Internals: Added TreeNodeIsOpen() to facilitate discoverability. (ocornut#7553, ocornut#1131, ocornut#2958, ocornut#2079, ocornut#722)

Author: ocornut

imgui_internal.h

@@ -3469,6 +3469,7 @@ namespace ImGui
     IMGUI_API bool          SplitterBehavior(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float* size1, float* size2, float min_size1, float min_size2, float hover_extend = 0.0f, float hover_visibility_delay = 0.0f, ImU32 bg_col = 0);
     IMGUI_API bool          TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* label, const char* label_end = NULL);
     IMGUI_API void          TreePushOverrideID(ImGuiID id);
+    IMGUI_API bool          TreeNodeIsOpen(ImGuiID id);
     IMGUI_API void          TreeNodeSetOpen(ImGuiID id, bool open);
     IMGUI_API bool          TreeNodeUpdateNextOpen(ImGuiID id, ImGuiTreeNodeFlags flags);   // Return open state. Consume previous SetNextItemOpen() data, if any. May return true when logging.
     IMGUI_API void          SetNextItemSelectionUserData(ImGuiSelectionUserData selection_user_data);

imgui_widgets.cpp

@@ -6257,6 +6257,13 @@ bool ImGui::TreeNodeExV(const void* ptr_id, ImGuiTreeNodeFlags flags, const char
     return TreeNodeBehavior(window->GetID(ptr_id), flags, label, label_end);
 }
 
+bool ImGui::TreeNodeIsOpen(ImGuiID id)
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiStorage* storage = g.CurrentWindow->DC.StateStorage;
+    return storage->GetInt(id, 0) != 0;
+}
+
 void ImGui::TreeNodeSetOpen(ImGuiID id, bool open)
 {
     ImGuiContext& g = *GImGui;
@@ -6269,7 +6276,7 @@ bool ImGui::TreeNodeUpdateNextOpen(ImGuiID id, ImGuiTreeNodeFlags flags)
     if (flags & ImGuiTreeNodeFlags_Leaf)
         return true;
 
-    // We only write to the tree storage if the user clicks (or explicitly use the SetNextItemOpen function)
+    // We only write to the tree storage if the user clicks, or explicitly use the SetNextItemOpen function
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
     ImGuiStorage* storage = window->DC.StateStorage;
@@ -6311,6 +6318,7 @@ bool ImGui::TreeNodeUpdateNextOpen(ImGuiID id, ImGuiTreeNodeFlags flags)
 }
 
 // Store ImGuiTreeNodeStackData for just submitted node.
+// Currently only supports 32 level deep and we are fine with (1 << Depth) overflowing into a zero, easy to increase.
 static void TreeNodeStoreStackData(ImGuiTreeNodeFlags flags)
 {
     ImGuiContext& g = *GImGui;
@@ -6393,7 +6401,6 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
     // Store data for the current depth to allow returning to this node from any child item.
     // For this purpose we essentially compare if g.NavIdIsAlive went from 0 to 1 between TreeNode() and TreePop().
     // It will become tempting to enable ImGuiTreeNodeFlags_NavLeftJumpsBackHere by default or move it to ImGuiStyle.
-    // Currently only supports 32 level deep and we are fine with (1 << Depth) overflowing into a zero, easy to increase.
     bool store_tree_node_stack_data = false;
     if (!(flags & ImGuiTreeNodeFlags_NoTreePushOnOpen))
     {
@@ -6517,7 +6524,6 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
             text_pos.x -= text_offset_x -padding.x;
         if (flags & ImGuiTreeNodeFlags_ClipLabelForTrailingButton)
             frame_bb.Max.x -= g.FontSize + style.FramePadding.x;
-
         if (g.LogEnabled)
             LogSetNextTextDecoration("###", "###");
     }
@@ -6550,7 +6556,7 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
     if (store_tree_node_stack_data && is_open)
         TreeNodeStoreStackData(flags); // Call before TreePushOverrideID()
     if (is_open && !(flags & ImGuiTreeNodeFlags_NoTreePushOnOpen))
-        TreePushOverrideID(id);
+        TreePushOverrideID(id); // Could use TreePush(label) but this avoid computing twice
 
     IMGUI_TEST_ENGINE_ITEM_INFO(id, label, g.LastItemData.StatusFlags | (is_leaf ? 0 : ImGuiItemStatusFlags_Openable) | (is_open ? ImGuiItemStatusFlags_Opened : 0));
     return is_open;