Migrating to 0.3.5

0.3.5 makes Tesserae Engine a small building-block engine: nodes, layout, paint, animation, events, text, accessibility, layers, and threading. Everything built from those blocks — declarative views, data binding and reactivity, the Material Design 3 widgets, theming, and file loading — now belongs to a framework built on Tesserae Engine, such as Tesserae. Every surviving name also takes one consistent form: window.create, node.set/get/on, and window.simulate.

It's a breaking release. Nothing is kept for compatibility; a removed name fails with Python's own AttributeError or ImportError.

Check a codebase first

Run your tests with TRE_FORBID_REMOVED=1 in the environment:

TRE_FORBID_REMOVED=1 python -m pytest

On 0.3.5, every name below that it removes or renames then raises an AttributeError naming its replacement, rather than Python's bare "has no attribute" — old property names too, in animate, get, get_target, and stop_animation, and animate's old positional on_complete. from tre import View fails with ImportError.

To find every use before upgrading, while the old names still work, copy tre/_removed.py into a project on 0.3.4 — it uses only names 0.3.4 has — and call its install() from conftest.py when TRE_FORBID_REMOVED=1 is set.

Moved to the framework

0.3.4	0.3.5
View (node, poll_reload, reconcile, set_stylesheet, set_theme, instantiate, click, hover, focus, right_click), Component, Window.from_view, Window.show_view	the framework's declarative layer; a screen is window.root.add_child(screen)
Signal, Computed, Effect, ViewModel, batch, untrack	the framework's reactivity
Theme, Window.theme, Window.set_theme	the framework's theming
The MD3 widget factories — add_button, add_icon_button, add_fab, add_extended_fab, add_segmented_button, add_chip, add_menu_item, add_badge, add_linear_progress, add_circular_progress, add_loading_indicator, add_time_picker_dial, add_card, add_divider, add_tooltip, add_dialog, add_snackbar, add_side_sheet, add_navigation_rail, add_navigation_drawer, add_top_app_bar, add_toolbar, add_split_button, add_button_group, add_tabs, add_search_bar, add_search_view, add_list_item, add_list, add_accordion_header, add_tree_node, add_date_picker_day, add_time_input_field, add_period_selector, add_popover, add_link, add_spin_box, add_pagination, add_status_bar, add_checkbox, add_radio_button, add_switch, add_slider, add_carousel, add_splitter, add_node_graph, add_graph_node	the framework's widgets, built from boxes, text, and paths
Their state — set_checked, get_checked, set_selected, get_selected, set_carousel_index, get_carousel_index, get_carousel_position, set_carousel_scroll, get_carousel_scroll, set_time_picker_dial_time, get_time_picker_dial_time, set_time_picker_dial_mode, get_time_picker_dial_mode — and their properties check_progress, select_progress, toggle_progress	the framework's own state and animation
build_menu, open_menu, close_menu, open_dialog, close_dialog, open_snackbar, close_snackbar, open_side_sheet, close_side_sheet, open_navigation_drawer, close_navigation_drawer, Node.set_context_menu	show_layer/hide_layer, and on("secondary_click") for a context menu
build_shell, begin_container_transform, end_container_transform	the framework's shell and transitions, with animate
Node.enable_interaction (the ripple and state layer)	the framework's hover and press feedback, from pointer_enter/pointer_leave/pointer_down
add_icon	a "path" node from the icon's SVG data
add_image(path)	decode the file yourself; an "image" node takes RGBA8 pixels
The MD3 named motion curves	cubic bezier values passed as animate(..., easing=(x1, y1, x2, y2))

Renamed

Creating nodes

window.create(kind, **props) makes a detached node; attach it with add_child — window.root.add_child(node) for a top-level one.

0.3.4	0.3.5
add_rect(background, width, height, x, y, border_color, border_width)	create("box", fill=, width=, height=, stroke_color=, stroke_width=); x/y with position="absolute"
add_text(content, foreground, ...)	create("text", text=, fill=, ...)
add_text_field(background, width, height, content, ...)	create("text_input", text=, ...) — a text input paints no box of its own: put it in a "box"
add_code_editor(content, ...)	create("text_input", text=, multiline=True, show_whitespace=True, font_family=MONOSPACE_FONT_FAMILY)
add_image_from_bytes(rgba, pixel_width, pixel_height, ...)	create("image", rgba=, pixel_width=, pixel_height=, ...)
add_video(...)	an "image" node; each frame is set(rgba=, pixel_width=, pixel_height=)
add_canvas(width, height, draw)	create("canvas", draw=, ...) — it draws when created
add_scroll_view(...)	create("scroll_view", ...)
add_virtual_list(...)	create("virtual_list", ...) — materialize(index) returns a node, and the list builds its visible rows itself
add_terminal(shell, cols, rows, background, ...)	create("terminal", shell=, cols=, rows=, palette={"background": ...})

Window

0.3.4	0.3.5
get_monospace_cell_size(font_size)	measure_text("M", font_family=MONOSPACE_FONT_FAMILY, font_size=)
resize_terminal(node, cols, rows)	terminal.set(cols=, rows=)
copy_terminal_selection()	terminal.get("selection"); Ctrl+Shift+C copies it
set_virtual_list_window(list, start, end)	nothing: a virtual list builds its visible rows
redraw_canvas(canvas)	canvas.redraw()
click, hover, focus, scroll, right_click, press_key, type_text, press_ctrl, copy, cut, paste, select_all	simulate — simulate("click", node=), ("pointer_move", node=), ("focus", node=), ("wheel", node=, delta_y=), ("secondary_click", node=), ("key_down", key=), ("input", text=), ("key_down", key="c", ctrl=True), ...
copy_to_system_clipboard, cut_to_system_clipboard, paste_from_system_clipboard	read_clipboard(), write_clipboard(text); a text input handles Ctrl+C/X/V/A itself
set_active_tab(side, index)	set_active_panel(side, index)
start_panel_drag(handle)	start_panel_drag(panel)
set_dock_handle, set_drop_zone_highlight, drag_panel_over, drop_panel_at	the framework draws the handle and highlight from the dock_target/dock_drop window events; simulate drives a drag

Node

0.3.4	0.3.5
set_layout(...)	set(...)
set_text(t)	set(text=t)
get_text()	get("text")
is_focused()	get("focused")
set_clip_children(b), set_syntax_spans(s), set_folded_ranges(r)	set(clip_children=), set(syntax_spans=), set(folded_ranges=)
set_terminal_selection(a, b, c, d)	set(selection=(a, b, c, d))
push_frame(rgba, width, height)	set(rgba=, pixel_width=, pixel_height=)
set_on_click, set_on_hover_enter, set_on_hover_exit, set_on_change, set_on_focus_enter, set_on_focus_exit	on("click"), on("pointer_enter"), on("pointer_leave"), on("change"), on("focus"), on("unfocus")

Properties

In animate, get, get_target, stop_animation, and set:

0.3.4	0.3.5
background, foreground	fill
border_color, border_width	stroke_color, stroke_width
corner_radii_override	corner_radius as a 4-tuple
elevation	shadows
transform	translate_x, translate_y, scale
rotation	rotation_deg
shape	a "path" node's data
value on a slider or progress indicator	the framework's own state; value stays the accessibility value

Events and the rest

0.3.4	0.3.5
Event.kind	Event.type
Event.node, Event.source	Event.target
Event.position	Event.window_x, Event.window_y
CanvasContext	Painter

Behavior changes

These keep their names but act differently:

• on("click") bubbles, to every ancestor's click listener, and doesn't make a node focusable: set focusable=True to put a node in the Tab order, where Enter and Space then fire click. set_on_click did both implicitly and fired on its own node only.
• set(text=...) fires no change — that event is for edits the user makes. set_text fired one.
• A canvas draws when it's created and when its draw is set, as well as on redraw(); add_canvas waited for the first redraw_canvas.
• A virtual list builds its own rows whenever layout runs, and releases the ones scrolled away; a materialize or size_hint that raises is logged and leaves its row empty rather than raising.
• A wheel over a terminal: a negative delta_y scrolls up into its history, as for any other scrollable node; window.scroll(terminal, 400) scrolled up.
• Ctrl+A in a text input selects all — it did nothing before.
• What an app copies stays on the clipboard while the app runs, with or without a clipboard manager.
• start_panel_drag raises ValueError for a node that isn't docked, instead of returning False.
• remove() keeps a node alive for reattaching; destroy() frees it — the 0.3.4 change, in case you're coming from 0.3.3.

Migration table

Every current public name, and what it becomes.

To check a codebase against it, run its tests with TRE_FORBID_REMOVED=1 set: every name below that 0.3.5 removes or renames then raises an AttributeError naming its replacement — old property names too, in animate and get, and animate's old positional on_complete. from tre import View fails with Python's own ImportError. The list lives in tre/_removed.py, kept in step with this table by tests/test_removed.py; the file uses only names 0.3.4 has, so a project pinned to 0.3.4 can copy it and call its install().

Window — creation

Today	Target
add_rect, Container kind	create("box")
add_text	create("text")
add_text_field, add_code_editor	create("text_input")
add_image_from_bytes, add_video	create("image"); frames via set(rgba=..., ...)
add_image(path)	removed (D6)
add_icon	create("path") (icon data from the app)
add_canvas	create("canvas")
add_scroll_view	create("scroll_view")
add_virtual_list	create("virtual_list")
add_terminal	create("terminal")
add_dock_zone	unchanged
add_button, add_icon_button, add_fab, add_extended_fab, add_segmented_button, add_chip, add_menu_item, add_badge, add_linear_progress, add_circular_progress, add_loading_indicator, add_time_picker_dial, add_card, add_divider, add_tooltip, add_dialog, add_snackbar, add_side_sheet, add_navigation_rail, add_navigation_drawer, add_top_app_bar, add_toolbar, add_split_button, add_button_group, add_tabs, add_search_bar, add_search_view, add_list_item, add_list, add_accordion_header, add_tree_node, add_date_picker_day, add_time_input_field, add_period_selector, add_popover, add_link, add_spin_box, add_pagination, add_status_bar, add_checkbox, add_radio_button, add_switch, add_slider, add_carousel, add_splitter, add_node_graph, add_graph_node	framework

Window — everything else

Today	Target
from_view, show_view	root.add_child(screen) (M96)
theme, set_theme	framework (D7)
build_menu, open_menu, close_menu, open_dialog, close_dialog, open_snackbar, close_snackbar, open_side_sheet, close_side_sheet, open_navigation_drawer, close_navigation_drawer	show_layer, hide_layer
build_shell, begin_container_transform, end_container_transform	framework
get_monospace_cell_size	measure_text
resize_terminal	terminal.set(cols=, rows=)
copy_terminal_selection	terminal.get("selection") + write_clipboard
click, hover, focus, scroll, right_click, press_key, type_text, press_ctrl, copy, cut, paste, select_all	simulate
copy_to_system_clipboard, cut_to_system_clipboard, paste_from_system_clipboard	read_clipboard, write_clipboard; text inputs handle the keys themselves
resize	unchanged
dock_panel	unchanged
set_active_tab	set_active_panel
start_panel_drag(handle)	start_panel_drag(panel)
set_dock_handle, set_drop_zone_highlight, drag_panel_over, drop_panel_at	removed; dock_target/dock_drop events and simulate
set_virtual_list_window	not needed: tre keeps the visible rows built (M96)
redraw_canvas(canvas)	canvas.redraw()

Node

Today	Target
animate(property, to, duration_ms, on_complete)	animate(name, to, duration_ms, easing, on_complete); plus stop_animation, get_target
get(property)	get(name)
set_layout(...), set_text, set_checked, set_selected, set_clip_children, set_syntax_spans, set_folded_ranges, set_terminal_selection	set(...)
get_text, get_checked, get_selected, is_focused	get("text"), get("focused"); checked/selected become framework state
set_on_click, set_on_hover_enter, set_on_hover_exit, set_on_change, set_on_focus_enter, set_on_focus_exit	on("click"), on("pointer_enter"), on("pointer_leave"), on("change"), on("focus"), on("unfocus")
set_context_menu	on("secondary_click") + show_layer
enable_interaction	framework (D8)
add_child	unchanged
remove	remove (now keeps the node alive, R5); destroy to free
push_frame	set(rgba=..., pixel_width=..., pixel_height=...) (R9)
set_carousel_index, get_carousel_index, get_carousel_position, set_carousel_scroll, get_carousel_scroll, set_time_picker_dial_time, get_time_picker_dial_time, set_time_picker_dial_mode, get_time_picker_dial_mode	framework

Properties

Today	Target
background, foreground	fill (R1)
border_color, border_width	stroke_color, stroke_width (R1)
corner_radii_override	corner_radius 4-tuple
elevation	shadows
transform (tuple)	translate_x, translate_y, scale
rotation (icons)	rotation_deg (every node)
shape (MD3 shape library)	a path's data
check_progress, select_progress, toggle_progress, value	framework-owned animation state
opacity, corner_radius, layout names	unchanged

Other

Today	Target
View (node, poll_reload, reconcile, set_stylesheet, set_theme, instantiate, click, hover, focus, right_click), Component (node, instantiate, remove)	removed; the declarative layer moves to the app layer (M98)
Theme (role, is_set, shape, elevation, typography)	removed; theming is the app's (D7)
Signal, Computed, Effect, ViewModel, batch, untrack	moved out of the engine (D5)
CanvasContext	Painter
Event.kind, Event.node, Event.source, Event.position	Event.type, Event.target; source goes (use target), and position becomes window_x/window_y (M100)
MD3 named motion curves	cubic bezier values (app code)
App, LoopHandle, register_font, MONOSPACE_FONT_FAMILY	unchanged