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

.. only:: html

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

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

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

.. _sphx_glr_gallery_imgui_cmap_picker.py:


ImGui cmap picker
-----------------


Imgui example that shows how to create a colormap picker menu

Uses the cmap library: https://github.com/tlambert03/cmap

pip install cmap

Instead of using the cmap library you can create 2D arrays in
the shape [2, 255, 3] that represent the LUT for the colormap

.. GENERATED FROM PYTHON SOURCE LINES 15-123

.. code-block:: Python


    # run_example = false

    import numpy as np

    import wgpu
    from imgui_bundle import imgui
    from rendercanvas.auto import RenderCanvas, loop
    from wgpu.utils.imgui import ImguiRenderer

    from cmap import Colormap

    # Create a canvas to render to
    canvas = RenderCanvas(
        title="imgui", size=(512, 256), max_fps=60, update_mode="continuous"
    )

    # Create a wgpu device
    adapter = wgpu.gpu.request_adapter_sync(power_preference="high-performance")
    device = adapter.request_device_sync()

    imgui_renderer = ImguiRenderer(device, canvas)


    def create_texture_and_upload(data: np.ndarray) -> int:
        # crates a GPUTexture and uploads it

        # create a GPUTexture
        texture = device.create_texture(
            size=(data.shape[1], data.shape[0], 4),
            usage=wgpu.TextureUsage.COPY_DST | wgpu.TextureUsage.TEXTURE_BINDING,
            dimension=wgpu.TextureDimension.d2,
            format=wgpu.TextureFormat.rgba8unorm,
            mip_level_count=1,
            sample_count=1,
        )

        # upload to the GPU
        device.queue.write_texture(
            {"texture": texture, "mip_level": 0, "origin": (0, 0, 0)},
            data,
            {"offset": 0, "bytes_per_row": data.shape[1] * 4},
            (data.shape[1], data.shape[0], 1),
        )

        # get a view
        texture_view = texture.create_view()

        # register the texture with backend
        return imgui_renderer.backend.register_texture(texture_view)


    # list of colormaps that we will display in the picker
    cmaps = ["viridis", "plasma", "turbo", "spring", "winter", "bwr", "gnuplot2"]
    cmap_data = dict()


    # creates texture for each colormap, uploads to the GPU, stores ids so we can display them in imgui
    for name in cmaps:
        # creates LUT
        data = Colormap(name)(np.linspace(0, 1)) * 255

        # vstack it so we have 2 rows to make a Texture, an array of shape [2, 255, 3], [rows, cols, RGB]
        tex_ref = create_texture_and_upload(np.vstack([[data]] * 2).astype(np.uint8))

        # store the texture
        cmap_data[name] = tex_ref


    current_cmap = cmaps[0]


    def update_gui():
        global current_cmap

        imgui.set_next_window_size((175, 0), imgui.Cond_.appearing)
        imgui.set_next_window_pos((0, 20), imgui.Cond_.appearing)

        imgui.begin("window", None)

        # make the cmap images display height similar to the text height so that it looks nice
        texture_height = imgui.get_font_size() - 2

        # add the items for the picker
        for cmap_name, tex_ref in cmap_data.items():
            # text part of each item
            _clicked, enabled = imgui.menu_item(
                cmap_name, "", p_selected=current_cmap == cmap_name
            )
            imgui.same_line()
            # the image part of each item, give it the texture id
            imgui.push_style_color(imgui.Col_.border, (1.0, 1.0, 1.0, 1.0))
            imgui.push_style_var(imgui.StyleVar_.image_border_size, 1.0)
            imgui.image(tex_ref, image_size=(50, texture_height))
            imgui.pop_style_var()
            imgui.pop_style_color()
            if enabled:
                current_cmap = cmap_name

        imgui.end()


    imgui_renderer.set_gui(update_gui)


    if __name__ == "__main__":
        canvas.request_draw(imgui_renderer.render)
        loop.run()


.. _sphx_glr_download_gallery_imgui_cmap_picker.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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