diff --git a/imgui_demo.cpp b/imgui_demo.cpp index eba615e1..08798e18 100644 --- a/imgui_demo.cpp +++ b/imgui_demo.cpp @@ -262,13 +262,14 @@ void* GImGuiDemoMarkerCallbackUserData = NULL; struct ExampleTreeNode { // Tree structure - char Name[28]; + char Name[28] = ""; int UID = 0; ExampleTreeNode* Parent = NULL; ImVector Childs; + unsigned short IndexInParent = 0; // Maintaining this allows us to implement linear traversal more easily // Leaf Data - bool HasData = false; // All leaves have data + bool HasData = false; // All leaves have data bool DataMyBool = true; int DataMyInt = 128; ImVec2 DataMyVec2 = ImVec2(0.0f, 3.141592f); @@ -298,6 +299,7 @@ static ExampleTreeNode* ExampleTree_CreateNode(const char* name, int uid, Exampl snprintf(node->Name, IM_ARRAYSIZE(node->Name), "%s", name); node->UID = uid; node->Parent = parent; + node->IndexInParent = parent ? (unsigned short)parent->Childs.Size : 0; if (parent) parent->Childs.push_back(node); return node; @@ -3442,6 +3444,160 @@ static void ShowDemoWindowMultiSelect(DemoWindowData* demo_data) ImGui::TreePop(); } + // Demonstrate supporting multiple-selection in a tree. + // - We don't use linear indices for selection user data, but our ExampleTreeNode* pointer directly! + // This showcase how SetNextItemSelectionUserData() never assume indices! + // - The difficulty here is to "interpolate" from RangeSrcItem to RangeDstItem in the SetAll/SetRange request. + // We want this interpolation to match what the user sees: in visible order, skipping closed nodes. + // This is implemented by our TreeGetNextNodeInVisibleOrder() user-space helper. + // - Important: In a real codebase aiming to implement full-featured selectable tree with custom filtering, you + // are more likely to build an array mapping sequential indices to visible tree nodes, since your + // filtering/search + clipping process will benefit from it. Having this will make this interpolation much easier. + // - Consider this a prototype: we are working toward simplifying some of it. + IMGUI_DEMO_MARKER("Widgets/Selection State/Multi-Select (trees)"); + if (ImGui::TreeNode("Multi-Select (trees)")) + { + HelpMarker( + "This is rather advanced and experimental. If you are getting started with multi-select," + "please don't start by looking at how to use it for a tree!\n\n" + "Future versions will try to simplify and formalize some of this."); + + struct ExampleTreeFuncs + { + static void DrawNode(ExampleTreeNode* node, ImGuiSelectionBasicStorage* selection) + { + ImGuiTreeNodeFlags tree_node_flags = ImGuiTreeNodeFlags_SpanAvailWidth | ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick; + tree_node_flags |= ImGuiTreeNodeFlags_NavLeftJumpsBackHere; // Enable pressing left to jump to parent + if (node->Childs.Size == 0) + tree_node_flags |= ImGuiTreeNodeFlags_Bullet | ImGuiTreeNodeFlags_Leaf; + if (selection->Contains((ImGuiID)node->UID)) + tree_node_flags |= ImGuiTreeNodeFlags_Selected; + + // Using SetNextItemStorageID() to specify storage id, so we can easily peek into + // the storage holding open/close stage, using our TreeNodeGetOpen/TreeNodeSetOpen() functions. + ImGui::SetNextItemSelectionUserData((ImGuiSelectionUserData)(intptr_t)node); + ImGui::SetNextItemStorageID((ImGuiID)node->UID); + if (ImGui::TreeNodeEx(node->Name, tree_node_flags)) + { + for (ExampleTreeNode* child : node->Childs) + DrawNode(child, selection); + ImGui::TreePop(); + } + else if (ImGui::IsItemToggledOpen()) + { + TreeCloseAndUnselectChildNodes(node, selection); + } + } + + static bool TreeNodeGetOpen(ExampleTreeNode* node) + { + return ImGui::GetStateStorage()->GetBool((ImGuiID)node->UID); + } + + static void TreeNodeSetOpen(ExampleTreeNode* node, bool open) + { + ImGui::GetStateStorage()->SetBool((ImGuiID)node->UID, open); + } + + // When closing a node: 1) close and unselect all child nodes, 2) select parent if any child was selected. + // FIXME: This is currently handled by user logic but I'm hoping to eventually provide tree node + // features to do this automatically, e.g. a ImGuiTreeNodeFlags_AutoCloseChildNodes etc. + static int TreeCloseAndUnselectChildNodes(ExampleTreeNode* node, ImGuiSelectionBasicStorage* selection, int depth = 0) + { + // Recursive close (the test for depth == 0 is because we call this on a node that was just closed!) + int unselected_count = selection->Contains((ImGuiID)node->UID) ? 1 : 0; + if (depth == 0 || TreeNodeGetOpen(node)) + { + for (ExampleTreeNode* child : node->Childs) + unselected_count += TreeCloseAndUnselectChildNodes(child, selection, depth + 1); + TreeNodeSetOpen(node, false); + } + + // Select root node if any of its child was selected, otherwise unselect + selection->SetItemSelected((ImGuiID)node->UID, (depth == 0 && unselected_count > 0)); + return unselected_count; + } + + // Apply multi-selection requests + static void ApplySelectionRequests(ImGuiMultiSelectIO* ms_io, ExampleTreeNode* tree, ImGuiSelectionBasicStorage* selection) + { + for (ImGuiSelectionRequest& req : ms_io->Requests) + { + if (req.Type == ImGuiSelectionRequestType_SetAll) + { + if (req.Selected) + TreeSetAllInOpenNodes(tree, selection, req.Selected); + else + selection->Clear(); + } + else if (req.Type == ImGuiSelectionRequestType_SetRange) + { + ExampleTreeNode* first_node = (ExampleTreeNode*)(intptr_t)req.RangeFirstItem; + ExampleTreeNode* last_node = (ExampleTreeNode*)(intptr_t)req.RangeLastItem; + for (ExampleTreeNode* node = first_node; node != NULL; node = TreeGetNextNodeInVisibleOrder(node, last_node)) + selection->SetItemSelected((ImGuiID)node->UID, req.Selected); + } + } + } + + static void TreeSetAllInOpenNodes(ExampleTreeNode* node, ImGuiSelectionBasicStorage* selection, bool selected) + { + if (node->Parent != NULL) // Root node isn't visible nor selectable in our scheme + selection->SetItemSelected((ImGuiID)node->UID, selected); + if (node->Parent == NULL || TreeNodeGetOpen(node)) + for (ExampleTreeNode* child : node->Childs) + TreeSetAllInOpenNodes(child, selection, selected); + } + + // Interpolate in *user-visible order* AND only *over opened nodes*. + // If you have a sequential mapping tables (e.g. generated after a filter/search pass) this would be simpler. + // Here the tricks are that: + // - we store/maintain ExampleTreeNode::IndexInParent which allows implementing a linear iterator easily, without searches, without recursion. + // this could be replaced by a search in parent, aka 'int index_in_parent = curr_node->Parent->Childs.find_index(curr_node)' + // which would only be called when crossing from child to a parent, aka not too much. + // - we call SetNextItemStorageID() before our TreeNode() calls with an ID which doesn't relate to UI stack, + // making it easier to call TreeNodeGetOpen()/TreeNodeSetOpen() from any location. + static ExampleTreeNode* TreeGetNextNodeInVisibleOrder(ExampleTreeNode* curr_node, ExampleTreeNode* last_node) + { + // Reached last node + if (curr_node == last_node) + return NULL; + + // Recurse into childs. Query storage to tell if the node is open. + if (curr_node->Childs.Size > 0 && TreeNodeGetOpen(curr_node)) + return curr_node->Childs[0]; + + // Next sibling, then into our own parent + while (curr_node->Parent != NULL) + { + if (curr_node->IndexInParent + 1 < curr_node->Parent->Childs.Size) + return curr_node->Parent->Childs[curr_node->IndexInParent + 1]; + curr_node = curr_node->Parent; + } + return NULL; + } + + }; // ExampleTreeFuncs + + static ImGuiSelectionBasicStorage selection; + static ExampleTreeNode* tree = ExampleTree_CreateDemoTree(); // Create tree once + ImGui::Text("Selection size: %d", selection.Size); + + if (ImGui::BeginChild("##Tree", ImVec2(-FLT_MIN, ImGui::GetFontSize() * 20), ImGuiChildFlags_FrameStyle | ImGuiChildFlags_ResizeY)) + { + ImGuiMultiSelectFlags ms_flags = ImGuiMultiSelectFlags_ClearOnEscape | ImGuiMultiSelectFlags_BoxSelect2d; + ImGuiMultiSelectIO* ms_io = ImGui::BeginMultiSelect(ms_flags, selection.Size, -1); + ExampleTreeFuncs::ApplySelectionRequests(ms_io, tree, &selection); + for (ExampleTreeNode* node : tree->Childs) + ExampleTreeFuncs::DrawNode(node, &selection); + ms_io = ImGui::EndMultiSelect(); + ExampleTreeFuncs::ApplySelectionRequests(ms_io, tree, &selection); + } + ImGui::EndChild(); + + ImGui::TreePop(); + } + // Advanced demonstration of BeginMultiSelect() // - Showcase clipping. // - Showcase deletion.