tooll3--t3/Editor/Gui/Graph/Legacy/InputNode.cs

using ImGuiNET;
using T3.Core.Operator;
using T3.Core.Utils;
using T3.Editor.Gui.Legacy.Interaction.Connections;
using T3.Editor.Gui.Styling;
using T3.Editor.Gui.UiHelpers;
using T3.Editor.UiModel;
using T3.Editor.UiModel.InputsAndTypes;
using T3.Editor.UiModel.ProjectHandling;

namespace T3.Editor.Gui.Legacy;

/// <summary>
/// Draws published input parameters of a <see cref="Symbol"/> and uses <see cref="ConnectionMaker"/> 
/// create new connections with it.
/// </summary>
internal static class InputNode
{
    internal static bool Draw(ProjectView components, GraphView view, ImDrawListPtr drawList, Symbol.InputDefinition inputDef, IInputUi inputUi, int index)
    { 
        var isSelectedOrHovered = false;
        ImGui.PushID(inputDef.Id.GetHashCode());
        {
            _lastScreenRect = view.TransformRect(new ImRect(inputUi.PosOnCanvas, inputUi.PosOnCanvas + inputUi.Size));
            _lastScreenRect.Floor();

            // Interaction
            ImGui.SetCursorScreenPos(_lastScreenRect.Min);
            ImGui.InvisibleButton("node", _lastScreenRect.GetSize());

            DrawUtils.DebugItemRect();
            var hovered = ImGui.IsItemHovered();
            if (hovered)
            {
                ImGui.SetMouseCursor(ImGuiMouseCursor.Hand);
                isSelectedOrHovered = true;
            }

            view.SelectableNodeMovement.Handle(inputUi);

            // Rendering
            var typeColor = TypeUiRegistry.GetPropertiesForType(inputDef.DefaultValue.ValueType).Color;

            drawList.AddRectFilled(_lastScreenRect.Min, _lastScreenRect.Max,
                                   hovered
                                       ? ColorVariations.OperatorBackgroundHover.Apply(typeColor)
                                       : ColorVariations.ConnectionLines.Apply(typeColor).Fade(0.5f));

            var inputUiIsSelected = components.NodeSelection.IsNodeSelected(inputUi);
            isSelectedOrHovered |= inputUiIsSelected;
                
            if (inputUiIsSelected)
            {
                const float thickness = 1;
                drawList.AddRect(_lastScreenRect.Min - Vector2.One * thickness,
                                 _lastScreenRect.Max + Vector2.One * thickness ,
                                 UiColors.Selection, 0f, 0, thickness);
            }
                
            // Label
            {
                    
                var isScaledDown = view.Scale.X < 1;
                ImGui.PushFont(isScaledDown ? Fonts.FontSmall : Fonts.FontBold);
                    
                // Index
                var size = ImGui.CalcTextSize(inputDef.Name);
                var yPos = _lastScreenRect.GetCenter().Y - size.Y / 2;
                drawList.AddText(new Vector2(_lastScreenRect.Min.X - 20, yPos),
                                 ColorVariations.ConnectionLines.Apply(typeColor),
                                 (index+1) + ".");
                    
                drawList.PushClipRect(_lastScreenRect.Min, _lastScreenRect.Max, true);
                var labelPos = new Vector2(
                                           _lastScreenRect.Max.X - size.X -4,
                                           yPos);

                drawList.AddText(labelPos,
                                 ColorVariations.OperatorLabel.Apply(typeColor),
                                 inputDef.Name);
                ImGui.PopFont();
                drawList.PopClipRect();
            }
                

            // Draw slot 
            {
                var usableSlotArea = GetUsableOutputSlotArea(_lastScreenRect, view);
                ImGui.SetCursorScreenPos(usableSlotArea.Min);
                ImGui.InvisibleButton("output", usableSlotArea.GetSize());
                DrawUtils.DebugItemRect();
                var color = ColorVariations.ConnectionLines.Apply(typeColor).Fade(0.5f);

                if (!ConnectionMaker.IsInputNodeCurrentConnectionSource(view, inputDef) && ImGui.IsItemHovered())
                {
                    color = ColorVariations.Highlight.Apply(typeColor).Fade(0.8f);
                    if (ConnectionMaker.IsMatchingInputType(view, inputDef.DefaultValue.ValueType))
                    {
                        if (ImGui.IsMouseReleased(0))
                        {
                            ConnectionMaker.CompleteAtSymbolInputNode(view, components.CompositionInstance.GetSymbolUi(), inputDef);
                        }
                    }
                    else
                    {
                        if (ImGui.IsItemClicked(0))
                        {
                            ConnectionMaker.StartFromInputNode(view, inputDef);
                        }
                    }
                }
                    
                float foldX = (int)(usableSlotArea.Min.X + usableSlotArea.GetWidth() * 0.5f);
                drawList.AddRectFilled(usableSlotArea.Min+new Vector2(0,0),
                                       new Vector2(foldX, usableSlotArea.Max.Y),
                                       color);
                drawList.AddTriangleFilled(new Vector2(foldX, usableSlotArea.Min.Y),
                                           new Vector2(usableSlotArea.Max.X, usableSlotArea.GetCenter().Y),
                                           new Vector2(foldX, usableSlotArea.Max.Y),
                                           color);
            }
        }
        ImGui.PopID();
        return isSelectedOrHovered;
    }
        
    private static ImRect GetUsableOutputSlotArea(ImRect opRect, GraphView view)
    {
        var thickness = (int)MathUtils.RemapAndClamp(view.Scale.X, 0.5f, 1.2f, (int)(GraphNode.UsableSlotThickness * 0.5f), GraphNode.UsableSlotThickness) *
                        T3Ui.UiScaleFactor;

        var outputHeight = opRect.GetHeight();
        if (outputHeight <= 0)
            outputHeight = 1;

        return ImRect.RectWithSize(
                                   new Vector2(
                                               opRect.Max.X + 1, // - GraphNode._usableSlotThickness,
                                               opRect.Min.Y
                                              ),
                                   new Vector2(
                                               thickness,
                                               outputHeight
                                              ));
    }

    internal static ImRect _lastScreenRect;
}