Docking: Docking node tab bar honors ItemInnerSpacing.x before first tab. Tweak rendering and alignment of dock node menu marker. (#4130)

+ Fix ~0 in EndFrameDrawDimmedBackgrounds() which is obsolete way of signifying "all round corners".

docs/CHANGELOG.txt

@@ -177,7 +177,9 @@ Docking+Viewports Branch:
   option set to false (dock/undock by default, hold shift to avoid docking). (#2109)
 - Docking: DockSpace() returns its node ID.
 - Docking: Dockspace() never draws a background. (#3924)
-- Docking: undocking nodes/windows covering most of the monitor max their size down to 90% to ease manipulations.
+- Docking: Undocking nodes/windows covering most of the monitor max their size down to 90% to ease manipulations.
+- Docking: Docking node tab bar honors ItemInnerSpacing.x before first tab. (#4130)
+- Docking: Tweak rendering and alignment of dock node menu marker. (#4130)
 - Docking: Fixed restoring of tab order within a dockspace or a split node.
 - Docking: Fixed reappearing docked windows with no close button showing a tab with extraneous space for one frame.
 - Docking: Fixed multiple simultaneously reappearing window from appearing undocked for one frame.

imgui.cpp

@@ -4600,7 +4600,7 @@ static void ImGui::EndFrameDrawDimmedBackgrounds()
             bb.Expand(-g.FontSize - 1.0f);
             rounding = window->WindowRounding;
         }
-        draw_list->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_NavWindowingHighlight, g.NavWindowingHighlightAlpha), rounding, ~0, 3.0f);
+        draw_list->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_NavWindowingHighlight, g.NavWindowingHighlightAlpha), rounding, 0, 3.0f);
         draw_list->PopClipRect();
     }
 }
@@ -5960,7 +5960,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
 }
 
 // Render title text, collapse button, close button
-// When inside a dock node, this is handled in DockNodeUpdateTabBar() instead.
+// When inside a dock node, this is handled in DockNodeCalcTabBarLayout() instead.
 void ImGui::RenderWindowTitleBarContents(ImGuiWindow* window, const ImRect& title_bar_rect, const char* name, bool* p_open)
 {
     ImGuiContext& g = *GImGui;
@@ -12361,7 +12361,7 @@ namespace ImGui
     static bool             DockNodeIsDropAllowed(ImGuiWindow* host_window, ImGuiWindow* payload_window);
     static void             DockNodePreviewDockSetup(ImGuiWindow* host_window, ImGuiDockNode* host_node, ImGuiWindow* payload_window, ImGuiDockPreviewData* preview_data, bool is_explicit_target, bool is_outer_docking);
     static void             DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDockNode* host_node, ImGuiWindow* payload_window, const ImGuiDockPreviewData* preview_data);
-    static void             DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_window_menu_button_pos);
+    static void             DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_window_menu_button_pos, ImVec2* out_close_button_pos);
     static void             DockNodeCalcSplitRects(ImVec2& pos_old, ImVec2& size_old, ImVec2& pos_new, ImVec2& size_new, ImGuiDir dir, ImVec2 size_new_desired);
     static bool             DockNodeCalcDropRectsAndTestMousePos(const ImRect& parent, ImGuiDir dir, ImRect& out_draw, bool outer_docking, ImVec2* test_mouse_pos);
     static const char*      DockNodeGetHostWindowTitle(ImGuiDockNode* node, char* buf, int buf_size) { ImFormatString(buf, buf_size, "##DockNode_%02X", node->ID); return buf; }
@@ -13872,7 +13872,8 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
     // Layout
     ImRect title_bar_rect, tab_bar_rect;
     ImVec2 window_menu_button_pos;
-    DockNodeCalcTabBarLayout(node, &title_bar_rect, &tab_bar_rect, &window_menu_button_pos);
+    ImVec2 close_button_pos;
+    DockNodeCalcTabBarLayout(node, &title_bar_rect, &tab_bar_rect, &window_menu_button_pos, &close_button_pos);
 
     // Submit new tabs, they will be added as Unsorted and sorted below based on relative DockOrder value.
     const int tabs_count_old = tab_bar->Tabs.Size;
@@ -13996,8 +13997,7 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
             PushItemFlag(ImGuiItemFlags_Disabled, true);
             PushStyleColor(ImGuiCol_Text, style.Colors[ImGuiCol_Text] * ImVec4(1.0f,1.0f,1.0f,0.4f));
         }
-        const float button_sz = g.FontSize;
-        if (CloseButton(host_window->GetID("#CLOSE"), title_bar_rect.GetTR() + ImVec2(-style.FramePadding.x * 2.0f - button_sz, 0.0f)))
+        if (CloseButton(host_window->GetID("#CLOSE"), close_button_pos))
             if (ImGuiTabItem* tab = TabBarFindTabByID(tab_bar, tab_bar->VisibleTabId))
             {
                 node->WantCloseTabId = tab->ID;
@@ -14115,27 +14115,35 @@ static bool ImGui::DockNodeIsDropAllowed(ImGuiWindow* host_window, ImGuiWindow*
 }
 
 // window menu button == collapse button when not in a dock node.
-// FIXME: This is similar to RenderWindowTitleBarContents, may want to share code.
-static void ImGui::DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_window_menu_button_pos)
+// FIXME: This is similar to RenderWindowTitleBarContents(), may want to share code.
+static void ImGui::DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_window_menu_button_pos, ImVec2* out_close_button_pos)
 {
     ImGuiContext& g = *GImGui;
+    ImGuiStyle& style = g.Style;
+
     ImRect r = ImRect(node->Pos.x, node->Pos.y, node->Pos.x + node->Size.x, node->Pos.y + g.FontSize + g.Style.FramePadding.y * 2.0f);
     if (out_title_rect) { *out_title_rect = r; }
 
+    r.Min.x += style.WindowBorderSize;
+    r.Max.x -= style.WindowBorderSize;
+
+    float button_sz = g.FontSize;
+
     ImVec2 window_menu_button_pos = r.Min;
-    r.Min.x += g.Style.FramePadding.x;
-    r.Max.x -= g.Style.FramePadding.x;
+    r.Min.x += style.FramePadding.x;
+    r.Max.x -= style.FramePadding.x;
     if (node->HasCloseButton)
     {
-        r.Max.x -= g.FontSize;// +1.0f; // In DockNodeUpdateTabBar() we currently display a disabled close button even if there is none.
+        r.Max.x -= button_sz;
+        if (out_close_button_pos) *out_close_button_pos = ImVec2(r.Max.x - style.FramePadding.x, r.Min.y);
     }
-    if (node->HasWindowMenuButton && g.Style.WindowMenuButtonPosition == ImGuiDir_Left)
+    if (node->HasWindowMenuButton && style.WindowMenuButtonPosition == ImGuiDir_Left)
     {
-        r.Min.x += g.FontSize; // + g.Style.ItemInnerSpacing.x; // <-- Adding ItemInnerSpacing makes the title text moves slightly when in a docking tab bar. Instead we adjusted RenderArrowDockMenu()
+        r.Min.x += button_sz + style.ItemInnerSpacing.x;
     }
-    else if (node->HasWindowMenuButton && g.Style.WindowMenuButtonPosition == ImGuiDir_Right)
+    else if (node->HasWindowMenuButton && style.WindowMenuButtonPosition == ImGuiDir_Right)
     {
-        r.Max.x -= g.FontSize + g.Style.FramePadding.x;
+        r.Max.x -= button_sz + style.FramePadding.x;
         window_menu_button_pos = ImVec2(r.Max.x, r.Min.y);
     }
     if (out_tab_bar_rect) { *out_tab_bar_rect = r; }
@@ -14352,7 +14360,7 @@ static void ImGui::DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDock
     {
         // Compute target tab bar geometry so we can locate our preview tabs
         ImRect tab_bar_rect;
-        DockNodeCalcTabBarLayout(&data->FutureNode, NULL, &tab_bar_rect, NULL);
+        DockNodeCalcTabBarLayout(&data->FutureNode, NULL, &tab_bar_rect, NULL, NULL);
         ImVec2 tab_pos = tab_bar_rect.Min;
         if (host_node && host_node->TabBar)
         {

imgui_draw.cpp

@@ -3811,8 +3811,8 @@ void ImGui::RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half
 // and because the saved space means that the left-most tab label can stay at exactly the same position as the label of a loose window.
 void ImGui::RenderArrowDockMenu(ImDrawList* draw_list, ImVec2 p_min, float sz, ImU32 col)
 {
-    draw_list->AddRectFilled(p_min + ImVec2(sz * 0.10f, sz * 0.15f), p_min + ImVec2(sz * 0.70f, sz * 0.30f), col);
-    RenderArrowPointingAt(draw_list, p_min + ImVec2(sz * 0.40f, sz * 0.85f), ImVec2(sz * 0.30f, sz * 0.40f), ImGuiDir_Down, col);
+    draw_list->AddRectFilled(p_min + ImVec2(sz * 0.20f, sz * 0.15f), p_min + ImVec2(sz * 0.80f, sz * 0.30f), col);
+    RenderArrowPointingAt(draw_list, p_min + ImVec2(sz * 0.50f, sz * 0.85f), ImVec2(sz * 0.30f, sz * 0.40f), ImGuiDir_Down, col);
 }
 
 static inline float ImAcos01(float x)

imgui_widgets.cpp

@@ -838,12 +838,11 @@ bool ImGui::CollapseButton(ImGuiID id, const ImVec2& pos, ImGuiDockNode* dock_no
 
     // Render
     //bool is_dock_menu = (window->DockNodeAsHost && !window->Collapsed);
-    ImVec2 off = dock_node ? ImVec2(IM_FLOOR(-g.Style.ItemInnerSpacing.x * 0.5f) + 0.5f, 0.0f) : ImVec2(0.0f, 0.0f);
     ImU32 bg_col = GetColorU32((held && hovered) ? ImGuiCol_ButtonActive : hovered ? ImGuiCol_ButtonHovered : ImGuiCol_Button);
     ImU32 text_col = GetColorU32(ImGuiCol_Text);
     ImVec2 center = bb.GetCenter();
     if (hovered || held)
-        window->DrawList->AddCircleFilled(center + off + ImVec2(0,-0.5f), g.FontSize * 0.5f + 1.0f, bg_col, 12);
+        window->DrawList->AddCircleFilled(center + ImVec2(0,-0.5f), g.FontSize * 0.5f + 1.0f, bg_col, 12);
 
     if (dock_node)
         RenderArrowDockMenu(window->DrawList, bb.Min + g.Style.FramePadding, g.FontSize, text_col);