Class for loading, manipulating and saving images. More...

#include <gf/Image.h>

Public Member Functions
	Image ()
	Default constructor. More...

	Image (const Image &)=default
	Default copy constructor. More...

Image &	operator= (const Image &)=default
	Default copy assignment. More...

	Image (Image &&)=default
	Default move constructor. More...

Image &	operator= (Image &&)=default
	Default move assignment. More...

void	create (Vector2u size, const Color4u &color=Color4u{0x00, 0x00, 0x00, 0xFF})
	Create the image and fill it with a unique color. More...

void	create (Vector2u size, const uint8_t *pixels)
	Create the image from an array of pixels. More...

void	createRGB (Vector2u size, const uint8_t *pixels)
	Create the image from an array of pixels. More...

bool	loadFromFile (const Path &filename)
	Load the image from a file on disk. More...

bool	loadFromMemory (const uint8_t *data, std::size_t length)
	Load the image from a file in memory. More...

bool	loadFromStream (InputStream &stream)
	Load the image from a custom stream. More...

bool	saveToFile (const Path &filename) const
	Save the image to a file on disk. More...

Vector2u	getSize () const
	Return the size (width and height) of the image. More...

void	createMaskFromColor (const Color4u &color, uint8_t alpha=0)
	Create a transparency mask from a specified color-key. More...

void	setPixel (Vector2u pos, const Color4u &color)
	Change the color of a pixel. More...

Color4u	getPixel (Vector2u pos) const
	Get the color of a pixel. More...

const uint8_t *	getPixelsPtr () const
	Get a read-only pointer to the array of pixels. More...

void	flipHorizontally ()
	Flip the pixels horizontally. More...

Detailed Description

Class for loading, manipulating and saving images.

gf::Image is an abstraction to manipulate images as bidimensional arrays of pixels. The class provides functions to load, read, write and save pixels, as well as many other useful functions.

gf::Image can handle a unique internal representation of pixels, which is RGBA 32 bits. This means that a pixel must be composed of 8 bits red, green, blue and alpha channels – just like a gf::Color4u.

All the functions that return an array of pixels follow this rule, and all parameters that you pass to gf::Image functions (such as loadFromMemory()) must use this representation as well.

A gf::Image can be copied, but it is a heavy resource and if possible you should always use (const) references to pass or return them to avoid useless copies.

Usage example:

// Load an image file from a file
gf::Image background;
if (!background.loadFromFile("background.jpg")) {
  return -1;
}
// Create a 20x20 image filled with black color
gf::Image image;
image.create({ 20, 20 }, sf::Color4u{0xFF, 0xFF, 0xFF, 0xFF});
// Make the top-left pixel transparent
gf::Color4u color = image.getPixel({ 0, 0 });
color.a = 0;
image.setPixel({ 0, 0 }, color);
// Save the image to a file
if (!image.saveToFile("result.png")) {
  return -1;
}

See also: gf::Texture

Constructor & Destructor Documentation

gf::Image::Image ( )

Default constructor.

Creates an empty image.

gf::Image::Image ( const Image & )

default

Default copy constructor.

gf::Image::Image ( Image && )

default

Default move constructor.

Member Function Documentation

void gf::Image::create	(	Vector2u	size,
		const Color4u &	color = `Color4u{0x00, 0x00, 0x00, 0xFF}`
	)

Create the image and fill it with a unique color.

Parameters

size	Size of the image
color	Fill color

void gf::Image::create	(	Vector2u	size,
		const uint8_t *	pixels
	)

Create the image from an array of pixels.

The pixel array is assumed to contain 32-bits RGBA pixels, and have the given size. If not, this is an undefined behavior. If pixels is null, an empty image is created.

Parameters

size	Size of the image
pixels	Array of pixels to copy to the image

void gf::Image::createMaskFromColor	(	const Color4u &	color,
		uint8_t	alpha = `0`
	)

Create a transparency mask from a specified color-key.

This function sets the alpha value of every pixel matching the given color to alpha (0 by default), so that they become transparent.

Parameters

color	Color to make transparent
alpha	Alpha value to assign to transparent pixels

void gf::Image::createRGB	(	Vector2u	size,
		const uint8_t *	pixels
	)

Create the image from an array of pixels.

The pixel array is assumed to contain 24-bits RGB pixels, and have the given size. If not, this is an undefined behavior. If pixels is null, an empty image is created.

Parameters

size	Size of the image
pixels	Array of pixels to copy to the image

void gf::Image::flipHorizontally ( )

Flip the pixels horizontally.

This function is needed internally. But you can use it if you want.

Color4u gf::Image::getPixel ( Vector2u pos ) const

Get the color of a pixel.

This function doesn't check the validity of the pixel coordinates, using out-of-range values will result in an undefined behavior.

Parameters

pos	Coordinate of pixel to get

Returns: Color of the pixel at coordinates (x, y)

See also: setPixel

const uint8_t* gf::Image::getPixelsPtr ( ) const

Get a read-only pointer to the array of pixels.

The returned value points to an array of RGBA pixels made of 8 bits integers components. The size of the array is width * height * 4. Warning: the returned pointer may become invalid if you modify the image, so you should never store it for too long. If the image is empty, a null pointer is returned.

Returns: Read-only pointer to the array of pixels

Vector2u gf::Image::getSize ( ) const

Return the size (width and height) of the image.

Returns: Size of the image, in pixels

bool gf::Image::loadFromFile ( const Path & filename )

Load the image from a file on disk.

The supported image formats are bmp, png, tga, jpg, gif, psd, hdr and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters

filename Path of the image file to load

Returns: true if loading was successful

See also: loadFromMemory(), loadFromStream(), saveToFile()

bool gf::Image::loadFromMemory	(	const uint8_t *	data,
		std::size_t	length
	)

Load the image from a file in memory.

The supported image formats are bmp, png, tga, jpg, gif, psd, hdr and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters

data	Pointer to the file data in memory
length	Length of the data to load, in bytes

Returns: true if loading was successful

See also: loadFromFile(), loadFromStream(), saveToFile()

bool gf::Image::loadFromStream ( InputStream & stream )

Load the image from a custom stream.

The supported image formats are bmp, png, tga, jpg, gif, psd, hdr and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters

stream Source stream to read from

Returns: True if loading was successful

See also: loadFromFile(), loadFromMemory()

Image& gf::Image::operator= ( const Image & )

default

Default copy assignment.

Image& gf::Image::operator= ( Image && )

default

Default move assignment.

bool gf::Image::saveToFile ( const Path & filename ) const

Save the image to a file on disk.

The format of the image is automatically deduced from the extension. The supported image formats are bmp, png and tga. The destination file is overwritten if it already exists. This function fails if the image is empty.

Parameters

filename Path of the file to save

Returns: true if saving was successful

See also: create, loadFromFile(), loadFromMemory(), loadFromStream()

void gf::Image::setPixel	(	Vector2u	pos,
		const Color4u &	color
	)

Change the color of a pixel.

This function doesn't check the validity of the pixel coordinates, using out-of-range values will result in an undefined behavior.

Parameters

pos	Coordinate of pixel to change
color	New color of the pixel

See also: getPixel

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation