Merge branch 'master' into viewport

# Conflicts:
#	imgui.cpp
#	imgui.h

imgui.cpp

@@ -43,6 +43,7 @@ DOCUMENTATION
   - How can I load multiple fonts?
   - How can I display and input non-latin characters such as Chinese, Japanese, Korean, Cyrillic?
   - How can I use the drawing facilities without an ImGui window? (using ImDrawList API)
+  - How can I use Dear ImGui on a platform that doesn't have a mouse or a keyboard? (input share, remoting, gamepad)
   - I integrated Dear ImGui in my engine and the text or lines are blurry..
   - I integrated Dear ImGui in my engine and some elements are clipping or disappearing when I move windows around..
   - How can I help?
@@ -834,6 +835,21 @@ CODE
     - You can create your own ImDrawList instance. You'll need to initialize them ImGui::GetDrawListSharedData(), or create your own ImDrawListSharedData,
       and then call your rendered code with your own ImDrawList or ImDrawData data.
 
+ Q: How can I use this without a mouse, without a keyboard or without a screen? (gamepad, input share, remote display)
+ A: - You can control Dear ImGui with a gamepad. Read about navigation in "Using gamepad/keyboard navigation controls".
+      (short version: map gamepad inputs into the io.NavInputs[] array + set io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad)
+    - You can share your computer mouse seamlessly with your console/tablet/phone using Synergy (https://symless.com/synergy) 
+      This is the preferred solution for developer productivity. 
+      In particular, the "micro-synergy-client" repository (https://github.com/symless/micro-synergy-client) has simple
+      and portable source code (uSynergy.c/.h) for a small embeddable client that you can use on any platform to connect 
+      to your host computer, based on the Synergy 1.x protocol. Make sure you download the Synergy 1 server on your computer.
+      Console SDK also sometimes provide equivalent tooling or wrapper for Synergy-like protocols.
+    - You may also use a third party solution such as Remote ImGui (https://github.com/JordiRos/remoteimgui) which sends 
+      the vertices to render over the local network, allowing you to use Dear ImGui even on a screen-less machine.
+    - For touch inputs, you can increase the hit box of widgets (via the style.TouchPadding setting) to accommodate 
+      for the lack of precision of touch inputs, but it is recommended you use a mouse or gamepad to allow optimizing
+      for screen real-estate and precision.
+
  Q: I integrated Dear ImGui in my engine and the text or lines are blurry..
  A: In your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f).
     Also make sure your orthographic projection matrix and io.DisplaySize matches your actual framebuffer dimension.
@@ -1115,6 +1131,7 @@ ImGuiIO::ImGuiIO()
 
     // Platform Functions
     BackendPlatformName = BackendRendererName = NULL;
+    BackendPlatformUserData = BackendRendererUserData = BackendLanguageUserData = NULL;
     GetClipboardTextFn = GetClipboardTextFn_DefaultImpl;   // Platform dependent default implementations
     SetClipboardTextFn = SetClipboardTextFn_DefaultImpl;
     ClipboardUserData = NULL;
@@ -4163,6 +4180,8 @@ bool ImGui::IsMousePosValid(const ImVec2* mouse_pos)
     return mouse_pos->x >= MOUSE_INVALID && mouse_pos->y >= MOUSE_INVALID;
 }
 
+// Return the delta from the initial clicking position.
+// This is locked and return 0.0f until the mouse moves past a distance threshold at least once.
 // NB: This is only valid if IsMousePosValid(). Back-ends in theory should always keep mouse position valid when dragging even outside the client window.
 ImVec2 ImGui::GetMouseDragDelta(int button, float lock_threshold)
 {
@@ -4333,6 +4352,10 @@ static bool ImGui::BeginChildEx(const char* name, ImGuiID id, const ImVec2& size
     child_window->ChildId = id;
     child_window->AutoFitChildAxises = auto_fit_axises;
 
+    // Set the cursor to handle case where the user called SetNextWindowPos()+BeginChild() manually.
+    // While this is not really documented/defined, it seems that the expected thing to do.
+    parent_window->DC.CursorPos = child_window->Pos;
+
     // Process navigation-in immediately so NavInit can run on first frame
     if (g.NavActivateId == id && !(flags & ImGuiWindowFlags_NavFlattened) && (child_window->DC.NavLayerActiveMask != 0 || child_window->DC.NavHasScroll))
     {
@@ -6435,10 +6458,10 @@ ImVec2 ImGui::GetCursorScreenPos()
     return window->DC.CursorPos;
 }
 
-void ImGui::SetCursorScreenPos(const ImVec2& screen_pos)
+void ImGui::SetCursorScreenPos(const ImVec2& pos)
 {
     ImGuiWindow* window = GetCurrentWindow();
-    window->DC.CursorPos = screen_pos;
+    window->DC.CursorPos = pos;
     window->DC.CursorMaxPos = ImMax(window->DC.CursorMaxPos, window->DC.CursorPos);
 }
 
@@ -6476,12 +6499,12 @@ void ImGui::SetScrollY(float scroll_y)
     window->ScrollTargetCenterRatio.y = 0.0f;
 }
 
-void ImGui::SetScrollFromPosY(float pos_y, float center_y_ratio)
+void ImGui::SetScrollFromPosY(float local_y, float center_y_ratio)
 {
     // We store a target position so centering can occur on the next frame when we are guaranteed to have a known window size
     ImGuiWindow* window = GetCurrentWindow();
     IM_ASSERT(center_y_ratio >= 0.0f && center_y_ratio <= 1.0f);
-    window->ScrollTarget.y = (float)(int)(pos_y + window->Scroll.y);
+    window->ScrollTarget.y = (float)(int)(local_y + window->Scroll.y);
     window->ScrollTargetCenterRatio.y = center_y_ratio;
 }