Created quick and dirty demo of layout saving/restoring using the set…

…tings API.

Related: ocornut#4033

examples/example_win32_directx11/main.cpp

@@ -6,6 +6,7 @@
 #include "imgui_impl_win32.h"
 #include "imgui_impl_dx11.h"
 #include <d3d11.h>
+#include <stdio.h>
 #include <tchar.h>
 
 // Data
@@ -14,6 +15,11 @@ static ID3D11DeviceContext*     g_pd3dDeviceContext = NULL;
 static IDXGISwapChain*          g_pSwapChain = NULL;
 static ID3D11RenderTargetView*  g_mainRenderTargetView = NULL;
 
+#define SAVED_LATYOUT_COUNT 12
+static char* saved_layouts[SAVED_LATYOUT_COUNT];
+static size_t saved_layout_sizes[SAVED_LATYOUT_COUNT];
+static int current_layout = 0;
+
 // Forward declarations of helper functions
 bool CreateDeviceD3D(HWND hWnd);
 void CleanupDeviceD3D();
@@ -114,6 +120,41 @@ int main(int, char**)
         if (done)
             break;
 
+        // Check if the user requested a layout change
+        unsigned int desired_layout = current_layout;
+        for (unsigned int i = 0; i < IM_ARRAYSIZE(saved_layouts); i++)
+        {
+            unsigned int key_code = VK_F1 + i;
+
+            if (io.KeysDown[key_code])
+            {
+                desired_layout = i;
+            }
+        }
+
+        if (desired_layout != current_layout)
+        {
+            printf("Changing layout F%d -> F%d\n", current_layout + 1, desired_layout + 1);
+
+            // Save the current layout
+            ImGui::MemFree((void*)saved_layouts[current_layout]);
+
+            size_t settings_size = 0;
+            const char* settings = ImGui::SaveIniSettingsToMemory(&settings_size);
+
+            saved_layouts[current_layout] = (char*)ImGui::MemAlloc(settings_size);
+            memcpy(saved_layouts[current_layout], settings, settings_size);
+            saved_layout_sizes[current_layout] = settings_size;
+
+            // Load the requested layout
+            // (Or if there is no layout in that slot, use the current layout for that slot.)
+            current_layout = desired_layout;
+            if (saved_layouts[current_layout] != nullptr)
+            {
+                ImGui::LoadIniSettingsFromMemory(saved_layouts[current_layout]);
+            }
+        }
+
         // Start the Dear ImGui frame
         ImGui_ImplDX11_NewFrame();
         ImGui_ImplWin32_NewFrame();
@@ -175,6 +216,13 @@ int main(int, char**)
     }
 
     // Cleanup
+    for (unsigned int i = 0; i < IM_ARRAYSIZE(saved_layouts); i++)
+    {
+        ImGui::MemFree(saved_layouts[i]);
+        saved_layouts[i] = nullptr;
+        saved_layout_sizes[i] = 0;
+    }
+
     ImGui_ImplDX11_Shutdown();
     ImGui_ImplWin32_Shutdown();
     ImGui::DestroyContext();