5. The display controller

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The controller is an interactive panel bound to an fmridisplay object. Because fmridisplay is a handle class whose layers remember their source and options, the controller can re-threshold, recolor, and re-render every view — montages and surfaces — live. Every control has a one-line command-line equivalent, and the controller echoes that line to the command window when you use it. So you can work by clicking or by scripting, interchangeably.

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5.1 Build a composite and open the controller

Put a montage and a surface on one object, add a second blob layer, then open the controller:

obj     = load_image_set('emotionreg', 'noverbose');
t       = threshold(ttest(obj), .05, 'unc');
tstrict = threshold(ttest(obj), .001, 'unc');

o = canlab_results_fmridisplay(t, 'compact2', 'noverbose');  % montage
o = surface(o, 'foursurfaces');                              % + surface, same object
o = addblobs(o, region(tstrict), 'color', [0 .4 1]);        % 2nd layer (solid blue)

controller(o);

The controller shows one panel per blob layer, plus global buttons at the bottom:

The montage and surface it drives:

Montage	Surface

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5.2 What each control does — and its command-line twin

Per-layer panel:

Control	What it does	Command-line equivalent
Color stripe + numeric labels	Shows the layer's colormap and value limits (the legend).	— (reflects the current colormap)
Opacity slider	Blends the layer with what's beneath it.	set_opacity(o, value, 'layers', k)
Threshold slider + box	Re-thresholds from retained source; p-value (log scale) for stat images, |x| for masks.	rethreshold(o, p, 'unc', 'layers', k)
Colors dropdown	Pick a colormap: split (hot/cool, mango), warm/cool ramps, perceptual (viridis, inferno, turbo…), indexed (atlas), or solid.	set_colormap(o, …, 'layers', k)
Color swatch (click)	Opens a color picker for a solid color.	set_colormap(o, 'color', [r g b], 'layers', k)
Visible checkbox	Hides/shows the layer (lower layers show through on surfaces).	(layer visible flag)
Remove layer	Deletes the layer from all views.	remove_layer(o, k) / removeblobs(o)

Global footer:

Button	Action	Command line
Re-render	Redraw all layers on all views.	refresh(o)
Toggle legend	Put/remove colorbar legends on the montage & surface figures.	remove_legend(o)

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5.3 Command line and GUI are the same thing

Anything you do in the panel you can script, and the object updates every view in place. These two command-line actions — recolor layer 1 to mango, and make layer 2 half-transparent — are exactly what dragging the dropdown and the opacity slider would do:

set_colormap(o, 'splitcolor', {[.5 0 1] [0 .8 .3] [1 .2 1] [1 1 .3]}, 'layers', 1);
set_opacity(o, 0.4, 'layers', 2);

Controller after the change	Montage after the change

Layer 1 is now mango; layer 2's blue blobs are translucent, letting layer 1 show through. The montage updated without redrawing the underlay, and the surface (not shown) updated identically — one object, all views in sync.

Tip. Change a layer from the command line while its controller is open and the panel refreshes to match — the controller always reflects the object's true state. Conversely, the controller echoes the equivalent code to the command window, which is a good way to learn the scripting API.

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5.4 Composing views: multiview

multiview lays a canonical multi-panel composition (any montage type) onto an existing object and renders its current layers there — handy for building a full figure from a display you were exploring interactively:

o = multiview(o, 'full');   % re-compose this object's blobs onto the 'full' layout

The full catalog of layouts and surfaces

It's worth having one place that lists everything you can compose. There are three families:

Montage sets — pass to canlab_results_fmridisplay(t, set), montage(t, set), or multiview(o, set):

Set	Layout
'compact'	Default: midline sagittal + two axial rows.
'compact2'	Single row: sagittal + axials.
'full'	All 3 planes + 4 cortical surfaces.
'full hcp'	full with HCP surfaces and subcortical volumes.
'multirow'	Several compact2 rows stacked, to compare maps.
'regioncenters'	One axis per region, centered on each blob.
'subcortex compact' / 'subcortex 3d'	Subcortical-focused layouts.

You can also build a montage set by hand with fmridisplay.montage — choosing orientation, slice range, and spacing yourself (see §2.6).

Whole-brain surface layouts — pass to surface(t, layout): 'foursurfaces', 'foursurfaces_hcp', 'inflated surfaces', 'flat surfaces', 'insula surfaces', 'multi_surface', plus the cutaways ('coronal_slabs_4', 'left_cutaway', …).

Surfaces and composites for building custom 3‑D scenes with addbrain — the full list of hemispheres, subcortical structures, and composites ('limbic', 'basal ganglia', 'thalamus_group', …) is catalogued in §3.6 The surface catalog.

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