Click events for GUI images

[brentyi]

Screen.Recording.2025-01-31.at.12.26.34.AM.mov

import numpy as np
import viser

server = viser.ViserServer()

# Create an empty image + add it to the GUI.
image = np.zeros((150, 300, 3), dtype=np.uint8)
image_handle = server.gui.add_image(image)
remove_button = server.gui.add_button("Remove click callback forever")

# Draw red squares at clicked locations.
@image_handle.on_click
def _(_):
    x, y = image_handle.clicked_xy
    assert 0 <= x <= 1.0
    assert 0 <= y <= 1.0

    # Scale click to image coordinates.
    h, w, _ = image.shape
    x = int(x * w)
    y = int(y * h)

    # Update the image.
    image[y - 5 : y + 5, x - 5 : x + 5] = (255, 0, 0)
    image_handle.image = image

# Remove callback when button is clicked.
@remove_button.on_click
def _(_) -> None:
    image_handle.remove_click_callback()
    remove_button.label = "Click callback removed!"
    remove_button.color = "green"

server.sleep_forever()