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# (C) Copyright 2005-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Helper functions for working with images
This module provides helper functions for converting between numpy arrays
and Qt QImages, as well as between the various image types in a standardized
way.
"""
from enum import Enum
from pyface.qt import qt_api
from pyface.qt.QtCore import Qt
from pyface.qt.QtGui import QImage, QPixmap, QIcon
class ScaleMode(Enum):
fast = Qt.TransformationMode.FastTransformation
smooth = Qt.TransformationMode.SmoothTransformation
class AspectRatio(Enum):
ignore = Qt.AspectRatioMode.IgnoreAspectRatio
keep_constrain = Qt.AspectRatioMode.KeepAspectRatio
keep_expand = Qt.AspectRatioMode.KeepAspectRatioByExpanding
def image_to_bitmap(image):
""" Convert a QImage to a QPixmap.
Parameters
----------
image : QImage
The QImage to convert.
Return
------
bitmap : QPixmap
The corresponding QPixmap.
"""
bitmap = QPixmap.fromImage(image)
# keep a reference to the QImage to ensure underlying data is available
bitmap._image = image
return bitmap
def bitmap_to_image(bitmap):
""" Convert a QPixmap to a QImage.
Parameters
----------
bitmap : QPixmap
The QPixmap to convert.
Return
------
image : QImage
The corresponding QImage.
"""
return bitmap.toImage()
def bitmap_to_icon(bitmap):
""" Convert a QPixmap to a QIcon.
Parameters
----------
bitmap : QPixmap
The QPixmap to convert.
Return
------
icon : QIcon
The corresponding QIcon.
"""
return QIcon(bitmap)
def resize_image(image, size, aspect_ratio=AspectRatio.ignore,
mode=ScaleMode.fast):
""" Resize a toolkit image to the given size. """
return image.scaled(*size, aspect_ratio.value, mode.value)
def resize_bitmap(bitmap, size, aspect_ratio=AspectRatio.ignore,
mode=ScaleMode.fast):
""" Resize a toolkit bitmap to the given size. """
return bitmap.scaled(*size, aspect_ratio.value, mode.value)
def image_to_array(image):
""" Convert a QImage to a numpy array.
This copies the data returned from Qt.
Parameters
----------
image : QImage
The QImage that we want to extract the values from. The format must
be either RGB32 or ARGB32.
Return
------
array : ndarray
An N x M x 4 array of unsigned 8-bit ints as RGBA values.
"""
import numpy as np
width, height = image.width(), image.height()
channels = image.pixelFormat().channelCount()
data = image.bits()
if qt_api in {'pyqt', 'pyqt5'}:
data = data.asarray(width * height * channels)
array = np.array(data, dtype='uint8')
array.shape = (height, width, channels)
if image.format() in {QImage.Format.Format_RGB32, QImage.Format.Format_ARGB32}:
# comes in as BGRA, but want RGBA
array = array[:, :, [2, 1, 0, 3]]
else:
raise ValueError(
"Unsupported QImage format {}".format(image.format())
)
return array
def array_to_image(array):
""" Convert a numpy array to a QImage.
This copies the data before passing it to Qt.
Parameters
----------
array : ndarray
An N x M x {3, 4} array of unsigned 8-bit ints. The image
format is assumed to be RGB or RGBA, based on the shape.
Return
------
image : QImage
The QImage created from the data. The pixel format is
QImage.Format.Format_RGB32.
"""
import numpy as np
if array.ndim != 3:
raise ValueError("Array must be either RGB or RGBA values.")
height, width, channels = array.shape
data = np.empty((height, width, 4), dtype='uint8')
if channels == 3:
data[:, :, [2, 1, 0]] = array
data[:, :, 3] = 0xff
elif channels == 4:
data[:, :, [2, 1, 0, 3]] = array
else:
raise ValueError("Array must be either RGB or RGBA values.")
bytes_per_line = 4 * width
if channels == 3:
image = QImage(data.data, width, height, bytes_per_line,
QImage.Format.Format_RGB32)
elif channels == 4:
image = QImage(data.data, width, height, bytes_per_line,
QImage.Format.Format_ARGB32)
# keep a reference to the array to ensure underlying data is available
image._numpy_data = data
return image
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