PushDisabled(): added bool + clarify support for stacked disabled (#211)

imgui.cpp

@@ -6592,24 +6592,27 @@ void ImGui::PopItemFlag()
 }
 
 // PushDisabled()/PopDisabled()
+// - Those can be nested but this cannot be used to enable an already disabled section (a single PushDisabled(true) in the stack is enough to keep things disabled)
 // - Those are not yet exposed in imgui.h because we are unsure of how to alter the style in a way that works for everyone.
 //   We may rework this. Hypothetically, a future styling system may set a flag which make widgets use different colors.
 // - Feedback welcome at https://github.com/ocornut/imgui/issues/211
 // - You may trivially implement your own variation of this if needed.
 //   Here we test (CurrentItemFlags & ImGuiItemFlags_Disabled) to allow nested PushDisabled() calls.
-void ImGui::PushDisabled()
+void ImGui::PushDisabled(bool disabled)
 {
     ImGuiContext& g = *GImGui;
-    if ((g.CurrentItemFlags & ImGuiItemFlags_Disabled) == 0)
+    bool was_disabled = (g.CurrentItemFlags & ImGuiItemFlags_Disabled) != 0;
+    if (!was_disabled && disabled)
         PushStyleVar(ImGuiStyleVar_Alpha, g.Style.Alpha * 0.6f);
-    PushItemFlag(ImGuiItemFlags_Disabled, true);
+    PushItemFlag(ImGuiItemFlags_Disabled, was_disabled || disabled);
 }
 
 void ImGui::PopDisabled()
 {
     ImGuiContext& g = *GImGui;
+    bool was_disabled = (g.CurrentItemFlags & ImGuiItemFlags_Disabled) != 0;
     PopItemFlag();
-    if ((g.CurrentItemFlags & ImGuiItemFlags_Disabled) == 0)
+    if (was_disabled && (g.CurrentItemFlags & ImGuiItemFlags_Disabled) == 0)
         PopStyleVar();
 }
 

imgui_internal.h

@@ -733,12 +733,12 @@ struct ImDrawDataBuilder
 enum ImGuiItemFlags_
 {
     ImGuiItemFlags_None                     = 0,
-    ImGuiItemFlags_NoTabStop                = 1 << 0,  // false
+    ImGuiItemFlags_NoTabStop                = 1 << 0,  // false     // Disable keyboard tabbing (FIXME: should merge with _NoNav)
     ImGuiItemFlags_ButtonRepeat             = 1 << 1,  // false     // Button() will return true multiple times based on io.KeyRepeatDelay and io.KeyRepeatRate settings.
-    ImGuiItemFlags_Disabled                 = 1 << 2,  // false    // [BETA] Disable interactions but doesn't affect visuals yet. See github.com/ocornut/imgui/issues/211
+    ImGuiItemFlags_Disabled                 = 1 << 2,  // false     // Disable interactions but doesn't affect visuals. See PushDisabled()/PushDisabled(). See github.com/ocornut/imgui/issues/211
-    ImGuiItemFlags_NoNav                    = 1 << 3,  // false
+    ImGuiItemFlags_NoNav                    = 1 << 3,  // false     // Disable keyboard/gamepad directional navigation (FIXME: should merge with _NoTabStop)
-    ImGuiItemFlags_NoNavDefaultFocus        = 1 << 4,  // false
+    ImGuiItemFlags_NoNavDefaultFocus        = 1 << 4,  // false     // Disable item being a candidate for default focus (e.g. used by title bar items)
-    ImGuiItemFlags_SelectableDontClosePopup = 1 << 5,  // false    // MenuItem/Selectable() automatically closes current Popup window
+    ImGuiItemFlags_SelectableDontClosePopup = 1 << 5,  // false     // Disable MenuItem/Selectable() automatically closing their popup window
     ImGuiItemFlags_MixedValue               = 1 << 6,  // false     // [BETA] Represent a mixed/indeterminate value, generally multi-selection where values differ. Currently only supported by Checkbox() (later should support all sorts of widgets)
     ImGuiItemFlags_ReadOnly                 = 1 << 7   // false     // [ALPHA] Allow hovering interactions but underlying value is not changed.
 };
@@ -2405,14 +2405,16 @@ namespace ImGui
     IMGUI_API ImVec2        CalcItemSize(ImVec2 size, float default_w, float default_h);
     IMGUI_API float         CalcWrapWidthForPos(const ImVec2& pos, float wrap_pos_x);
     IMGUI_API void          PushMultiItemsWidths(int components, float width_full);
-    IMGUI_API void          PushItemFlag(ImGuiItemFlags option, bool enabled);
-    IMGUI_API void          PopItemFlag();
-    IMGUI_API void          PushDisabled();
-    IMGUI_API void          PopDisabled();
     IMGUI_API bool          IsItemToggledSelection();                                   // Was the last item selection toggled? (after Selectable(), TreeNode() etc. We only returns toggle _event_ in order to handle clipping correctly)
     IMGUI_API ImVec2        GetContentRegionMaxAbs();
     IMGUI_API void          ShrinkWidths(ImGuiShrinkWidthItem* items, int count, float width_excess);
 
+    // Parameter stacks
+    IMGUI_API void          PushItemFlag(ImGuiItemFlags option, bool enabled);
+    IMGUI_API void          PopItemFlag();
+    IMGUI_API void          PushDisabled(bool disabled = true);
+    IMGUI_API void          PopDisabled();
+
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     // If you have old/custom copy-and-pasted widgets that used FocusableItemRegister():
     //  (Old) IMGUI_VERSION_NUM  < 18209: using 'ItemAdd(....)'                              and 'bool focused = FocusableItemRegister(...)'