magnum.ImageView2D class

Memory ownership and reference counting

Similarly to corrade.containers.ArrayView (and unlike in C++), the view keeps a reference to the original memory owner object in the owner field, meaning that calling del on the original object will not invalidate the view. Slicing a view creates a new view referencing the same original object, without any dependency on the previous view. That means a long chained slicing operation will not cause increased memory usage.

The owner is None if the view is empty.

Pixel data access

The class makes use of Python’s dynamic nature and provides direct access to pixel data in their concrete types via pixels. The returned views point to the underlying image data, element access coverts to a type corresponding to a particular PixelFormat and for performance-oriented access the view implements a buffer protocol with a corresponding type annotation.

Normalized formats (such as PixelFormat.RGB8_UNORM but also PixelFormat.RGBA8_SRGB) are unpacked to a corresponding floating-point representation in element access and packed from a floating-point representation in mutable acess. The type annotation is however still matching the original type (such as '3B' / '4B' in these cases), so code consuming these via the buffer protocol needs to handle the normalization explicitly if needed.

>>> data = array.array('B', [0xf3, 0x2a, 0x80, 0x23, 0x00, 0xff, 0x00, 0xff])
>>> image = ImageView2D(PixelFormat.RGBA8_SRGB, (2, 1), data)
>>> image.pixels[0, 0] # sRGB -> float conversion
Vector(0.896269, 0.0231534, 0.215861, 0.137255)
>>> np.array(image.pixels, copy=False)[0]
array([[243,  42, 128,  35],
       [  0, 255,   0, 255]], dtype=uint8)

Special methods

def __init__(self, arg0: PixelStorage, arg1: PixelFormat, arg2: Vector2i, arg3: corrade.containers.ArrayView, /) -> None

Constructor

def __init__(self, arg0: PixelFormat, arg1: Vector2i, arg2: corrade.containers.ArrayView, /) -> None

Constructor

def __init__(self, arg0: PixelStorage, arg1: PixelFormat, arg2: Vector2i, /) -> None

Construct an empty view

def __init__(self, arg0: PixelFormat, arg1: Vector2i, /) -> None

Construct an empty view

def __init__(self, arg0: Image2D, /) -> None

Construct a view on an image

def __init__(self, arg0: ImageView2D, /) -> None

Construct from any type convertible to an image view

def __init__(self, arg0: MutableImageView2D, /) -> None

Construct from a mutable view

Properties

data: corrade.containers.ArrayView get set

Raw image data

format: PixelFormat get

Format of pixel data

owner: object get

Memory owner

pixel_size: int get

Pixel size (in bytes)

pixels: corrade.containers.StridedArrayView2D get

Pixel data

size: Vector2i get

Image size

storage: PixelStorage get

Storage of pixel data

Method documentation