UnrealImGui/Source/ImGui/Private/ImGuiContextProxy.h

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// Distributed under the MIT License (MIT) (see accompanying LICENSE file)
#pragma once
#include "ImGuiDrawData.h"
#include <ICursor.h>
#include <imgui.h>
#include <string>
class FImGuiInputState;
// Represents a single ImGui context. All the context updates should be done through this proxy. During update it
// broadcasts draw events to allow listeners draw their controls. After update it stores draw data.
class FImGuiContextProxy
{
public:
FImGuiContextProxy(const FString& Name, FSimpleMulticastDelegate* InSharedDrawEvent);
~FImGuiContextProxy();
FImGuiContextProxy(const FImGuiContextProxy&) = delete;
FImGuiContextProxy& operator=(const FImGuiContextProxy&) = delete;
FImGuiContextProxy(FImGuiContextProxy&& Other) = default;
FImGuiContextProxy& operator=(FImGuiContextProxy&& Other) = default;
// Get the name of this context.
const FString& GetName() const { return Name; }
// Get draw data from the last frame.
const TArray<FImGuiDrawList>& GetDrawData() const { return DrawLists; }
// Get input state used by this context.
const FImGuiInputState* GetInputState() const { return InputState; }
// Set input state to be used by this context.
void SetInputState(const FImGuiInputState* SourceInputState) { InputState = SourceInputState; }
// If context is currently using input state to remove then remove that binding.
void RemoveInputState(const FImGuiInputState* InputStateToRemove) { if (InputState == InputStateToRemove) InputState = nullptr; }
// Is this context the current ImGui context.
bool IsCurrentContext() const { return ImGui::GetCurrentContext() == Context.Get(); }
// Set this context as current ImGui context.
void SetAsCurrent() { ImGui::SetCurrentContext(Context.Get()); }
bool HasActiveItem() const { return bHasActiveItem; }
EMouseCursor::Type GetMouseCursor() const { return MouseCursor; }
// Delegate called right before ending the frame to allows listeners draw their controls.
FSimpleMulticastDelegate& OnDraw() { return DrawEvent; }
// Call draw events to allow listeners draw their widgets. Only one call per frame is processed. If it is not
// called manually before, then it will be called from the Tick function.
void Draw();
// Tick to advance context to the next frame. Only one call per frame will be processed.
void Tick(float DeltaSeconds);
private:
void BeginFrame(float DeltaTime = 1.f / 60.f);
void EndFrame();
void UpdateDrawData(ImDrawData* DrawData);
TUniquePtr<ImGuiContext> Context;
EMouseCursor::Type MouseCursor = EMouseCursor::None;
bool bHasActiveItem = false;
bool bIsFrameStarted = false;
FSimpleMulticastDelegate DrawEvent;
FSimpleMulticastDelegate* SharedDrawEvent = nullptr;
uint32 LastTickFrameNumber = 0;
uint32 LastDrawFrameNumber = 0;
const FImGuiInputState* InputState = nullptr;
TArray<FImGuiDrawList> DrawLists;
FString Name;
std::string IniFilename;
};