IO, Inputs: setting io.WantSetMousePos ignores incoming MousePos events. (#6837, #228)

Allow easily implementing wrapping behaviors.

docs/CHANGELOG.txt

@@ -92,6 +92,7 @@ Other changes:
 - MenuBar: Fixed an issue where layouting an item in the menu-bar would erroneously
   register contents size in a way that would affect the scrolling layer.
   Was most often noticable when using an horizontal scrollbar. (#6789)
+- IO: Setting io.WantSetMousePos ignores incoming MousePos events. (#6837, #228)
 - ImDrawList: Added AddEllipse(), AddEllipseFilled(), PathEllipticalArcTo(). (#2743) [@Doohl]
 - ImVector: Added find_index() helper.
 - Backends: GLFW: Clear emscripten's MouseWheel callback before shutdown. (#6790, #6096, #4019) [@halx99]

imgui.cpp

@@ -7888,6 +7888,7 @@ bool ImGui::IsRectVisible(const ImVec2& rect_min, const ImVec2& rect_max)
 // - IsMouseDragPastThreshold() [Internal]
 // - IsMouseDragging()
 // - GetMousePos()
+// - SetMousePos() [Internal]
 // - GetMousePosOnOpeningCurrentPopup()
 // - IsMousePosValid()
 // - IsAnyMouseDown()
@@ -8415,6 +8416,15 @@ ImVec2 ImGui::GetMousePos()
     return g.IO.MousePos;
 }
 
+// It is expected you only call this if (io.BackendFlags & ImGuiBackendFlags_HasSetMousePos) is set and supported by backend.
+void ImGui::SetMousePos(const ImVec2& pos)
+{
+    ImGuiContext& g = *GImGui;
+    g.IO.MousePos = g.IO.MousePosPrev = pos;
+    g.IO.WantSetMousePos = true;
+    //IMGUI_DEBUG_LOG_IO("SetMousePos: (%.1f,%.1f)\n", io.MousePos.x, io.MousePos.y);
+}
+
 // NB: prefer to call right after BeginPopup(). At the time Selectable/MenuItem is activated, the popup is already closed!
 ImVec2 ImGui::GetMousePosOnOpeningCurrentPopup()
 {
@@ -8903,6 +8913,8 @@ void ImGui::UpdateInputEvents(bool trickle_fast_inputs)
         ImGuiInputEvent* e = &g.InputEventsQueue[event_n];
         if (e->Type == ImGuiInputEventType_MousePos)
         {
+            if (g.IO.WantSetMousePos)
+                continue;
             // Trickling Rule: Stop processing queued events if we already handled a mouse button change
             ImVec2 event_pos(e->MousePos.PosX, e->MousePos.PosY);
             if (trickle_fast_inputs && (mouse_button_changed != 0 || mouse_wheeled || key_changed || text_inputted))
@@ -11550,11 +11562,7 @@ static void ImGui::NavUpdate()
     // Update mouse position if requested
     // (This will take into account the possibility that a Scroll was queued in the window to offset our absolute mouse position before scroll has been applied)
     if (set_mouse_pos && (io.ConfigFlags & ImGuiConfigFlags_NavEnableSetMousePos) && (io.BackendFlags & ImGuiBackendFlags_HasSetMousePos))
-    {
-        io.MousePos = io.MousePosPrev = NavCalcPreferredRefPos();
-        io.WantSetMousePos = true;
-        //IMGUI_DEBUG_LOG_IO("SetMousePos: (%.1f,%.1f)\n", io.MousePos.x, io.MousePos.y);
-    }
+        SetMousePos(NavCalcPreferredRefPos());
 
     // [DEBUG]
     g.NavScoringDebugCount = 0;

imgui_internal.h

@@ -3059,6 +3059,7 @@ namespace ImGui
     IMGUI_API float         GetNavTweakPressedAmount(ImGuiAxis axis);
     IMGUI_API int           CalcTypematicRepeatAmount(float t0, float t1, float repeat_delay, float repeat_rate);
     IMGUI_API void          GetTypematicRepeatRate(ImGuiInputFlags flags, float* repeat_delay, float* repeat_rate);
+    IMGUI_API void          SetMousePos(const ImVec2& pos);
     IMGUI_API void          SetActiveIdUsingAllKeyboardKeys();
     inline bool             IsActiveIdUsingNavDir(ImGuiDir dir)                         { ImGuiContext& g = *GImGui; return (g.ActiveIdUsingNavDirMask & (1 << dir)) != 0; }