Saving / Displaying Images

draw

draw(clear_buffer: bool = False) -> 'Gw'

Draw the visualisation to the raster surface. Caches state for using with interactive functions.

Creates the raster surface if it doesn’t exist yet.

Parameters:

  • clear_buffer (bool): Clears any buffered reads before re-drawing

Returns:

  • Gw: Self for method chaining

draw_image

draw_image() -> Image.Image

Draw the visualisation and return it as a PIL Image.

Returns:

  • PIL.Image: The visualisation as a PIL Image

Raises:

  • ImportError: If Pillow could not be imported

Example:

# Get the visualisation as a PIL Image
img = gw.draw_image()
img.save("output.png")

show

show() -> None

Convenience method for showing the image on screen. Equivalent to gw.draw_image().show()

Raises:

  • ImportError: If Pillow could not be imported

save_png

save_png(path: str) -> 'Gw'

Draws and saves the raster canvas to a PNG file.

Parameters:

  • path (str): Path to save the PNG file

Returns:

  • Gw: Self for method chaining

Example:

gw.save_png("visualisation.png")

save_pdf

save_pdf(path: str) -> 'Gw'

Draws and saves a PDF file using the current configuration.

Parameters:

  • path (str): Path to save the PDF file

Returns:

  • Gw: Self for method chaining

Example:

gw.save_pdf("visualization.pdf")

save_svg

save_svg(path: str) -> 'Gw'

Saves an SVG file using the current configuration.

Parameters:

  • path (str): Path to save the SVG file

Returns:

  • Gw: Self for method chaining

Example:

gw.save_svg("visualization.svg")

encode_as_png

encode_as_png(compression_level: int = 6) -> Optional[bytes]

Encode the current canvas as PNG and return the binary data.

Parameters:

  • compression_level (int): PNG compression level (0-9)

Returns:

  • bytes or None: PNG encoded image data or None if the raster surface hasn’t been created

encode_as_jpeg

encode_as_jpeg(quality: int = 80) -> Optional[bytes]

Encode the current canvas as JPEG and return the binary data.

Parameters:

  • quality (int): JPEG quality (0-100)

Returns:

  • bytes or None: JPEG encoded image data or None if the raster surface hasn’t been created

Raises:

  • RuntimeError: If image encoding failed

array

array() -> Optional[np.ndarray]

Convert the pixel data to a numpy array using zero-copy interface.

Returns:

  • numpy.ndarray or None: RGBA image data as a 3D numpy array (height × width × 4) or None if the raster surface hasn’t been created

Example:

# Get the visualization as a numpy array
img_array = gw.draw().array()

make_raster_surface

make_raster_surface(width: int = -1, height: int = -1) -> 'Gw'

Create a raster surface for rendering. This is usually called automatically by drawing functions if needed, but can be called explicitly to pre-allocate the rendering surface.

Parameters:

  • width (int, optional): Width of the raster surface. If -1, uses the current canvas width.
  • height (int, optional): Height of the raster surface. If -1, uses the current canvas height.

Returns:

  • Gw: Self for method chaining

Raises:

  • RuntimeError: If the raster surface could not be created

Example:

# Explicitly create a raster surface
gw.make_raster_surface(1200, 800)