Added CollapsingHeader() variant with close button, obsoleted 4 parameters version. Refactored code into TreeNodeBehavior. (#600)

New flag and declaration makes uses of SetNextTreeNode() functions on
collapsing header more obvious as well (#579).

imgui.cpp

@@ -152,6 +152,7 @@
  Here is a change-log of API breaking changes, if you are using one of the functions listed, expect to have to fix some code.
  Also read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2016/05/01 (1.49) - obsoleted old signature of CollapsingHeader(const char* label, const char* str_id = NULL, bool display_frame = true, bool default_open = false) as extra parameters were badly designed and rarely used. You can replace the "default_open = true" flag in new API with CollapsingHeader(label, ImGuiTreeNodeFlags_DefaultOpen).
  - 2016/04/26 (1.49) - changed ImDrawList::PushClipRect(ImVec4 rect) to ImDraw::PushClipRect(Imvec2 min,ImVec2 max,bool intersect_with_current_clip_rect=false). Note that higher-level ImGui::PushClipRect() is preferable because it will clip at logic/widget level, whereas ImDrawList::PushClipRect() only affect your renderer.
  - 2016/04/03 (1.48) - removed style.WindowFillAlphaDefault setting which was redundant. Bake default BG alpha inside style.Colors[ImGuiCol_WindowBg] and all other Bg color values. (ref github issue #337).
  - 2016/04/03 (1.48) - renamed ImGuiCol_TooltipBg to ImGuiCol_PopupBg, used by popups/menus and tooltips. popups/menus were previously using ImGuiCol_WindowBg. (ref github issue #337)
@@ -5260,7 +5261,15 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     }
 
     bool pressed = false;
-    const bool hovered = IsHovered(bb, id, (flags & ImGuiButtonFlags_FlattenChilds) != 0);
+    bool hovered = IsHovered(bb, id, (flags & ImGuiButtonFlags_FlattenChilds) != 0);
+
+    // AllowOverlap mode (rarely used) requires previous frame HoveredId to be null or to match. This allows using patterns where a later submitted widget overlaps a previous one.
+    if (hovered && (flags & ImGuiButtonFlags_AllowOverlapMode) && (g.HoveredIdPreviousFrame != id && g.HoveredIdPreviousFrame != 0))
+    {
+        SetHoveredID(id);
+        hovered = false;
+    }
+
     if (hovered)
     {
         SetHoveredID(id);
@@ -5626,14 +5635,13 @@ bool ImGui::TreeNodeBehaviorIsOpened(ImGuiID id, ImGuiTreeNodeFlags flags)
 
     // When logging is enabled, we automatically expand tree nodes (but *NOT* collapsing headers.. seems like sensible behavior).
     // NB- If we are above max depth we still allow manually opened nodes to be logged.
-    if (g.LogEnabled && !(flags & ImGuiTreeNodeFlags_NoAutoExpandOnLog) && window->DC.TreeDepth < g.LogAutoExpandMaxDepth)
+    if (g.LogEnabled && !(flags & ImGuiTreeNodeFlags_NoAutoOpenOnLog) && window->DC.TreeDepth < g.LogAutoExpandMaxDepth)
         opened = true;
 
     return opened;
 }
 
-// FIXME: Split into CollapsingHeader(label, default_open?) and TreeNodeBehavior(label), obsolete the 4 parameters function.
-bool ImGui::CollapsingHeader(const char* label, const char* str_id, bool display_frame, bool default_open)
+bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* label, const char* label_end)
 {
     ImGuiWindow* window = GetCurrentWindow();
     if (window->SkipItems)
@@ -5641,20 +5649,16 @@ bool ImGui::CollapsingHeader(const char* label, const char* str_id, bool display
 
     ImGuiState& g = *GImGui;
     const ImGuiStyle& style = g.Style;
+    const bool display_frame = (flags & ImGuiTreeNodeFlags_Framed) != 0;
     const ImVec2 padding = display_frame ? style.FramePadding : ImVec2(style.FramePadding.x, 0.0f);
 
-    IM_ASSERT(str_id != NULL || label != NULL);
-    if (str_id == NULL)
-        str_id = label;
-    if (label == NULL)
-        label = str_id;
-    const bool label_hide_text_after_double_hash = (label == str_id); // Only search and hide text after ## if we have passed label and ID separately, otherwise allow "##" within format string.
-    const ImGuiID id = window->GetID(str_id);
-    const ImVec2 label_size = CalcTextSize(label, NULL, label_hide_text_after_double_hash);
+    if (!label_end)
+        label_end = FindRenderedTextEnd(label);
+    const ImVec2 label_size = CalcTextSize(label, label_end, false);
 
     // We vertically grow up to current line height up the typical widget height.
     const float text_base_offset_y = ImMax(0.0f, window->DC.CurrentLineTextBaseOffset - padding.y); // Latch before ItemSize changes it
-    const float frame_height = ImMax(ImMin(window->DC.CurrentLineHeight, g.FontSize + g.Style.FramePadding.y*2), label_size.y + padding.y*2);
+    const float frame_height = ImMax(ImMin(window->DC.CurrentLineHeight, g.FontSize + style.FramePadding.y*2), label_size.y + padding.y*2);
     ImRect bb = ImRect(window->DC.CursorPos, ImVec2(window->Pos.x + GetContentRegionMax().x, window->DC.CursorPos.y + frame_height));
     if (display_frame)
     {
@@ -5670,12 +5674,15 @@ bool ImGui::CollapsingHeader(const char* label, const char* str_id, bool display
     // For regular tree nodes, we arbitrary allow to click past 2 worth of ItemSpacing
     // (Ideally we'd want to add a flag for the user to specify we want want the hit test to be done up to the right side of the content or not)
     const ImRect interact_bb = display_frame ? bb : ImRect(bb.Min.x, bb.Min.y, bb.Min.x + text_width + style.ItemSpacing.x*2, bb.Max.y);
-    bool opened = TreeNodeBehaviorIsOpened(id, (default_open ? ImGuiTreeNodeFlags_DefaultOpen : 0) | (display_frame ? ImGuiTreeNodeFlags_NoAutoExpandOnLog : 0));
+    bool opened = TreeNodeBehaviorIsOpened(id, flags);
     if (!ItemAdd(interact_bb, &id))
+    {
+        if (opened && !(flags & ImGuiTreeNodeFlags_NoTreePushOnOpen))
+            TreePushRawID(id);
         return opened;
+    }
 
-    bool hovered, held;
-    bool pressed = ButtonBehavior(interact_bb, id, &hovered, &held, ImGuiButtonFlags_NoKeyModifiers);
+    bool hovered, held, pressed = ButtonBehavior(interact_bb, id, &hovered, &held, ImGuiButtonFlags_NoKeyModifiers | ((flags & ImGuiTreeNodeFlags_AllowOverlapMode) ? ImGuiButtonFlags_AllowOverlapMode : 0));
     if (pressed)
     {
         opened = !opened;
@@ -5696,12 +5703,12 @@ bool ImGui::CollapsingHeader(const char* label, const char* str_id, bool display
             const char log_prefix[] = "\n##";
             const char log_suffix[] = "##";
             LogRenderedText(text_pos, log_prefix, log_prefix+3);
-            RenderTextClipped(text_pos, bb.Max, label, NULL, &label_size);
+            RenderTextClipped(text_pos, bb.Max, label, label_end, &label_size);
             LogRenderedText(text_pos, log_suffix+1, log_suffix+3);
         }
         else
         {
-            RenderTextClipped(text_pos, bb.Max, label, NULL, &label_size);
+            RenderTextClipped(text_pos, bb.Max, label, label_end, &label_size);
         }
     }
     else
@@ -5713,44 +5720,58 @@ bool ImGui::CollapsingHeader(const char* label, const char* str_id, bool display
         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, NULL, label_hide_text_after_double_hash);
+        RenderText(text_pos, label, label_end, false);
     }
 
+    if (opened && !(flags & ImGuiTreeNodeFlags_NoTreePushOnOpen))
+        TreePushRawID(id);
     return opened;
 }
 
-// If returning 'true' the node is open and the user is responsible for calling TreePop
-bool ImGui::TreeNodeV(const char* str_id, const char* fmt, va_list args)
+bool ImGui::CollapsingHeader(const char* label, ImGuiTreeNodeFlags flags)
 {
     ImGuiWindow* window = GetCurrentWindow();
     if (window->SkipItems)
         return false;
 
-    ImGuiState& g = *GImGui;
-    ImFormatStringV(g.TempBuffer, IM_ARRAYSIZE(g.TempBuffer), fmt, args);
-    if (!str_id || !str_id[0])
-        str_id = fmt;
+    return TreeNodeBehavior(window->GetID(label), flags | ImGuiTreeNodeFlags_CollapsingHeader | ImGuiTreeNodeFlags_NoTreePushOnOpen, label);
+}
 
-    ImGui::PushID(str_id);
-    const bool opened = ImGui::CollapsingHeader(g.TempBuffer, "", false);
-    ImGui::PopID();
+bool ImGui::CollapsingHeader(const char* label, bool* p_open, ImGuiTreeNodeFlags flags)
+{
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems)
+        return false;
 
-    if (opened)
-        ImGui::TreePush(str_id);
+    if (p_open && !*p_open)
+        return false;
+
+    ImGuiID id = window->GetID(label);
+    bool opened = TreeNodeBehavior(id, flags | ImGuiTreeNodeFlags_CollapsingHeader | ImGuiTreeNodeFlags_NoTreePushOnOpen | (p_open ? ImGuiTreeNodeFlags_AllowOverlapMode : 0), label);
+    if (p_open)
+    {
+        // Create a small overlapping close button // FIXME: We can evolve this into user accessible helpers to add extra buttons on title bars, headers, etc.
+        ImGuiState& g = *GImGui;
+        SetItemAllowOverlap();
+        float button_sz = g.FontSize * 0.5f;
+        if (CloseButton(window->GetID((void*)(intptr_t)(id+1)), ImVec2(window->DC.LastItemRect.Max.x - g.Style.FramePadding.x - button_sz, window->DC.LastItemRect.Min.y + g.Style.FramePadding.y + button_sz), button_sz))
+            *p_open = false;
+    }
 
     return opened;
 }
 
-bool ImGui::TreeNode(const char* str_id, const char* fmt, ...)
+bool ImGui::TreeNodeV(const char* str_id, const char* fmt, va_list args)
 {
-    va_list args;
-    va_start(args, fmt);
-    bool s = TreeNodeV(str_id, fmt, args);
-    va_end(args);
-    return s;
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems)
+        return false;
+
+    ImGuiState& g = *GImGui;
+    const char* label_end = g.TempBuffer + ImFormatStringV(g.TempBuffer, IM_ARRAYSIZE(g.TempBuffer), fmt, args);
+    return TreeNodeBehavior(window->GetID(str_id), 0, g.TempBuffer, label_end);
 }
 
-// If returning 'true' the node is open and the user is responsible for calling TreePop
 bool ImGui::TreeNodeV(const void* ptr_id, const char* fmt, va_list args)
 {
     ImGuiWindow* window = GetCurrentWindow();
@@ -5758,18 +5779,16 @@ bool ImGui::TreeNodeV(const void* ptr_id, const char* fmt, va_list args)
         return false;
 
     ImGuiState& g = *GImGui;
-    ImFormatStringV(g.TempBuffer, IM_ARRAYSIZE(g.TempBuffer), fmt, args);
-
-    if (!ptr_id)
-        ptr_id = fmt;
-
-    ImGui::PushID(ptr_id);
-    const bool opened = ImGui::CollapsingHeader(g.TempBuffer, "", false);
-    ImGui::PopID();
-
-    if (opened)
-        ImGui::TreePush(ptr_id);
+    const char* label_end = g.TempBuffer + ImFormatStringV(g.TempBuffer, IM_ARRAYSIZE(g.TempBuffer), fmt, args);
+    return TreeNodeBehavior(window->GetID(ptr_id ? ptr_id : fmt), 0, g.TempBuffer, label_end);
+}
 
+bool ImGui::TreeNode(const char* str_id, const char* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    bool opened = TreeNodeV(str_id, fmt, args);
+    va_end(args);
     return opened;
 }
 
@@ -5777,14 +5796,18 @@ bool ImGui::TreeNode(const void* ptr_id, const char* fmt, ...)
 {
     va_list args;
     va_start(args, fmt);
-    bool s = TreeNodeV(ptr_id, fmt, args);
+    bool opened = TreeNodeV(ptr_id, fmt, args);
     va_end(args);
-    return s;
+    return opened;
 }
 
-bool ImGui::TreeNode(const char* str_label_id)
+bool ImGui::TreeNode(const char* label)
 {
-    return TreeNode(str_label_id, "%s", str_label_id);
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems)
+        return false;
+
+    return TreeNodeBehavior(window->GetID(label), 0, label, NULL);
 }
 
 void ImGui::SetNextTreeNodeOpened(bool opened, ImGuiSetCond cond)
@@ -9127,6 +9150,14 @@ void ImGui::TreePush(const void* ptr_id)
     PushID(ptr_id ? ptr_id : (const void*)"#TreePush");
 }
 
+void ImGui::TreePushRawID(ImGuiID id)
+{
+    ImGuiWindow* window = GetCurrentWindow();
+    ImGui::Indent();
+    window->DC.TreeDepth++;
+    window->IDStack.push_back(id);
+}
+
 void ImGui::TreePop()
 {
     ImGuiWindow* window = GetCurrentWindow();

imgui.h

@@ -70,6 +70,7 @@ typedef int ImGuiWindowFlags;       // window flags for Begin*()            // e
 typedef int ImGuiSetCond;           // condition flags for Set*()           // enum ImGuiSetCond_
 typedef int ImGuiInputTextFlags;    // flags for InputText*()               // enum ImGuiInputTextFlags_
 typedef int ImGuiSelectableFlags;   // flags for Selectable()               // enum ImGuiSelectableFlags_
+typedef int ImGuiTreeNodeFlags;     // flags for TreeNode*(), Collapsing*() // enum ImGuiTreeNodeFlags_
 typedef int (*ImGuiTextEditCallback)(ImGuiTextEditCallbackData *data);
 
 // Others helpers at bottom of the file:
@@ -251,7 +252,6 @@ namespace ImGui
     IMGUI_API bool          InvisibleButton(const char* str_id, const ImVec2& size);
     IMGUI_API void          Image(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0 = ImVec2(0,0), const ImVec2& uv1 = ImVec2(1,1), const ImVec4& tint_col = ImVec4(1,1,1,1), const ImVec4& border_col = ImVec4(0,0,0,0));
     IMGUI_API bool          ImageButton(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0 = ImVec2(0,0),  const ImVec2& uv1 = ImVec2(1,1), int frame_padding = -1, const ImVec4& bg_col = ImVec4(0,0,0,0), const ImVec4& tint_col = ImVec4(1,1,1,1));    // <0 frame_padding uses default frame padding settings. 0 for no padding
-    IMGUI_API bool          CollapsingHeader(const char* label, const char* str_id = NULL, bool display_frame = true, bool default_open = false);
     IMGUI_API bool          Checkbox(const char* label, bool* v);
     IMGUI_API bool          CheckboxFlags(const char* label, unsigned int* flags, unsigned int flags_value);
     IMGUI_API bool          RadioButton(const char* label, bool active);
@@ -307,15 +307,17 @@ namespace ImGui
     IMGUI_API bool          VSliderInt(const char* label, const ImVec2& size, int* v, int v_min, int v_max, const char* display_format = "%.0f");
 
     // Widgets: Trees
-    IMGUI_API bool          TreeNode(const char* str_label_id);                                     // if returning 'true' the node is open and the user is responsible for calling TreePop().
+    IMGUI_API bool          TreeNode(const char* label);                                            // if returning 'true' the node is open and the tree id is pushed into the id stack. user is responsible for calling TreePop().
     IMGUI_API bool          TreeNode(const char* str_id, const char* fmt, ...) IM_PRINTFARGS(2);    // read the FAQ about why and how to use ID. to align arbitrary text at the same level as a TreeNode() you can use Bullet().
     IMGUI_API bool          TreeNode(const void* ptr_id, const char* fmt, ...) IM_PRINTFARGS(2);    // "
     IMGUI_API bool          TreeNodeV(const char* str_id, const char* fmt, va_list args);           // "
     IMGUI_API bool          TreeNodeV(const void* ptr_id, const char* fmt, va_list args);           // "
-    IMGUI_API void          TreePush(const char* str_id = NULL);                                    // already called by TreeNode(), but you can call Push/Pop yourself for layouting purpose
+    IMGUI_API void          TreePush(const char* str_id = NULL);                                    // already called by TreeNode(), but you can call Push/Pop yourself for layout purpose
     IMGUI_API void          TreePush(const void* ptr_id = NULL);                                    // "
     IMGUI_API void          TreePop();
     IMGUI_API void          SetNextTreeNodeOpened(bool opened, ImGuiSetCond cond = 0);              // set next tree node/collapsing header to be opened.
+    IMGUI_API bool          CollapsingHeader(const char* label, ImGuiTreeNodeFlags flags = 0);      // if returning 'true' the header is open. user doesn't have to call TreePop().
+    IMGUI_API bool          CollapsingHeader(const char* label, bool* p_open, ImGuiTreeNodeFlags flags = 0); // when 'p_open' isn't NULL, display an additional small close button on upper right of the header
 
     // Widgets: Selectable / Lists
     IMGUI_API bool          Selectable(const char* label, bool selected = false, ImGuiSelectableFlags flags = 0, const ImVec2& size = ImVec2(0,0));  // size.x==0.0: use remaining width, size.x>0.0: specify width. size.y==0.0: use label height, size.y>0.0: specify height
@@ -441,6 +443,7 @@ namespace ImGui
 
     // Obsolete (will be removed)
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+    static inline bool      CollapsingHeader(const char* label, const char* str_id, bool display_frame = true, bool default_open = false) { (void)str_id; (void)display_frame; ImGuiTreeNodeFlags default_open_flags = 1<<5; return CollapsingHeader(label, (default_open ? default_open_flags : 0)); } // OBSOLETE 1.49+
     static inline ImFont*   GetWindowFont() { return GetFont(); }                              // OBSOLETE 1.48+
     static inline float     GetWindowFontSize() { return GetFontSize(); }                      // OBSOLETE 1.48+
     static inline void      OpenNextNode(bool open) { ImGui::SetNextTreeNodeOpened(open, 0); } // OBSOLETE 1.34+
@@ -512,6 +515,18 @@ enum ImGuiInputTextFlags_
     ImGuiInputTextFlags_Multiline           = 1 << 20   // For internal use by InputTextMultiline()
 };
 
+// Flags for ImGui::TreeNode*(), ImGui::CollapsingHeader*()
+enum ImGuiTreeNodeFlags_
+{
+    ImGuiTreeNodeFlags_Selected             = 1 << 0,
+    ImGuiTreeNodeFlags_Framed               = 1 << 1,
+    ImGuiTreeNodeFlags_AllowOverlapMode     = 1 << 2,
+    ImGuiTreeNodeFlags_NoTreePushOnOpen     = 1 << 3,
+    ImGuiTreeNodeFlags_NoAutoOpenOnLog      = 1 << 4,
+    ImGuiTreeNodeFlags_DefaultOpen          = 1 << 5,
+    ImGuiTreeNodeFlags_CollapsingHeader     = ImGuiTreeNodeFlags_Framed | ImGuiTreeNodeFlags_NoAutoOpenOnLog,
+};
+
 // Flags for ImGui::Selectable()
 enum ImGuiSelectableFlags_
 {

imgui_demo.cpp

@@ -284,6 +284,23 @@ void ImGui::ShowTestWindow(bool* p_opened)
             ImGui::TreePop();
         }
 
+        if (ImGui::TreeNode("Collapsing Headers"))
+        {
+            static bool closable_group = true;
+            if (ImGui::CollapsingHeader("Header"))
+            {
+                ImGui::Checkbox("Enable extra group", &closable_group);
+                for (int i = 0; i < 5; i++)
+                    ImGui::Text("Some content %d", i);
+            }
+            if (ImGui::CollapsingHeader("Header with a close button", &closable_group))
+            {
+                for (int i = 0; i < 5; i++)
+                    ImGui::Text("More content %d", i);
+            }
+            ImGui::TreePop();
+        }
+
         if (ImGui::TreeNode("Bullets"))
         {
             ImGui::BulletText("Bullet point 1");

imgui_internal.h

@@ -161,13 +161,8 @@ enum ImGuiButtonFlags_
     ImGuiButtonFlags_DontClosePopups        = 1 << 5,   // disable automatically closing parent popup on press
     ImGuiButtonFlags_Disabled               = 1 << 6,   // disable interaction
     ImGuiButtonFlags_AlignTextBaseLine      = 1 << 7,   // vertically align button to match text baseline - ButtonEx() only
-    ImGuiButtonFlags_NoKeyModifiers         = 1 << 8    // disable interaction if a key modifier is held
-};
-
-enum ImGuiTreeNodeFlags_
-{
-    ImGuiTreeNodeFlags_DefaultOpen          = 1 << 0,
-    ImGuiTreeNodeFlags_NoAutoExpandOnLog    = 1 << 1
+    ImGuiButtonFlags_NoKeyModifiers         = 1 << 8,   // disable interaction if a key modifier is held
+    ImGuiButtonFlags_AllowOverlapMode       = 1 << 9    // require previous frame HoveredId to either match id or be null before being usable
 };
 
 enum ImGuiSliderFlags_
@@ -730,7 +725,9 @@ namespace ImGui
     IMGUI_API bool          InputScalarEx(const char* label, ImGuiDataType data_type, void* data_ptr, void* step_ptr, void* step_fast_ptr, const char* scalar_format, ImGuiInputTextFlags extra_flags);
     IMGUI_API bool          InputScalarAsWidgetReplacement(const ImRect& aabb, const char* label, ImGuiDataType data_type, void* data_ptr, ImGuiID id, int decimal_precision);
 
+    IMGUI_API bool          TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* label, const char* label_end = NULL);
     IMGUI_API bool          TreeNodeBehaviorIsOpened(ImGuiID id, ImGuiTreeNodeFlags flags = 0);                     // Consume previous SetNextTreeNodeOpened() data, if any. May return true when logging
+    IMGUI_API void          TreePushRawID(ImGuiID id);
 
     IMGUI_API void          PlotEx(ImGuiPlotType plot_type, const char* label, float (*values_getter)(void* data, int idx), void* data, int values_count, int values_offset, const char* overlay_text, float scale_min, float scale_max, ImVec2 graph_size);