OverlayRegistry

Overlay Registry #

Some tools draw over the network editor: bars above every operator, outlines, markers. This registry gives them one shared surface. Each tool renders its own image; the registry stacks them into one, fits it over the network you are looking at, and shows it above the nodes.

It follows the network editor you work in. Pan, zoom or open another network and the overlay follows. Everything stays where it belongs at any zoom, and lines stay sharp on high DPI screens.

Your network is left as it is: no display flag is switched, no annotation is dimmed, and the overlay is not one of your operators. It is taken out before every project save, so it never ends up in your file.

With nothing drawing, there is no overlay at all and nothing runs.

Tools that draw overlays install it with them. It is promoted to /sys (global shortcut op.FNS_OVERLAYREGISTRY), like the toolkit's other registries.

Widgets #

Tools can also pin a small panel you can click to a corner of the network editor, such as Cook Bar's Top List. A widget keeps its size on screen at any zoom and stays in its corner as you pan or change networks. Widgets in the same corner stack instead of overlapping.

Each tool sets its widget's corner and margin among its own parameters: the margin is how far the widget sits from the edges of the network editor, and from the widget before it when several share a corner.

Managing the overlay #

The Overlay tab of FNS_Hub lists every layer and every corner widget. Reorder them, hide one without switching its tool off, and move a widget to another corner or margin there. The settings stay with each tool, on its own parameters, so they travel with your other FNSTools settings.

For tool authors #

A tool hands over one TOP, its layer. The registry composites it with every other layer and shows the result. What the layer draws is entirely up to the tool.

To publish a layer, ship a small host copy of this registry in the tool. Its Registration page names the layer TOP (Layer TOP), a canonical name, its stacking order (Layer Order: higher draws on top), whether the user shows it (Displayed, a plain switch that never turns the tool off) and whether the tool is drawing (Layer Active, which follows the tool's Active unless you point it at something else). The layer is drawn only when both are on.

Pick the order by what the layer draws: 0 to 99 for fills and heat maps, 100 to 199 for marks on operators (Cook Bar's bars are 100), 200 to 299 for labels and text, 300 and up for cursors. Users can change it per tool with Layer Order on the tool's Registry page. From Python, op.FNS_OVERLAYREGISTRY.RegisterWidget(top, 'mytool', order=10) does the same, with UnregisterWidget('mytool') to take it out.

In return the registry tells the layer where it is drawing. Its View page holds the rectangle the overlay covers in network units (Viewx0, Viewy0, Viewx1, Viewy1), the resolution to render at (Resolutionw, Resolutionh), network units per pixel, pixels per screen point, the editor's zoom and the network being viewed. Bind a shader's uniforms and the layer's resolution to those parameters and the layer recooks only when the view moves. From Python, View() returns the same values as a dict, and NetworkToPixel(x, y) turns a network position into layer pixels.

Render the layer premultiplied and transparent wherever it draws nothing. It sits above the nodes, so leave the node tiles clear.

A widget is a panel COMP of your tool, shown at its own size: op.FNS_OVERLAYREGISTRY.RegisterPanelWidget(panel, 'mytool', anchor='topleft', order=100, margin=12) pins it to a corner (topleft, topright, bottomleft or bottomright), and UnregisterPanelWidget('mytool') takes it away. order places it in its corner's stack, lowest nearest the corner, using the same bands as layers. margin is its distance from the edges and from the widget before it, in screen points. Offer the corner and the margin as parameters of your tool and register again when they change. The whole panel takes clicks, so keep it small.