

Raw contents of an image file (PNG or JPEG).

Definition at line 59 of file image_data.cpp.

{
    if (fileBytes.size() < 4)
        throw std::runtime_error("Invalid image buffer");
 
    // PNG signature
    if (fileBytes[0] == 0x89 &&
        fileBytes[1] == 'P' &&
        fileBytes[2] == 'N' &&
        fileBytes[3] == 'G')
    {
        std::vector<unsigned int> pixelsRGBA;
 
        if (!ReadPngFromMemory(fileBytes.data(), fileBytes.size(), mWidth, mHeight, pixelsRGBA))
            throw std::runtime_error("PNG memory decode failed");
 
        AllocateMemory(mWidth, mHeight);
        Fill(Color(0, 0, 0, 255));
        LoadImageDataRGBA(pixelsRGBA);
        return;
    }
 
    // JPEG signature: FF D8 FF
    if (fileBytes[0] == 0xFF &&
        fileBytes[1] == 0xD8 &&
        fileBytes[2] == 0xFF)
    {
        std::vector<unsigned int> pixelsRGB;
 
        if (!ReadJpegFromMemory(fileBytes.data(), fileBytes.size(), mWidth, mHeight, pixelsRGB))
            throw std::runtime_error("JPEG memory decode failed");
 
        AllocateMemory(mWidth, mHeight);
        LoadImageDataRGB(pixelsRGB);
 
        return;
    }
 
    throw std::runtime_error("Unsupported image format in memory buffer");
}

ImageData() [5/6]

rendering_engine::ImageData::ImageData	(	unsigned int	width,
		unsigned int	height,
		std::vector< unsigned int > const &	pixelsRGBA )

Constructs image from raw RGBA pixel buffer.

Parameters

width	Image width
height	Image height
pixelsRGBA	Vector of RGBA pixel data (4 bytes per pixel)

Definition at line 100 of file image_data.cpp.

    :
ImageData::ImageData(width, height)
{
    Fill(Color(255, 255, 255, 255));
    LoadImageDataRGBA( pixelsRGBA );
}

~ImageData()

rendering_engine::ImageData::~ImageData

(

)

Destructor that frees memory.

Definition at line 108 of file image_data.cpp.

{
    CleanAllocatedMemory();
}

ImageData() [6/6]

rendering_engine::ImageData::ImageData

(

const ImageData &

src

)

Copy constructor.

Definition at line 113 of file image_data.cpp.

    :
    mWidth( src.GetWidth() ),
    mHeight( src.GetHeight() )
{
    AllocateMemory(src.mWidth, src.mHeight);
 
    for( unsigned int y = 0; y < mHeight; y++ )
    {
        for( unsigned int x = 0; x < mWidth; x++ )
        {
            mData[x][y] = src.mData[x][y];
        }
    }
}

Member Function Documentation

AllocateMemory()

void rendering_engine::ImageData::AllocateMemory ( unsigned int width, unsigned int height )

protected

Allocates memory for internal pixel storage.

Parameters

width	Image width
height	Image height

Definition at line 311 of file image_data.cpp.

{
    mWidth = width;
    mHeight = height;
    mData = new Color*[mWidth];
 
    for( unsigned int x = 0; x < mWidth; x++ )
    {
        mData[x] = new Color[mHeight];
    }
}

CleanAllocatedMemory()

void rendering_engine::ImageData::CleanAllocatedMemory ( )

protected

Frees allocated memory.

Definition at line 323 of file image_data.cpp.

{
    for( unsigned int x = 0; x < mWidth; x++ )
    {
        if( mData[x] )
        {
            delete[] mData[x];
        }
    }
    if( mData )
    {
        delete[] mData;
    }
 
    mWidth = 0U;
    mHeight = 0U;
}

DrawImageOnImageAtPos()

void rendering_engine::ImageData::DrawImageOnImageAtPos ( unsigned int const x, unsigned int const y, ImageData & toImage, ImageData & fromImage )

static

Overlays one image on top of another at a given position.

Parameters

x	Top-left X coordinate for the overlay
y	Top-left Y coordinate for the overlay
toImage	Destination image
fromImage	Source image

Definition at line 180 of file image_data.cpp.

{
    //If fromImage can not be placed entirely, it will be cropped on right and bottom side
 
    //Source image draw from top left pixel
 
    //At first check if point pos is inside toImage
    if( !(x >= 0 && y >= 0 && x < toImage.GetWidth() && y < toImage.GetHeight()) )
    {
        return;
    }
 
    //Crop
    int left;
    if( (toImage.GetWidth() - x) < fromImage.GetWidth() )
    {
        left = toImage.GetWidth() - x;
    }
    else
    {
        left = fromImage.GetWidth();
    }
 
    int bottom;
    if( (toImage.GetHeight() - y) < fromImage.GetHeight() )
    {
        bottom = toImage.GetHeight() - y;
    }
    else
    {
        bottom = fromImage.GetHeight();
    }
 
    for( int deltaY = 0; deltaY < bottom; deltaY++ )
    {
        for( int deltaX = 0; deltaX < left; deltaX++ )
        {
            toImage.SetPixel(x + deltaX, y + deltaY, fromImage.GetPixel(deltaX, deltaY));
        }
    }
}

Fill()

void rendering_engine::ImageData::Fill

(

Color

color

)

Fills the image with a solid color.

Parameters

color

The color to fill with

Definition at line 149 of file image_data.cpp.

{
    for( unsigned int y = 0; y < mHeight; y++ )
    {
        for( unsigned int x = 0; x < mWidth; x++ )
        {
            mData[x][y] = color;
        }
    }
}

GetHeight()

unsigned int rendering_engine::ImageData::GetHeight ( ) const

inline

Returns the image height.

Definition at line 138 of file image_data.hpp.

    {
        return mHeight;
    }

GetImageDataRGB()

std::vector< uint8_t > rendering_engine::ImageData::GetImageDataRGB

(

)

const

Gets raw image data in RGB format.

Returns

A vector containing 3 bytes per pixel (RGB)

Definition at line 243 of file image_data.cpp.

{
    std::vector<uint8_t> result;
    if( GetHeight() == 0 && GetWidth() == 0 )
    {
        return result;
    }
 
    for( unsigned int y = 0; y < mHeight; y++ )
    {
        for( unsigned int x = 0; x < mWidth; x++ )
        {
            result.push_back(GetPixel(x, y).r);
            result.push_back(GetPixel(x, y).g);
            result.push_back(GetPixel(x, y).b);
        }
    }
    return result;
}

GetImageDataRGBA()

std::vector< uint8_t > rendering_engine::ImageData::GetImageDataRGBA

(

)

const

Gets raw image data in RGBA format.

Returns

A vector containing 4 bytes per pixel (RGBA)

Definition at line 222 of file image_data.cpp.

{
    std::vector<uint8_t> result;
    if(GetHeight() == 0 && GetWidth() == 0)
    {
        return result;
    }
 
    for( unsigned int y = 0; y < mHeight; y++ )
    {
        for( unsigned int x = 0; x < mWidth; x++ )
        {
            result.push_back(GetPixel(x, y).r);
            result.push_back(GetPixel(x, y).g);
            result.push_back(GetPixel(x, y).b);
            result.push_back(GetPixel(x, y).a);
        }
    }
    return result;
}

GetPixel()

const Color rendering_engine::ImageData::GetPixel	(	unsigned int	x,
		unsigned int	y ) const

Retrieves the color of a specific pixel.

Parameters

x	X coordinate
y	Y coordinate

Returns

The color of the pixel

Definition at line 168 of file image_data.cpp.

{
    if( x < mWidth && y < mHeight )
    {
        return (mData[x][y]);
    }
    else
    {
        throw std::runtime_error("Inapropriate access to data");
    }
}

GetSizeInBytes()

size_t rendering_engine::ImageData::GetSizeInBytes ( ) const

inline

Gets the total size of the image in memory.

Returns

Size in bytes

Definition at line 190 of file image_data.hpp.

    {
        return static_cast<size_t>(mWidth) * static_cast<size_t>(mHeight) * sizeof(Color);
    }

GetWidth()

unsigned int rendering_engine::ImageData::GetWidth ( ) const

inline

Returns the image width.

Definition at line 130 of file image_data.hpp.

    {
        return mWidth;
    }

LoadImageDataRGB()

void rendering_engine::ImageData::LoadImageDataRGB ( std::vector< unsigned int > const & pixels )

protected

Loads image data from a 24-bit RGB buffer.

Definition at line 367 of file image_data.cpp.

{
    //Check for data numbers matching
    if( (GetHeight() * GetWidth() * 3) != pixels.size() )
    {
        throw std::runtime_error("Array data size doesn't match image dimension.");
    }
    auto it = pixels.begin();
    for( unsigned int y = 0; y < GetHeight(); y++ )
    {
        for( unsigned int x = 0; x < GetWidth(); x++ )
        {
            uint8_t const r = static_cast<uint8_t>(*it);
            ++it;
            uint8_t const g = static_cast<uint8_t>(*it);
            ++it;
            uint8_t const b = static_cast<uint8_t>(*it);
            ++it;
 
            Color const color(r, g, b);
            SetPixel(x, y, color);
        }
    }
}

LoadImageDataRGBA()

void rendering_engine::ImageData::LoadImageDataRGBA ( std::vector< unsigned int > const & pixels )

protected

Loads image data from a 32-bit RGBA buffer.

Definition at line 341 of file image_data.cpp.

{
    //Check for data numbers matching
    if( (GetHeight() * GetWidth() * 4) != pixels.size() )
    {
        throw std::runtime_error("Array data size doesn't match image dimension.");
    }
    auto it = pixels.begin();
    for( unsigned int y = 0; y < GetHeight(); y++ )
    {
        for( unsigned int x = 0; x < GetWidth(); x++ )
        {
            uint8_t const r = *it;
            ++it;
            uint8_t const g = *it;
            ++it;
            uint8_t const b = *it;
            ++it;
            uint8_t const a = *it;
            ++it;
            Color const color(r, g, b, a);
            SetPixel(x, y, color);
        }
    }
}

LoadTextureJpegFile()

bool rendering_engine::ImageData::LoadTextureJpegFile ( char const * filename )

protected

Loads image from a JPEG file.

Definition at line 268 of file image_data.cpp.

{
    CleanAllocatedMemory();
    unsigned int width = 0;
    unsigned int height = 0;
    std::vector<unsigned int> rgbImageDataVector;
 
    bool result = ReadJpegFile(filename, width, height, rgbImageDataVector);
    if(result && (rgbImageDataVector.size() == (3U * width * height)))
    {
        mWidth = width;
        mHeight = height;
        AllocateMemory(width, height);
        LoadImageDataRGB(rgbImageDataVector);
    }
 
    return result;
}

LoadTexturePngFile()

bool rendering_engine::ImageData::LoadTexturePngFile ( char const * filename )

protected

Loads image from a PNG file.

Definition at line 292 of file image_data.cpp.

{
    CleanAllocatedMemory();
    unsigned int width = 0;
    unsigned int height = 0;
    std::vector<unsigned int> rgbaImageDataVector;
 
    bool result = ReadPngFile(filename, width, height, rgbaImageDataVector);
 
    if( result && (rgbaImageDataVector.size() == (4U * width * height)) )
    {
        mWidth = width;
        mHeight = height;
        AllocateMemory(width, height);
        LoadImageDataRGBA(rgbaImageDataVector);
    }
    return true;
}

operator=()

ImageData & rendering_engine::ImageData::operator=

(

const ImageData &

rhs

)

Copy assignment operator.

Definition at line 129 of file image_data.cpp.

{
    if( this == &rhs )
    {
        return *this;
    }
    CleanAllocatedMemory();
    AllocateMemory( rhs.mWidth, rhs.mHeight );
 
    for( unsigned int y = 0; y < mHeight; y++ )
    {
        for( unsigned int x = 0; x < mWidth; x++ )
        {
            mData[x][y] = rhs.mData[x][y];
        }
    }
 
    return *this;
}

SetPixel()

void rendering_engine::ImageData::SetPixel	(	unsigned int	x,
		unsigned int	y,
		Color	color )

Sets the color of a specific pixel.

Parameters

x	X coordinate
y	Y coordinate
color	The color to set

Definition at line 160 of file image_data.cpp.

{
    if( x < mWidth && y < mHeight )
    {
        mData[x][y] = color;
    }
}

WriteJpegFile()

void rendering_engine::ImageData::WriteJpegFile

(

char const *

filename

)

Writes the image data to a JPEG file.

Parameters

filename

Path to output file

Definition at line 263 of file image_data.cpp.

{
    SaveTextureFileJpeg(*this, filename);
}

WritePngFile()

void rendering_engine::ImageData::WritePngFile

(

char const *

filename

)

Writes the image data to a PNG file.

Parameters

filename

Path to output file

Definition at line 287 of file image_data.cpp.

{
    SaveTextureFilePng(*this, filename);
}

---

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

• image_data.hpp
• image_data.cpp