[olympic/studio] Add new ImGui util functions

src/olympic/studio/modlib/include/studio/imguiutil.hpp

@@ -8,6 +8,8 @@
 
 #include <imgui.h>
 
+#include <ox/std/bit.hpp>
+
 #include <turbine/context.hpp>
 #include <studio/context.hpp>
 
@@ -15,6 +17,91 @@ namespace studio::ig {
 
 inline constexpr auto BtnSz = ImVec2{52, 22};
 
+
+constexpr ImTextureID toImTextureID(ox::Unsigned_c auto id) noexcept
+	requires(sizeof(id) <= sizeof(ox::Uint<sizeof(ImTextureID)*8>)) {
+	return std::bit_cast<ImTextureID>(ox::Uint<sizeof(ImTextureID)*8>{id});
+}
+
+template<typename T>
+ox::Result<T> getDragDropPayload(ox::CStringView name) noexcept {
+	auto const payload = ImGui::AcceptDragDropPayload(name.c_str());
+	if (!payload) {
+		return OxError(1, "No drag/drop payload");
+	}
+	return ox::readClaw<T>(
+			reinterpret_cast<char const*>(payload->Data),
+			static_cast<size_t>(payload->DataSize));
+}
+
+ox::Error setDragDropPayload(ox::CStringView name, auto const &obj) noexcept {
+	oxRequire(buff, ox::writeClaw(obj, ox::ClawFormat::Metal));
+	ImGui::SetDragDropPayload(name.c_str(), buff.data(), buff.size());
+	return {};
+}
+
+
+class DragDropSource {
+	private:
+		bool const m_active{};
+	public:
+		inline DragDropSource() noexcept:
+			m_active(ImGui::BeginDragDropSource()) {
+		}
+		inline ~DragDropSource() noexcept {
+			if (m_active) {
+				ImGui::EndDragDropSource();
+			}
+		}
+		constexpr operator bool() const noexcept {
+			return m_active;
+		}
+};
+
+inline auto dragDropSource(auto const&cb) noexcept {
+	if constexpr(ox::is_same_v<decltype(cb()), ox::Error>) {
+		if (ig::DragDropSource const tgt; tgt) [[unlikely]] {
+			return cb();
+		}
+	} else {
+		if (ig::DragDropSource const tgt; tgt) [[unlikely]] {
+			cb();
+		}
+	}
+}
+
+
+class DragDropTarget {
+	private:
+		bool const m_active{};
+	public:
+		inline DragDropTarget() noexcept:
+			m_active(ImGui::BeginDragDropTarget()) {
+		}
+		inline ~DragDropTarget() noexcept {
+			if (m_active) {
+				ImGui::EndDragDropTarget();
+			}
+		}
+		constexpr operator bool() const noexcept {
+			return m_active;
+		}
+};
+
+inline auto dragDropTarget(auto const&cb) noexcept {
+	if constexpr(ox::is_same_v<decltype(cb()), ox::Error>) {
+		if (ig::DragDropTarget const tgt; tgt) [[unlikely]] {
+			return cb();
+		}
+		return ox::Error{};
+	} else {
+		if (ig::DragDropTarget const tgt; tgt) [[unlikely]] {
+			cb();
+		}
+	}
+}
+
+
 class ChildStackItem {
 	public:
 		explicit ChildStackItem(ox::CStringView id, ImVec2 const&sz = {}) noexcept;