IO: added io.WantCaptureMouseAllowPopupClose (#4480) + comments

docs/CHANGELOG.txt

@@ -47,6 +47,9 @@ Other Changes:
   the whole widget is clipped.
 - TextUnformatted: Accept null ranges including (NULL,NULL) without asserting, in order to conform
   to common idioms (e.g. passing .data(), .data() + .size() from a null string). (#3615)
+- IO: Added 'io.WantCaptureMouseUnlessPopupClose' alternative to `io.WantCaptureMouse'. (#4480)
+  This allows apps to receive the click on void when that click is used to close popup (by default,
+  clicking on a void when a popup is open will close the popup but not release io.WantCaptureMouse).
 - Fonts: imgui_freetype: Fixed crash when FT_Render_Glyph() fails to render a glyph and returns NULL
   (which apparently happens with Freetype 2.11). (#4394, #4145?).
 - Fonts: Fixed ImFontAtlas::ClearInputData() marking atlas as not built. (#4455, #3487)

imgui.cpp

@@ -3872,6 +3872,7 @@ void ImGui::UpdateTabFocus()
 void ImGui::UpdateHoveredWindowAndCaptureFlags()
 {
     ImGuiContext& g = *GImGui;
+    ImGuiIO& io = g.IO;
     g.WindowsHoverPadding = ImMax(g.Style.TouchExtraPadding, ImVec2(WINDOWS_HOVER_PADDING, WINDOWS_HOVER_PADDING));
 
     // Find the window hovered by mouse:
@@ -3887,48 +3888,61 @@ void ImGui::UpdateHoveredWindowAndCaptureFlags()
         clear_hovered_windows = true;
 
     // Disabled mouse?
-    if (g.IO.ConfigFlags & ImGuiConfigFlags_NoMouse)
+    if (io.ConfigFlags & ImGuiConfigFlags_NoMouse)
         clear_hovered_windows = true;
 
-    // We track click ownership. When clicked outside of a window the click is owned by the application and won't report hovering nor request capture even while dragging over our windows afterward.
-    int mouse_earliest_button_down = -1;
+    // We track click ownership. When clicked outside of a window the click is owned by the application and
+    // won't report hovering nor request capture even while dragging over our windows afterward.
+    const bool has_open_popup = (g.OpenPopupStack.Size > 0);
+    const bool has_open_modal = (modal_window != NULL);
+    int mouse_earliest_down = -1;
     bool mouse_any_down = false;
-    for (int i = 0; i < IM_ARRAYSIZE(g.IO.MouseDown); i++)
+    for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++)
     {
-        if (g.IO.MouseClicked[i])
-            g.IO.MouseDownOwned[i] = (g.HoveredWindow != NULL) || (g.OpenPopupStack.Size > 0);
-        mouse_any_down |= g.IO.MouseDown[i];
-        if (g.IO.MouseDown[i])
-            if (mouse_earliest_button_down == -1 || g.IO.MouseClickedTime[i] < g.IO.MouseClickedTime[mouse_earliest_button_down])
-                mouse_earliest_button_down = i;
+        if (io.MouseClicked[i])
+        {
+            io.MouseDownOwned[i] = (g.HoveredWindow != NULL) || has_open_popup;
+            io.MouseDownOwnedUnlessPopupClose[i] = (g.HoveredWindow != NULL) || has_open_modal;
+        }
+        mouse_any_down |= io.MouseDown[i];
+        if (io.MouseDown[i])
+            if (mouse_earliest_down == -1 || io.MouseClickedTime[i] < io.MouseClickedTime[mouse_earliest_down])
+                mouse_earliest_down = i;
     }
-    const bool mouse_avail_to_imgui = (mouse_earliest_button_down == -1) || g.IO.MouseDownOwned[mouse_earliest_button_down];
+    const bool mouse_avail = (mouse_earliest_down == -1) || io.MouseDownOwned[mouse_earliest_down];
+    const bool mouse_avail_unless_popup_close = (mouse_earliest_down == -1) || io.MouseDownOwnedUnlessPopupClose[mouse_earliest_down];
 
     // If mouse was first clicked outside of ImGui bounds we also cancel out hovering.
     // FIXME: For patterns of drag and drop across OS windows, we may need to rework/remove this test (first committed 311c0ca9 on 2015/02)
     const bool mouse_dragging_extern_payload = g.DragDropActive && (g.DragDropSourceFlags & ImGuiDragDropFlags_SourceExtern) != 0;
-    if (!mouse_avail_to_imgui && !mouse_dragging_extern_payload)
+    if (!mouse_avail && !mouse_dragging_extern_payload)
         clear_hovered_windows = true;
 
     if (clear_hovered_windows)
         g.HoveredWindow = g.HoveredWindowUnderMovingWindow = NULL;
 
-    // Update io.WantCaptureMouse for the user application (true = dispatch mouse info to imgui, false = dispatch mouse info to Dear ImGui + app)
+    // Update io.WantCaptureMouse for the user application (true = dispatch mouse info to Dear ImGui only, false = dispatch mouse to Dear ImGui + underlying app)
+    // Update io.WantCaptureMouseAllowPopupClose (experimental) to give a chance for app to react to popup closure with a drag
     if (g.WantCaptureMouseNextFrame != -1)
-        g.IO.WantCaptureMouse = (g.WantCaptureMouseNextFrame != 0);
+    {
+        io.WantCaptureMouse = io.WantCaptureMouseUnlessPopupClose = (g.WantCaptureMouseNextFrame != 0);
+    }
     else
-        g.IO.WantCaptureMouse = (mouse_avail_to_imgui && (g.HoveredWindow != NULL || mouse_any_down)) || (g.OpenPopupStack.Size > 0);
+    {
+        io.WantCaptureMouse = (mouse_avail && (g.HoveredWindow != NULL || mouse_any_down)) || has_open_popup;
+        io.WantCaptureMouseUnlessPopupClose = (mouse_avail_unless_popup_close && (g.HoveredWindow != NULL || mouse_any_down)) || has_open_modal;
+    }
 
-    // Update io.WantCaptureKeyboard for the user application (true = dispatch keyboard info to imgui, false = dispatch keyboard info to Dear ImGui + app)
+    // Update io.WantCaptureKeyboard for the user application (true = dispatch keyboard info to Dear ImGui only, false = dispatch keyboard info to Dear ImGui + underlying app)
     if (g.WantCaptureKeyboardNextFrame != -1)
-        g.IO.WantCaptureKeyboard = (g.WantCaptureKeyboardNextFrame != 0);
+        io.WantCaptureKeyboard = (g.WantCaptureKeyboardNextFrame != 0);
     else
-        g.IO.WantCaptureKeyboard = (g.ActiveId != 0) || (modal_window != NULL);
-    if (g.IO.NavActive && (g.IO.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard) && !(g.IO.ConfigFlags & ImGuiConfigFlags_NavNoCaptureKeyboard))
-        g.IO.WantCaptureKeyboard = true;
+        io.WantCaptureKeyboard = (g.ActiveId != 0) || (modal_window != NULL);
+    if (io.NavActive && (io.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard) && !(io.ConfigFlags & ImGuiConfigFlags_NavNoCaptureKeyboard))
+        io.WantCaptureKeyboard = true;
 
     // Update io.WantTextInput flag, this is to allow systems without a keyboard (e.g. mobile, hand-held) to show a software keyboard if possible
-    g.IO.WantTextInput = (g.WantTextInputNextFrame != -1) ? (g.WantTextInputNextFrame != 0) : false;
+    io.WantTextInput = (g.WantTextInputNextFrame != -1) ? (g.WantTextInputNextFrame != 0) : false;
 }
 
 ImGuiKeyModFlags ImGui::GetMergedKeyModFlags()

imgui.h

@@ -64,7 +64,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.85 WIP"
-#define IMGUI_VERSION_NUM           18409
+#define IMGUI_VERSION_NUM           18410
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 
@@ -1918,6 +1918,7 @@ struct ImGuiIO
     // [Internal] Dear ImGui will maintain those fields. Forward compatibility not guaranteed!
     //------------------------------------------------------------------
 
+    bool        WantCaptureMouseUnlessPopupClose;// Alternative to WantCaptureMouse: (WantCaptureMouse == true && WantCaptureMouseUnlessPopupClose == false) when a click over void is expected to close a popup.
     ImGuiKeyModFlags KeyMods;                   // Key mods flags (same as io.KeyCtrl/KeyShift/KeyAlt/KeySuper but merged into flags), updated by NewFrame()
     ImGuiKeyModFlags KeyModsPrev;               // Previous key mods
     ImVec2      MousePosPrev;                   // Previous mouse position (note that MouseDelta is not necessary == MousePos-MousePosPrev, in case either position is invalid)
@@ -1926,7 +1927,8 @@ struct ImGuiIO
     bool        MouseClicked[5];                // Mouse button went from !Down to Down
     bool        MouseDoubleClicked[5];          // Has mouse button been double-clicked?
     bool        MouseReleased[5];               // Mouse button went from Down to !Down
-    bool        MouseDownOwned[5];              // Track if button was clicked inside a dear imgui window. We don't request mouse capture from the application if click started outside ImGui bounds.
+    bool        MouseDownOwned[5];              // Track if button was clicked inside a dear imgui window or over void blocked by a popup. We don't request mouse capture from the application if click started outside ImGui bounds.
+    bool        MouseDownOwnedUnlessPopupClose[5];//Track if button was clicked inside a dear imgui window.
     bool        MouseDownWasDoubleClick[5];     // Track if button down was a double-click
     float       MouseDownDuration[5];           // Duration the mouse button has been down (0.0f == just clicked)
     float       MouseDownDurationPrev[5];       // Previous time the mouse button has been down

imgui_demo.cpp

@@ -5481,6 +5481,7 @@ static void ShowDemoWindowMisc()
 
         // Display ImGuiIO output flags
         ImGui::Text("WantCaptureMouse: %d", io.WantCaptureMouse);
+        ImGui::Text("WantCaptureMouseUnlessPopupClose: %d", io.WantCaptureMouseUnlessPopupClose);
         ImGui::Text("WantCaptureKeyboard: %d", io.WantCaptureKeyboard);
         ImGui::Text("WantTextInput: %d", io.WantTextInput);
         ImGui::Text("WantSetMousePos: %d", io.WantSetMousePos);