Add Scalar Bar Range Dialog with clim preservation across time steps

[eskandarih]

Summary

Adds a new Scalar Bar Range dialog for customizing scalar bar color ranges, with manual min/max editing and automatic range computation across all time steps. Also fixes a critical issue where changing time steps would reset the scalar bar range, and fixes vector glyph rendering.

New Features

Scalar Bar Range Dialog (scalar_bar_range_dialog.py)

• Non-modal dialog accessible from a new "Scalar Bar Range" toolbar action (adjacent to existing "Scalar Bars" action)
• Displays one group per active scalar bar with:
  • Read-only scalar bar name label
  • Min / Max QDoubleSpinBox editors for manual range control
  • "Auto From All Time Steps" button that scans all time points to find the global min/max
• Auto button shows a confirmation warning before scanning (potentially long operation)
• OK applies and closes; Apply applies without closing; Cancel restores original ranges

clim Preservation Across Time Steps

• _plot_scalar_field(): Before re-plotting, reads the existing scalar bar's lookup table range and passes it as clim to add_mesh(). On first render (no scalar bar yet), clim=None lets PyVista auto-compute.
• _plot_vector_field(): Same pattern — reads existing vector actor's mapper.scalar_range and injects as clim.
• This means manually-set or dialog-set ranges survive time step changes.

Bug Fixes

Vector glyph scalar_bar_args error

• Before: scalar_bar_args was incorrectly passed to block.glyph(), which doesn't accept it → TypeError: DataSetFilters.glyph() got an unexpected keyword argument 'scalar_bar_args'
• After: Moved scalar_bar_args to plotter.add_mesh() where it belongs

Vector glyph scalar bar source registration

• _plot_vector_field() now registers the glyph's active scalars name (e.g., "GlyphScale") as a scalar bar source mapped back to the original vector array. This allows the Scalar Bar Range dialog to resolve vector plot scalar bars.

Duplicate method removal

• Removed duplicate _open_scalar_bar_settings_dialog() definition in qt_window.py

Plotter Helpers Added (plotter.py)

Method	Purpose
_register_scalar_bar_source()	Tracks how a rendered scalar bar maps to a mesh array + association
_range_from_array()	Computes finite scalar range for scalar or vector arrays
_infer_scalar_bar_source()	Fallback inference from _scalar_props, _contour_props, _vector_props
_resolve_scalar_bar_source()	Returns registered or inferred source, raises if not found
_current_scalar_range()	Computes visible min/max for current time step
get_scalar_bar_ranges()	Reads live lookup table ranges from plotter.scalar_bars
compute_scalar_bar_data_range()	Sweeps all time points to find global min/max, restores original time
apply_scalar_bar_range()	Calls update_scalar_bar_range AND GetLookupTable().SetRange() explicitly
_iter_visible_blocks()	Yields only visibility-enabled blocks

New Toolbar Icons

• Blocks.svg, EditScalarBar.svg, EditScalarRange.svg, ScalarBar.svg

Tests

test_scalar_bar_range_dialog.py (6 tests)

• Apply range updates lookup table and plotter call
• Compute range scans all time steps and restores active time
• Dialog applies manual ranges
• Auto button updates fields (with monkeypatched Yes confirmation)
• Auto button stops when user declines (monkeypatched No)
• Cancel restores initial ranges

test_clim_preservation.py (5 tests)

• First render auto-computes clim (no existing actors)
• Manual range adjustment survives re-render with different mesh data
• Switching scalar name resets clim (no matching bar → auto-compute)
• Full render() path preserves clim across time step change
• Vector field preserves clim across re-render

All 11 tests pass.

[eskandarih]

Architecture & Workflow Documentation

---

_scalar_bar_sources Registry

_scalar_bar_sources is a dict[str, dict[str, str]] initialized in Plotter.__init__(). It acts as a lookup table that maps the name of a rendered scalar bar (as it appears in the PyVista plotter) back to the original mesh data source that produced it.

Structure:

_scalar_bar_sources = {
    "Temperature": {"array_name": "Temperature", "association": "point"},
    "GlyphScale":  {"array_name": "B",           "association": "point"},
}

This registry exists because scalar bar names don't always match the source array. For example, PyVista's glyph() filter renames the active scalars to "GlyphScale" — without this mapping, the dialog would not know which mesh array to scan when computing auto-range for a vector plot's scalar bar.

---

Source Resolution Chain

When the dialog needs to find the data source behind a scalar bar, it follows this resolution chain:

flowchart TB
    A["_resolve_scalar_bar_source(name)"]
    A --> B{"name in<br/>_scalar_bar_sources?"}
    B -- Yes --> C["Return cached source<br/>{array_name, association}"]
    B -- No --> D["_infer_scalar_bar_source(name)"]
    D --> E{"Check _scalar_props<br/>_contour_props<br/>_vector_props"}
    E -- "Match found in<br/>visible blocks" --> F["Cache result &<br/>return source"]
    E -- "No match" --> G["Raise ValueError"]

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---

Scalar Bar Range Dialog — Manual Edit Workflow

sequenceDiagram
    actor User
    participant Dialog as ScalarBarRangeDialog
    participant Plotter
    participant VTK as ScalarBar<br/>LookupTable

    User ->> Dialog: Open from toolbar
    Dialog ->> Plotter: get_scalar_bar_ranges()
    Plotter ->> VTK: scalar_bars[name]<br/>.GetLookupTable()<br/>.GetRange()
    VTK -->> Dialog: {name: (min, max)}
    Dialog ->> Dialog: Populate Min/Max spinboxes
    User ->> Dialog: Edit Min/Max & click Apply
    Dialog ->> Plotter: apply_scalar_bar_range(name, min, max)
    Plotter ->> VTK: update_scalar_bar_range(clim, name)
    Plotter ->> VTK: GetLookupTable().SetRange(min, max)

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---

Scalar Bar Range Dialog — Auto Range Workflow

sequenceDiagram
    actor User
    participant Dialog as ScalarBarRangeDialog
    participant Plotter

    User ->> Dialog: Click "Auto From<br/>All Time Steps"
    Dialog ->> Dialog: Show QMessageBox<br/>confirmation warning
    User ->> Dialog: Confirm Yes
    Dialog ->> Plotter: compute_scalar_bar_data_range(name)
    Plotter ->> Plotter: _resolve_scalar_bar_source(name)
    loop Each time step
        Plotter ->> Plotter: reader.set_active_time_point(t)
        Plotter ->> Plotter: _current_scalar_range(array, assoc)
    end
    Plotter ->> Plotter: Restore original time point
    Plotter -->> Dialog: (global_min, global_max)
    Dialog ->> Dialog: Update spinbox values

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---

Scalar Bar Range Dialog — Cancel / Restore Workflow

sequenceDiagram
    actor User
    participant Dialog as ScalarBarRangeDialog
    participant Plotter

    Note over Dialog: Initial ranges saved at open time
    User ->> Dialog: Click Cancel
    Dialog ->> Plotter: apply_scalar_bar_range(<br/>name, orig_min, orig_max)
    Note over Plotter: Original ranges restored

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---

Clim Preservation — Scalar Field

When the user changes the active time step, render() re-calls _plot_scalar_field(). Without clim preservation, the method would auto-compute new ranges — discarding any manual adjustment.

flowchart TB
    S1["_plot_scalar_field() called"]
    S1 --> S2{"name in<br/>plotter.scalar_bars?"}
    S2 -- Yes --> S3["existing_clim =<br/>scalar_bar<br/>.GetLookupTable()<br/>.GetRange()"]
    S2 -- No --> S4["existing_clim = None<br/>(first render)"]
    S3 --> S5["Loop over visible blocks"]
    S4 --> S5
    S5 --> S6["add_mesh(block,<br/>clim=existing_clim)"]
    S6 --> S7["_register_scalar_bar_source(<br/>name, name, assoc)"]

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---

Clim Preservation — Vector Field

Vector fields follow the same pattern but read ranges from the actor's mapper instead of the scalar bar lookup table.

flowchart TB
    V1["_plot_vector_field() called"]
    V1 --> V2["Scan renderer.actors<br/>for keys starting with<br/>'vector_field'"]
    V2 --> V3{"Actor found?"}
    V3 -- Yes --> V4["clim =<br/>actor.mapper<br/>.scalar_range"]
    V3 -- No --> V5["clim not set<br/>(first render,<br/>auto-compute)"]
    V4 --> V6["block.glyph(...)<br/>to create glyphs"]
    V5 --> V6
    V6 --> V7["add_mesh(glyphs,<br/>clim=clim,<br/>scalar_bar_args=...)"]
    V7 --> V8["glyph_scalars_name =<br/>glyphs.active_scalars_name"]
    V8 --> V9["_register_scalar_bar_source(<br/>glyph_scalars_name,<br/>original_name, assoc)"]

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---

Method Reference

Method	Purpose
_register_scalar_bar_source(bar_name, array_name, assoc)	Stores the mapping from a rendered scalar bar name to its mesh array source
_range_from_array(values)	Computes finite (min, max) from scalar or vector (magnitude) arrays
_infer_scalar_bar_source(bar_name)	Fallback inference — searches _scalar_props, _contour_props, _vector_props against visible blocks
_resolve_scalar_bar_source(bar_name)	Returns cached source or falls back to inference; raises if neither works
_current_scalar_range(array_name, assoc)	Computes visible (min, max) across all visible blocks for the current time step
get_scalar_bar_ranges()	Reads live lookup table ranges from all active scalar bars
compute_scalar_bar_data_range(bar_name)	Iterates all time steps, calls _current_scalar_range at each, returns global (min, max)
apply_scalar_bar_range(bar_name, min, max)	Updates both the plotter scalar bar range and the VTK lookup table
_iter_visible_blocks(skip_empty)	Yields blocks that are currently set to visible (used by range computation)