sf::Image Class Reference

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

#include <SFML/Graphics/Image.hpp>

Public Member Functions
	Image ()
	Default constructor.
	~Image ()
	Destructor.
void	create (unsigned int width, unsigned int height, const Color &color=Color(0, 0, 0))
	Create the image and fill it with a unique color.
void	create (unsigned int width, unsigned int height, const Uint8 *pixels)
	Create the image from an array of pixels.
bool	loadFromFile (const std::string &filename)
	Load the image from a file on disk.
bool	loadFromMemory (const void *data, std::size_t size)
	Load the image from a file in memory.
bool	loadFromStream (InputStream &stream)
	Load the image from a custom stream.
bool	saveToFile (const std::string &filename) const
	Save the image to a file on disk.
bool	saveToMemory (std::vector< sf::Uint8 > &output, const std::string &format) const
	Save the image to a buffer in memory.
Vector2u	getSize () const
	Return the size (width and height) of the image.
void	createMaskFromColor (const Color &color, Uint8 alpha=0)
	Create a transparency mask from a specified color-key.
void	copy (const Image &source, unsigned int destX, unsigned int destY, const IntRect &sourceRect=IntRect(0, 0, 0, 0), bool applyAlpha=false)
	Copy pixels from another image onto this one.
void	setPixel (unsigned int x, unsigned int y, const Color &color)
	Change the color of a pixel.
Color	getPixel (unsigned int x, unsigned int y) const
	Get the color of a pixel.
const Uint8 *	getPixelsPtr () const
	Get a read-only pointer to the array of pixels.
void	flipHorizontally ()
	Flip the image horizontally (left <-> right)
void	flipVertically ()
	Flip the image vertically (top <-> bottom)

Detailed Description

Class for loading, manipulating and saving images.

sf::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.

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

A sf::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
sf::Image background;
if (!background.loadFromFile("background.jpg"))
    return -1;
 
// Create a 20x20 image filled with black color
sf::Image image;
image.create(20, 20, sf::Color::Black);
 
// Copy image1 on image2 at position (10, 10)
image.copy(background, 10, 10);
 
// Make the top-left pixel transparent
sf::Color 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

sf::Texture

Definition at line 46 of file Image.hpp.

Constructor & Destructor Documentation

Image()

sf::Image::Image

(

)

Default constructor.

Creates an empty image.

~Image()

sf::Image::~Image

(

)

Destructor.

Member Function Documentation

copy()

void sf::Image::copy	(	const Image &	source,
		unsigned int	destX,
		unsigned int	destY,
		const IntRect &	sourceRect = IntRect(0, 0, 0, 0),
		bool	applyAlpha = false
	)

Copy pixels from another image onto this one.

This function does a slow pixel copy and should not be used intensively. It can be used to prepare a complex static image from several others, but if you need this kind of feature in real-time you'd better use sf::RenderTexture.

If sourceRect is empty, the whole image is copied. If applyAlpha is set to true, alpha blending is applied from the source pixels to the destination pixels using the over operator. If it is false, the source pixels are copied unchanged with their alpha value.

See https://en.wikipedia.org/wiki/Alpha_compositing for details on the over operator.

Parameters

source	Source image to copy
destX	X coordinate of the destination position
destY	Y coordinate of the destination position
sourceRect	Sub-rectangle of the source image to copy
applyAlpha	Should the copy take into account the source transparency?

create() [1/2]

void sf::Image::create	(	unsigned int	width,
		unsigned int	height,
		const Color &	color = Color(0, 0, 0)
	)

Create the image and fill it with a unique color.

Parameters

width	Width of the image
height	Height of the image
color	Fill color

create() [2/2]

void sf::Image::create	(	unsigned int	width,
		unsigned int	height,
		const Uint8 *	pixels
	)

Create the image from an array of pixels.

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

Parameters

width	Width of the image
height	Height of the image
pixels	Array of pixels to copy to the image

createMaskFromColor()

void sf::Image::createMaskFromColor	(	const Color &	color,
		Uint8	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

flipHorizontally()

void sf::Image::flipHorizontally

(

)

Flip the image horizontally (left <-> right)

flipVertically()

void sf::Image::flipVertically

(

)

Flip the image vertically (top <-> bottom)

getPixel()

Color sf::Image::getPixel	(	unsigned int	x,
		unsigned int	y
	)		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

x	X coordinate of pixel to get
y	Y coordinate of pixel to get

Returns

Color of the pixel at coordinates (x, y)

See also

setPixel

getPixelsPtr()

const Uint8 * sf::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 (getSize().x * getSize().y * 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

getSize()

Vector2u sf::Image::getSize

(

)

const

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

Returns

Size of the image, in pixels

loadFromFile()

bool sf::Image::loadFromFile

(

const std::string &

filename

)

Load the image from a file on disk.

The supported image formats are bmp, png, tga, jpg, gif, psd, hdr, pic and pnm. Some format options are not supported, like jpeg with arithmetic coding or ASCII pnm. 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

loadFromMemory()

bool sf::Image::loadFromMemory	(	const void *	data,
		std::size_t	size
	)

Load the image from a file in memory.

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

Parameters

data	Pointer to the file data in memory
size	Size of the data to load, in bytes

Returns

True if loading was successful

See also

loadFromFile, loadFromStream

loadFromStream()

bool sf::Image::loadFromStream

(

InputStream &

stream

)

Load the image from a custom stream.

The supported image formats are bmp, png, tga, jpg, gif, psd, hdr, pic and pnm. Some format options are not supported, like jpeg with arithmetic coding or ASCII pnm. 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

saveToFile()

bool sf::Image::saveToFile

(

const std::string &

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, tga and jpg. 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

saveToMemory()

bool sf::Image::saveToMemory	(	std::vector< sf::Uint8 > &	output,
		const std::string &	format
	)		const

Save the image to a buffer in memory.

The format of the image must be specified. The supported image formats are bmp, png, tga and jpg. This function fails if the image is empty, or if the format was invalid.

Parameters

output	Buffer to fill with encoded data
format	Encoding format to use

Returns

True if saving was successful

See also

create, loadFromFile, loadFromMemory, saveToFile

setPixel()

void sf::Image::setPixel	(	unsigned int	x,
		unsigned int	y,
		const Color &	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

x	X coordinate of pixel to change
y	Y coordinate of pixel to change
color	New color of the pixel

See also

getPixel

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

• Image.hpp