/// <summary>Returns list of all layer groups in correct z-order (Takes into account the fact that some of them are merged).</summary>
/// <returns>List of all layer groups in correct z-order.</returns>
public List <LayerGroup> GetLayerGroups()
{
var visited = new HashSet <GraphNode>();
var layerGroups = new List <LayerGroup>();
var mapping = new LayersIndexMapper();
var generator = new LayersIndexMapper.IndexGenerator();
// Topological sorting.
foreach (var node in nodes)
{
WalkGraph(node, visited, layerGroups, mapping, generator);
}
layerGroups = mapping.RemapLayerGroups(layerGroups);
return(layerGroups);
}
/// <summary>
/// Simple depth-first search for topological sorting.
/// </summary>
void WalkGraph(GraphNode node, HashSet <GraphNode> visited, List <LayerGroup> layerGroups, LayersIndexMapper mapping, LayersIndexMapper.IndexGenerator generator)
{
if (visited.Contains(node))
{
return;
}
visited.Add(node);
// If this node is merged with another node then we mark it as visited too.
if (node.MergedWithNode is not null)
{
visited.Add(node.MergedWithNode !);
}
foreach (var parent in node.Parents)
{
WalkGraph(parent, visited, layerGroups, mapping, generator);
}
if (node.MergedWithNode is not null)
{
foreach (var parent in ((GraphNode)node.MergedWithNode !).Parents)
{
WalkGraph(parent, visited, layerGroups, mapping, generator);
}
}
if (node.MergedGroup is not null)
{
// Remap indexes for matte layers.
if (node.Group.MatteLayer is not null)
{
int matteIndex = generator.GenerateIndex();
mapping.SetMapping(node.Group.MatteLayer !.Index, matteIndex);
mapping.SetMapping(node.MergedWithNode !.Group.MatteLayer !.Index, matteIndex);
}
// Remap indexes for main layers.
int index = generator.GenerateIndex();
mapping.SetMapping(node.Group.MainLayer.Index, index);
mapping.SetMapping(node.MergedWithNode !.Group.MainLayer.Index, index);
// Add merged layer group of current node to the result.
layerGroups.Add(node.MergedGroup !);
}
else
{
// Remap indexes for matte layers.
if (node.Group.MatteLayer is not null)
{
mapping.SetMapping(node.Group.MatteLayer !.Index, generator.GenerateIndex());
}
// Remap indexes for main layers.
mapping.SetMapping(node.Group.MainLayer.Index, generator.GenerateIndex());
// Add layer group of current node to the result.
layerGroups.Add(node.Group);
}
}