Visualization

Classes for plotting, drawing, and displaying images and video.

Figures

class mytk.figures.Figure(figure=None, figsize=None)

Bases: Base

Wrapper around matplotlib Figure for embedding plots in tkinter.

is_environment_valid()

Check that matplotlib is installed and importable.

create_widget(master)

Create the matplotlib canvas and navigation toolbar.

property figure

The underlying matplotlib Figure.

property first_axis

The first axes of the figure, or None if unavailable.

property axes

All axes of the figure, or None if the figure is not set.

styles_pointmarker(linestyle='')

Return a list of point-marker style dictionaries for plotting.

styles_points_linemarkers(linestyle='-')

Return a list of point-and-line marker style dictionaries for plotting.

class mytk.figures.XYPlot(figsize)

Bases: Figure

Simple XY line plot backed by matplotlib.

create_widget(master, **kwargs)

Create the plot widget and draw the initial plot.

clear_plot()

Clear all data and redraw the plot.

update_plot()

Redraw the plot with the current data.

append(x, y)

Append a data point to the plot.

class mytk.figures.Histogram(figsize)

Bases: Figure

Histogram plot backed by matplotlib and numpy.

is_environment_valid()

Check that matplotlib and numpy are installed and importable.

create_widget(master, **kwargs)

Create the histogram widget and draw the initial plot.

clear_plot()

Clear all histogram data and the axes.

update_plot()

Redraw the histogram with the current data.

CanvasView

class mytk.canvasview.CanvasView(width=200, height=200, **kwargs)

Bases: Base

Tkinter Canvas wrapper with coordinate system support.

property relative_basis

A dynamic basis that tracks the current canvas size.

create_widget(master, **kwargs)

Create the underlying tkinter Canvas widget.

property is_disabled

Whether the canvas and its children are disabled.

on_resize(event)

Handle canvas resize events and post a notification.

place(element, position=None)

Place a CanvasElement on the canvas at the given position.

element(id)

Return the CanvasElement with the given id, or None.

save_to_pdf(filepath, bbox=None, **kwargs)

Export the canvas content to a PDF file via PostScript conversion.

class mytk.canvasview.CanvasElement(basis=None, **kwargs)

Bases: object

Base class for drawable elements on a CanvasView.

itemconfigure(**kwargs)

Configure options on the underlying canvas item.

property coords

The current coordinates of this element on the canvas.

property tags

The tags associated with this element on the canvas.

add_tag(tag)

Add a tag to this element.

add_group_tag(tag)

Add a group tag to this element.

move_by(dx, dy)

Move this element by the given pixel offsets.

create(canvas, position)

Create the element on the canvas. Override in subclasses.

class mytk.canvasview.Rectangle(size: (<class 'int'>, <class 'int'>), basis=None, position_is_center=True, **kwargs)

Bases: CanvasElement

A rectangle element for drawing on a CanvasView.

create(canvas, position=None)

Create the rectangle on the canvas and return its id.

class mytk.canvasview.Oval(size: (<class 'int'>, <class 'int'>), basis=None, position_is_center=True, **kwargs)

Bases: CanvasElement

An oval element for drawing on a CanvasView.

create(canvas, position=None)

Create the oval on the canvas and return its id.

class mytk.canvasview.Line(points=None, basis=None, **kwargs)

Bases: CanvasElement

A line element connecting a series of points on a CanvasView.

create(canvas, position=None)

Create the line on the canvas and return its id.

class mytk.canvasview.Arrow(start=None, end=None, **kwargs)

Bases: Line

A line with an arrowhead at the end.

class mytk.canvasview.CanvasLabel(font_size=20, basis=None, **kwargs)

Bases: CanvasElement

A text label element for drawing on a CanvasView.

create(canvas, position=None)

Create the text label on the canvas and return its id.

class mytk.canvasview.Arc(radius, basis=None, **kwargs)

Bases: CanvasElement

An arc element for drawing on a CanvasView.

create(canvas, position=None)

Create the arc on the canvas and return its id.

Data Views

class mytk.dataviews.DataPoint(size: float, **kwargs)

Bases: Oval

A circular data point drawn as an oval on a canvas.

class mytk.dataviews.Function(fct, xs, basis=None, **kwarg)

Bases: CanvasElement

A canvas element that draws a mathematical function as a polyline.

create(canvas, position=None)

Create the function polyline on the given canvas.

class mytk.dataviews.XYCoordinateSystemElement(size=None, normalized_size=None, axes_limits=((0, 1), (0, 1)), **kwargs)

Bases: CanvasElement

An XY coordinate system with axes, ticks, and labels drawn on a canvas.

property basis

Compute the coordinate basis from axes limits and canvas size.

create(canvas, position=None)

Create the full coordinate system on the given canvas.

create_x_axis(origin=None)

Draw the positive and negative x-axis arrows on the canvas.

create_y_axis(origin=None)

Draw the positive and negative y-axis on the canvas.

x_major_ticks()

Return a list of nicely spaced major tick values for the x-axis.

y_major_ticks()

Return a list of nicely spaced major tick values for the y-axis.

create_x_major_ticks(origin=None)

Draw major tick marks along the x-axis.

create_x_major_ticks_labels(origin=None)

Draw numeric labels below each x-axis major tick.

create_y_major_ticks(origin=None)

Draw major tick marks along the y-axis.

create_y_major_ticks_labels(origin=None)

Draw numeric labels beside each y-axis major tick.

place(element, position)

Place an element at a data-coordinate position within this coordinate system.

mytk.dataviews.nice_number(x, round_to_nearest=True)

Rounds or ceilings the number x to a ‘nice’ value, which is one of 1, 2, or 5 times a power of 10.

mytk.dataviews.get_nice_ticks(x_min, x_max, num_ticks=5)

Generate ‘nice’ tick marks for the axis spanning from x_min to x_max.

Images

class mytk.images.Image(filepath=None, url=None, pil_image=None)

Bases: Base

Widget for displaying a PIL image in a tkinter label.

property width

The width of the source PIL image in pixels.

property height

The height of the source PIL image in pixels.

property displayed_width

The width of the currently displayed image in pixels.

property displayed_height

The height of the currently displayed image in pixels.

is_environment_valid()

Check that Pillow and its submodules are installed and importable.

read_pil_image(filepath=None, url=None)

Load a PIL image from a local file path or a URL.

observed_property_changed(observed_object, observed_property_name, new_value, context)

Handle changes to observed properties such as is_rescalable.

create_widget(master)

Create a tkinter Label widget to display the image.

event_resized(event)

Resize the image if is_rescalable, throttling to avoid infinite loops.

resize_image_to_fit_widget()

Resize the PIL image to fit the parent grid cell while preserving aspect ratio.

update_display(image_to_display=None)

Update the widget to show the given image, or the source image if None.

class mytk.images.ImageWithGrid(filepath=None, url=None, pil_image=None)

Bases: Image

Image widget with an optional grid overlay drawn on top.

observed_property_changed(observed_object, observed_property_name, new_value, context)

Handle changes to grid visibility or grid count.

update_display(image_to_display=None)

Update the widget, adding a grid overlay if enabled.

image_with_grid_overlay(pil_image)

Return a copy of the image with grid lines drawn on it.

class mytk.images.DynamicImage(width=200, height=200)

Bases: CanvasView

Canvas-based image that can be redrawn dynamically.

draw_canvas()

Draw the canvas contents. Override in subclasses.

VideoView

class mytk.videoview.VideoView(device=0, zoom_level=3, auto_start=True)

Bases: Base

Live video capture and display widget backed by OpenCV.

is_environment_valid()

Check that OpenCV and Pillow are available, installing them if needed.

signal_handler(sig, frame)

Handle SIGINT to stop capture gracefully before propagating.

classmethod available_devices()

Return a list of indices for available video capture devices.

create_widget(master)

Create the label widget used to display video frames.

property is_running

Return True if video capture is currently active.

property startstop_button_label

Return the appropriate label for the start/stop button.

start_capturing()

Open the video device and begin reading frames.

stop_capturing()

Release the video device and cancel scheduled display updates.

start_streaming(filepath)

Begin writing captured frames to a video file at the given path.

stop_streaming()

Stop writing frames and release the video writer.

update_display(readonly_frame=None)

Read the next frame, update the display widget, and schedule the next refresh.

update_histogram()

Recompute and redraw the per-channel histogram from the current image.

create_behaviour_popups()

Create a popup menu listing available camera devices.

create_behaviour_buttons()

Create start/stop, save, and stream buttons with their callbacks.

bind_button_to_startstop_behaviour(button)

Bind a button to toggle video capture on and off.

bind_button_to_save_behaviour(button)

Bind a button to save the current frame as an image file.

bind_button_to_stream_behaviour(button)

Bind a button to start streaming frames to a video file.

bind_popup_to_camera_selection_behaviour(popup)

Bind a popup menu to switch the active camera device.

click_start_stop_button(event, button)

Toggle capture and update the button label accordingly.

click_save_button(event, button)

Prompt the user for a filename and save the current frame.

click_stream_button(event, button)

Prompt for a filename and begin streaming frames to an AVI file.

camera_selection_changed(index)

Switch capture to a different camera device by index.

prop_ids()

Print all major OpenCV capture properties to stdout.

get_prop_id(prop_id)

Return the value of an OpenCV capture property, or None if not capturing.

Common prop_id constants include CAP_PROP_FRAME_WIDTH, CAP_PROP_FRAME_HEIGHT, CAP_PROP_FPS, CAP_PROP_FOURCC, and CAP_PROP_CONVERT_RGB.

Indicators

class mytk.indicators.NumericIndicator(value_variable=None, value=0, format_string='{0}')

Bases: Base

A label that displays a formatted numeric value from a tkinter variable.

create_widget(master)

Create the label widget and display the initial value.

value_updated(var, index, mode)

Callback triggered when the value variable changes.

update_text()

Format the current value and update the label text.

class mytk.indicators.BooleanIndicator(diameter=15)

Bases: CanvasView

A colored circle indicator that is green when True and red when False.

create_widget(master, **kwargs)

Create the canvas widget and draw the initial indicator.

value_updated(var, index, mode)

Callback triggered when the boolean variable changes.

draw_canvas()

Draw the indicator circle with the appropriate color.

class mytk.indicators.Level(maximum=100, width=200, height=20)

Bases: CanvasView

A horizontal bar indicator that fills proportionally to a value.

create_widget(master, **kwargs)

Create the canvas widget and draw the initial level bar.

value_updated(var, index, mode)

Clamp the value to the valid range and redraw the bar.

draw_canvas()

Draw the level bar reflecting the current value.