Merge branch 'master' into docking

# Conflicts:
#	imgui.cpp
#	imgui.h
#	imgui_internal.h
#	imgui_widgets.cpp

imgui.cpp

@@ -383,6 +383,15 @@ CODE
  - 2020/XX/XX (1.XX) - Moved IME support functions from io.ImeSetInputScreenPosFn, io.ImeWindowHandle to the PlatformIO api.
 
 
+ - 2020/08/17 (1.78) - obsoleted use of the trailing 'float power=1.0f' parameter for DragFloat(), DragFloat2(), DragFloat3(), DragFloat4(), DragFloatRange2(), DragScalar(), DragScalarN(), SliderFloat(), SliderFloat2(), SliderFloat3(), SliderFloat4(), SliderScalar(), SliderScalarN(), VSliderFloat() and VSliderScalar().
+                       replaced the 'float power=1.0f' argument with integer-based flags defaulting to 0 (as with all our flags).
+                       worked out a backward-compatibility scheme so hopefully most C++ codebase should not be affected. in short, when calling those functions:
+                       - if you omitted the 'power' parameter (likely!), you are not affected.
+                       - if you set the 'power' parameter to 1.0f (same as previous default value): 1/ your compiler may warn on float>int conversion, 2/ everything else will work. 3/ you can replace the 1.0f value with 0 to fix the warning, and be technically correct.
+                       - if you set the 'power' parameter to >1.0f (to enable non-linear editing): 1/ your compiler may warn on float>int conversion, 2/ code will assert at runtime, 3/ in case asserts are disabled, the code will not crash and enable the _Logarithmic flag. 4/ you can replace the >1.0f value with ImGuiDragFlags_Logarithmic or ImGuiSliderFlags_Logarithmic flag to fix the warning/assert and get a _similar_ effect as previous uses of power >1.0f.
+                       see https://github.com/ocornut/imgui/issues/3361 for all details.
+                       kept inline redirection functions (will obsolete) apart for: DragFloatRange2(), VSliderFloat(), VSliderScalar(). For those three the 'float power=1.0f' version were removed directly as they were most unlikely ever used.
+                     - obsoleted use of v_min > v_max in DragInt, DragFloat, DragScalar to lock edits (introduced in 1.73, was not demoed nor documented very), will be replaced by a more generic ReadOnly feature. You may use the ImGuiDragFlags_ReadOnly internal flag in the meantime.
  - 2020/06/23 (1.77) - removed BeginPopupContextWindow(const char*, int mouse_button, bool also_over_items) in favor of BeginPopupContextWindow(const char*, ImGuiPopupFlags flags) with ImGuiPopupFlags_NoOverItems.
  - 2020/06/15 (1.77) - renamed OpenPopupOnItemClick() to OpenPopupContextItem(). Kept inline redirection function (will obsolete).
  - 2020/06/15 (1.77) - removed CalcItemRectClosestPoint() entry point which was made obsolete and asserting in December 2017.
@@ -952,6 +961,7 @@ ImGuiStyle::ImGuiStyle()
     ScrollbarRounding       = 9.0f;             // Radius of grab corners rounding for scrollbar
     GrabMinSize             = 10.0f;            // Minimum width/height of a grab box for slider/scrollbar
     GrabRounding            = 0.0f;             // Radius of grabs corners rounding. Set to 0.0f to have rectangular slider grabs.
+    LogSliderDeadzone       = 4.0f;             // The size in pixels of the dead-zone around zero on logarithmic sliders that cross zero.
     TabRounding             = 4.0f;             // Radius of upper corners of a tab. Set to 0.0f to have rectangular tabs.
     TabBorderSize           = 0.0f;             // Thickness of border around tabs.
     TabMinWidthForUnselectedCloseButton = 0.0f; // Minimum width for close button to appears on an unselected tab when hovered. Set to 0.0f to always show when hovering, set to FLT_MAX to never show close button unless selected.
@@ -991,6 +1001,7 @@ void ImGuiStyle::ScaleAllSizes(float scale_factor)
     ScrollbarRounding = ImFloor(ScrollbarRounding * scale_factor);
     GrabMinSize = ImFloor(GrabMinSize * scale_factor);
     GrabRounding = ImFloor(GrabRounding * scale_factor);
+    LogSliderDeadzone = ImFloor(LogSliderDeadzone * scale_factor);
     TabRounding = ImFloor(TabRounding * scale_factor);
     if (TabMinWidthForUnselectedCloseButton != FLT_MAX)
         TabMinWidthForUnselectedCloseButton = ImFloor(TabMinWidthForUnselectedCloseButton * scale_factor);
@@ -6720,7 +6731,7 @@ void ImGui::BringWindowToDisplayFront(ImGuiWindow* window)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* current_front_window = g.Windows.back();
-    if (current_front_window == window || current_front_window->RootWindow == window)
+    if (current_front_window == window || current_front_window->RootWindow == window) // Cheap early out (could be better)
         return;
     for (int i = g.Windows.Size - 2; i >= 0; i--) // We can ignore the top-most window
         if (g.Windows[i] == window)
@@ -8421,13 +8432,14 @@ void ImGui::OpenPopupEx(ImGuiID id, ImGuiPopupFlags popup_flags)
     }
 }
 
+// When popups are stacked, clicking on a lower level popups puts focus back to it and close popups above it.
+// This function closes any popups that are over 'ref_window'.
 void ImGui::ClosePopupsOverWindow(ImGuiWindow* ref_window, bool restore_focus_to_window_under_popup)
 {
     ImGuiContext& g = *GImGui;
     if (g.OpenPopupStack.Size == 0)
         return;
 
-    // When popups are stacked, clicking on a lower level popups puts focus back to it and close popups above it.
     // Don't close our own child popup windows.
     int popup_count_to_keep = 0;
     if (ref_window)
@@ -8442,13 +8454,20 @@ void ImGui::ClosePopupsOverWindow(ImGuiWindow* ref_window, bool restore_focus_to
             if (popup.Window->Flags & ImGuiWindowFlags_ChildWindow)
                 continue;
 
-            // Trim the stack when popups are not direct descendant of the reference window (the reference window is often the NavWindow)
-            bool popup_or_descendent_is_ref_window = false;
-            for (int m = popup_count_to_keep; m < g.OpenPopupStack.Size && !popup_or_descendent_is_ref_window; m++)
-                if (ImGuiWindow* popup_window = g.OpenPopupStack[m].Window)
+            // Trim the stack unless the popup is a direct parent of the reference window (the reference window is often the NavWindow)
+            // - With this stack of window, clicking/focusing Popup1 will close Popup2 and Popup3:
+            //     Window -> Popup1 -> Popup2 -> Popup3
+            // - Each popups may contain child windows, which is why we compare ->RootWindow!
+            //     Window -> Popup1 -> Popup1_Child -> Popup2 -> Popup2_Child
+            bool ref_window_is_descendent_of_popup = false;
+            for (int n = popup_count_to_keep; n < g.OpenPopupStack.Size; n++)
+                if (ImGuiWindow* popup_window = g.OpenPopupStack[n].Window)
                     if (popup_window->RootWindow == ref_window->RootWindow)
-                        popup_or_descendent_is_ref_window = true;
-            if (!popup_or_descendent_is_ref_window)
+                    {
+                        ref_window_is_descendent_of_popup = true;
+                        break;
+                    }
+            if (!ref_window_is_descendent_of_popup)
                 break;
         }
     }