an incomplete ImGui::Slider wrapper with support for scrolling to change the underlying value, includes support for glm::vec's and can be easily extended

imgui_slider.cpp

template<typename F, typename T>
concept ImGuiSliderFunc = requires(
	F f, std::string_view label, T * v, value_or_ref_t<T> v_min, value_or_ref_t<T> v_max, char const * format, ImGuiSliderFlags flags
) {
	{ f(label.data(), v, v_min, v_max, format, flags) } -> std::convertible_to<bool>;
};

template<typename T>
struct delayed_false : std::false_type {};

template<typename T>
constexpr auto delayed_false_v = delayed_false<T>::value;

template<typename T>
using value_or_ref = std::conditional<std::is_trivially_copyable_v<T>, T, T const &>;

template<typename T>
using value_or_ref_t = value_or_ref<T>::type;

template<typename F, typename T>
concept ImGuiSliderFunc = requires(
	F f, std::string_view label, T * v, value_or_ref_t<T> v_min, value_or_ref_t<T> v_max, char const * format, ImGuiSliderFlags flags
) {
	{ f(label.data(), v, v_min, v_max, format, flags) } -> std::convertible_to<bool>;
};

template<typename T>
auto Slider(std::string_view label, T * v, value_or_ref_t<T> v_min, value_or_ref_t<T> v_max) -> bool {
	auto slider = []<typename T2>(
					  ImGuiSliderFunc<T2> auto slider_func,
					  std::string_view label,
					  T2 * v,
					  value_or_ref_t<T2> v_min,
					  value_or_ref_t<T2> v_max,
					  value_or_ref_t<T2> small_increment,
					  value_or_ref_t<T2> large_increment
				  ) -> bool {
		auto changed = slider_func(label.data(), v, v_min, v_max, nullptr, 0);

		if (ImGui::IsItemHovered()) {
			value_or_ref_t<T2> increment = ImGui::GetIO().KeyCtrl ? large_increment : small_increment;

			if (ImGui::GetIO().MouseWheel > 1e-6f) {
				changed = *v + increment <= v_max;
				*v += increment;
			} else if (ImGui::GetIO().MouseWheel < -1e-6f) {
				changed = *v - increment >= v_min;
				*v -= increment;
			}
			*v = glm::clamp(*v, v_min, v_max);
		}

		return changed;
	};

	auto multi_slider = [&slider]<std::size_t N, typename T2>(
							ImGuiSliderFunc<T2> auto slider_func,
							std::string_view label,
							glm::vec<N, T2> * v,
							glm::vec<N, T2> const & v_min,
							glm::vec<N, T2> const & v_max,
							value_or_ref_t<T2> small_increment,
							value_or_ref_t<T2> large_increment
						) -> bool {
		ImGui::BeginGroup();
		ImGui::PushID(label.data());
		ImGui::PushItemWidth(
			ImGui::CalcItemWidth() / static_cast<float>(N) -
			ImGui::GetStyle().ItemInnerSpacing.x * (static_cast<float>(N) - 1.0f) / static_cast<float>(N)
		);

		bool changed = false;
		for (std::size_t i = 0; i < N; ++i) {
			ImGui::PushID(static_cast<int>(i));
			changed |= slider(slider_func, "", &(*v)[i], v_min[i], v_max[i], small_increment, large_increment);
			if (i != N - 1) {
				ImGui::SameLine(0, ImGui::GetStyle().ItemInnerSpacing.x);
			}
			ImGui::PopID();
		}

		ImGui::PopItemWidth();

		// mimic the calculation of ImGui::SliderScalarN for the label position
		ImGui::SameLine(0, ImGui::GetStyle().FramePadding.x - ImGui::GetStyle().ItemInnerSpacing.x);
		ImGui::LabelText("", "%s", label.data());

		ImGui::PopID();
		ImGui::EndGroup();

		return changed;
	};

	if constexpr (std::same_as<T, float>) {
		return slider(&ImGui::SliderFloat, label, v, v_min, v_max, 0.01f, 0.1f);
	} else if constexpr (std::same_as<T, int32_t>) {
		return slider(&ImGui::SliderInt, label, v, v_min, v_max, 1, 10);
	} else if constexpr (std::same_as<T, uint32_t>) {
		int temp = static_cast<int>(*v);
		int temp_min = static_cast<int>(v_min);
		int temp_max = static_cast<int>(v_max);
		if (slider(&ImGui::SliderInt, label, &temp, temp_min, temp_max, 1, 10)) {
			*v = static_cast<uint32_t>(temp);
			return true;
		}
		return false;
	} else if constexpr (std::same_as<T, glm::vec2>) {
		return multi_slider.template operator()<2, float>(&ImGui::SliderFloat, label, v, v_min, v_max, 0.01f, 0.1f);
	} else if constexpr (std::same_as<T, glm::vec3>) {
		return multi_slider.template operator()<3, float>(&ImGui::SliderFloat, label, v, v_min, v_max, 0.01f, 0.1f);
	} else if constexpr (std::same_as<T, glm::vec4>) {
		return multi_slider.template operator()<4, float>(&ImGui::SliderFloat, label, v, v_min, v_max, 0.01f, 0.1f);
	} else {
		static_assert(delayed_false_v<T>, "unsupported slider type");
	}

	return false;
}