CaptureKeyboardFromApp() / CaptureMouseFromApp(): allow to enforce clearing the capture flag (#533) + demo + made code a little less messy

imgui.cpp

@@ -1990,7 +1990,7 @@ void ImGui::NewFrame()
     }
 
     // Are we using inputs? Tell user so they can capture/discard the inputs away from the rest of their application.
-    // When clicking outside of a window we assume the click is owned by the application and won't request capture.
+    // When clicking outside of a window we assume the click is owned by the application and won't request capture. We need to track click ownership.
     int mouse_earliest_button_down = -1;
     bool mouse_any_down = false;
     for (int i = 0; i < IM_ARRAYSIZE(g.IO.MouseDown); i++)
@@ -2002,16 +2002,19 @@ void ImGui::NewFrame()
             if (mouse_earliest_button_down == -1 || g.IO.MouseClickedTime[mouse_earliest_button_down] > g.IO.MouseClickedTime[i])
                 mouse_earliest_button_down = i;
     }
-    bool mouse_owned_by_application = mouse_earliest_button_down != -1 && !g.IO.MouseDownOwned[mouse_earliest_button_down];
-    g.IO.WantCaptureMouse = (!mouse_owned_by_application && g.HoveredWindow != NULL) || (!mouse_owned_by_application && mouse_any_down) || (g.ActiveId != 0) || (!g.OpenedPopupStack.empty()) || (g.CaptureMouseNextFrame);
-    g.IO.WantCaptureKeyboard = (g.ActiveId != 0) || (g.CaptureKeyboardNextFrame);
+    bool mouse_avail_to_imgui = (mouse_earliest_button_down == -1) || g.IO.MouseDownOwned[mouse_earliest_button_down];
+    if (g.CaptureMouseNextFrame != -1)
+        g.IO.WantCaptureMouse = (g.CaptureMouseNextFrame != 0);
+    else
+        g.IO.WantCaptureMouse = (mouse_avail_to_imgui && (g.HoveredWindow != NULL || mouse_any_down)) || (g.ActiveId != 0) || (!g.OpenedPopupStack.empty());
+    g.IO.WantCaptureKeyboard = (g.CaptureKeyboardNextFrame != -1) ? (g.CaptureKeyboardNextFrame != 0) : (g.ActiveId != 0);
     g.IO.WantTextInput = (g.ActiveId != 0 && g.InputTextState.Id == g.ActiveId);
     g.MouseCursor = ImGuiMouseCursor_Arrow;
-    g.CaptureMouseNextFrame = g.CaptureKeyboardNextFrame = false;
+    g.CaptureMouseNextFrame = g.CaptureKeyboardNextFrame = -1;
     g.OsImePosRequest = ImVec2(1.0f, 1.0f); // OS Input Method Editor showing on top-left of our window by default
 
     // If mouse was first clicked outside of ImGui bounds we also cancel out hovering.
-    if (mouse_owned_by_application)
+    if (!mouse_avail_to_imgui)
         g.HoveredWindow = g.HoveredRootWindow = NULL;
 
     // Scale & Scrolling
@@ -2990,14 +2993,14 @@ void ImGui::SetMouseCursor(ImGuiMouseCursor cursor_type)
     GImGui->MouseCursor = cursor_type;
 }
 
-void ImGui::CaptureKeyboardFromApp()
+void ImGui::CaptureKeyboardFromApp(bool capture)
 {
-    GImGui->CaptureKeyboardNextFrame = true;
+    GImGui->CaptureKeyboardNextFrame = capture ? 1 : 0;
 }
 
-void ImGui::CaptureMouseFromApp()
+void ImGui::CaptureMouseFromApp(bool capture)
 {
-    GImGui->CaptureMouseNextFrame = true;
+    GImGui->CaptureMouseNextFrame = capture ? 1 : 0;
 }
 
 bool ImGui::IsItemHovered()

imgui.h

@@ -415,8 +415,8 @@ namespace ImGui
     IMGUI_API void          ResetMouseDragDelta(int button = 0);                                //
     IMGUI_API ImGuiMouseCursor GetMouseCursor();                                                // get desired cursor type, reset in ImGui::NewFrame(), this updated during the frame. valid before Render(). If you use software rendering by setting io.MouseDrawCursor ImGui will render those for you
     IMGUI_API void          SetMouseCursor(ImGuiMouseCursor type);                              // set desired cursor type
-    IMGUI_API void          CaptureKeyboardFromApp();                                           // manually enforce imgui setting the io.WantCaptureKeyboard flag next frame (your application needs to handle it). e.g. capture keyboard when your widget is being hovered.
-    IMGUI_API void          CaptureMouseFromApp();                                              // manually enforce imgui setting the io.WantCaptureMouse flag next frame (your application needs to handle it).
+    IMGUI_API void          CaptureKeyboardFromApp(bool capture = true);                        // manually override io.WantCaptureKeyboard flag next frame (said flag is entirely left for your application handle). e.g. force capture keyboard when your widget is being hovered.
+    IMGUI_API void          CaptureMouseFromApp(bool capture = true);                           // manually override io.WantCaptureMouse flag next frame (said flag is entirely left for your application handle).
 
     // Helpers functions to access functions pointers in ImGui::GetIO()
     IMGUI_API void*         MemAlloc(size_t sz);

imgui_demo.cpp

@@ -1503,9 +1503,13 @@ void ImGui::ShowTestWindow(bool* p_opened)
             ImGui::Text("WantCaptureKeyboard: %s", io.WantCaptureKeyboard ? "true" : "false");
             ImGui::Text("WantTextInput: %s", io.WantTextInput ? "true" : "false");
 
-            ImGui::Button("Hover me\nto enforce\ninputs capture");
+            ImGui::Button("Hovering me sets the\nkeyboard capture flag");
             if (ImGui::IsItemHovered())
-                ImGui::CaptureKeyboardFromApp();
+                ImGui::CaptureKeyboardFromApp(true);
+            ImGui::SameLine();
+            ImGui::Button("Holding me clears the\nthe keyboard capture flag");
+            if (ImGui::IsItemActive())
+                ImGui::CaptureKeyboardFromApp(false);
             
             ImGui::TreePop();
         }

imgui_internal.h

@@ -434,8 +434,8 @@ struct ImGuiState
     float                   FramerateSecPerFrame[120];          // calculate estimate of framerate for user
     int                     FramerateSecPerFrameIdx;
     float                   FramerateSecPerFrameAccum;
-    bool                    CaptureMouseNextFrame;              // explicit capture via CaptureInputs() sets those flags
-    bool                    CaptureKeyboardNextFrame;
+    int                     CaptureMouseNextFrame;              // explicit capture via CaptureInputs() sets those flags
+    int                     CaptureKeyboardNextFrame;
     char                    TempBuffer[1024*3+1];               // temporary text buffer
 
     ImGuiState()
@@ -501,7 +501,7 @@ struct ImGuiState
         memset(FramerateSecPerFrame, 0, sizeof(FramerateSecPerFrame));
         FramerateSecPerFrameIdx = 0;
         FramerateSecPerFrameAccum = 0.0f;
-        CaptureMouseNextFrame = CaptureKeyboardNextFrame = false;
+        CaptureMouseNextFrame = CaptureKeyboardNextFrame = -1;
         memset(TempBuffer, 0, sizeof(TempBuffer));
     }
 };