.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "_gallery/validation/validate_image_colormap.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download__gallery_validation_validate_image_colormap.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr__gallery_validation_validate_image_colormap.py:


Validate Colormap
=================

Show an image with four different colormaps.

* The first (top) one is a colormap consisting of 3 values, interpolated
  with nearest neighbours. E.g. to denote categories.
* The next one uses the same colormap, interpolated linearly. One can see how
  this causes the colors near the edges of the image to not show a gradient.
* In the next image the same transition (from red to green to blue) is shown
  with a colormap of 256 values.
* The bottom image shows the standard Viridis colormap.

.. GENERATED FROM PYTHON SOURCE LINES 15-100



.. image-sg:: /_gallery/validation/images/sphx_glr_validate_image_colormap_001.webp
   :alt: validate image colormap
   :srcset: /_gallery/validation/images/sphx_glr_validate_image_colormap_001.webp
   :class: sphx-glr-single-img





.. code-block:: Python



    import numpy as np
    from rendercanvas.auto import RenderCanvas, loop
    import pygfx as gfx


    renderer = gfx.renderers.WgpuRenderer(RenderCanvas(size=(600, 600)))

    im = np.repeat(np.linspace(0, 1, 100).reshape(1, -1), 24, 0).astype(np.float32)
    geometry = gfx.Geometry(grid=gfx.Texture(im, dim=2))


    colormap_data1 = np.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]], np.float32)

    colormap_data2 = np.zeros((256, 3), np.float32)
    colormap_data2[0:128, 0] = np.linspace(1, 0, 128)
    colormap_data2[0:128, 1] = np.linspace(0, 1, 128)
    colormap_data2[128:, 1] = np.linspace(1, 0, 128)
    colormap_data2[128:, 2] = np.linspace(0, 1, 128)

    colormap1 = gfx.Texture(colormap_data1, dim=1)
    colormap2 = gfx.Texture(colormap_data2, dim=1)


    image1 = gfx.Image(
        geometry,
        gfx.ImageBasicMaterial(
            clim=(0, 1),
            map=gfx.TextureMap(
                colormap1,
                filter="nearest",
                wrap="clamp",
            ),
        ),
    )
    image1.local.y = 75

    image2 = gfx.Image(
        geometry,
        gfx.ImageBasicMaterial(
            clim=(0, 1),
            map=gfx.TextureMap(
                colormap1,
                filter="linear",
                wrap="clamp",
            ),
        ),
    )
    image2.local.y = 50

    image3 = gfx.Image(
        geometry,
        gfx.ImageBasicMaterial(
            clim=(0, 1),
            map=gfx.TextureMap(
                colormap2,
                filter="nearest",
                wrap="clamp",
            ),
        ),
    )
    image3.local.y = 25

    image4 = gfx.Image(
        geometry,
        gfx.ImageBasicMaterial(
            clim=(0, 1),
            map=gfx.cm.viridis,
        ),
    )
    image4.local.y = 0

    scene = gfx.Scene()
    scene.add(image1, image2, image3, image4)

    camera = gfx.OrthographicCamera()
    camera.show_rect(-4, 103, -4, 103)

    renderer.request_draw(lambda: renderer.render(scene, camera))


    if __name__ == "__main__":
        print(__doc__)
        loop.run()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.295 seconds)


.. _sphx_glr_download__gallery_validation_validate_image_colormap.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: validate_image_colormap.ipynb <validate_image_colormap.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: validate_image_colormap.py <validate_image_colormap.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: validate_image_colormap.zip <validate_image_colormap.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_

.. only:: html

    Interactive example
    -------------------

    Try this example in your browser using Pyodide. Might not work with all examples and all devices. Check the output and your browser's console for details.

    .. raw:: html

        <iframe src="./../pyodide.html#validate_image_colormap.py"></iframe>