Image Canvas

ImageCanvas displays a numpy image in a dedicated 2D scene with a y-down pixel frame (1 unit = 1 pixel), and lets you draw overlays in pixel coordinates, swap in custom GLSL shaders, and bind mouse drag/click interaction.

Topics

Guide	What you will learn
Image Canvas	ImageCanvas/ImageData, the pixel frame, overlays, scene_view()
Custom Shaders	register_shader/register_uniform/set_uniform, the GLSL contract
Interaction	DragBinding/ClickBinding, drag/click handlers, cursors, ActRectangle2D
Image transport	codec/jpeg_quality, JPEG vs lossless zlib, when to use which
Tiled images	register_image_pyramid, tile pyramids for very large images
Image streams	register_camera_stream, 15–30 Hz MJPEG camera feeds

Runnable examples

• py/examples/viz/image/image_canvas.py — gradient with a rectangle overlay and a ctrl+drag brightness/contrast handler.
• py/examples/viz/image/custom_shader_rgb_rotate.py — a custom fragment shader that rotates each pixel's RGB vector, driven by a drag uniform.
• py/examples/viz/image/rectangle_labeling.py — a toolbar button arms a drag-to-draw rectangle mode (ActRectangle2D).
• py/examples/viz/image/standard_image.py — an 8-bit image over the default (JPEG) transport.
• py/examples/viz/image/raw_image.py — a 16-bit image over the lossless (zlib) transport.
• py/examples/viz/image/huge_image.py — a programmatic noise image served as a tile pyramid.
• py/examples/viz/camera/camera_stream.py — a 30 Hz MJPEG camera feed.