Opening images¶
Images can be either opened from a file or an existing Pillow/Wand object.
From a file¶
To open an image, call Image.open()
passing in a file-like object that
contains the image data.
from willow.image import Image
with open('test.jpg', 'rb') as f:
i = Image.open(f)
isinstance(i, Image)
from willow.image import ImageFile, JPEGImageFile
isinstance(i, ImageFile)
isinstance(i, JPEGImageFile)
If it succeeded, this will return a subclass of ImageFile
(which itself
is a subclass of Image
).
The ImageFile
subclass it chooses depends on the format of the image (
detected by inspecting the file header). In this case, it used
JPEGImageFile
as the image we loaded was in JPEG format.
Using different image classes for different formats allows Willow to decide which plugin to use for performing operations on the image. For example, Willow will always favour Wand for resizing GIF images but will always favour Pillow for resizing JPEG and PNG images.
From an existing Pillow object¶
You can create a Willow Image
from an existing
PIL.Image
object by creating an instance of the
PillowImage
class
(passing the PIL.Image
object as the only parameter):
from willow.plugins.pillow import PillowImage
pillow_image = PIL.Image.open(...)
i = PillowImage(pillow_image)
isinstance(i, PillowImage)
from willow.image import Image
isinstance(i, Image)
The same can be done with Wand and OpenCV, which use the
WandImage
and
OpenCVColorImage
classes respectively.