utilitaires pour manipuler des images

Files
file	src/gKit/color.h
file	src/gKit/image.h
file	src/gKit/image_io.h

Classes
struct	Color
	representation d'une couleur (rgba) transparente ou opaque. More...
class	Image
	representation d'une image. More...
struct	ImageData
	stockage temporaire des donnees d'une image. More...

Functions
Color	Black ()
	utilitaire. renvoie une couleur noire.
Color	White ()
	utilitaire. renvoie une couleur blanche.
Color	Red ()
	utilitaire. renvoie une couleur rouge.
Color	Green ()
	utilitaire. renvoie une couleur verte.
Color	Blue ()
	utilitaire. renvoie une couleur bleue.
Color	Yellow ()
	utilitaire. renvoie une couleur jaune.
Color	operator+ (const Color &a, const Color &b)
Color	operator- (const Color &a, const Color &b)
Color	operator- (const Color &c)
Color	operator* (const Color &a, const Color &b)
Color	operator* (const Color &c, const float k)
Color	operator* (const float k, const Color &c)
Color	operator/ (const Color &a, const Color &b)
Color	operator/ (const float k, const Color &c)
Color	operator/ (const Color &c, const float k)
Color	srgb (const Color &color)
	transformation couleur : rgb lineaire vers srgb
Color	linear (const Color &color)
	transformation couleur : srgb vers rgb lineaire
Color	abs (const Color &color)
Image	read_image (const char *filename, const bool flipY=true)
Image	read_image_hdr (const char *filename, const bool flipY=true)
unsigned	read_image_size (const char *filename)
	renvoie la taille en octets de l'image chargee. ou 0 si erreur.
bool	write_image (const Image &image, const char *filename, const bool flipY=true)
	enregistre une image au format .png
bool	write_image_png (const Image &image, const char *filename, const bool flipY=true)
	enregistre une image au format .png
bool	write_image_bmp (const Image &image, const char *filename, const bool flipY=true)
	enregistre une image au format .bmp
bool	write_image_hdr (const Image &image, const char *filename, const bool flipY=true)
	enregistre une image au format .hdr
bool	write_image_preview (const Image &image, const char *filename, const bool flipY=true)
	raccourci pour write_image_png(tone(image, range(image)), "image.png")
Image	mipmap (const Image &image)
	reduit une image.
Image	srgb (const Image &image)
	transformation couleur : rgb lineaire vers srgb
Image	linear (const Image &image)
	transformation couleur : srgb vers rgb lineaire
Image	flipY (const Image &image)
	retourne l'image
Image	flipX (const Image &image)
	retourne l'image
Image	copy (const Image &image, const unsigned xmin, const unsigned ymin, const unsigned width, const unsigned height)
	renvoie un bloc de l'image
ImageData	read_image_data (const char *filename, const bool flipY=true)
	charge les donnees d'un fichier png. renvoie une image initialisee par defaut en cas d'echec.
int	write_image_data (ImageData &image, const char *filename, const bool flipY=true)
	enregistre des donnees dans un fichier png.
ImageData	read_image_data (const void *buffer, const unsigned size, const bool flipY=true)
	charge les donnees d'un fichier png stocke en memoire. renvoie une image initialisee par defaut en cas d'echec.
ImageData	flipY (const ImageData &image)
	retourne l'image
ImageData	flipX (const ImageData &image)
	retourne l'image
ImageData	copy (const ImageData &image, const unsigned xmin, const unsigned ymin, const unsigned width, const unsigned height)
	renvoie un bloc de l'image
ImageData	mipmap (const ImageData &image)
	renvoie une image filtree plus petite.
int	miplevels (const int width, const int height)
	renvoie le nombre de mipmap d'une image width x height.

Detailed Description

Function Documentation

Black()

Color Black

(

)

utilitaire. renvoie une couleur noire.

Definition at line 18 of file color.cpp.

{
    return Color(0, 0, 0);
}

White()

Color White

(

)

utilitaire. renvoie une couleur blanche.

Definition at line 23 of file color.cpp.

{
    return Color(1, 1, 1);
}

Red()

Color Red

(

)

utilitaire. renvoie une couleur rouge.

Definition at line 28 of file color.cpp.

{
    return Color(1, 0, 0);
}

Green()

Color Green

(

)

utilitaire. renvoie une couleur verte.

Definition at line 33 of file color.cpp.

{
    return Color(0, 1, 0);
}

Blue()

Color Blue

(

)

utilitaire. renvoie une couleur bleue.

Definition at line 38 of file color.cpp.

{
    return Color(0, 0, 1);
}

Yellow()

Color Yellow

(

)

utilitaire. renvoie une couleur jaune.

Definition at line 43 of file color.cpp.

{
    return Color(1, 1, 0);
}

operator+()

Color operator+	(	const Color &	a,
		const Color &	b )

Definition at line 73 of file color.cpp.

{
    return Color(a.r + b.r, a.g + b.g, a.b + b.b, a.a + b.a);
}

operator-() [1/2]

Color operator-	(	const Color &	a,
		const Color &	b )

Definition at line 83 of file color.cpp.

{
    return a + (-b);
}

operator-() [2/2]

Color operator-

(

const Color &

c

)

Definition at line 78 of file color.cpp.

{
    return Color(-c.r, -c.g, -c.b, -c.a);
}

operator*() [1/3]

Color operator*	(	const Color &	a,
		const Color &	b )

Definition at line 88 of file color.cpp.

{
    return Color(a.r * b.r, a.g * b.g, a.b * b.b, a.a * b.a);
}

operator*() [2/3]

Color operator*	(	const Color &	c,
		const float	k )

Definition at line 98 of file color.cpp.

{
    return k * c;
}

operator*() [3/3]

Color operator*	(	const float	k,
		const Color &	c )

Definition at line 93 of file color.cpp.

{
    return Color(c.r * k, c.g * k, c.b * k, c.a * k);
}

operator/() [1/3]

Color operator/	(	const Color &	a,
		const Color &	b )

Definition at line 103 of file color.cpp.

{
    return Color(a.r / b.r, a.g / b.g, a.b / b.b, a.a / b.a);
}

operator/() [2/3]

Color operator/	(	const float	k,
		const Color &	c )

Definition at line 108 of file color.cpp.

{
    return Color(k / c.r, k / c.g, k / c.b, k / c.a);
}

operator/() [3/3]

Color operator/	(	const Color &	c,
		const float	k )

Definition at line 113 of file color.cpp.

{
    float kk= 1 / k;
    return kk * c;
}

srgb() [1/2]

Color srgb

(

const Color &

color

)

transformation couleur : rgb lineaire vers srgb

Definition at line 61 of file color.cpp.

{
    return Color(srgb(color.r), srgb(color.g), srgb(color.b), color.a);
    
}

linear() [1/2]

Color linear

(

const Color &

color

)

transformation couleur : srgb vers rgb lineaire

Definition at line 67 of file color.cpp.

{
    return Color(linear(color.r), linear(color.g), linear(color.b), color.a);
}

abs()

Color abs

(

const Color &

color

)

Definition at line 129 of file color.cpp.

{
    return Color( std::abs(color.r), std::abs(color.g), std::abs(color.b), std::abs(color.a) ); 
}

read_image()

Image read_image	(	const char *	filename,
		const bool	flipY = true )

charge une image a partir d'un fichier. renvoie Image::error() en cas d'echec. a detruire avec image::release( ).

Parameters

filemane

nom de l'image a charger

Definition at line 171 of file image_io.cpp.

{
    stbi_ldr_to_hdr_scale(1);
    stbi_ldr_to_hdr_gamma(1);
    stbi_set_flip_vertically_on_load(flipY);
    
    int width, height, channels;
    float *data= stbi_loadf(filename, &width, &height, &channels, 4);
    if(!data)
    {
        printf("[error] loading '%s'...\n", filename);
        return {};
    }
    
    Image image(width, height);
    for(unsigned i= 0, offset= 0; i < image.size(); i++, offset+= 4)
        image(i)= Color( data[offset], data[offset + 1], data[offset + 2], data[offset + 3]);
    
    stbi_image_free(data);
    return image;
}

read_image_hdr()

Image read_image_hdr	(	const char *	filename,
		const bool	flipY = true )

Definition at line 193 of file image_io.cpp.

{ 
    return read_image(filename, flipY ); 
}

read_image_size()

unsigned read_image_size

(

const char *

filename

)

renvoie la taille en octets de l'image chargee. ou 0 si erreur.

Definition at line 162 of file image_io.cpp.

{
    int w, h, c;
    if(!stbi_info(filename, &w, &h, &c))
        return 0;
    
    return sizeof(Color)*w*h;
}

write_image()

bool write_image	(	const Image &	image,
		const char *	filename,
		const bool	flipY = true )

enregistre une image au format .png

Definition at line 225 of file image_io.cpp.

{
    return write_image_png(image, filename, flipY );
}

write_image_png()

bool write_image_png	(	const Image &	image,
		const char *	filename,
		const bool	flipY = true )

enregistre une image au format .png

Definition at line 206 of file image_io.cpp.

{
    if(image.size() == 0)
        return false;
    
    std::vector<unsigned char> tmp(image.width()*image.height()*4);
    for(unsigned i= 0, offset= 0; i < image.size(); i++, offset+= 4)
    {
        Color pixel= image(i) * 255;
        tmp[offset   ]= clamp(pixel.r, 0, 255);
        tmp[offset +1]= clamp(pixel.g, 0, 255);
        tmp[offset +2]= clamp(pixel.b, 0, 255);
        tmp[offset +3]= clamp(pixel.a, 0, 255);
    }
    
    stbi_flip_vertically_on_write(flipY);
    return stbi_write_png(filename, image.width(), image.height(), 4, tmp.data(), image.width() * 4) != 0;
}

write_image_bmp()

bool write_image_bmp	(	const Image &	image,
		const char *	filename,
		const bool	flipY = true )

enregistre une image au format .bmp

Definition at line 230 of file image_io.cpp.

{
    if(image.size() == 0)
        return false;
    
    std::vector<unsigned char> tmp(image.width()*image.height()*4);
    for(unsigned i= 0, offset= 0; i < image.size(); i++, offset+= 4)
    {
        Color pixel= image(i) * 255;
        tmp[offset   ]= clamp(pixel.r, 0, 255);
        tmp[offset +1]= clamp(pixel.g, 0, 255);
        tmp[offset +2]= clamp(pixel.b, 0, 255);
        tmp[offset +3]= clamp(pixel.a, 0, 255);
    }
    
    stbi_flip_vertically_on_write(flipY);
    return stbi_write_bmp(filename, image.width(), image.height(), 4, tmp.data()) != 0;
}

write_image_hdr()

bool write_image_hdr	(	const Image &	image,
		const char *	filename,
		const bool	flipY = true )

enregistre une image au format .hdr

Definition at line 249 of file image_io.cpp.

{
    if(image.size() == 0)
        return false;
    
    stbi_flip_vertically_on_write(flipY);
    return stbi_write_hdr(filename, image.width(), image.height(), 4, image.data()) != 0;
}

write_image_preview()

bool write_image_preview	(	const Image &	image,
		const char *	filename,
		const bool	flipY = true )

raccourci pour write_image_png(tone(image, range(image)), "image.png")

Definition at line 258 of file image_io.cpp.

{
    if(image.size() == 0)
        return false;
    
    Image tmp= tone(image, range(image));
    return write_image_png(tmp, filename, flipY);
}

mipmap() [1/2]

Image mipmap

(

const Image &

image

)

reduit une image.

Definition at line 94 of file image_io.cpp.

{
    unsigned w= std::max(unsigned(1), image.width() / 2);
    unsigned h= std::max(unsigned(1), image.height() / 2);
    
    Image tmp(w, h);
    
    for(unsigned py= 0; py < h; py++)
    for(unsigned px= 0; px < w; px++)
    {
        unsigned x= 2*px;
        unsigned y= 2*py;
        tmp(px, py)= (image(x, y) + image(x +1, y) + image(x +1, y +1) + image(x, y +1)) / 4;   
    }
    
    return tmp;
}

srgb() [2/2]

Image srgb

(

const Image &

image

)

transformation couleur : rgb lineaire vers srgb

Definition at line 15 of file image_io.cpp.

{
    Image tmp(image.width(), image.height());
    
    for(unsigned i= 0; i < image.size(); i++)
        tmp(i)= srgb(image(i));
    
    return tmp;
}

linear() [2/2]

Image linear

(

const Image &

image

)

transformation couleur : srgb vers rgb lineaire

Definition at line 25 of file image_io.cpp.

{
    Image tmp(image.width(), image.height());
    
    for(unsigned i= 0; i < image.size(); i++)
        tmp(i)= linear(image(i));
    
    return tmp;
}

flipY() [1/2]

Image flipY

(

const Image &

image

)

retourne l'image

Definition at line 112 of file image_io.cpp.

{
    // flip de l'image : origine en haut a gauche
    Image flip(image.width(), image.height());
 
    for(unsigned y= 0; y < image.height(); y++)
    for(unsigned x= 0; x < image.width(); x++)
    {
        unsigned s= image.offset(x, y);
        unsigned d= flip.offset(x, flip.height() - y -1);
        
        flip(d)= image(s);
    }
 
    return flip;
}

flipX() [1/2]

Image flipX

(

const Image &

image

)

retourne l'image

Definition at line 129 of file image_io.cpp.

{
    Image flip(image.width(), image.height());
 
    for(unsigned y= 0; y < image.height(); y++)
    for(unsigned x= 0; x < image.width(); x++)
    {
        unsigned s= image.offset(x, y);
        unsigned d= flip.offset(flip.width() -x -1, y);
        
        flip(d)= image(s);
    }
 
    return flip;
}

copy() [1/2]

Image copy	(	const Image &	image,
		const unsigned	xmin,
		const unsigned	ymin,
		const unsigned	width,
		const unsigned	height )

renvoie un bloc de l'image

Definition at line 145 of file image_io.cpp.

{
    Image copy(width, height);
    
    for(unsigned y= 0; y < height; y++)
    for(unsigned x= 0; x < width; x++)
    {
        unsigned s= image.offset(xmin+x, ymin+y);
        unsigned d= copy.offset(x, y);
        
        copy(d)= image(s);
    }
    
    return copy;
}

read_image_data() [1/2]

ImageData read_image_data	(	const char *	filename,
		const bool	flipY = true )

charge les donnees d'un fichier png. renvoie une image initialisee par defaut en cas d'echec.

Definition at line 330 of file image_io.cpp.

{
    stbi_set_flip_vertically_on_load(flipY);
    
    int width, height, channels;
    unsigned char *data= stbi_load(filename, &width, &height, &channels, 0);
    if(!data)
    {
        printf("[error] loading '%s'...\n", filename);
        return {};
    }
    
    return image_data(data, width, height, channels);
}

write_image_data()

int write_image_data	(	ImageData &	image,
		const char *	filename,
		const bool	flipY = true )

enregistre des donnees dans un fichier png.

Definition at line 346 of file image_io.cpp.

{
    if(image.size != 1)
    {
        printf("[error] writing color image '%s'... not an 8 bits image.\n", filename);
        return -1;
    }
 
    stbi_flip_vertically_on_write(flipY);
    
    int code= 0;
    if(std::string(filename).rfind(".png") != std::string::npos)
        code= stbi_write_png(filename, image.width, image.height, image.channels, image.pixels.data(), image.width * image.channels) != 0;
    else if(std::string(filename).rfind(".bmp") != std::string::npos)
        code= stbi_write_bmp(filename, image.width, image.height, image.channels, image.pixels.data()) != 0;
    
    else 
    {
        printf("[error] writing color image '%s'... not a .png / .bmp image.\n", filename);
        return -1;
    }
    
    if(code > 0)
        return 0;
    
    printf("[error] writing color image '%s'...\n", filename);
    return -1;
}

read_image_data() [2/2]

ImageData read_image_data	(	const void *	buffer,
		const unsigned	size,
		const bool	flipY = true )

charge les donnees d'un fichier png stocke en memoire. renvoie une image initialisee par defaut en cas d'echec.

Definition at line 315 of file image_io.cpp.

{
    stbi_set_flip_vertically_on_load(flipY);
    
    int width, height, channels;
    unsigned char *data= stbi_load_from_memory((const unsigned char *) buffer, size, &width, &height, &channels, 0);
    if(!data)
    {
        printf("[error] reading buffer image...\n");
        return {};
    }
    
    return image_data(data, width, height, channels);
}

flipY() [2/2]

ImageData flipY

(

const ImageData &

image

)

retourne l'image

Definition at line 376 of file image_io.cpp.

{
    // flip de l'image : origine en haut a gauche
    ImageData flip(image.width, image.height, image.channels);
 
    for(unsigned y= 0; y < image.height; y++)
    for(unsigned x= 0; x < image.width; x++)
    {
        unsigned s= image.offset(x, y);
        unsigned d= flip.offset(x, flip.height - y -1);
        
        for(unsigned i= 0; i < image.channels; i++)
            flip.pixels[d +i]= image.pixels[s +i];
    }
 
    return flip;
}

flipX() [2/2]

ImageData flipX

(

const ImageData &

image

)

retourne l'image

Definition at line 394 of file image_io.cpp.

{
    ImageData flip(image.width, image.height, image.channels);
 
    for(unsigned y= 0; y < image.height; y++)
    for(unsigned x= 0; x < image.width; x++)
    {
        unsigned s= image.offset(x, y);
        unsigned d= flip.offset(flip.width -x -1, y);
        
        for(unsigned i= 0; i < image.channels; i++)
            flip.pixels[d +i]= image.pixels[s +i];
    }
 
    return flip;
}

copy() [2/2]

ImageData copy	(	const ImageData &	image,
		const unsigned	xmin,
		const unsigned	ymin,
		const unsigned	width,
		const unsigned	height )

renvoie un bloc de l'image

Definition at line 411 of file image_io.cpp.

{
    ImageData copy(width, height, image.channels);
    
    for(unsigned y= 0; y < height; y++)
    for(unsigned x= 0; x < width; x++)
    {
        unsigned s= image.offset(xmin +x, ymin +y);
        unsigned d= copy.offset(x, y);
        
        for(unsigned i= 0; i < image.channels; i++)
            copy.pixels[d +i]= image.pixels[s +i];
    }
    
    return copy;
}

mipmap() [2/2]

ImageData mipmap

(

const ImageData &

image

)

renvoie une image filtree plus petite.

miplevels()

int miplevels	(	const int	width,
		const int	height )

renvoie le nombre de mipmap d'une image width x height.

Definition at line 453 of file image_io.cpp.

{
    int w= width;
    int h= height;
    int levels= 1;
    while(w > 1 || h > 1)
    {
        w= std::max(1, w / 2);
        h= std::max(1, h / 2);
        levels= levels + 1;
    }
    
    return levels;
}