Nav: Record/restore preferred position on each given axis.

Tagging #6344 #6003 #2694 #1688 as it relates to scoring, however this doesn't technically fix any of them fully yet.
But e.g. once we restore axial path for #2694 this commit will allow going back and forth to initial location.

docs/CHANGELOG.txt

@@ -51,6 +51,10 @@ Other changes:
 - Drag, Sliders: if the format string doesn't contain any %, CTRL+Click to input text will
   use the default format specifier for the type. Allow display/input of raw value when using
   "enums" patterns (display label instead of value) + allow using when value is hidden. (#6405)
+- Nav: Record/restore preferred position on each given axis after a movement on that axis,
+  then score movement on the other axis using this as a bias. This allows going up and down
+  between e.g. a large header spanning horizontal space and three-ways-columns, landing
+  on the same column as before.
 - Nav: Fixed navigation within tables/columns where item boundaries goes beyond columns limits,
   unclipped bounding boxes would interfere with other columns. (#2221) [@zzzyap, @ocornut]
 - Nav: Fixed CTRL+Tab into a root window with only childs with _NavFlattened flags

imgui.cpp

@@ -3688,6 +3688,7 @@ ImGuiWindow::ImGuiWindow(ImGuiContext* ctx, const char* name) : DrawListInst(NUL
     DrawList = &DrawListInst;
     DrawList->_Data = &Ctx->DrawListSharedData;
     DrawList->_OwnerName = Name;
+    NavPreferredScoringPosRel[0] = NavPreferredScoringPosRel[1] = ImVec2(FLT_MAX, FLT_MAX);
 }
 
 ImGuiWindow::~ImGuiWindow()
@@ -10620,6 +10621,12 @@ void ImGui::SetNavWindow(ImGuiWindow* window)
     NavUpdateAnyRequestFlag();
 }
 
+void ImGui::NavClearPreferredPosForAxis(ImGuiAxis axis)
+{
+    ImGuiContext& g = *GImGui;
+    g.NavWindow->RootWindowForNav->NavPreferredScoringPosRel[g.NavLayer][axis] = FLT_MAX;
+}
+
 void ImGui::SetNavID(ImGuiID id, ImGuiNavLayer nav_layer, ImGuiID focus_scope_id, const ImRect& rect_rel)
 {
     ImGuiContext& g = *GImGui;
@@ -10630,6 +10637,10 @@ void ImGui::SetNavID(ImGuiID id, ImGuiNavLayer nav_layer, ImGuiID focus_scope_id
     g.NavFocusScopeId = focus_scope_id;
     g.NavWindow->NavLastIds[nav_layer] = id;
     g.NavWindow->NavRectRel[nav_layer] = rect_rel;
+
+    // Clear preferred scoring position (NavMoveRequestApplyResult() will tend to restore it)
+    NavClearPreferredPosForAxis(ImGuiAxis_X);
+    NavClearPreferredPosForAxis(ImGuiAxis_Y);
 }
 
 void ImGui::SetFocusID(ImGuiID id, ImGuiWindow* window)
@@ -10654,6 +10665,10 @@ void ImGui::SetFocusID(ImGuiID id, ImGuiWindow* window)
         g.NavDisableMouseHover = true;
     else
         g.NavDisableHighlight = true;
+
+    // Clear preferred scoring position (NavMoveRequestApplyResult() will tend to restore it)
+    NavClearPreferredPosForAxis(ImGuiAxis_X);
+    NavClearPreferredPosForAxis(ImGuiAxis_Y);
 }
 
 ImGuiDir ImGetDirQuadrantFromDelta(float dx, float dy)
@@ -10746,17 +10761,23 @@ static bool ImGui::NavScoreItem(ImGuiNavItemData* result)
             draw_list->AddText(cand.Min, IM_COL32(255, 255, 255, 255), buf);
         }
     }
-    if (IsMouseHoveringRect(cand.Min, cand.Max))
+    const bool debug_hovering = IsMouseHoveringRect(cand.Min, cand.Max);
+    const bool debug_tty = (g.IO.KeyCtrl && IsKeyPressed(ImGuiKey_Space));
+    if (debug_hovering || debug_tty)
     {
         ImFormatString(buf, IM_ARRAYSIZE(buf),
             "d-box    (%7.3f,%7.3f) -> %7.3f\nd-center (%7.3f,%7.3f) -> %7.3f\nd-axial  (%7.3f,%7.3f) -> %7.3f\nnav %c, quadrant %c",
-            dbx, dby, dist_box, dcx, dcy, dist_center, dax, day, dist_axial, "WENS"[g.NavMoveDir], "WENS"[quadrant]);
+            dbx, dby, dist_box, dcx, dcy, dist_center, dax, day, dist_axial, "-WENS"[move_dir+1], "-WENS"[quadrant+1]);
+        if (debug_hovering)
+        {
             ImDrawList* draw_list = GetForegroundDrawList(window);
-        draw_list->AddRect(curr.Min, curr.Max, IM_COL32(255,200,0,100));
+            draw_list->AddRect(curr.Min, curr.Max, IM_COL32(255, 200, 0, 100));
-        draw_list->AddRect(cand.Min, cand.Max, IM_COL32(255,255,0,200));
+            draw_list->AddRect(cand.Min, cand.Max, IM_COL32(255, 255, 0, 200));
-        draw_list->AddRectFilled(cand.Max - ImVec2(4, 4), cand.Max + CalcTextSize(buf) + ImVec2(4, 4), IM_COL32(40,0,0,200));
+            draw_list->AddRectFilled(cand.Max - ImVec2(4, 4), cand.Max + CalcTextSize(buf) + ImVec2(4, 4), IM_COL32(40, 0, 0, 200));
             draw_list->AddText(cand.Max, ~0U, buf);
         }
+        if (debug_tty) { IMGUI_DEBUG_LOG_NAV("id 0x%08X\n%s\n", g.LastItemData.ID, buf); }
+    }
 #endif
 
     // Is it in the quadrant we're interested in moving to?
@@ -11322,11 +11343,11 @@ static void ImGui::NavUpdate()
     // [DEBUG]
     g.NavScoringDebugCount = 0;
 #if IMGUI_DEBUG_NAV_RECTS
-    if (g.NavWindow)
+    if (ImGuiWindow* debug_window = g.NavWindow)
     {
-        ImDrawList* draw_list = GetForegroundDrawList(g.NavWindow);
+        ImDrawList* draw_list = GetForegroundDrawList(debug_window);
-        if (1) { for (int layer = 0; layer < 2; layer++) { ImRect r = WindowRectRelToAbs(g.NavWindow, g.NavWindow->NavRectRel[layer]); draw_list->AddRect(r.Min, r.Max, IM_COL32(255,200,0,255)); } } // [DEBUG]
+        int layer = g.NavLayer; /* for (int layer = 0; layer < 2; layer++)*/ { ImRect r = WindowRectRelToAbs(debug_window, debug_window->NavRectRel[layer]); draw_list->AddRect(r.Min, r.Max, IM_COL32(255, 200, 0, 255)); }
-        if (1) { ImU32 col = (!g.NavWindow->Hidden) ? IM_COL32(255,0,255,255) : IM_COL32(255,0,0,255); ImVec2 p = NavCalcPreferredRefPos(); char buf[32]; ImFormatString(buf, 32, "%d", g.NavLayer); draw_list->AddCircleFilled(p, 3.0f, col); draw_list->AddText(NULL, 13.0f, p + ImVec2(8,-4), col, buf); }
+        //if (1) { ImU32 col = (!debug_window->Hidden) ? IM_COL32(255,0,255,255) : IM_COL32(255,0,0,255); ImVec2 p = NavCalcPreferredRefPos(); char buf[32]; ImFormatString(buf, 32, "%d", g.NavLayer); draw_list->AddCircleFilled(p, 3.0f, col); draw_list->AddText(NULL, 13.0f, p + ImVec2(8,-4), col, buf); }
     }
 #endif
 }
@@ -11347,6 +11368,28 @@ void ImGui::NavInitRequestApplyResult()
         NavRestoreHighlightAfterMove();
 }
 
+// Bias scoring rect ahead of scoring + update preferred pos (if missing) using source position
+static void NavBiasScoringRect(ImRect& r, ImVec2& preferred_pos_rel, ImGuiDir move_dir)
+{
+    // Bias initial rect
+    ImGuiContext& g = *GImGui;
+    const ImVec2 rel_to_abs_offset = g.NavWindow->DC.CursorStartPos;
+
+    // Initialize bias on departure if we don't have any. So mouse-click + arrow will record bias.
+    // - We default to L/U bias, so moving down from a large source item into several columns will land on left-most column.
+    // - But each successful move sets new bias on one axis, only cleared when using mouse.
+    if (preferred_pos_rel.x == FLT_MAX)
+        preferred_pos_rel.x = ImMin(r.Min.x + 1.0f, r.Max.x) - rel_to_abs_offset.x;
+    if (preferred_pos_rel.y == FLT_MAX)
+        preferred_pos_rel.y = r.GetCenter().y - rel_to_abs_offset.y;
+
+    // Apply general bias on the other axis
+    if (move_dir == ImGuiDir_Up || move_dir == ImGuiDir_Down)
+        r.Min.x = r.Max.x = preferred_pos_rel.x + rel_to_abs_offset.x;
+    else
+        r.Min.y = r.Max.y = preferred_pos_rel.y + rel_to_abs_offset.y;
+}
+
 void ImGui::NavUpdateCreateMoveRequest()
 {
     ImGuiContext& g = *GImGui;
@@ -11453,8 +11496,8 @@ void ImGui::NavUpdateCreateMoveRequest()
         ImRect nav_rect_rel = !window->NavRectRel[g.NavLayer].IsInverted() ? window->NavRectRel[g.NavLayer] : ImRect(0, 0, 0, 0);
         scoring_rect = WindowRectRelToAbs(window, nav_rect_rel);
         scoring_rect.TranslateY(scoring_rect_offset_y);
-        scoring_rect.Min.x = ImMin(scoring_rect.Min.x + 1.0f, scoring_rect.Max.x);
+        if (g.NavMoveSubmitted)
-        scoring_rect.Max.x = scoring_rect.Min.x;
+            NavBiasScoringRect(scoring_rect, window->RootWindowForNav->NavPreferredScoringPosRel[g.NavLayer], g.NavMoveDir);
         IM_ASSERT(!scoring_rect.IsInverted()); // Ensure if we have a finite, non-inverted bounding box here will allow us to remove extraneous ImFabs() calls in NavScoreItem().
         //GetForegroundDrawList()->AddRect(scoring_rect.Min, scoring_rect.Max, IM_COL32(255,200,0,255)); // [DEBUG]
         //if (!g.NavScoringNoClipRect.IsInverted()) { GetForegroundDrawList()->AddRect(g.NavScoringNoClipRect.Min, g.NavScoringNoClipRect.Max, IM_COL32(255, 200, 0, 255)); } // [DEBUG]
@@ -11508,12 +11551,14 @@ void ImGui::NavMoveRequestApplyResult()
             result = &g.NavTabbingResultFirst;
 
     // In a situation when there are no results but NavId != 0, re-enable the Navigation highlight (because g.NavId is not considered as a possible result)
+    const ImGuiAxis axis = (g.NavMoveDir == ImGuiDir_Up || g.NavMoveDir == ImGuiDir_Down) ? ImGuiAxis_Y : ImGuiAxis_X;
     if (result == NULL)
     {
         if (g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing)
             g.NavMoveFlags |= ImGuiNavMoveFlags_DontSetNavHighlight;
         if (g.NavId != 0 && (g.NavMoveFlags & ImGuiNavMoveFlags_DontSetNavHighlight) == 0)
             NavRestoreHighlightAfterMove();
+        NavClearPreferredPosForAxis(axis); // On a failed move, clear preferred pos for this axis.
         IMGUI_DEBUG_LOG_NAV("[nav] NavMoveSubmitted but not led to a result!\n");
         return;
     }
@@ -11558,10 +11603,19 @@ void ImGui::NavMoveRequestApplyResult()
         g.NavJustMovedToKeyMods = g.NavMoveKeyMods;
     }
 
-    // Focus
+    // Apply new NavID/Focus
     IMGUI_DEBUG_LOG_NAV("[nav] NavMoveRequest: result NavID 0x%08X in Layer %d Window \"%s\"\n", result->ID, g.NavLayer, g.NavWindow->Name);
+    ImVec2 preferred_scoring_pos_rel = g.NavWindow->RootWindowForNav->NavPreferredScoringPosRel[g.NavLayer];
     SetNavID(result->ID, g.NavLayer, result->FocusScopeId, result->RectRel);
 
+    // Restore last preferred position for current axis
+    // (storing in RootWindowForNav-> as the info is desirable at the beginning of a Move Request. In theory all storage should use RootWindowForNav..)
+    if ((g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) == 0)
+    {
+        preferred_scoring_pos_rel[axis] = result->RectRel.GetCenter()[axis];
+        g.NavWindow->RootWindowForNav->NavPreferredScoringPosRel[g.NavLayer] = preferred_scoring_pos_rel;
+    }
+
     // Tabbing: Activates Inputable or Focus non-Inputable
     if ((g.NavMoveFlags & ImGuiNavMoveFlags_Tabbing) && (result->InFlags & ImGuiItemFlags_Inputable))
     {
@@ -11775,6 +11829,8 @@ static void ImGui::NavUpdateCreateWrappingRequest()
     if (!do_forward)
         return;
     window->NavRectRel[g.NavLayer] = bb_rel;
+    NavClearPreferredPosForAxis(ImGuiAxis_X);
+    NavClearPreferredPosForAxis(ImGuiAxis_Y);
     NavMoveRequestForward(g.NavMoveDir, clip_dir, move_flags, g.NavMoveScrollFlags);
 }
 
@@ -14285,6 +14341,9 @@ void ImGui::DebugNodeWindow(ImGuiWindow* window, const char* label)
             BulletText("NavLastIds[%d]: 0x%08X at +(%.1f,%.1f)(%.1f,%.1f)", layer, window->NavLastIds[layer], r.Min.x, r.Min.y, r.Max.x, r.Max.y);
         DebugLocateItemOnHover(window->NavLastIds[layer]);
     }
+    const ImVec2* pr = window->NavPreferredScoringPosRel;
+    for (int layer = 0; layer < ImGuiNavLayer_COUNT; layer++)
+        BulletText("NavPreferredScoringPosRel[%d] = {%.1f,%.1f)", layer, (pr[layer].x == FLT_MAX ? -99999.0f : pr[layer].x), (pr[layer].y == FLT_MAX ? -99999.0f : pr[layer].y)); // Display as 99999.0f so it looks neater.
     BulletText("NavLayersActiveMask: %X, NavLastChildNavWindow: %s", window->DC.NavLayersActiveMask, window->NavLastChildNavWindow ? window->NavLastChildNavWindow->Name : "NULL");
     if (window->RootWindow != window)       { DebugNodeWindow(window->RootWindow, "RootWindow"); }
     if (window->ParentWindow != NULL)       { DebugNodeWindow(window->ParentWindow, "ParentWindow"); }

imgui.h

@@ -23,7 +23,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM > 12345')
 #define IMGUI_VERSION               "1.89.6 WIP"
-#define IMGUI_VERSION_NUM           18955
+#define IMGUI_VERSION_NUM           18956
 #define IMGUI_HAS_TABLE
 
 /*

imgui_internal.h

@@ -2366,6 +2366,7 @@ struct IMGUI_API ImGuiWindow
     ImGuiWindow*            NavLastChildNavWindow;              // When going to the menu bar, we remember the child window we came from. (This could probably be made implicit if we kept g.Windows sorted by last focused including child window.)
     ImGuiID                 NavLastIds[ImGuiNavLayer_COUNT];    // Last known NavId for this window, per layer (0/1)
     ImRect                  NavRectRel[ImGuiNavLayer_COUNT];    // Reference rectangle, in window relative space
+    ImVec2                  NavPreferredScoringPosRel[ImGuiNavLayer_COUNT]; // Preferred X/Y position updated when moving on a given axis, reset to FLT_MAX.
     ImGuiID                 NavRootFocusScopeId;                // Focus Scope ID at the time of Begin()
 
     int                     MemoryDrawListIdxCapacity;          // Backup of last idx/vtx count, so when waking up the window we can preallocate and avoid iterative alloc/copy
@@ -2761,6 +2762,7 @@ namespace ImGui
     IMGUI_API void          SetWindowHiddendAndSkipItemsForCurrentFrame(ImGuiWindow* window);
     inline ImRect           WindowRectAbsToRel(ImGuiWindow* window, const ImRect& r) { ImVec2 off = window->DC.CursorStartPos; return ImRect(r.Min.x - off.x, r.Min.y - off.y, r.Max.x - off.x, r.Max.y - off.y); }
     inline ImRect           WindowRectRelToAbs(ImGuiWindow* window, const ImRect& r) { ImVec2 off = window->DC.CursorStartPos; return ImRect(r.Min.x + off.x, r.Min.y + off.y, r.Max.x + off.x, r.Max.y + off.y); }
+    inline ImVec2           WindowPosRelToAbs(ImGuiWindow* window, const ImVec2& p)  { ImVec2 off = window->DC.CursorStartPos; return ImVec2(p.x + off.x, p.y + off.y); }
 
     // Windows: Display Order and Focus Order
     IMGUI_API void          FocusWindow(ImGuiWindow* window, ImGuiFocusRequestFlags flags = 0);
@@ -2908,6 +2910,7 @@ namespace ImGui
     IMGUI_API void          NavMoveRequestCancel();
     IMGUI_API void          NavMoveRequestApplyResult();
     IMGUI_API void          NavMoveRequestTryWrapping(ImGuiWindow* window, ImGuiNavMoveFlags move_flags);
+    IMGUI_API void          NavClearPreferredPosForAxis(ImGuiAxis axis);
     IMGUI_API void          NavUpdateCurrentWindowIsScrollPushableX();
     IMGUI_API void          ActivateItem(ImGuiID id);   // Remotely activate a button, checkbox, tree node etc. given its unique ID. activation is queued and processed on the next frame when the item is encountered again.
     IMGUI_API void          SetNavWindow(ImGuiWindow* window);

imgui_widgets.cpp

@@ -6219,11 +6219,13 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
         if (g.NavId == id && g.NavMoveDir == ImGuiDir_Left && is_open)
         {
             toggled = true;
+            NavClearPreferredPosForAxis(ImGuiAxis_X);
             NavMoveRequestCancel();
         }
         if (g.NavId == id && g.NavMoveDir == ImGuiDir_Right && !is_open) // If there's something upcoming on the line we may want to give it the priority?
         {
             toggled = true;
+            NavClearPreferredPosForAxis(ImGuiAxis_X);
             NavMoveRequestCancel();
         }