Tables: clamp vertical border Y2 position when not using scrolling table, so that ImDrawCmd AABB stays reasonable.

This does not fix any screen visible issue, and should not be noticeable if correct.
(context: investigated this while looking at #4678, but not actually directly related)

docs/CHANGELOG.txt

@@ -78,6 +78,9 @@ Other Changes:
 - Popups:
   - Modals: fixed an assert displaying a modal in an environment where
     `io.DisplayFramebufferScale` is not an integer (regression in 1.93.0). (#9598)
+- Tables:
+  - In non-scrolling tables, clamp lower border coordinates to stay within visible
+    range (no visible changes, but ImDrawCmd AABB becomes more sensible).
 - ImVec2: added a check for cases where a custom `IM_VEC2_CLASS_EXTRA` macro
   adds an extra `operator=` to ImVec2. This isn't supported but should not
   be needed as you should have a constructor to convert from your type to ImVec2.

imgui.h

@@ -30,7 +30,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM >= 12345')
 #define IMGUI_VERSION       "1.93.1 WIP"
-#define IMGUI_VERSION_NUM   19301
+#define IMGUI_VERSION_NUM   19302
 #define IMGUI_HAS_TABLE             // Added BeginTable() - from IMGUI_VERSION_NUM >= 18000
 #define IMGUI_HAS_TEXTURES          // Added ImGuiBackendFlags_RendererHasTextures - from IMGUI_VERSION_NUM >= 19198
 

imgui_tables.cpp

@@ -2951,19 +2951,24 @@ static ImU32 TableGetColumnBorderCol(ImGuiTable* table, int order_n, int column_
 void ImGui::TableDrawBorders(ImGuiTable* table)
 {
     ImGuiWindow* inner_window = table->InnerWindow;
-    if (!table->OuterWindow->ClipRect.Overlaps(table->OuterRect))
+    if (!table->OuterWindow->ClipRect.Overlaps(table->OuterRect)) // Note how OuterWindow->ClipRect == table->Bg0ClipRectForDrawCmd
         return;
 
     ImDrawList* inner_drawlist = inner_window->DrawList;
     table->DrawSplitter->SetCurrentChannel(inner_drawlist, TABLE_DRAW_CHANNEL_BG0);
-    inner_drawlist->PushClipRect(table->Bg0ClipRectForDrawCmd.Min, table->Bg0ClipRectForDrawCmd.Max, false);
+    inner_drawlist->PushClipRect(table->OuterWindow->ClipRect.Min, table->OuterWindow->ClipRect.Max, false);
+
+    const float border_size = TABLE_BORDER_SIZE;
+
+    // For e.g. non scrolling table we limit vertex coordinates in order to keep ImDrawCmd AABB roughly within visible range.
+    const float draw_y2_limit = table->OuterWindow->ClipRect.Max.y + (2.0f * ImMax(border_size, inner_drawlist->_FringeScale));
 
     // Draw inner border and resizing feedback
     ImGuiTableInstanceData* table_instance = TableGetInstanceData(table, table->InstanceCurrent);
-    const float border_size = TABLE_BORDER_SIZE;
     const float draw_y1 = ImMax(table->InnerRect.Min.y, (table->FreezeRowsCount >= 1 ? table->InnerRect.Min.y : table->WorkRect.Min.y) + table->AngledHeadersHeight) + ((table->Flags & ImGuiTableFlags_BordersOuterH) ? border_size : 0.0f);
-    const float draw_y2_body = table->InnerRect.Max.y;
+    const float draw_y2_body = ImMin(table->InnerRect.Max.y, draw_y2_limit);
-    const float draw_y2_head = table->IsUsingHeaders ? ImMin(table->InnerRect.Max.y, (table->FreezeRowsCount >= 1 ? table->InnerRect.Min.y : table->WorkRect.Min.y) + table_instance->LastTopHeadersRowHeight) : draw_y1;
+    const float draw_y2_head = table->IsUsingHeaders ? ImMin(draw_y2_body, (table->FreezeRowsCount >= 1 ? table->InnerRect.Min.y : table->WorkRect.Min.y) + table_instance->LastTopHeadersRowHeight) : draw_y1;
+
     if (table->Flags & ImGuiTableFlags_BordersInnerV)
     {
         for (int order_n = 0; order_n < table->ColumnsCount; order_n++)
@@ -3009,7 +3014,8 @@ void ImGui::TableDrawBorders(ImGuiTable* table)
         // parent. In inner_window, it won't reach out over scrollbars. Another weird solution would be to display part
         // of it in inner window, and the part that's over scrollbars in the outer window..)
         // Either solution currently won't allow us to use a larger border size: the border would clipped.
-        const ImRect outer_border = table->OuterRect;
+        ImRect outer_border = table->OuterRect;
+        outer_border.Max.y = ImMin(outer_border.Max.y, draw_y2_limit); // Clamp but keep bottom border non-visible.
         const ImU32 outer_col = table->BorderColorStrong;
         if ((table->Flags & ImGuiTableFlags_BordersOuter) == ImGuiTableFlags_BordersOuter)
         {