Nav: Draft internal api to forward move request with loop/wrap options. Will rework for parallel scoring of two paths (as a generalization of the NavFlattened concept). (#787)

imgui.cpp

@@ -2251,7 +2251,7 @@ static bool NavScoreItem(ImGuiNavMoveResult* result, ImRect cand)
 
     // We perform scoring on items bounding box clipped by the current clipping rectangle on the other axis (clipping on our movement axis would give us equal scores for all clipped items)
     // For example, this ensure that items in one column are not reached when moving vertically from items in another column.
-    NavClampRectToVisibleAreaForMoveDir(g.NavMoveDir, cand, window->ClipRect);
+    NavClampRectToVisibleAreaForMoveDir(g.NavMoveClipDir, cand, window->ClipRect);
 
     // Compute distance between boxes
     // FIXME-NAV: Introducing biases for vertical navigation, needs to be removed.
@@ -3227,6 +3227,7 @@ static void ImGui::NavUpdate()
     if (g.NavMoveRequestForward == ImGuiNavForward_None)
     {
         g.NavMoveDir = ImGuiDir_None;
+        g.NavMoveRequestFlags = 0;
         if (g.NavWindow && !g.NavWindowingTarget && allowed_dir_flags && !(g.NavWindow->Flags & ImGuiWindowFlags_NoNavInputs))
         {
             if ((allowed_dir_flags & (1<<ImGuiDir_Left))  && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadLeft, ImGuiNavInput_KeyLeft_, ImGuiInputReadMode_Repeat)) g.NavMoveDir = ImGuiDir_Left;
@@ -3234,11 +3235,13 @@ static void ImGui::NavUpdate()
             if ((allowed_dir_flags & (1<<ImGuiDir_Up))    && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadUp,   ImGuiNavInput_KeyUp_,   ImGuiInputReadMode_Repeat)) g.NavMoveDir = ImGuiDir_Up;
             if ((allowed_dir_flags & (1<<ImGuiDir_Down))  && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadDown, ImGuiNavInput_KeyDown_, ImGuiInputReadMode_Repeat)) g.NavMoveDir = ImGuiDir_Down;
         }
+        g.NavMoveClipDir = g.NavMoveDir;
     }
     else
     {
         // Forwarding previous request (which has been modified, e.g. wrap around menus rewrite the requests with a starting rectangle at the other side of the window)
-        IM_ASSERT(g.NavMoveDir != ImGuiDir_None);
+        // (Preserve g.NavMoveRequestFlags, g.NavMoveClipDir which were set by the NavMoveRequestForward() function)
+        IM_ASSERT(g.NavMoveDir != ImGuiDir_None && g.NavMoveClipDir != ImGuiDir_None);
         IM_ASSERT(g.NavMoveRequestForward == ImGuiNavForward_ForwardQueued);
         g.NavMoveRequestForward = ImGuiNavForward_ForwardActive;
     }
@@ -4547,9 +4550,11 @@ void ImGui::CalcListClipping(int items_count, float items_height, int* out_items
     const ImVec2 pos = window->DC.CursorPos;
     int start = (int)((window->ClipRect.Min.y - pos.y) / items_height);
     int end = (int)((window->ClipRect.Max.y - pos.y) / items_height);
-    if (g.NavMoveRequest && g.NavMoveDir == ImGuiDir_Up) // When performing a navigation request, ensure we have one item extra in the direction we are moving to
+
+    // When performing a navigation request, ensure we have one item extra in the direction we are moving to
+    if (g.NavMoveRequest && g.NavMoveClipDir == ImGuiDir_Up)
         start--;
-    if (g.NavMoveRequest && g.NavMoveDir == ImGuiDir_Down)
+    if (g.NavMoveRequest && g.NavMoveClipDir == ImGuiDir_Down)
         end++;
 
     start = ImClamp(start, 0, items_count);
@@ -5101,15 +5106,50 @@ bool ImGui::BeginPopupModal(const char* name, bool* p_open, ImGuiWindowFlags fla
     return is_open;
 }
 
-static void NavProcessMoveRequestWrapAround(ImGuiWindow* window)
+void ImGui::NavMoveRequestForward(ImGuiDir move_dir, ImGuiDir clip_dir, const ImRect& bb_rel, ImGuiNavMoveFlags move_flags)
 {
     ImGuiContext& g = *GImGui;
-    if (g.NavWindow == window && NavMoveRequestButNoResultYet())
+    IM_ASSERT(g.NavMoveRequestForward == ImGuiNavForward_None);
-        if ((g.NavMoveDir == ImGuiDir_Up || g.NavMoveDir == ImGuiDir_Down) && g.NavMoveRequestForward == ImGuiNavForward_None && g.NavLayer == 0)
-        {
-            g.NavMoveRequestForward = ImGuiNavForward_ForwardQueued;
     ImGui::NavMoveRequestCancel();
-            g.NavWindow->NavRectRel[0].Min.y = g.NavWindow->NavRectRel[0].Max.y = ((g.NavMoveDir == ImGuiDir_Up) ? ImMax(window->SizeFull.y, window->SizeContents.y) : 0.0f) - window->Scroll.y;
+    g.NavMoveDir = move_dir;
+    g.NavMoveClipDir = clip_dir;
+    g.NavMoveRequestForward = ImGuiNavForward_ForwardQueued;
+    g.NavMoveRequestFlags = move_flags;
+    g.NavWindow->NavRectRel[g.NavLayer] = bb_rel;
+}
+
+void ImGui::NavMoveRequestTryWrapping(ImGuiWindow* window, ImGuiNavMoveFlags move_flags)
+{
+    ImGuiContext& g = *GImGui;
+    if (g.NavWindow != window || !NavMoveRequestButNoResultYet() || g.NavMoveRequestForward != ImGuiNavForward_None || g.NavLayer != 0)
+        return;
+    IM_ASSERT(move_flags != 0); // No points calling this with no wrapping
+    ImRect bb_rel = window->NavRectRel[0];
+
+    ImGuiDir clip_dir = g.NavMoveDir;
+    if (g.NavMoveDir == ImGuiDir_Left && (move_flags & (ImGuiNavMoveFlags_WrapX | ImGuiNavMoveFlags_LoopX)))
+    {
+        bb_rel.Min.x = bb_rel.Max.x = ImMax(window->SizeFull.x, window->SizeContents.x) - window->Scroll.x;
+        if (move_flags & ImGuiNavMoveFlags_WrapX) { bb_rel.TranslateY(-bb_rel.GetHeight()); clip_dir = ImGuiDir_Up; }
+        NavMoveRequestForward(g.NavMoveDir, clip_dir, bb_rel, move_flags);
+    }
+    if (g.NavMoveDir == ImGuiDir_Right && (move_flags & (ImGuiNavMoveFlags_WrapX | ImGuiNavMoveFlags_LoopX)))
+    {
+        bb_rel.Min.x = bb_rel.Max.x = -window->Scroll.x;
+        if (move_flags & ImGuiNavMoveFlags_WrapX) { bb_rel.TranslateY(+bb_rel.GetHeight()); clip_dir = ImGuiDir_Down; }
+        NavMoveRequestForward(g.NavMoveDir, clip_dir, bb_rel, move_flags);
+    }
+    if (g.NavMoveDir == ImGuiDir_Up && (move_flags & (ImGuiNavMoveFlags_WrapY | ImGuiNavMoveFlags_LoopY)))
+    {
+        bb_rel.Min.y = bb_rel.Max.y = ImMax(window->SizeFull.y, window->SizeContents.y) - window->Scroll.y;
+        if (move_flags & ImGuiNavMoveFlags_WrapY) { bb_rel.TranslateX(-bb_rel.GetWidth()); clip_dir = ImGuiDir_Left; }
+        NavMoveRequestForward(g.NavMoveDir, clip_dir, bb_rel, move_flags);
+    }
+    if (g.NavMoveDir == ImGuiDir_Down && (move_flags & (ImGuiNavMoveFlags_WrapY | ImGuiNavMoveFlags_LoopY)))
+    {
+        bb_rel.Min.y = bb_rel.Max.y = -window->Scroll.y;
+        if (move_flags & ImGuiNavMoveFlags_WrapY) { bb_rel.TranslateX(+bb_rel.GetWidth()); clip_dir = ImGuiDir_Right; }
+        NavMoveRequestForward(g.NavMoveDir, clip_dir, bb_rel, move_flags);
     }
 }
 
@@ -5120,7 +5160,7 @@ void ImGui::EndPopup()
     IM_ASSERT(g.CurrentPopupStack.Size > 0);
 
     // Make all menus and popups wrap around for now, may need to expose that policy.
-    NavProcessMoveRequestWrapAround(g.CurrentWindow);
+    NavMoveRequestTryWrapping(g.CurrentWindow, ImGuiNavMoveFlags_LoopY);
     
     End();
 }

imgui_internal.h

@@ -50,6 +50,7 @@ typedef int ImGuiItemFlags;         // flags: for PushItemFlag()
 typedef int ImGuiItemStatusFlags;   // flags: storage for DC.LastItemXXX        // enum ImGuiItemStatusFlags_
 typedef int ImGuiNavHighlightFlags; // flags: for RenderNavHighlight()          // enum ImGuiNavHighlightFlags_
 typedef int ImGuiNavDirSourceFlags; // flags: for GetNavInputAmount2d()         // enum ImGuiNavDirSourceFlags_
+typedef int ImGuiNavMoveFlags;      // flags: for navigation requests           // enum ImGuiNavMoveFlags_
 typedef int ImGuiSeparatorFlags;    // flags: for Separator() - internal        // enum ImGuiSeparatorFlags_
 typedef int ImGuiSliderFlags;       // flags: for SliderBehavior()              // enum ImGuiSliderFlags_
 
@@ -302,6 +303,14 @@ enum ImGuiNavDirSourceFlags_
     ImGuiNavDirSourceFlags_PadLStick    = 1 << 2
 };
 
+enum ImGuiNavMoveFlags_
+{
+    ImGuiNavMoveFlags_LoopX     = 1 << 0,   // On failed request, restart from opposite side
+    ImGuiNavMoveFlags_LoopY     = 1 << 1,
+    ImGuiNavMoveFlags_WrapX     = 1 << 2,   // On failed request, request from opposite side one line down (when NavDir==right) or one line up (when NavDir==left)
+    ImGuiNavMoveFlags_WrapY     = 1 << 3    // This is not super useful for provided for completeness
+};
+
 enum ImGuiNavForward
 {
     ImGuiNavForward_None,
@@ -337,6 +346,8 @@ struct IMGUI_API ImRect
     void        Expand(const float amount)          { Min.x -= amount;   Min.y -= amount;   Max.x += amount;   Max.y += amount; }
     void        Expand(const ImVec2& amount)        { Min.x -= amount.x; Min.y -= amount.y; Max.x += amount.x; Max.y += amount.y; }
     void        Translate(const ImVec2& d)          { Min.x += d.x; Min.y += d.y; Max.x += d.x; Max.y += d.y; }
+    void        TranslateX(float dx)                { Min.x += dx; Max.x += dx; }
+    void        TranslateY(float dy)                { Min.y += dy; Max.y += dy; }
     void        ClipWith(const ImRect& r)           { Min = ImMax(Min, r.Min); Max = ImMin(Max, r.Max); }                   // Simple version, may lead to an inverted rectangle, which is fine for Contains/Overlaps test but not for display.
     void        ClipWithFull(const ImRect& r)       { Min = ImClamp(Min, r.Min, r.Max); Max = ImClamp(Max, r.Min, r.Max); } // Full version, ensure both points are fully clipped.
     void        Floor()                             { Min.x = (float)(int)Min.x; Min.y = (float)(int)Min.y; Max.x = (float)(int)Max.x; Max.y = (float)(int)Max.y; }
@@ -645,8 +656,10 @@ struct ImGuiContext
     ImRect                  NavInitResultRectRel;
     bool                    NavMoveFromClampedRefRect;          // Set by manual scrolling, if we scroll to a point where NavId isn't visible we reset navigation from visible items
     bool                    NavMoveRequest;                     // Move request for this frame
+    ImGuiNavMoveFlags       NavMoveRequestFlags;
     ImGuiNavForward         NavMoveRequestForward;              // None / ForwardQueued / ForwardActive (this is used to navigate sibling parent menus from a child menu)
     ImGuiDir                NavMoveDir, NavMoveDirLast;         // Direction of the move request (left/right/up/down), direction of the previous move request
+    ImGuiDir                NavMoveClipDir;
     ImGuiNavMoveResult      NavMoveResultLocal;                 // Best move request candidate within NavWindow
     ImGuiNavMoveResult      NavMoveResultOther;                 // Best move request candidate within NavWindow's flattened hierarchy (when using the NavFlattened flag)
 
@@ -762,8 +775,9 @@ struct ImGuiContext
         NavInitResultId = 0;
         NavMoveFromClampedRefRect = false;
         NavMoveRequest = false;
+        NavMoveRequestFlags = 0;
         NavMoveRequestForward = ImGuiNavForward_None;
-        NavMoveDir = NavMoveDirLast = ImGuiDir_None;
+        NavMoveDir = NavMoveDirLast = NavMoveClipDir = ImGuiDir_None;
 
         ModalWindowDarkeningRatio = 0.0f;
         OverlayDrawList._Data = &DrawListSharedData;
@@ -1069,6 +1083,8 @@ namespace ImGui
 
     IMGUI_API void          NavInitWindow(ImGuiWindow* window, bool force_reinit);
     IMGUI_API void          NavMoveRequestCancel();
+    IMGUI_API void          NavMoveRequestForward(ImGuiDir move_dir, ImGuiDir clip_dir, const ImRect& bb_rel, ImGuiNavMoveFlags move_flags);
+    IMGUI_API void          NavMoveRequestTryWrapping(ImGuiWindow* window, ImGuiNavMoveFlags move_flags);
     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 float         GetNavInputAmount(ImGuiNavInput n, ImGuiInputReadMode mode);