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|
Quantize
========
..
This document covers methods defined in MagickCore's quantize.c file.
https://imagemagick.org/api/MagickCore/quantize_8c.html
.. _kmeans:
Kmeans
------
.. versionadded:: 0.6.4
Reduces the number of colors to a target number. Processing stops if
max number of iterations, or tolerance are reached.
.. code-block:: python
from wand.image import Image
with Image(filename='hummingbird.jpg') as img:
img.kmeans(number_colors=32, max_iterations=100, tolerance=0.01)
img.save(filename='quantize_kmeans.jpg')
+---------------------------------------+-------------------------------------------+
| Original | Quantize Kmeans |
+---------------------------------------+-------------------------------------------+
| .. image:: ../_images/hummingbird.jpg | .. image:: ../_images/quantize_kmeans.jpg |
| :alt: Original | :alt: Quantize Kmeans |
+---------------------------------------+-------------------------------------------+
We can also seed the initial colors used on the first iteration by
defining a semicolon delimited list of colors.
.. code-block:: python
from wand.image import Image
with Image(filename='hummingbird.jpg') as img:
img.artifacts['kmeans:seed-colors'] = 'teal;#586f5f;#4d545c;#617284'
img.kmeans(number_colors=32, max_iterations=100, tolerance=0.01)
img.save(filename='quantize_kmeans_seed.jpg')
+---------------------------------------+------------------------------------------------+
| Original | Quantize Kmeans (seed) |
+---------------------------------------+------------------------------------------------+
| .. image:: ../_images/hummingbird.jpg | .. image:: ../_images/quantize_kmeans_seed.jpg |
| :alt: Original | :alt: Quantize Kmeans (seed) |
+---------------------------------------+------------------------------------------------+
.. note:: Requires ImageMagick-7.0.10-37
.. _posterize:
Posterize
---------
.. versionadded:: 0.5.0
Reduces number of colors per channel. Dither can be defined by passing
``'no'``, ``'riemersma'``, or ``'floyd_steinberg'`` arguments.
.. code-block:: python
from wand.image import Image
with Image(filename='hummingbird.jpg') as img:
img.posterize(levels=16, dither='floyd_steinberg')
img.save(filename='quantize_posterize.jpg')
+---------------------------------------+----------------------------------------------+
| Original | Quantize Posterize |
+---------------------------------------+----------------------------------------------+
| .. image:: ../_images/hummingbird.jpg | .. image:: ../_images/quantize_posterize.jpg |
| :alt: Original | :alt: Quantize Posterize |
+---------------------------------------+----------------------------------------------+
.. _quantize:
Quantize
--------
.. versionadded:: 0.4.2
Analyzes the colors in an image, and replace pixel values from a fixed number
of color.
.. code-block:: python
from wand.image import Image
with Image(filename='hummingbird.jpg') as img:
img.quantize(number_colors=8, colorspace_type='srgb',
treedepth=1, dither=True, measure_error=False)
img.save(filename='quantize_quantize.jpg')
+---------------------------------------+---------------------------------------------+
| Original | Quantize |
+---------------------------------------+---------------------------------------------+
| .. image:: ../_images/hummingbird.jpg | .. image:: ../_images/quantize_quantize.jpg |
| :alt: Original | :alt: Quantize |
+---------------------------------------+---------------------------------------------+
.. _remap:
Remap
-----
.. versionadded:: 0.5.3
Remap replaces all pixels with the closest matching pixel found in the
*affinity* reference image.
.. code-block:: python
from wand.image import Image
with Image(filename='hummingbird.jpg') as img:
with Image(width=256, height=1,
pseudo='gradient:SaddleBrown-LavenderBlush') as amap:
img.remap(affinity=amap, method='riemersma')
img.save(filename='quantize_remap.jpg')
+---------------------------------------+------------------------------------------+
| Original | Quantize Remap |
+---------------------------------------+------------------------------------------+
| .. image:: ../_images/hummingbird.jpg | .. image:: ../_images/quantize_remap.jpg |
| :alt: Original | :alt: Quantize Remap |
+---------------------------------------+------------------------------------------+
|
