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)
	renvoie la valeur absolue de chaque canal.
float	clamp (const float x, const float a, const float b)
	renvoie une valeur comprise entre a et b.
Color	clamp (const Color &color, const float a, const float b)
	renvoie une couleur dont chaque canal est compris entre a et b.
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
Image &	blit (Image &image, const unsigned xmin, const unsigned ymin, const Image &pixels)
	remplace un bout d'image par une autre. copie l'image pixels dans image [xmin, xmin+pixels.width] x [ymin, ymin+pixels.height].
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 (const 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	srgb (const ImageData &image)
	transformation couleur : rgb lineaire vers srgb
ImageData	linear (const ImageData &image)
	transformation couleur : srgb vers rgb lineaire
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 &	blit (ImageData &image, const unsigned xmin, const unsigned ymin, const ImageData &pixels)
	remplace un bout d'image par une autre. copie l'image pixels dans image [xmin, xmin+pixels.width] x [ymin, ymin+pixels.height].
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 89 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 99 of file color.cpp.

{
    return a + (-b);
}

operator-() [2/2]

Color operator-

(

const Color &

c

)

Definition at line 94 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 104 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 114 of file color.cpp.

{
    return k * c;
}

operator*() [3/3]

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

Definition at line 109 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 119 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 124 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 129 of file color.cpp.

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

srgb() [1/3]

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() [1/3]

Color linear

(

const Color &

color

)

transformation couleur : srgb vers rgb lineaire

Definition at line 66 of file color.cpp.

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

abs()

Color abs

(

const Color &

color

)

renvoie la valeur absolue de chaque canal.

Definition at line 71 of file color.cpp.

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

clamp() [1/2]

float clamp ( const float x, const float a, const float b )

inline

renvoie une valeur comprise entre a et b.

Definition at line 76 of file color.cpp.

{
    if(x < a) return a;
    else if(x > b) return b;
    else return x;
}

clamp() [2/2]

Color clamp	(	const Color &	color,
		const float	a,
		const float	b )

renvoie une couleur dont chaque canal est compris entre a et b.

Definition at line 83 of file color.cpp.

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

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 191 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 213 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 182 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 245 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 226 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 250 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 269 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 278 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 95 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() [2/3]

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() [2/3]

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 113 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 130 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 146 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;
}

blit() [1/2]

Image & blit	(	Image &	image,
		const unsigned	xmin,
		const unsigned	ymin,
		const Image &	pixels )

remplace un bout d'image par une autre. copie l'image pixels dans image [xmin, xmin+pixels.width] x [ymin, ymin+pixels.height].

Definition at line 162 of file image_io.cpp.

{
    if(image.size() == 0)
        return image;
    if(pixels.size() == 0)
        return image;
    
    unsigned xmax= std::min( image.width(), xmin + pixels.width() );
    unsigned ymax= std::min( image.height(), ymin + pixels.height() );
    unsigned w= xmax - xmin;
    unsigned h= ymax - ymin;
    
    for(unsigned y= 0; y < h; y++)
    for(unsigned x= 0; x < w; x++)
        image(x + xmin, y + ymin)= pixels(x, y);
    
    return image;
}

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

enregistre des donnees dans un fichier png.

Definition at line 366 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 335 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);
}

srgb() [3/3]

ImageData srgb

(

const ImageData &

image

)

transformation couleur : rgb lineaire vers srgb

Definition at line 397 of file image_io.cpp.

{
    ImageData tmp(image.width, image.height, image.channels);
    
    for(unsigned i= 0; i < image.pixels.size(); i+= image.channels)
    {
        Color pixel= srgb( Color( image.pixels[i], image.pixels[i+1], image.pixels[i+2], (image.channels > 3) ? image.pixels[i+3] : 255 ) / 255 );
        
        tmp.pixels[i]= clamp(pixel.r * 255, 0, 255); 
        tmp.pixels[i +1]= clamp(pixel.g * 255, 0, 255); 
        tmp.pixels[i +2]= clamp(pixel.b * 255, 0, 255); 
        if(image.channels > 3) 
            tmp.pixels[i +3]= clamp(pixel.a * 255, 0, 255); 
    }
    
    return tmp;
}

linear() [3/3]

ImageData linear

(

const ImageData &

image

)

transformation couleur : srgb vers rgb lineaire

Definition at line 415 of file image_io.cpp.

{
    ImageData tmp(image.width, image.height, image.channels);
    
    for(unsigned i= 0; i < image.pixels.size(); i+= image.channels)
    {
        Color pixel= linear( Color( image.pixels[i], image.pixels[i+1], image.pixels[i+2], (image.channels > 3) ? image.pixels[i+3] : 255 ) / 255 );
        
        tmp.pixels[i]= clamp(pixel.r * 255, 0, 255); 
        tmp.pixels[i +1]= clamp(pixel.g * 255, 0, 255); 
        tmp.pixels[i +2]= clamp(pixel.b * 255, 0, 255); 
        if(image.channels > 3) 
            tmp.pixels[i +3]= clamp(pixel.a * 255, 0, 255); 
    }
    
    return tmp;
}

flipY() [2/2]

ImageData flipY

(

const ImageData &

image

)

retourne l'image

Definition at line 433 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 451 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 468 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;
}

blit() [2/2]

ImageData & blit	(	ImageData &	image,
		const unsigned	xmin,
		const unsigned	ymin,
		const ImageData &	pixels )

remplace un bout d'image par une autre. copie l'image pixels dans image [xmin, xmin+pixels.width] x [ymin, ymin+pixels.height].

Definition at line 486 of file image_io.cpp.

{
    if(image.pixels.size() == 0)
        return image;
    if(pixels.pixels.size() == 0)
        return image;
    if(image.channels != pixels.channels)
        return image;
    
    unsigned xmax= std::min( image.width, xmin + pixels.width );
    unsigned ymax= std::min( image.height, ymin + pixels.height );
    unsigned w= xmax - xmin;
    unsigned h= ymax - ymin;
    
    for(unsigned y= 0; y < h; y++)
    for(unsigned x= 0; x < w; x++)
    {
        unsigned char *dst= image.pixels.data() + image.offset(x + xmin, y + ymin);
        const unsigned char *src= pixels.pixels.data() + pixels.offset(x, y);
        for(unsigned i= 0; i < pixels.channels; i++)
            dst[i]= src[i];
    }
    
    return image;
}

mipmap() [2/2]

ImageData mipmap

(

const ImageData &

image

)

renvoie une image filtree plus petite.

Definition at line 512 of file image_io.cpp.

{
    unsigned w= std::max(unsigned(1), image.width / 2);
    unsigned h= std::max(unsigned(1), image.height / 2);
    
    ImageData tmp(w, h, image.channels);
    
    for(unsigned py= 0; py < h; py++)
    for(unsigned px= 0; px < w; px++)
    {
        unsigned x= 2*px;
        unsigned y= 2*py;
        unsigned d= tmp.offset(px, py);
        
        for(unsigned i= 0; i < image.channels; i++)
            tmp.pixels[d +i]= (
                    image.pixels[image.offset(x, y) +i] 
                + image.pixels[image.offset(x+1, y) +i] 
                + image.pixels[image.offset(x, y+1) +i] 
                + image.pixels[image.offset(x+1, y+1) +i] ) / 4;
    }
    
    return tmp;
}

miplevels()

int miplevels	(	const int	width,
		const int	height )

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

Definition at line 537 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;
}