From a4629b0b36f8ef1ac588a74b9eca5fb46701e23c Mon Sep 17 00:00:00 2001
From: omar <omarcornut@gmail.com>
Date: Fri, 9 Mar 2018 15:37:16 +0100
Subject: [PATCH] Viewport, DPI: Select viewport before locking style sizes and
 before handling double-click-on-title-bar to collapse. (#1542, #1676)

---
 imgui.cpp        | 29 +++++++++++++++--------------
 imgui_internal.h |  2 +-
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/imgui.cpp b/imgui.cpp
index d7048fcd..3dac7cea 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -6291,7 +6291,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     if (g.NextWindowData.CollapsedCond)
         SetWindowCollapsed(window, g.NextWindowData.CollapsedVal, g.NextWindowData.CollapsedCond);
     if (g.NextWindowData.FocusCond)
-        SetWindowFocus();
+        FocusWindow(window);
     if (window->Appearing)
         SetWindowConditionAllowFlags(window, ImGuiCond_Appearing, false);
 
@@ -6317,6 +6317,20 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->LastFrameActive = current_frame;
         window->IDStack.resize(1);
 
+        // VIEWPORT
+        // We need to do this before using any style/font sizes, as viewport with a different DPI will affect those sizes.
+
+        UpdateWindowViewport(window, window_pos_set_by_api);
+        SetCurrentViewport(window->Viewport);
+        window->Viewport->LastFrameActive = g.FrameCount;
+        flags = window->Flags;
+
+        if (p_open != NULL && window->Viewport->PlatformRequestClose && !(window->Viewport->Flags & ImGuiViewportFlags_MainViewport))
+        {
+            window->Viewport->PlatformRequestClose = false;
+            *p_open = false;
+        }
+
         // Lock window rounding, border size and padding for the frame (so that altering them doesn't cause inconsistencies)
         window->WindowRounding = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildRounding : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupRounding : style.WindowRounding;
         window->WindowBorderSize = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildBorderSize : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupBorderSize : style.WindowBorderSize;
@@ -6342,19 +6356,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         }
         window->CollapseToggleWanted = false;
 
-        // VIEWPORT
-
-        UpdateWindowViewport(window, window_pos_set_by_api);
-        SetCurrentViewport(window->Viewport);
-        window->Viewport->LastFrameActive = g.FrameCount;
-        flags = window->Flags;
-
-        if (p_open != NULL && window->Viewport->PlatformRequestClose && !(window->Viewport->Flags & ImGuiViewportFlags_MainViewport))
-        {
-            window->Viewport->PlatformRequestClose = false;
-            *p_open = false;
-        }
-
         // SIZE
 
         // Update contents size from last frame for auto-fitting (unless explicitly specified)
diff --git a/imgui_internal.h b/imgui_internal.h
index 06bdbbc8..4aa9a3b9 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -1076,7 +1076,7 @@ namespace ImGui
     inline    ImGuiWindow*  GetCurrentWindowRead()      { ImGuiContext& g = *GImGui; return g.CurrentWindow; }
     inline    ImGuiWindow*  GetCurrentWindow()          { ImGuiContext& g = *GImGui; g.CurrentWindow->WriteAccessed = true; return g.CurrentWindow; }
     IMGUI_API ImGuiWindow*  FindWindowByName(const char* name);
-    IMGUI_API void          FocusWindow(ImGuiWindow* window);
+    IMGUI_API void          FocusWindow(ImGuiWindow* window); // FIXME: Rename to SetWindowFocus()
     IMGUI_API void          BringWindowToFront(ImGuiWindow* window);
     IMGUI_API void          BringWindowToBack(ImGuiWindow* window);
     IMGUI_API bool          IsWindowChildOf(ImGuiWindow* window, ImGuiWindow* potential_parent);