Chalkcast

Start a project session and make it the current one (later calls without project_id target it). quality: low (480p) | medium (720p) | high (1080p). fps: frame rate, default 15/30/60 for low/medium/high. theme: chalkboard|whiteboard|dark.

Current project state: scenes, objects, steps, parameters and open obligations.

Release a project session (default: the current one). If others are open, the most recently opened becomes current; the result names it.

Append a scene to the project; it becomes the default target of later calls without scene_id. The title is a label for you (it is not drawn: use add_text).

Declare a continuous scene parameter (e.g. time t). Use it by name in plot expressions or shape anchors (expr='sin(x - t)'), then animate it smoothly with add_step(kind='tween', param=name, value=...). Curves, areas and anchored shapes that use it are redrawn every frame.

Add a LaTeX equation (math mode, e.g. tex=r'e^{i\pi}+1=0'). Dirac notation (\ket{n}, \bra{n}, \braket{a}{b}, \expval{A}) and physics macros work.

Add axes with functions of x. Each function: {'expr': 'sin(x)', 'color': 'YELLOW'}. Expressions use x, bare math functions (sin, exp, sqrt, sign, ...), np.<fn>, and declared scene parameters; they are validated now. Sampling is adaptive (dense, no spline overshoot on jumps, curves split at poles and clipped to the axes); optional overrides: 'smooth': bool, 'dx': step. x_label/y_label are LaTeX. Defaults: x_range [-5, 5, 1], y_range [-3, 3, 1]; a [min, max] range gets a readable tick step (4-8 ticks, starting at min, or at 0 if 0 is inside the range); the result echoes the ranges used. Curves without a color get distinct colors suited to the theme. The axes are centred at (x, y); labels hang off them. Without functions you get bare axes.

Add a title/label/callout (plain text, any language). The rendered size is font_size x scale.

Add primitive geometry: circle|square|rectangle|triangle|arrow|dot|line, centred at (x, y) (default 0, 0). size (default 1): circle = diameter, square = side, triangle = circumradius, dot = 10 x radius (minimum radius 0.05), line/arrow = length (horizontal). rectangle: width x height (default 1 x 0.5) instead of size. line/arrow: give x1,y1,x2,y2 for an explicit segment (any direction) instead of size/x/y. Anchor in a plot's coordinates with plot_id + at_x + at_y expressions instead of x/y (they may use scene parameters, so a dot can track <x>(t) while a tween runs). Arguments that do not apply to the chosen shape are rejected.

Shade the area between a plotted function and the x-axis on [x_min, x_max] (the integral). [x_min, x_max] must lie within the plot's x_range, y = 0 must be on the axes, and the function must be defined and inside y_range there (otherwise an error says what to widen). It follows its plot (move the plot, not it).

Riemann rectangles (left endpoints, fill opacity 0.6, one color) under a plotted function on [x_min, x_max] within the plot's x_range; (x_max - x_min)/dx must be a whole number, y = 0 must be on the axes and the function inside y_range there. Smaller dx = finer; transform coarse->fine to show convergence. They follow their plot.

Append a timed beat. kind: write|transform|highlight|fade|camera_move|wait|tween. write/highlight/fade: all targets animate together, over `duration` (a plot's axes and curves are drawn together; highlight is a brief 1.2x pulse in the theme's accent color). An object driven by a parameter cannot be written, highlighted or faded in the same beat as a tween of that parameter (Manim freezes it). transform: one target morphs into `to` (the target keeps its id afterwards). camera_move: zoom is absolute (1 = the full frame, 2 = twice as close); focus_x/ focus_y recentre the camera, omitted = keep the current centre. tween: animate scene parameter `param` to `value` continuously (linear in time). with_previous=true plays this step at the same time as the previous one (e.g. move a curve and a dot together); not after a wait. `note` is a label for you (not drawn). Arguments that do not apply to `kind` are rejected.

Change an existing object in place (only the fields you pass). Use it to reposition, rescale, recolor, retype text/LaTeX, replace plot functions or ranges, or adjust an area/Riemann interval -- no need to rebuild the scene. Explicit line/arrow segments move by their endpoints x1, y1, x2, y2. Everything is validated first: on error nothing changes. A plot's color is the default color of its curves without one (axes keep the theme ink). Areas, Riemann sums and anchored shapes follow their plot: move the plot instead.

Delete an object. If steps or other objects (areas, anchored shapes) depend on it, nothing is removed unless cascade=true, which also removes the dependent objects and takes the removed ids out of steps (a step left with nothing to animate is deleted; other targets of a shared step stay). The reply lists exactly what was deleted or changed, and any object left without a step.

Delete one step of the timeline (later steps are renumbered). A with_previous step that was joined to the removed one starts its own beat; it is listed in regrouped_steps.

Verify a scene WITHOUT rendering video (~1-2 s): builds the real Manim objects and measures them -- LaTeX/expression compile errors, off-screen objects, label collisions, curve fidelity (drawn vs true function), legibility, timing. Call it after authoring and fix what it reports before render_scene.

Automatically repair measured problems that have a mechanical fix: objects pushed back inside the frame, labels moved to the nearest free spot, curve sampling corrected, too-small text enlarged. Repeats measure->fix up to max_rounds, reports every change, and lists what still needs the author.

Render one scene to video + sampled frames, then run verification lanes. The scene is measured first; if it cannot compile, no render is attempted.

Fast single-still preview of a scene (last frame).

Export the latest render of a scene as a shareable GIF, resampled to `width` pixels wide at `fps` (defaults keep GIFs small). Blocked by open error obligations of that render and by edits made since it.

Which providers are present (Manim, LaTeX, ffmpeg, vision) and what degrades without each.

Takes no parameters.