Fix trackpad scroll bounce in ImGui panels

2026-10-15 11:51:33 +00:00 · 2026-10-15 15:34:05 +08:00
parent 20c157b0f4
commit 92b5301bf6
3 changed files with 67 additions and 3 deletions
@@ -0,0 +1,61 @@
+// How ImGuiWrapper turns wx mouse events into ImGui input. ImGuiWrapper lives in libslic3r_gui; this is
+// the suite that links it. Same Windows include prologue as test_texture_color_palette.cpp (wx pulls in
+// <windows.h>; keep WIN32_LEAN_AND_MEAN / NOMINMAX ahead of it).
+#ifdef WIN32
+    #ifndef WIN32_LEAN_AND_MEAN
+        #define WIN32_LEAN_AND_MEAN
+    #endif
+    #ifndef NOMINMAX
+        #define NOMINMAX
+    #endif
+    #include <Windows.h>
+#endif
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+
+#include <imgui/imgui.h>
+#include <wx/event.h>
+
+#include "slic3r/GUI/ImGuiWrapper.hpp"
+
+using Catch::Matchers::WithinAbs;
+using Slic3r::GUI::ImGuiWrapper;
+
+namespace {
+
+// ImGui's wheel after one wheel event, as wx on macOS builds it: a delta of 10 and the rotation in whole
+// points of trackpad travel.
+float wheel_after(int rotation, wxMouseWheelAxis axis)
+{
+    ImGuiWrapper imgui;
+    imgui.set_display_size(800.f, 600.f); // update_mouse_data() ignores input until the display has a size
+
+    wxMouseEvent evt(wxEVT_MOUSEWHEEL);
+    evt.m_wheelRotation = rotation;
+    evt.m_wheelDelta    = 10;
+    evt.m_wheelAxis     = axis;
+    imgui.update_mouse_data(evt);
+    return ImGui::GetIO().MouseWheel;
+}
+
+} // namespace
+
+TEST_CASE("a vertical wheel event steps ImGui's wheel in its own direction", "[ImGuiWrapper]")
+{
+    const int rotation = GENERATE(1, 7, 120, -1, -7, -120);
+    CHECK_THAT(wheel_after(rotation, wxMOUSE_WHEEL_VERTICAL), WithinAbs(rotation > 0 ? 1.0 : -1.0, 0.0));
+}
+
+// Both kinds arrive from a macOS trackpad while scrolling; see ImGuiWrapper::update_mouse_data().
+TEST_CASE("a wheel event with no rotation or on the horizontal axis does not step ImGui's wheel", "[ImGuiWrapper][Regression]")
+{
+    const auto [rotation, axis] = GENERATE(table<int, wxMouseWheelAxis>({
+        { 0, wxMOUSE_WHEEL_VERTICAL },
+        { 5, wxMOUSE_WHEEL_HORIZONTAL },
+        { -5, wxMOUSE_WHEEL_HORIZONTAL },
+    }));
+    CHECK_THAT(wheel_after(rotation, axis), WithinAbs(0.0, 0.0));
+}