Layer stack¶

Icon Symmetry Radial

Presentation¶

The Layer Stack operator in the Layer Editor is a mix operator that allows stacking Layers in the desired order.
Each integrated element is connected to an entry in the Layer Stack, where its opacity and blending mode can be adjusted.

It is possible to use a single Layer Stack for the entire drawing, or, when working with multiple layers, several Layer Stacks can be used for better organization.

Example:

Little Witch

The Layer Stack operator¶

Layer Stack operator

Clicking on the Layer Stack icon opens a menu, allowing:

Duplicate the entire Layer Stack
Duplicate the Layer Stack as a single flattened layer

Quick actions icons¶

Quick action icons

These icons allow direct addition to the Layer Stack:

If at least one layer is selected, a mask operator, another Layer Stack, or deletion of the selected layer(s) can be integrated.
A new layer, even if no layer is selected.

Layer stack input¶

Rename a Layer¶

Each input can be renamed by double-clicking on it, which will also rename the connected operator.

Display or Hide a Layer¶

Clicking the icon in front of the layer preview allows displaying or hiding the layer.

Expand Layer Stack Input¶

When a Layer Stack input is accessible, it can be expanded to reveal the connected operator inside. By default, the operator displays with normal blending and 100% opacity.

Input settings¶

The settings can be adjusted directly within each input of the Layer Stack or accessed through the Layer Operator Properties panel.

Blending¶

In a Layer Stack, blending refers to how the colors of one layer combine with those of the layers below it to create a specific visual effect.

Each blending mode alters the way the pixels of the selected layer interact with those of other layers, adjusting aspects like brightness, contrast, and saturation to achieve different looks. For example, the "multiply" mode darkens the image, while "overlay" enhances contrast by blending the colors.

Blending modes

Opacity¶

Opacity controls the transparency of a layer, determining how much of the underlying layers are visible.

At 100% opacity, the layer is fully opaque and completely covers the layers beneath it.
As the opacity decreases, the layer becomes more transparent, allowing the colors and details of the lower layers to show through.
At 0%, the layer is fully transparent and completely invisible, although it remains in the stack.

This is useful for blending elements together subtly or gradually fading certain aspects of a design.

Selection Modes¶

Single Layer Selection¶

To select a layer, simply click on it once. The selected layer will be highlighted, and its preview will be surrounded by white brackets (indicating that this is the layer where drawing will occur).

Group Selection¶

There are two ways to make a group selection:

Use a selection frame starting from outside the stack, which will select a group of layers within the stack.
Click on a layer and hold the Shift key to select another layer in the list; all layers in between will also be selected.

Multi-Layer Selection¶

Individual inputs can be selected by holding the Ctrl key and clicking on the desired layers to select multiple inputs.

Contextual menu

Right-clicking on a selection opens a contextual menu.

Common actions include Copy, Cut, Paste, Duplicate as Layer, and Delete.
Merge Layers consolidates all selected layers in the stack into a single layer, while Merge Visible Layers only merges those that are both selected and visible.

Note: If a merge includes operators connected to the stack externally, an image will be generated in the stack at the time of the merge, but the external operators will remain intact, although disconnected from the stack.

Layer Stack Interactions¶

Reorder in the Layer Stack¶

To change the order of layers within the Layer Stack, drag the selected layer to the highlighted line and release it. Blending and opacity settings linked to the input will be preserved.

Connect an Operator¶

Simply drag the operator's link and drop it into the Layer Stack input to connect it.

Extract Operator¶

Dragging a layer outside the Layer Stack sets it aside and removes it from the drawing. In this case, its blending and opacity values disappear. However, if it is moved directly to another Layer Stack, these values will be preserved.

Connected Extract¶

Holding the Ctrl key while dragging an entry out of the Layer Stack allows the layer to be removed while remaining connected to the Layer Stack input, retaining the blending and opacity values. This is useful for quick access or for connecting the layer to another operator.

Properties¶

The properties are visible in the Layer Operator Properties panel.

When selecting the Layer Stack, only its preview and the number of layers it contains are displayed.
If, for example, another Layer Stack is connected, it will be treated as a single layer.

Layer stack property

When selecting an input, the connected operator, along with its default blending mode set to normal and opacity at 100%, will be displayed.
In the following example, the layer is another Layer Stack with 3 layers.

Layer stack property with a layer stack connected

And in this case, it is a single drawing layer with a blending mode set to multiply and an opacity of 46%.

Layer stack property with a simple layer connected