Merge branch 'master' into docking

# Conflicts:
#	imgui.cpp
#	imgui_demo.cpp
#	imgui_widgets.cpp

docs/CHANGELOG.txt

@@ -68,12 +68,15 @@ Other Changes:
   (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 
+- Window: Contents size is preserved while a window collapsed. Fix auto-resizing window losing their size for one frame when uncollapsed.
+- Window: Contents size is preserved while a window contents is hidden (unless it is hidden for resizing purpose).
+- Window: 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).
+- Window: Added io.ConfigWindowsMoveFromTitleBarOnly option. Still is ignored by window with no title bars (often popups).
   This affects clamping window within the visible area: with this option enabled title bars need to be visible. (#899)
 - Style: Tweaked default value of style.DisplayWindowPadding from (20,20) to (19,19) so the default style as a value
   which is the same as the title bar height.
+- Demo: "Simple Layout" and "Style Editor" are now using tabs.
 - Examples: DirectX10/11/12: Made imgui_impl_dx10/dx11/dx12.cpp link d3dcompiler.lib from the .cpp file
   to ease integration.
 

imgui.cpp

@@ -4650,6 +4650,8 @@ static ImVec2 CalcSizeAfterConstraint(ImGuiWindow* window, ImVec2 new_size)
 
 static ImVec2 CalcSizeContents(ImGuiWindow* window)
 {
+    if (window->Collapsed)
+        return window->SizeContents;
     if (window->Hidden && window->HiddenFramesForResize == 0 && window->HiddenFramesRegular > 0)
         return window->SizeContents;
 

imgui.h

@@ -548,7 +548,7 @@ namespace ImGui
     // [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();
+    IMGUI_API void          EndTabBar();                                                        // only call EndTabBar() if BeginTabBar() returns true!
     IMGUI_API bool          BeginTabItem(const char* label, bool* p_open = NULL, ImGuiTabItemFlags flags = 0);// create a Tab. Returns true if the Tab is selected.
     IMGUI_API void          EndTabItem();                                                       // only call EndTabItem() if BeginTabItem() returns true!
     IMGUI_API void          SetTabItemClosed(const char* tab_or_docked_window_label);           // notify TabBar or Docking system of a closed tab/window ahead (useful to reduce visual flicker on reorderable tab bars). For tab-bar: call after BeginTabBar() and before Tab submissions. Otherwise call with a window name.

imgui_demo.cpp

@@ -2578,7 +2578,11 @@ static void ShowDemoWindowMisc()
 
 void ImGui::ShowAboutWindow(bool* p_open)
 {
-    ImGui::Begin("About Dear ImGui", p_open, ImGuiWindowFlags_AlwaysAutoResize);
+    if (!ImGui::Begin("About Dear ImGui", p_open, ImGuiWindowFlags_AlwaysAutoResize))
+    {
+        ImGui::End();
+        return;
+    }
     ImGui::Text("Dear ImGui %s", ImGui::GetVersion());
     ImGui::Separator();
     ImGui::Text("By Omar Cornut and all dear imgui contributors.");
@@ -2792,20 +2796,13 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
     ImGui::SameLine();
     ShowHelpMarker("Save/Revert in local non-persistent storage. Default Colors definition are not affected. Use \"Export Colors\" below to save them somewhere.");
 
-    if (ImGui::TreeNode("Rendering"))
+    ImGui::Separator();
-    {
-        ImGui::Checkbox("Anti-aliased lines", &style.AntiAliasedLines); ImGui::SameLine(); ShowHelpMarker("When disabling anti-aliasing lines, you'll probably want to disable borders in your style as well.");
-        ImGui::Checkbox("Anti-aliased fill", &style.AntiAliasedFill);
-        ImGui::PushItemWidth(100);
-        ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, FLT_MAX, "%.2f", 2.0f);
-        if (style.CurveTessellationTol < 0.10f) style.CurveTessellationTol = 0.10f;
-        ImGui::DragFloat("Global Alpha", &style.Alpha, 0.005f, 0.20f, 1.0f, "%.2f"); // Not exposing zero here so user doesn't "lose" the UI (zero alpha clips all widgets). But application code could have a toggle to switch between zero and non-zero.
-        ImGui::PopItemWidth();
-        ImGui::TreePop();
-    }
 
-    if (ImGui::TreeNode("Settings"))
+    if (ImGui::BeginTabBar("##tabs", ImGuiTabBarFlags_None))
     {
+        if (ImGui::BeginTabItem("Sizes"))
+        {
+            ImGui::Text("Main");
             ImGui::SliderFloat2("WindowPadding", (float*)&style.WindowPadding, 0.0f, 20.0f, "%.0f");
             ImGui::SliderFloat("PopupRounding", &style.PopupRounding, 0.0f, 16.0f, "%.0f");
             ImGui::SliderFloat2("FramePadding", (float*)&style.FramePadding, 0.0f, 20.0f, "%.0f");
@@ -2815,7 +2812,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             ImGui::SliderFloat("IndentSpacing", &style.IndentSpacing, 0.0f, 30.0f, "%.0f");
             ImGui::SliderFloat("ScrollbarSize", &style.ScrollbarSize, 1.0f, 20.0f, "%.0f");
             ImGui::SliderFloat("GrabMinSize", &style.GrabMinSize, 1.0f, 20.0f, "%.0f");
-        ImGui::Text("BorderSize");
+            ImGui::Text("Borders");
             ImGui::SliderFloat("WindowBorderSize", &style.WindowBorderSize, 0.0f, 1.0f, "%.0f");
             ImGui::SliderFloat("ChildBorderSize", &style.ChildBorderSize, 0.0f, 1.0f, "%.0f");
             ImGui::SliderFloat("PopupBorderSize", &style.PopupBorderSize, 0.0f, 1.0f, "%.0f");
@@ -2833,10 +2830,10 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             ImGui::SliderFloat2("ButtonTextAlign", (float*)&style.ButtonTextAlign, 0.0f, 1.0f, "%.2f"); ImGui::SameLine(); ShowHelpMarker("Alignment applies when a button is larger than its text content.");
             ImGui::Text("Safe Area Padding"); ImGui::SameLine(); ShowHelpMarker("Adjust if you cannot see the edges of your screen (e.g. on a TV where scaling has not been configured).");
             ImGui::SliderFloat2("DisplaySafeAreaPadding", (float*)&style.DisplaySafeAreaPadding, 0.0f, 30.0f, "%.0f");
-        ImGui::TreePop();
+            ImGui::EndTabItem();
         }
 
-    if (ImGui::TreeNode("Colors"))
+        if (ImGui::BeginTabItem("Colors"))
         {
             static int output_dest = 0;
             static bool output_only_modified = true;
@@ -2859,17 +2856,16 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             ImGui::SameLine(); ImGui::PushItemWidth(120); ImGui::Combo("##output_type", &output_dest, "To Clipboard\0To TTY\0"); ImGui::PopItemWidth();
             ImGui::SameLine(); ImGui::Checkbox("Only Modified Colors", &output_only_modified);
 
-        ImGui::Text("Tip: Left-click on colored square to open color picker,\nRight-click to open edit options menu.");
-
             static ImGuiTextFilter filter;
-        filter.Draw("Filter colors", 200);
+            filter.Draw("Filter colors", ImGui::GetFontSize() * 16);
 
             static ImGuiColorEditFlags alpha_flags = 0;
             ImGui::RadioButton("Opaque", &alpha_flags, 0); ImGui::SameLine();
             ImGui::RadioButton("Alpha", &alpha_flags, ImGuiColorEditFlags_AlphaPreview); ImGui::SameLine();
-        ImGui::RadioButton("Both", &alpha_flags, ImGuiColorEditFlags_AlphaPreviewHalf);
+            ImGui::RadioButton("Both", &alpha_flags, ImGuiColorEditFlags_AlphaPreviewHalf); ImGui::SameLine();
+            ShowHelpMarker("In the color list:\nLeft-click on colored square to open color picker,\nRight-click to open edit options menu.");
 
-        ImGui::BeginChild("#colors", ImVec2(0, 300), true, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar | ImGuiWindowFlags_NavFlattened);
+            ImGui::BeginChild("##colors", ImVec2(0, 0), true, ImGuiWindowFlags_AlwaysVerticalScrollbar | ImGuiWindowFlags_AlwaysHorizontalScrollbar | ImGuiWindowFlags_NavFlattened);
             ImGui::PushItemWidth(-160);
             for (int i = 0; i < ImGuiCol_COUNT; i++)
             {
@@ -2892,24 +2888,19 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
             ImGui::PopItemWidth();
             ImGui::EndChild();
 
-        ImGui::TreePop();
+            ImGui::EndTabItem();
         }
 
-    bool fonts_opened = ImGui::TreeNode("Fonts", "Fonts (%d)", ImGui::GetIO().Fonts->Fonts.Size);
+        if (ImGui::BeginTabItem("Fonts"))
-    if (fonts_opened)
         {
             ImFontAtlas* atlas = ImGui::GetIO().Fonts;
-        if (ImGui::TreeNode("Atlas texture", "Atlas texture (%dx%d pixels)", atlas->TexWidth, atlas->TexHeight))
+            ShowHelpMarker("Read FAQ and misc/fonts/README.txt for details on font loading.");
-        {
+            ImGui::PushItemWidth(120);
-            ImGui::Image(atlas->TexID, ImVec2((float)atlas->TexWidth, (float)atlas->TexHeight), ImVec2(0,0), ImVec2(1,1), ImColor(255,255,255,255), ImColor(255,255,255,128));
-            ImGui::TreePop();
-        }
-        ImGui::PushItemWidth(100);
             for (int i = 0; i < atlas->Fonts.Size; i++)
             {
                 ImFont* font = atlas->Fonts[i];
                 ImGui::PushID(font);
-            bool font_details_opened = ImGui::TreeNode(font, "Font %d: \'%s\', %.2f px, %d glyphs", i, font->ConfigData ? font->ConfigData[0].Name : "", font->FontSize, font->Glyphs.Size);
+                bool font_details_opened = ImGui::TreeNode(font, "Font %d: \"%s\"\n%.2f px, %d glyphs, %d file(s)", i, font->ConfigData ? font->ConfigData[0].Name : "", font->FontSize, font->Glyphs.Size, font->ConfigDataCount);
                 ImGui::SameLine(); if (ImGui::SmallButton("Set as default")) ImGui::GetIO().FontDefault = font;
                 if (font_details_opened)
                 {
@@ -2968,12 +2959,35 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                 }
                 ImGui::PopID();
             }
+            if (ImGui::TreeNode("Atlas texture", "Atlas texture (%dx%d pixels)", atlas->TexWidth, atlas->TexHeight))
+            {
+                ImGui::Image(atlas->TexID, ImVec2((float)atlas->TexWidth, (float)atlas->TexHeight), ImVec2(0, 0), ImVec2(1, 1), ImColor(255, 255, 255, 255), ImColor(255, 255, 255, 128));
+                ImGui::TreePop();
+            }
+
             static float window_scale = 1.0f;
-        ImGui::DragFloat("this window scale", &window_scale, 0.005f, 0.3f, 2.0f, "%.1f");              // scale only this window
+            if (ImGui::DragFloat("this window scale", &window_scale, 0.005f, 0.3f, 2.0f, "%.1f"))           // scale only this window
+                ImGui::SetWindowFontScale(window_scale);
             ImGui::DragFloat("global scale", &ImGui::GetIO().FontGlobalScale, 0.005f, 0.3f, 2.0f, "%.1f");  // scale everything
             ImGui::PopItemWidth();
-        ImGui::SetWindowFontScale(window_scale);
+
-        ImGui::TreePop();
+            ImGui::EndTabItem();
+        }
+
+        if (ImGui::BeginTabItem("Rendering"))
+        {
+            ImGui::Checkbox("Anti-aliased lines", &style.AntiAliasedLines); ImGui::SameLine(); ShowHelpMarker("When disabling anti-aliasing lines, you'll probably want to disable borders in your style as well.");
+            ImGui::Checkbox("Anti-aliased fill", &style.AntiAliasedFill);
+            ImGui::PushItemWidth(100);
+            ImGui::DragFloat("Curve Tessellation Tolerance", &style.CurveTessellationTol, 0.02f, 0.10f, FLT_MAX, "%.2f", 2.0f);
+            if (style.CurveTessellationTol < 0.10f) style.CurveTessellationTol = 0.10f;
+            ImGui::DragFloat("Global Alpha", &style.Alpha, 0.005f, 0.20f, 1.0f, "%.2f"); // Not exposing zero here so user doesn't "lose" the UI (zero alpha clips all widgets). But application code could have a toggle to switch between zero and non-zero.
+            ImGui::PopItemWidth();
+
+            ImGui::EndTabItem();
+        }
+
+        ImGui::EndTabBar();
     }
 
     ImGui::PopItemWidth();
@@ -3513,7 +3527,20 @@ static void ShowExampleAppLayout(bool* p_open)
             ImGui::BeginChild("item view", ImVec2(0, -ImGui::GetFrameHeightWithSpacing())); // Leave room for 1 line below us
                 ImGui::Text("MyObject: %d", selected);
                 ImGui::Separator();
+                if (ImGui::BeginTabBar("##Tabs", ImGuiTabBarFlags_None))
+                {
+                    if (ImGui::BeginTabItem("Description"))
+                    {
                         ImGui::TextWrapped("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. ");
+                        ImGui::EndTabItem();
+                    }
+                    if (ImGui::BeginTabItem("Details"))
+                    {
+                        ImGui::Text("ID: 0123456789");
+                        ImGui::EndTabItem();
+                    }
+                    ImGui::EndTabBar();
+                }
             ImGui::EndChild();
             if (ImGui::Button("Revert")) {}
             ImGui::SameLine();
@@ -4090,7 +4117,11 @@ void ShowExampleAppDocuments(bool* p_open)
 {
     static ExampleAppDocuments app;
 
-    ImGui::Begin("Examples: Documents", p_open, ImGuiWindowFlags_MenuBar);
+    if (!ImGui::Begin("Examples: Documents", p_open, ImGuiWindowFlags_MenuBar))
+    {
+        ImGui::End();
+        return;
+    }
 
     // Options
     enum Target

imgui_widgets.cpp

@@ -6329,7 +6329,10 @@ bool    ImGui::BeginTabItem(const char* label, bool* p_open, ImGuiTabItemFlags f
     ImGuiTabBar* tab_bar = g.CurrentTabBar.back();
     bool ret = TabItemEx(tab_bar, label, p_open, flags, NULL);
     if (ret && !(flags & ImGuiTabItemFlags_NoPushId))
-        PushID(tab_bar->Tabs[tab_bar->LastTabItemIdx].ID);
+    {
+        ImGuiTabItem* tab = &tab_bar->Tabs[tab_bar->LastTabItemIdx];
+        g.CurrentWindow->IDStack.push_back(tab->ID);    // We already hashed 'label' so push into the ID stack directly instead of doing another hash through PushID(label)
+    }
     return ret;
 }
 
@@ -6343,7 +6346,7 @@ void    ImGui::EndTabItem()
     ImGuiTabBar* tab_bar = g.CurrentTabBar.back();
     ImGuiTabItem* tab = &tab_bar->Tabs[tab_bar->LastTabItemIdx];
     if (!(tab->Flags & ImGuiTabItemFlags_NoPushId))
-        PopID();
+        g.CurrentWindow->IDStack.pop_back();
 }
 
 bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open, ImGuiTabItemFlags flags, ImGuiWindow* docked_window)