# Module PIL.Image

#### Module Summary:

    def blend(im1, im2, alpha)

> Creates a new image by interpolating between the given images, using a constant alpha.

    def composite(image1, image2, mask)

> Creates a new image by interpolating between the given images, using the mask as alpha.

    def eval(image, function)

> Applies the function (which should take one argument) to each pixel in the given image.

    def frombuffer(mode, size, data, decoder_name='raw', *args)

> Creates an image memory from pixel data in a string or byte buffer.

    def fromstring(mode, size, data, decoder_name='raw', *args)

> Creates an image memory from pixel data in a string.

    def getmodebase(mode)

> Get "base" mode.

    def getmodetype(mode)

> Get storage type mode.

    def init()

> Explicitly load all available file format drivers.

    def merge(mode, bands)

> Creates a new image from a number of single-band images.

    def new(mode, size, color=0)

> Creates a new image with the given mode and size.

    def open(file, mode="r")

> Opens and identifies the given image file.

    def preinit()

> Explicitly load standard file format drivers.

    def register_extension(id, extension)

> Register an image extension.

    def register_mime(id, mimetype)

> Register an image MIME type.

    def register_open(id, factory, accept=None)

> Register an image file plugin.

    def register_save(id, driver)

> Register an image save function.

    class Image:
        def __init__(self)

> This class represents an image object.

## Functions

### blend

    blend(im1, im2, alpha)

Creates a new image by interpolating between the given images, using a constant alpha.

       out = image1 * (1.0 - alpha) + image2 * alpha

#### Parameters:

`im1` -- The first image.

`im2` -- The second image. Must have the same mode and size as the first image.

`alpha` -- The interpolation alpha factor. If alpha is 0.0, a copy of the first image is returned. If alpha is 1.0, a copy of the second image is returned. There are no restrictions on the alpha value. If necessary, the result is clipped to fit into the allowed output range.

#### Returns:

An Image object.

### composite

    composite(image1, image2, mask)

Creates a new image by interpolating between the given images, using the mask as alpha.

#### Parameters:

`image1` -- The first image.

`image2` -- The second image. Must have the same mode and size as the first image.

`mask` -- A mask image. This image can can have mode "1", "L", or "RGBA", and most have the same size as the other two images.

### eval

    eval(image, function)

Applies the function (which should take one argument) to each pixel in the given image. If the image has more than one band, the same function is applied to each band. Note that the function is evaluated once for each possible pixel value, so you cannot use random components or other generators.

#### Parameters:

`image` -- The input image.

`function` -- A function object, taking one integer argument.

#### Returns:

An Image object.

### frombuffer

    frombuffer(mode, size, data, decoder_name='raw', *args)

Creates an image memory from pixel data in a string or byte buffer.

This function is similar to fromstring, but it data in the byte buffer, where possible. Images created by this function are usually marked as readonly.

Note that this function decodes pixel data only, not entire images. If you have an entire image in a string, wrap it in a StringIO object, and use open to load it.

#### Parameters:

`mode` -- The image mode.

`size` -- The image size.

`data` -- An 8-bit string or other buffer object containing raw data for the given mode.

`decoder_name` -- What decoder to use.

`*args` -- Additional parameters for the given decoder.

#### Returns:

An Image object.

### fromstring

    fromstring(mode, size, data, decoder_name='raw', *args)

Creates an image memory from pixel data in a string.

In its simplest form, this function takes three arguments (mode, size, and unpacked pixel data).

You can also use any pixel decoder supported by PIL. For more information on available decoders, see the section Writing Your Own File Decoder.

Note that this function decodes pixel data only, not entire images. If you have an entire image in a string, wrap it in a StringIO object, and use open to load it.

#### Parameters:

`mode` -- The image mode.

`size` -- The image size.

`data` -- An 8-bit string containing raw data for the given mode.

`decoder_name` -- What decoder to use.

`*args` -- Additional parameters for the given decoder.

#### Returns:

An Image object.

### getmodebase

    getmodebase(mode)

Get "base" mode. Given a mode, this function returns "L" for images that contain grayscale data, and "RGB" for images that contain color data.

#### Parameters:

`mode` -- Input mode.

#### Returns:

"L" or "RGB".

#### Exceptions:

`KeyError` -- The input mode was not a standard mode.

### getmodetype

    getmodetype(mode)

Get storage type mode. Given a mode, this function returns a single-layer mode suitable for storing individual bands.

#### Parameters:

`mode` -- Input mode.

#### Returns:

"L", "I", or "F".

#### Exceptions:

`KeyError` -- The input mode was not a standard mode.

### init

    init()

Explicitly load all available file format drivers.

### merge

    merge(mode, bands)

Creates a new image from a number of single-band images.

#### Parameters:

`mode` -- The mode to use for the output image.

`bands` -- A sequence containing one single-band image for each band in the output image. All bands must have the same size.

#### Returns:

An Image object.

### new

    new(mode, size, color=0)

Creates a new image with the given mode and size.

#### Parameters:

`mode` -- The mode to use for the new image.

`size` -- A 2-tuple, containing (width, height)

`color` -- What colour to use for the image. Default is black. If given, this should be a single integer or floating point value for single-band modes, and a tuple for multi-band modes (one value per band). When creating RGB images, you can also use colour strings as supported by the ImageColor module. If the colour is None, the image is not initialised.

#### Returns:

An Image object.

### open

    open(file, mode="r")

Opens and identifies the given image file.

This is a lazy operation; this function identifies the file, but the actual image data is not read from the file until you try to process the data (or call the load method).

#### Parameters:

`file` -- A filename (string) or a file object. The file object must implement read, seek, and tell methods, and be opened in binary mode.

`mode` -- The mode. If given, this argument must be "r".

#### Returns:

An Image object.

#### Exceptions:

`IOError` -- If the file cannot be found, or the image cannot be opened and identified.

### preinit

    preinit()

Explicitly load standard file format drivers.

### register_extension

    register_extension(id, extension)

Register an image extension. This function should not be used in application code.

#### Parameters:

`id` -- An image format identifier.

`extension` -- An extension used for this format.

### register_mime

    register_mime(id, mimetype)

Register an image MIME type. This function should not be used in application code.

#### Parameters:

`id` -- An image format identifier.

`mimetype` -- The image MIME type for this format.

### register_open

    register_open(id, factory, accept=None)

Register an image file plugin. This function should not be used in application code.

#### Parameters:

`id` -- An image format identifier.

`factory` -- An image file factory method.

`accept` -- An optional function that can be used to quickly reject images having another format.

### register_save

    register_save(id, driver)

Register an image save function. This function should not be used in application code.

#### Parameters:

`id` -- An image format identifier.

`driver` -- A function to save images in this format.

## Classes

### The Image Class

    Image()

This class represents an image object. To create Image objects, use the appropriate factory functions. There's hardly ever any reason to call the Image constructor directly.

#### Method Summary:

    convert(mode, matrix=None)

> Returns a converted copy of an image.

    copy()

> Copies the image.

    crop(box=None)

> Returns a rectangular region from the current image.

    draft(mode, size)

> Configures the image file loader so it returns a version of the image that as closely as possible matches the given mode and size.

    filter(filter)

> Filter image by the given filter.

    fromstring(data, decoder_name='raw', *args)

> Same as the fromstring function, but loads data into the current image.

    getbands()

> Returns a tuple containing the name of each band.

    getbbox()

> Calculates the bounding box of the non-zero regions in the image.

    getdata(band=None)

> Returns the contents of an image as a sequence object containing pixel values.

    getextrema()

> Get the the minimum and maximum pixel values for each band in the image.

    getpixel(xy)

> Returns the pixel value at a given position.

    histogram(mask=None)

> Returns a histogram for the image.

    load()

> Allocates storage for the image and loads the pixel data.

    offset(xoffset, yoffset=None)

> (Deprecated) Returns a copy of the image where the data has been offset by the given distances.

    paste(im, box=None, mask=None)

> Pastes another image into this image.

    point(lut, mode=None)

> Map image through lookup table or function.

    putalpha(im)

> Replace the alpha layer in the current image.

    putdata(data, scale=1.0, offset=0.0)

> Copy pixel data to this image.

    putpalette(data)

> Attach a palette to a "P" or "L" image.

    putpixel(xy, value)

> Modifies the pixel at the given position.

    resize(size, filter=NEAREST)

> Returns a resized copy of an image.

    rotate(angle, filter=NEAREST)

> Returns a rotated image.

    save(file, format=None, **options)

> Saves the image under the given filename.

    seek(frame)

> Seeks to the given frame in a sequence file.

    show(title=None)

> Displays an image.

    split()

> Split image into individual bands.

    tell()

> Returns the current frame number.

    thumbnail(size, resample=0)

> Make thumbnail.

    tobitmap(name='image')

> Returns the image converted to an X11 bitmap.

    tostring(encoder_name='raw', *args)

> Returns a string containing pixel data.

    transform(size, method, data, resample=NEAREST)

> Transform image.

    transpose(method)

> Returns a flipped or rotated copy of an image.

    verify()

> Verify file contents.

### convert

    convert(mode, matrix=None)

Returns a converted copy of an image. For the "P" mode, this translates pixels through the palette. If mode is omitted, a mode is chosen so that all information in the image and the palette can be represented without a palette.

The current version supports all possible conversions between "L", "RGB" and "CMYK."

When translating a colour image to black and white (mode "L"), the library uses the ITU-R 601-2 luma transform:

L = R * 299/1000 + G * 587/1000 + B * 114/1000

When translating a greyscale image into a bilevel image (mode "1"), all non-zero values are set to 255 (white). To use other thresholds, use the point method.

#### Parameters:

`mode` -- The requested mode.

`matrix` -- An optional conversion matrix. If given, this should be 4- or 16-tuple containing floating point values.

#### Returns:

An Image object.

### copy

    copy()

Copies the image. Use this method if you wish to paste things into an image, but still retain the original.

#### Returns:

An Image object.

### crop

    crop(box=None)

Returns a rectangular region from the current image. The box is a 4-tuple defining the left, upper, right, and lower pixel coordinate.

This is a lazy operation. Changes to the source image may or may not be reflected in the cropped image. To break the connection, call the load method on the cropped copy.

#### Returns:

An Image object.

### draft

    draft(mode, size)

Configures the image file loader so it returns a version of the image that as closely as possible matches the given mode and size. For example, you can use this method to convert a colour JPEG to greyscale while loading it, or to extract a 128x192 version from a PCD file.

Note that this method modifies the Image object in place. If the image has already been loaded, this method has no effect.

#### Parameters:

`mode` -- The requested mode.

`size` -- The requested size.

### filter

    filter(filter)

Filter image by the given filter. For a list of available filters, see the ImageFilter module.

#### Parameters:

`filter` -- Filter kernel.

#### Returns:

An Image object.

### fromstring

    fromstring(data, decoder_name='raw', *args)

Same as the fromstring function, but loads data into the current image.

### getbands

    getbands()

Returns a tuple containing the name of each band. For example, getbands on an RGB image returns ("R", "G", "B").

#### Returns:

A tuple containing band names.

### getbbox

    getbbox()

Calculates the bounding box of the non-zero regions in the image.

#### Returns:

The bounding box is returned as a 4-tuple defining the left, upper, right, and lower pixel coordinate. If the image is completely empty, this method returns None.

### getdata

    getdata(band=None)

Returns the contents of an image as a sequence object containing pixel values. The sequence object is flattened, so that values for line one follow directly after the values of line zero, and so on.

Note that the sequence object returned by this method is an internal PIL data type, which only supports certain sequence operations. To convert it to an ordinary sequence (e.g. for printing), use list(im.getdata()).

#### Parameters:

`band` -- What band to return. The default is to return all bands. To return a single band, pass in the index value (e.g. 0 to get the "R" band from an "RGB" image).

#### Returns:

A sequence-like object.

### getextrema

    getextrema()

Get the the minimum and maximum pixel values for each band in the image.

#### Returns:

For a single-band image, a 2-tuple containing the minimum and maximum pixel value. For a multi-band image, a tuple containing one 2-tuple for each band.

### getpixel

    getpixel(xy)

Returns the pixel value at a given position.

#### Parameters:

`xy` -- The coordinate, given as (x, y).

#### Returns:

The pixel value. If the image is a multi-layer image, this method returns a tuple.

### histogram

    histogram(mask=None)

Returns a histogram for the image. The histogram is returned as a list of pixel counts, one for each pixel value in the source image. If the image has more than one band, the histograms for all bands are concatenated (for example, the histogram for an "RGB" image contains 768 values).

A bilevel image (mode "1") is treated as a greyscale ("L") image by this method.

If a mask is provided, the method returns a histogram for those parts of the image where the mask image is non-zero. The mask image must have the same size as the image, and be either a bi-level image (mode "1") or a greyscale image ("L").

#### Parameters:

`mask` -- An optional mask.

#### Returns:

A list containing pixel counts.

### load

    load()

Allocates storage for the image and loads the pixel data. In normal cases, you don't need to call this method, since the Image class automatically loads an opened image when it is accessed for the first time.

### offset

    offset(xoffset, yoffset=None)

(Deprecated) Returns a copy of the image where the data has been offset by the given distances. Data wraps around the edges. If yoffset is omitted, it is assumed to be equal to xoffset.

This method is deprecated. New code should use the offset function in the ImageChops module.

#### Parameters:

`xoffset` -- The horizontal distance.

`yoffset` -- The vertical distance. If omitted, both distances are set to the same value.

#### Returns:

An Image object.

### paste

    paste(im, box=None, mask=None)

Pastes another image into this image. The box argument is either a 2-tuple giving the upper left corner, a 4-tuple defining the left, upper, right, and lower pixel coordinate, or None (same as (0, 0)). If a 4-tuple is given, the size of the pasted image must match the size of the region.

If the modes don't match, the pasted image is converted to the mode of this image (see the convert method for details).

Instead of an image, the source can be a integer or tuple containing pixel values. The method then fills the region with the given colour. When creating RGB images, you can also use colour strings as supported by the ImageColor module.

If a mask is given, this method updates only the regions indicated by the mask. You can use either "1", "L" or "RGBA" images (in the latter case, the alpha band is used as mask). Where the mask is 255, the given image is copied as is. Where the mask is 0, the current value is preserved. Intermediate values can be used for transparency effects.

Note that if you paste an "RGBA" image, the alpha band is ignored. You can work around this by using the same image as both source image and mask.

#### Parameters:

`im` -- Source image or pixel value (integer or tuple).

`box` -- A 4-tuple giving the region to paste into. If a 2-tuple is used instead, it's treated as the upper left corner. If None is used instead, the source is pasted into the upper left corner.

`mask` -- An optional mask image.

#### Returns:

An Image object.

### point

    point(lut, mode=None)

Map image through lookup table or function.

#### Parameters:

`lut` -- A lookup table, containing 256 values per band in the image. A function can be used instead, it should take a single argument. The function is called once for each possible pixel value, and the resulting table is applied to all bands of the image.

`mode` -- Output mode (default is same as input). In the current version, this can only be used if the source image has mode "L" or "P", and the output has mode "1".

#### Returns:

An Image object.

### putalpha

    putalpha(im)

Replace the alpha layer in the current image. The image must be an "RGBA" image, and the band must be either "L" or "1".

#### Parameters:

`im` -- The new alpha layer.

### putdata

    putdata(data, scale=1.0, offset=0.0)

Copy pixel data to this image. This method copies data from a sequence object into the image, starting at the upper left corner (0, 0), and continuing until either the image or the sequence ends. The scale and offset values are used to adjust the sequence values: pixel = value*scale + offset.

#### Parameters:

`data` -- A sequence object.

`scale` -- An optional scale value. The default is 1.0.

`offset` -- An optional offset value. The default is 0.0.

### putpalette

    putpalette(data)

Attach a palette to a "P" or "L" image. The palette sequence should contain 768 integer values, where each group of three values represent the red, green, and blue values for the corresponding pixel index. Instead of an integer sequence, you can use an 8-bit string.

#### Parameters:

`data` -- A palette sequence.

### putpixel

    putpixel(xy, value)

Modifies the pixel at the given position. The colour is given as a single numerical value for single-band images, and a tuple for multi-band images.

Note that this method is relatively slow. For more extensive changes, use paste or the ImageDraw module instead.

#### Parameters:

`xy` -- The pixel coordinate, given as (x, y).

`value` -- The pixel value.

### resize

    resize(size, filter=NEAREST)

Returns a resized copy of an image.

#### Parameters:

`size` -- The requested size in pixels, as a 2-tuple: (width, height).

`filter` -- An optional resampling filter. This can be one of NEAREST (use nearest neighbour), BILINEAR (linear interpolation in a 2x2 environment), BICUBIC (cubic spline interpolation in a 4x4 environment), or ANTIALIAS (a high-quality downsampling filter). If omitted, or if the image has mode "1" or "P", it is set NEAREST.

#### Returns:

An Image object.

### rotate

    rotate(angle, filter=NEAREST)

Returns a rotated image. This method returns a copy of an image, rotated the given number of degrees counter clockwise around its centre.

#### Parameters:

`angle` -- In degrees counter clockwise.

`filter` -- An optional resampling filter. This can be one of NEAREST (use nearest neighbour), BILINEAR (linear interpolation in a 2x2 environment), or BICUBIC (cubic spline interpolation in a 4x4 environment). If omitted, or if the image has mode "1" or "P", it is set NEAREST.

#### Returns:

An Image object.

### save

    save(file, format=None, **options)

Saves the image under the given filename. If no format is specified, the format to use is determined from the filename extension, if possible.

Keyword options can be used to provide additional instructions to the writer. If a writer doesn't recognise an option, it is silently ignored. The available options are described later in this handbook.

You can use a file object instead of a filename. In this case, you must always specify the format. The file object must implement the seek, tell, and write methods, and be opened in binary mode.

#### Parameters:

`file` -- File name or file object.

`format` -- Optional format override. If omitted, the format to use is determined from the filename extension. If a file object was used instead of a filename, this parameter should always be used.

`**options` -- Extra parameters to the image writer.

#### Returns:

None

### seek

    seek(frame)

Seeks to the given frame in a sequence file. If you seek beyond the end of the sequence, the method raises an EOFError exception. When a sequence file is opened, the library automatically seeks to frame 0.

Note that in the current version of the library, most sequence formats only allows you to seek to the next frame.

#### Parameters:

`frame` -- Frame number, starting at 0.

#### Exceptions:

`EOFError` -- Attempt to seek beyond the end of the sequence.

### show

    show(title=None)

Displays an image. This method is mainly intended for debugging purposes.

On Unix platforms, this method saves the image to a temporary PPM file, and calls the xv utility.

On Windows, it saves the image to a temporary BMP file, and uses the standard BMP display utility to show it (usually Paint).

#### Parameters:

`title` -- Optional title to use for the image window, where possible.

### split

    split()

Split image into individual bands. This methods returns a tuple of individual image bands from an image. For example, splitting an "RGB" image creates three new images each containing a copy of one of the original bands (red, green, blue).

#### Returns:

A tuple containing bands.

### tell

    tell()

Returns the current frame number.

#### Returns:

Frame number, starting with 0.

### thumbnail

    thumbnail(size, resample=0)

Make thumbnail. This method modifies the image to contain a thumbnail version of itself, no larger than the given size. This method calculates an appropriate thumbnail size to preserve the aspect of the image, calls the draft method to configure the file reader (where applicable), and finally resizes the image.

Note that the bilinear and bicubic filters in the current version of PIL are not well-suited for thumbnail generation. You should use ANTIALIAS unless speed is much more important than quality.

Also note that this function modifies the Image object in place. If you need to use the full resolution image as well, apply this method to a copy of the original image.

#### Parameters:

`size` -- Requested size.

`resample` -- Optional resampling filter. This can be one of NEAREST, BILINEAR, BICUBIC, or ANTIALIAS (best quality). If omitted, it defaults to NEAREST (this will be changed to ANTIALIAS in future versions).

#### Returns:

None

### tobitmap

    tobitmap(name='image')

Returns the image converted to an X11 bitmap. This method only works for mode "1" images.

#### Parameters:

`name` -- The name prefix to use for the bitmap variables.

#### Returns:

A string containing an X11 bitmap.

#### Exceptions:

`ValueError` -- If the mode is not "1"

### tostring

    tostring(encoder_name='raw', *args)

Returns a string containing pixel data.

#### Parameters:

`encoder_name` -- What encoder to use. The default is to use the standard "raw" encoder.

`*args` -- Extra arguments to the encoder.

#### Returns:

An 8-bit string.

### transform

    transform(size, method, data, resample=NEAREST)

Transform image. This method creates a new image with the given size, and the same mode as the original, and copies data to the new image using the given transform.

#### Parameters:

`size` -- The output size.

`method` -- The transformation method. This is one of EXTENT (cut out a rectangular subregion), AFFINE (affine transform), QUAD (map a quadrilateral to a rectangle), or MESH (map a number of source quadrilaterals in one operation).

`data` -- Extra data to the transformation method.

`resample` -- Optional resampling filter. It can be one of NEAREST (use nearest neighbour), BILINEAR (linear interpolation in a 2x2 environment), or BICUBIC (cubic spline interpolation in a 4x4 environment). If omitted, or if the image has mode "1" or "P", it is set to NEAREST.

#### Returns:

An Image object.

### transpose

    transpose(method)

Returns a flipped or rotated copy of an image.

#### Parameters:

`method` -- One of FLIP_LEFT_RIGHT, FLIP_TOP_BOTTOM, ROTATE_90, ROTATE_180, or ROTATE_270.

### verify

    verify()

Verify file contents. For data read from a file, this method attempts to determine if the file is broken, without actually decoding the image data. If this method finds any problems, it raises suitable exceptions. If you need to load the image after using this method, you must reopen the image file.