Merge branch 'viewport' into docking

# Conflicts:
#	docs/TODO.txt
#	imgui.cpp
#	imgui.h
#	imgui_demo.cpp
#	imgui_draw.cpp
#	imgui_internal.h
#	imgui_widgets.cpp

docs/CHANGELOG.txt

@@ -45,15 +45,6 @@ HOW TO UPDATE?
   - Added io.ConfigDockingWithShift option to configure docking mode.
   - Style: Added ImGuiCol_DockingPreview, ImGuiCol_DockingEmptyBg colors.
   - Demo: Added "DockSpace" example app showcasing use of explicit dockspace nodes.
-- Added Tab Bar/Tabs widgets: (#261, #351)
-  - Added BeginTabBar(), EndTabBar(), BeginTabItem(), EndTabItem(), SetTabItemClosed() API.
-  - Added ImGuiTabBarFlags flags for BeginTabBar().
-  - Added ImGuiTabItemFlags flags for BeginTabItem().
-  - Style: Added ImGuiCol_Tab, ImGuiCol_TabHovered, ImGuiCol_TabActive, ImGuiCol_TabUnfocused, ImGuiCol_TabUnfocusedActive colors.
-  - Demo: Added Layout->Tabs demo code.
-  - Demo: Added "Documents" example app showcasing possible use for tabs.
-- Added ImGuiWindowFlags_UnsavedDocument window flag to append '*' to title without altering 
-  the ID, as a convenience to avoid using the ### operator. 
 
 
 -----------------------------------------------------------------------
@@ -66,6 +57,17 @@ Breaking Changes:
   The addition of new configuration options in the Docking branch is pushing for a little reorganization of those names.
 
 Other Changes:
+- Added BETA api for Tab Bar/Tabs widgets: (#261, #351)
+  - Added BeginTabBar(), EndTabBar(), BeginTabItem(), EndTabItem(), SetTabItemClosed() API.
+  - Added ImGuiTabBarFlags flags for BeginTabBar().
+  - Added ImGuiTabItemFlags flags for BeginTabItem().
+  - Style: Added ImGuiCol_Tab, ImGuiCol_TabHovered, ImGuiCol_TabActive, ImGuiCol_TabUnfocused, ImGuiCol_TabUnfocusedActive colors.
+  - Demo: Added Layout->Tabs demo code.
+  - Demo: Added "Documents" example app showcasing possible use for tabs.
+  This feature was merged from the Docking branch in order to allow the use of regular tabs in your code.
+  (It does not provide the docking/splitting/merging of windows available in the Docking branch)
+- Added ImGuiWindowFlags_UnsavedDocument window flag to append '*' to title without altering 
+  the ID, as a convenience to avoid using the ### operator.
 - Resizing windows from edge is now enabled by default (io.ConfigWindowsResizeFromEdges=true). Note that 
   it only works _if_ the back-end sets ImGuiBackendFlags_HasMouseCursors, which the standard back-end do.
 - Added io.ConfigWindowsMoveFromTitleBarOnly option. Still is ignored by window with no title bars (often popups).

imgui.cpp

@@ -2368,7 +2368,7 @@ ImGuiWindow::ImGuiWindow(ImGuiContext* context, const char* name)
     Name = ImStrdup(name);
     ID = ImHash(name, 0);
     IDStack.push_back(ID);
-    Flags = FlagsPreviousFrame = 0;
+    Flags = FlagsPreviousFrame = ImGuiWindowFlags_None;
     Viewport = NULL;
     ViewportId = 0;
     ViewportAllowPlatformMonitorExtend = -1;
@@ -2677,7 +2677,7 @@ bool ImGui::ItemAdd(const ImRect& bb, ImGuiID id, const ImRect* nav_bb_arg)
 
     window->DC.LastItemId = id;
     window->DC.LastItemRect = bb;
-    window->DC.LastItemStatusFlags = 0;
+    window->DC.LastItemStatusFlags = ImGuiItemStatusFlags_None;
 
 #ifdef IMGUI_ENABLE_TEST_ENGINE
     ImGuiTestEngineHook_ItemAdd(id, bb);
@@ -8691,7 +8691,7 @@ static void ImGui::NavUpdate()
     if (g.NavMoveRequestForward == ImGuiNavForward_None)
     {
         g.NavMoveDir = ImGuiDir_None;
-        g.NavMoveRequestFlags = 0;
+        g.NavMoveRequestFlags = ImGuiNavMoveFlags_None;
         if (g.NavWindow && !g.NavWindowingTarget && allowed_dir_flags && !(g.NavWindow->Flags & ImGuiWindowFlags_NoNavInputs))
         {
             if ((allowed_dir_flags & (1<<ImGuiDir_Left))  && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadLeft, ImGuiNavInput_KeyLeft_, ImGuiInputReadMode_Repeat)) g.NavMoveDir = ImGuiDir_Left;
@@ -9446,7 +9446,7 @@ void ImGui::ClearDragDrop()
     ImGuiContext& g = *GImGui;
     g.DragDropActive = false;
     g.DragDropPayload.Clear();
-    g.DragDropAcceptFlags = 0;
+    g.DragDropAcceptFlags = ImGuiDragDropFlags_None;
     g.DragDropAcceptIdCurr = g.DragDropAcceptIdPrev = 0;
     g.DragDropAcceptIdCurrRectSurface = FLT_MAX;
     g.DragDropAcceptFrameCount = -1;
@@ -10305,7 +10305,7 @@ void ImGui::DockContextProcessDock(ImGuiContext* ctx, ImGuiDockRequest* req)
         {
             target_node->TabBar = IM_NEW(ImGuiTabBar)();
             for (int n = 0; n < target_node->Windows.Size; n++)
-                TabBarAddTab(target_node->TabBar, target_node->Windows[n], ImGuiTabItemFlags_None);
+                TabBarAddTab(target_node->TabBar, ImGuiTabItemFlags_None, target_node->Windows[n]);
         }
 
         if (payload_node != NULL)
@@ -10477,9 +10477,9 @@ static void ImGui::DockNodeAddWindow(ImGuiDockNode* node, ImGuiWindow* window, b
             
             // Add existing windows
             for (int n = 0; n < node->Windows.Size - 1; n++)
-                TabBarAddTab(node->TabBar, node->Windows[n], ImGuiTabItemFlags_None);
+                TabBarAddTab(node->TabBar, ImGuiTabItemFlags_None, node->Windows[n]);
         }
-        TabBarAddTab(node->TabBar, window, ImGuiTabItemFlags_Unsorted);
+        TabBarAddTab(node->TabBar, ImGuiTabItemFlags_Unsorted, window);
     }
 
     DockNodeUpdateVisibleFlag(node);
@@ -11089,7 +11089,7 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
         if (g.NavWindow && g.NavWindow->RootWindowDockStop == window)
             tab_bar->SelectedTabId = window->ID;
         if (TabBarFindTabByID(tab_bar, window->ID) == NULL)
-            TabBarAddTab(tab_bar, window, ImGuiTabItemFlags_Unsorted);
+            TabBarAddTab(tab_bar, ImGuiTabItemFlags_Unsorted, window);
     }
 
     // If multiple tabs are appearing on the same frame, sort them based on their persistent DockOrder value
@@ -13466,7 +13466,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         }
         ImGui::TreePop();
     }
-    if (ImGui::TreeNode("Docking & Tabs"))
+    if (ImGui::TreeNode("Docking & Tab Bars"))
     {
         ShowDockingDebug();
         ImGui::TreePop();
@@ -13546,9 +13546,10 @@ void ImGui::ShowDockingDebug()
                 ImGui::TreePop();
             }
         }
+
         static void NodeTabBar(ImGuiTabBar* tab_bar)
         {
-            // Previous window list
+            // Note that standalone tab bars (not associated to docking/windows functionality) currently hold no discernable strings.
             char buf[256];
             char* p = buf;
             const char* buf_end = buf + IM_ARRAYSIZE(buf);

imgui.h

@@ -544,7 +544,8 @@ namespace ImGui
     IMGUI_API void          SetColumnOffset(int column_index, float offset_x);                  // set position of column line (in pixels, from the left side of the contents region). pass -1 to use current column
     IMGUI_API int           GetColumnsCount();
 
-    // Tabs
+    // Tab Bars, Tabs
+    // [BETA API] API may evolve!
     // Note: Tabs are automatically created by the docking system. Use this to create tab bars/tabs yourself without docking being involved.
     IMGUI_API bool          BeginTabBar(const char* str_id, ImGuiTabBarFlags flags = 0);        // create and append into a TabBar
     IMGUI_API void          EndTabBar();
@@ -573,7 +574,7 @@ namespace ImGui
     IMGUI_API void          LogText(const char* fmt, ...) IM_FMTARGS(1);                        // pass text data straight to log (without being displayed)
 
     // Drag and Drop
-    // [BETA API] Missing Demo code. API may evolve.
+    // [BETA API] Missing Demo code. API may evolve!
     IMGUI_API bool          BeginDragDropSource(ImGuiDragDropFlags flags = 0);                                      // call when the current item is active. If this return true, you can call SetDragDropPayload() + EndDragDropSource()
     IMGUI_API bool          SetDragDropPayload(const char* type, const void* data, size_t size, ImGuiCond cond = 0);// type is a user defined string of maximum 32 characters. Strings starting with '_' are reserved for dear imgui internal types. Data is copied and held by imgui.
     IMGUI_API void          EndDragDropSource();                                                                    // only call EndDragDropSource() if BeginDragDropSource() returns true!

imgui_demo.cpp

@@ -4068,7 +4068,7 @@ struct ExampleAppDocuments
     }
 };
 
-// [Optional] Notify the system of Tabs/Windows of closure that happened outside the regular tab interface
+// [Optional] Notify the system of Tabs/Windows closure that happened outside the regular tab interface.
 // If a tab has been closed programmatically (aka closed from another source such as the Checkbox() in the demo, as opposed
 // to clicking on the regular tab closing button) and stops being submitted, it will take a frame for the tab bar to notice its absence. 
 // During this frame there will be a gap in the tab bar, and if the tab that has disappeared was the selected one, the tab bar 

imgui_draw.cpp

@@ -206,10 +206,10 @@ void ImGui::StyleColorsDark(ImGuiStyle* dst)
     colors[ImGuiCol_ResizeGripHovered]      = ImVec4(0.26f, 0.59f, 0.98f, 0.67f);
     colors[ImGuiCol_ResizeGripActive]       = ImVec4(0.26f, 0.59f, 0.98f, 0.95f);
     colors[ImGuiCol_Tab]                    = ImLerp(colors[ImGuiCol_Header],       colors[ImGuiCol_TitleBgActive], 0.80f);
+    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
-    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_HeaderActive] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
     colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(0.61f, 0.61f, 0.61f, 1.00f);
@@ -263,10 +263,10 @@ void ImGui::StyleColorsClassic(ImGuiStyle* dst)
     colors[ImGuiCol_ResizeGripHovered]      = ImVec4(0.78f, 0.82f, 1.00f, 0.60f);
     colors[ImGuiCol_ResizeGripActive]       = ImVec4(0.78f, 0.82f, 1.00f, 0.90f);
     colors[ImGuiCol_Tab]                    = ImLerp(colors[ImGuiCol_Header],       colors[ImGuiCol_TitleBgActive], 0.80f);
+    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
-    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
     colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(1.00f, 1.00f, 1.00f, 1.00f);
@@ -321,10 +321,10 @@ void ImGui::StyleColorsLight(ImGuiStyle* dst)
     colors[ImGuiCol_ResizeGripHovered]      = ImVec4(0.26f, 0.59f, 0.98f, 0.67f);
     colors[ImGuiCol_ResizeGripActive]       = ImVec4(0.26f, 0.59f, 0.98f, 0.95f);
     colors[ImGuiCol_Tab]                    = ImLerp(colors[ImGuiCol_Header],       colors[ImGuiCol_TitleBgActive], 0.90f);
+    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_TabActive]              = ImLerp(colors[ImGuiCol_HeaderActive], colors[ImGuiCol_TitleBgActive], 0.60f);
     colors[ImGuiCol_TabUnfocused]           = ImLerp(colors[ImGuiCol_Tab],          colors[ImGuiCol_TitleBg], 0.80f);
     colors[ImGuiCol_TabUnfocusedActive]     = ImLerp(colors[ImGuiCol_TabActive],    colors[ImGuiCol_TitleBg], 0.40f);
-    colors[ImGuiCol_TabHovered]             = colors[ImGuiCol_HeaderHovered];
     colors[ImGuiCol_DockingPreview]         = colors[ImGuiCol_Header] * ImVec4(1.0f, 1.0f, 1.0f, 0.7f);
     colors[ImGuiCol_DockingEmptyBg]         = ImVec4(0.20f, 0.20f, 0.20f, 1.00f);
     colors[ImGuiCol_PlotLines]              = ImVec4(0.39f, 0.39f, 0.39f, 1.00f);
@@ -2990,8 +2990,9 @@ void ImGui::RenderRectFilledWithHole(ImDrawList* draw_list, ImRect outer, ImRect
     if (fill_R && fill_D) draw_list->AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, ImDrawCornerFlags_BotRight);
 }
 
-// FIXME: Rendering an ellipsis "..." is a surprisingly tricky problem... can't rely on font glyph having it, and regular dot are typically too wide.
-// If we render a dot/shape ourselves it comes with the risk that it wouldn't match the boldness or positioning of what the font uses...
+// FIXME: Rendering an ellipsis "..." is a surprisingly tricky problem for us... we cannot rely on font glyph having it, 
+// and regular dot are typically too wide. If we render a dot/shape ourselves it comes with the risk that it wouldn't match 
+// the boldness or positioning of what the font uses...
 void ImGui::RenderPixelEllipsis(ImDrawList* draw_list, ImFont* font, ImVec2 pos, int count, ImU32 col)
 {
     pos.y += (float)(int)(font->DisplayOffset.y + font->Ascent + 0.5f - 1.0f);

imgui_internal.h

@@ -1548,7 +1548,7 @@ namespace ImGui
     // Tab Bars
     IMGUI_API bool          BeginTabBarEx(ImGuiTabBar* tab_bar, const ImRect& bb, ImGuiTabBarFlags flags, ImGuiDockNode* dock_node);
     IMGUI_API ImGuiTabItem* TabBarFindTabByID(ImGuiTabBar* tab_bar, ImGuiID tab_id);
-    IMGUI_API void          TabBarAddTab(ImGuiTabBar* tab_bar, ImGuiWindow* window, ImGuiTabItemFlags tab_flags = ImGuiTabItemFlags_None);
+    IMGUI_API void          TabBarAddTab(ImGuiTabBar* tab_bar, ImGuiTabItemFlags tab_flags, ImGuiWindow* window);
     IMGUI_API void          TabBarRemoveTab(ImGuiTabBar* tab_bar, ImGuiID tab_id);
     IMGUI_API void          TabBarCloseTab(ImGuiTabBar* tab_bar, ImGuiTabItem* tab);
     IMGUI_API void          TabBarQueueChangeTabOrder(ImGuiTabBar* tab_bar, const ImGuiTabItem* tab, int dir);

imgui_widgets.cpp

@@ -5790,6 +5790,8 @@ bool ImGui::MenuItem(const char* label, const char* shortcut, bool* p_selected,
 //-------------------------------------------------------------------------
 // [SECTION] Widgets: BeginTabBar, EndTabBar, etc.
 //-------------------------------------------------------------------------
+// [BETA API] API may evolve!
+//-------------------------------------------------------------------------
 // - BeginTabBar()
 // - BeginTabBarEx() [Internal]
 // - EndTabBar()
@@ -5980,7 +5982,7 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
     {
         if (ImGuiTabItem* tab1 = TabBarFindTabByID(tab_bar, tab_bar->ReorderRequestTabId))
         {
-            IM_ASSERT(tab_bar->Flags & ImGuiTabBarFlags_Reorderable);
+            //IM_ASSERT(tab_bar->Flags & ImGuiTabBarFlags_Reorderable); // <- this may happen when using debug tools
             int tab2_order = tab_bar->GetTabOrder(tab1) + tab_bar->ReorderRequestDir;
             if (tab2_order >= 0 && tab2_order < tab_bar->Tabs.Size)
             {
@@ -6142,7 +6144,7 @@ ImGuiTabItem* ImGui::TabBarFindTabByID(ImGuiTabBar* tab_bar, ImGuiID tab_id)
 
 // The purpose of this call is to register tab in advance so we can control their order at the time they appear. 
 // Otherwise calling this is unnecessary as tabs are appending as needed by the BeginTabItem() function.
-void ImGui::TabBarAddTab(ImGuiTabBar* tab_bar, ImGuiWindow* window, ImGuiTabItemFlags tab_flags)
+void ImGui::TabBarAddTab(ImGuiTabBar* tab_bar, ImGuiTabItemFlags tab_flags, ImGuiWindow* window)
 {
     ImGuiContext& g = *GImGui;
     IM_ASSERT(TabBarFindTabByID(tab_bar, window->ID) == NULL);
@@ -6306,6 +6308,8 @@ static ImGuiTabItem* ImGui::TabBarTabListPopupButton(ImGuiTabBar* tab_bar)
 //-------------------------------------------------------------------------
 // [SECTION] Widgets: BeginTabItem, EndTabItem, etc.
 //-------------------------------------------------------------------------
+// [BETA API] API may evolve!
+//-------------------------------------------------------------------------
 // - BeginTabItem()
 // - EndTabItem()
 // - TabItemEx() [Internal]
@@ -6472,8 +6476,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     }
     else if (held && !tab_appearing && IsMouseDragging(0))
     {
-        // Drag and drop
-        // Re-order local or dockable tabs
+        // Drag and drop: re-order tabs
         float drag_distance_from_edge_x = 0.0f;
         if (!g.DragDropActive && ((tab_bar->Flags & ImGuiTabBarFlags_Reorderable) || (flags & ImGuiTabItemFlags_DockedWindow)))
         {
@@ -6628,7 +6631,7 @@ void ImGui::TabItemBackground(ImDrawList* draw_list, const ImRect& bb, ImGuiTabI
     draw_list->PathClear();
 }
 
-// Render text label (with clipping + alpha gradient) + unsaved marker + Close Button logic
+// Render text label (with custom clipping) + Unsaved Document marker + Close Button logic
 bool ImGui::TabItemLabelAndCloseButton(ImDrawList* draw_list, const ImRect& bb, ImGuiTabItemFlags flags, const char* label, ImGuiID tab_id, ImGuiID close_button_id)
 {
     ImGuiContext& g = *GImGui;
@@ -6674,7 +6677,7 @@ bool ImGui::TabItemLabelAndCloseButton(ImDrawList* draw_list, const ImRect& bb,
     }
 
     // Label with ellipsis
-    // FIXME: This could be extracted into a helper but or use of text_pixel_clip_bb and !close_button_visible makes it tricky to abstract at the moment
+    // FIXME: This should be extracted into a helper but the use of text_pixel_clip_bb and !close_button_visible makes it tricky to abstract at the moment
     const char* label_display_end = FindRenderedTextEnd(label);
     if (label_size.x > text_ellipsis_clip_bb.GetWidth())
     {