TreeNode: added ImGuiTreeNodeFlags_AlwaysOpen flag (#581, #324)

imgui.cpp

@@ -5600,6 +5600,9 @@ void ImGui::LogButtons()
 
 bool ImGui::TreeNodeBehaviorIsOpened(ImGuiID id, ImGuiTreeNodeFlags flags)
 {
+    if (flags & ImGuiTreeNodeFlags_AlwaysOpen)
+        return true;
+
     // We only write to the tree storage if the user clicks (or explicitely use SetNextTreeNode*** functions)
     ImGuiState& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
@@ -5692,7 +5695,7 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
     if (flags & ImGuiTreeNodeFlags_OpenOnDoubleClick)
         button_flags |= ImGuiButtonFlags_PressedOnDoubleClick | ((flags & ImGuiTreeNodeFlags_OpenOnArrow) ? ImGuiButtonFlags_PressedOnClickRelease : 0);
     bool hovered, held, pressed = ButtonBehavior(interact_bb, id, &hovered, &held, button_flags);
-    if (pressed)
+    if (pressed && !(flags & ImGuiTreeNodeFlags_AlwaysOpen))
     {
         bool toggled = !(flags & (ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick));
         if (flags & ImGuiTreeNodeFlags_OpenOnArrow)
@@ -5736,7 +5739,10 @@ bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* l
         if (hovered || (flags & ImGuiTreeNodeFlags_Selected))
             RenderFrame(bb.Min, bb.Max, col, false);
 
-        RenderCollapseTriangle(bb.Min + ImVec2(padding.x, g.FontSize*0.15f + text_base_offset_y), opened, 0.70f, false);
+        if (flags & ImGuiTreeNodeFlags_AlwaysOpen)
+            RenderBullet(bb.Min + ImVec2((padding.x + collapser_width) * 0.5f, g.FontSize*0.50f + text_base_offset_y));
+        else
+            RenderCollapseTriangle(bb.Min + ImVec2(padding.x, g.FontSize*0.15f + text_base_offset_y), opened, 0.70f, false);
         if (g.LogEnabled)
             LogRenderedText(text_pos, ">");
         RenderText(text_pos, label, label_end, false);

imgui.h

@@ -532,7 +532,7 @@ enum ImGuiTreeNodeFlags_
     ImGuiTreeNodeFlags_DefaultOpen          = 1 << 5,   // Default node to be opened
     ImGuiTreeNodeFlags_OpenOnDoubleClick    = 1 << 6,   // Need double-click to open node
     ImGuiTreeNodeFlags_OpenOnArrow          = 1 << 7,   // Only open when clicking on the arrow part. If ImGuiTreeNodeFlags_OpenOnDoubleClick is also set, single-click arrow or double-click all box to open.
-    //ImGuiTreeNodeFlags_AlwaysOpen         = 1 << 8,   // No collapsing, no arrow (use as a convenience for leaf nodes). 
+    ImGuiTreeNodeFlags_AlwaysOpen           = 1 << 8,   // No collapsing, no arrow (use as a convenience for leaf nodes). 
     //ImGuiTreeNodeFlags_UnindentArrow      = 1 << 9,   // FIXME: TODO: Unindent tree so that Label is aligned to current X position
     //ImGuITreeNodeFlags_SpanAllAvailWidth  = 1 << 10,  // FIXME: TODO: Extend hit box horizontally even if not framed
     //ImGuiTreeNodeFlags_NoScrollOnOpen     = 1 << 11,  // FIXME: TODO: Automatically scroll on TreePop() if node got just opened and contents is not visible
@@ -695,7 +695,7 @@ struct ImGuiStyle
     ImVec2      ItemSpacing;                // Horizontal and vertical spacing between widgets/lines
     ImVec2      ItemInnerSpacing;           // Horizontal and vertical spacing between within elements of a composed widget (e.g. a slider and its label)
     ImVec2      TouchExtraPadding;          // Expand reactive bounding box for touch-based system where touch position is not accurate enough. Unfortunately we don't sort widgets so priority on overlap will always be given to the first widget. So don't grow this too much!
-    float       IndentSpacing;              // Horizontal indentation when e.g. entering a tree node
+    float       IndentSpacing;              // Horizontal indentation when e.g. entering a tree node. Generally == (FontSize + FramePadding.x*2)
     float       ColumnsMinSpacing;          // Minimum horizontal spacing between two columns
     float       ScrollbarSize;              // Width of the vertical scrollbar, Height of the horizontal scrollbar
     float       ScrollbarRounding;          // Radius of grab corners for scrollbar

imgui_demo.cpp

@@ -291,11 +291,14 @@ void ImGui::ShowTestWindow(bool* p_opened)
                 for (int i = 0; i < 6; i++)
                 {
                     ImGuiTreeNodeFlags node_flags = ((selection_mask & (1 << i)) ? ImGuiTreeNodeFlags_Selected : 0) | ImGuiTreeNodeFlags_OpenOnArrow | ImGuiTreeNodeFlags_OpenOnDoubleClick;
-                    bool opened = ImGui::TreeNodeEx((void*)(intptr_t)i, node_flags, "Selectable Child %d", i);
+                    if (i >= 3)
+                        node_flags |= ImGuiTreeNodeFlags_AlwaysOpen;
+                    bool opened = ImGui::TreeNodeEx((void*)(intptr_t)i, node_flags, "Selectable %s %d", (i >= 3) ? "Leaf" : "Node", i);
                     if (ImGui::IsItemClicked()) 
                         node_clicked = i;
                     if (opened)
                     {
+                        ImGui::Text("Blah blah");
                         ImGui::Text("Blah blah");
                         ImGui::TreePop();
                     }