Documentation of SFML 2.0

sf::Image Class Reference

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

#include <Image.hpp>

Public Member Functions

 Image ()
 Default constructor.
 
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.
 
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 loadFromPixels) 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

sf::Image::Image ( )

Default constructor.

Creates an empty image.

Member Function Documentation

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, the transparency of source pixels is applied. If it is false, the pixels are copied unchanged with their alpha value.

Parameters
sourceSource image to copy
destXX coordinate of the destination position
destYY coordinate of the destination position
sourceRectSub-rectangle of the source image to copy
applyAlphaShould the copy take in account the source transparency?
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
widthWidth of the image
heightHeight of the image
colorFill color
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 behaviour. If pixels is null, an empty image is created.

Parameters
widthWidth of the image
heightHeight of the image
pixelsArray of pixels to copy to the image
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
colorColor to make transparent
alphaAlpha value to assign to transparent pixels
void sf::Image::flipHorizontally ( )

Flip the image horizontally (left <-> right)

void sf::Image::flipVertically ( )

Flip the image vertically (top <-> bottom)

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 behaviour.

Parameters
xX coordinate of pixel to get
yY coordinate of pixel to get
Returns
Color of the pixel at coordinates (x, y)
See Also
setPixel
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
Vector2u sf::Image::getSize ( ) const

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

Returns
Size of the image, in pixels
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 and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters
filenamePath of the image file to load
Returns
True if loading was successful
See Also
loadFromMemory, loadFromStream, saveToFile
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 and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters
dataPointer to the file data in memory
sizeSize of the data to load, in bytes
Returns
True if loading was successful
See Also
loadFromFile, 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 and pic. Some format options are not supported, like progressive jpeg. If this function fails, the image is left unchanged.

Parameters
streamSource stream to read from
Returns
True if loading was successful
See Also
loadFromFile, loadFromMemory
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
filenamePath of the file to save
Returns
True if saving was successful
See Also
create, loadFromFile, loadFromMemory
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 behaviour.

Parameters
xX coordinate of pixel to change
yY coordinate of pixel to change
colorNew color of the pixel
See Also
getPixel

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