Internals: added facility to hide windows from render without interfering with the HiddenFramesCanSkipItems/HiddenFramesCannotSkipItems fields which have effects on layout. Compact some fields.

Ideally we'd have a simpler system but it's not easy to make the capture system change to hook at the right spot. Will rework.

imgui.cpp

@@ -5668,6 +5668,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             window->HiddenFramesCanSkipItems--;
         if (window->HiddenFramesCannotSkipItems > 0)
             window->HiddenFramesCannotSkipItems--;
+        if (window->HiddenFramesForRenderOnly > 0)
+            window->HiddenFramesForRenderOnly--;
 
         // Hide new windows for one frame until they calculate their size
         if (window_just_created && (!window_size_x_set_by_api || !window_size_y_set_by_api))
@@ -6121,7 +6123,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             window->HiddenFramesCanSkipItems = 1;
 
         // Update the Hidden flag
-        window->Hidden = (window->HiddenFramesCanSkipItems > 0) || (window->HiddenFramesCannotSkipItems > 0);
+        window->Hidden = (window->HiddenFramesCanSkipItems > 0) || (window->HiddenFramesCannotSkipItems > 0) || (window->HiddenFramesForRenderOnly > 0);
 
         // Update the SkipItems flag, used to early out of all items functions (no layout required)
         bool skip_items = false;
@@ -7788,7 +7790,7 @@ void ImGui::BeginTooltipEx(ImGuiWindowFlags extra_flags, ImGuiTooltipFlags toolt
             {
                 // Hide previous tooltip from being displayed. We can't easily "reset" the content of a window so we create a new one.
                 window->Hidden = true;
-                window->HiddenFramesCanSkipItems = 1;
+                window->HiddenFramesCanSkipItems = 1; // FIXME: This may not be necessary?
                 ImFormatString(window_name, IM_ARRAYSIZE(window_name), "##Tooltip_%02d", ++g.TooltipOverrideCount);
             }
     ImGuiWindowFlags flags = ImGuiWindowFlags_Tooltip | ImGuiWindowFlags_NoInputs | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_AlwaysAutoResize;

imgui_internal.h

@@ -1722,11 +1722,12 @@ struct IMGUI_API ImGuiWindow
     ImS8                    AutoFitChildAxises;
     bool                    AutoFitOnlyGrows;
     ImGuiDir                AutoPosLastDirection;
-    int                     HiddenFramesCanSkipItems;           // Hide the window for N frames
-    int                     HiddenFramesCannotSkipItems;        // Hide the window for N frames while allowing items to be submitted so we can measure their size
-    ImGuiCond               SetWindowPosAllowFlags;             // store acceptable condition flags for SetNextWindowPos() use.
-    ImGuiCond               SetWindowSizeAllowFlags;            // store acceptable condition flags for SetNextWindowSize() use.
-    ImGuiCond               SetWindowCollapsedAllowFlags;       // store acceptable condition flags for SetNextWindowCollapsed() use.
+    ImS8                    HiddenFramesCanSkipItems;           // Hide the window for N frames
+    ImS8                    HiddenFramesCannotSkipItems;        // Hide the window for N frames while allowing items to be submitted so we can measure their size
+    ImS8                    HiddenFramesForRenderOnly;          // Hide the window until frame N at Render() time only
+    ImGuiCond               SetWindowPosAllowFlags : 8;         // store acceptable condition flags for SetNextWindowPos() use.
+    ImGuiCond               SetWindowSizeAllowFlags : 8;        // store acceptable condition flags for SetNextWindowSize() use.
+    ImGuiCond               SetWindowCollapsedAllowFlags : 8;   // store acceptable condition flags for SetNextWindowCollapsed() use.
     ImVec2                  SetWindowPosVal;                    // store window position when using a non-zero Pivot (position set needs to be processed when we know the window size)
     ImVec2                  SetWindowPosPivot;                  // store window pivot for positioning. ImVec2(0, 0) when positioning from top-left corner; ImVec2(0.5f, 0.5f) for centering; ImVec2(1, 1) for bottom right.
 

imgui_tables.cpp

@@ -716,8 +716,8 @@ void ImGui::TableUpdateLayout(ImGuiTable* table)
         // Combine width from regular rows + width from headers unless requested not to.
         if (!column->IsPreserveWidthAuto)
         {
-            const float content_width_body = (float)ImMax(column->ContentMaxXFrozen, column->ContentMaxXUnfrozen) - column->WorkMinX;
-            const float content_width_headers = (float)column->ContentMaxXHeadersIdeal - column->WorkMinX;
+            const float content_width_body = ImMax(column->ContentMaxXFrozen, column->ContentMaxXUnfrozen) - column->WorkMinX;
+            const float content_width_headers = column->ContentMaxXHeadersIdeal - column->WorkMinX;
             float width_auto = content_width_body;
             if (!(table->Flags & ImGuiTableFlags_NoHeadersWidth) && !(column->Flags & ImGuiTableColumnFlags_NoHeaderWidth))
                 width_auto = ImMax(width_auto, content_width_headers);