NewFrame: Extract some code into a NewFrameUpdateHoveredWindowAndCaptureFlags() which can be of use with touch-based inputs systems.

imgui.cpp

@@ -3344,6 +3344,62 @@ static void ImGui::NewFrameUpdateMouseInputs()
     }
 }
 
+// The reason this is exposed in imgui_internal.h is: on touch-based system that don't have hovering, we want to dispatch inputs to the right target (imgui vs imgui+app)
+void ImGui::NewFrameUpdateHoveredWindowAndCaptureFlags()
+{
+    ImGuiContext& g = *GImGui;
+
+    // Find the window hovered by mouse:
+    // - Child windows can extend beyond the limit of their parent so we need to derive HoveredRootWindow from HoveredWindow.
+    // - When moving a window we can skip the search, which also conveniently bypasses the fact that window->WindowRectClipped is lagging as this point of the frame.
+    // - We also support the moved window toggling the NoInputs flag after moving has started in order to be able to detect windows below it, which is useful for e.g. docking mechanisms.
+    g.HoveredWindow = (g.MovingWindow && !(g.MovingWindow->Flags & ImGuiWindowFlags_NoInputs)) ? g.MovingWindow : FindHoveredWindow();
+    g.HoveredRootWindow = g.HoveredWindow ? g.HoveredWindow->RootWindow : NULL;
+
+    // Modal windows prevents cursor from hovering behind them.
+    ImGuiWindow* modal_window = GetFrontMostModalRootWindow();
+    if (modal_window)
+        if (g.HoveredRootWindow && !IsWindowChildOf(g.HoveredRootWindow, modal_window))
+            g.HoveredRootWindow = g.HoveredWindow = NULL;
+
+    // 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;
+    bool mouse_any_down = false;
+    for (int i = 0; i < IM_ARRAYSIZE(g.IO.MouseDown); i++)
+    {
+        if (g.IO.MouseClicked[i])
+            g.IO.MouseDownOwned[i] = (g.HoveredWindow != NULL) || (!g.OpenPopupStack.empty());
+        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;
+    }
+    const bool mouse_avail_to_imgui = (mouse_earliest_button_down == -1) || g.IO.MouseDownOwned[mouse_earliest_button_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)
+        g.HoveredWindow = g.HoveredRootWindow = NULL;
+
+    // Update io.WantCaptureMouse for the user application (true = dispatch mouse info to imgui, false = dispatch mouse info to imgui + app)
+    if (g.WantCaptureMouseNextFrame != -1)
+        g.IO.WantCaptureMouse = (g.WantCaptureMouseNextFrame != 0);
+    else
+        g.IO.WantCaptureMouse = (mouse_avail_to_imgui && (g.HoveredWindow != NULL || mouse_any_down)) || (!g.OpenPopupStack.empty());
+
+    // Update io.WantCaptureKeyboard for the user application (true = dispatch keyboard info to imgui, false = dispatch keyboard info to imgui + app)
+    if (g.WantCaptureKeyboardNextFrame != -1)
+        g.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;
+
+    // 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) : 0;
+}
+
 void ImGui::NewFrame()
 {
     IM_ASSERT(GImGui != NULL && "No current context. Did you call ImGui::CreateContext() or ImGui::SetCurrentContext()?");
@@ -3446,63 +3502,17 @@ void ImGui::NewFrame()
 
     // Handle user moving window with mouse (at the beginning of the frame to avoid input lag or sheering)
     NewFrameUpdateMovingWindow();
-
-    // Find the window we are hovering
-    // - Child windows can extend beyond the limit of their parent so we need to derive HoveredRootWindow from HoveredWindow.
-    // - When moving a window we can skip the search, which also conveniently bypasses the fact that window->WindowRectClipped is lagging as this point.
-    // - We also support the moved window toggling the NoInputs flag after moving has started in order to be able to detect windows below it, which is useful for e.g. docking mechanisms.
-    g.HoveredWindow = (g.MovingWindow && !(g.MovingWindow->Flags & ImGuiWindowFlags_NoInputs)) ? g.MovingWindow : FindHoveredWindow();
-    g.HoveredRootWindow = g.HoveredWindow ? g.HoveredWindow->RootWindow : NULL;
-
-    ImGuiWindow* modal_window = GetFrontMostModalRootWindow();
-    if (modal_window != NULL)
-    {
+    NewFrameUpdateHoveredWindowAndCaptureFlags();
+    
+    if (ImGuiWindow* modal_window = GetFrontMostModalRootWindow())
         g.ModalWindowDarkeningRatio = ImMin(g.ModalWindowDarkeningRatio + g.IO.DeltaTime * 6.0f, 1.0f);
-        if (g.HoveredRootWindow && !IsWindowChildOf(g.HoveredRootWindow, modal_window))
-            g.HoveredRootWindow = g.HoveredWindow = NULL;
-    }
     else
-    {
         g.ModalWindowDarkeningRatio = 0.0f;
-    }
 
-    // Update the WantCaptureMouse/WantCaptureKeyboard flags, so user 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. 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++)
-    {
-        if (g.IO.MouseClicked[i])
-            g.IO.MouseDownOwned[i] = (g.HoveredWindow != NULL) || (!g.OpenPopupStack.empty());
-        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;
-    }
-    bool mouse_avail_to_imgui = (mouse_earliest_button_down == -1) || g.IO.MouseDownOwned[mouse_earliest_button_down];
-    if (g.WantCaptureMouseNextFrame != -1)
-        g.IO.WantCaptureMouse = (g.WantCaptureMouseNextFrame != 0);
-    else
-        g.IO.WantCaptureMouse = (mouse_avail_to_imgui && (g.HoveredWindow != NULL || mouse_any_down)) || (!g.OpenPopupStack.empty());
-
-    if (g.WantCaptureKeyboardNextFrame != -1)
-        g.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;
-
-    g.IO.WantTextInput = (g.WantTextInputNextFrame != -1) ? (g.WantTextInputNextFrame != 0) : 0;
     g.MouseCursor = ImGuiMouseCursor_Arrow;
     g.WantCaptureMouseNextFrame = g.WantCaptureKeyboardNextFrame = g.WantTextInputNextFrame = -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.
-    // FIXME: For patterns of drag and drop across OS windows, we may need to rework/remove this test (first committed 311c0ca9 on 2015/02)
-    bool mouse_dragging_extern_payload = g.DragDropActive && (g.DragDropSourceFlags & ImGuiDragDropFlags_SourceExtern) != 0;
-    if (!mouse_avail_to_imgui && !mouse_dragging_extern_payload)
-        g.HoveredWindow = g.HoveredRootWindow = NULL;
-
     // Mouse wheel scrolling, scale
     if (g.HoveredWindow && !g.HoveredWindow->Collapsed && (g.IO.MouseWheel != 0.0f || g.IO.MouseWheelH != 0.0f))
     {

imgui_internal.h

@@ -1017,6 +1017,8 @@ namespace ImGui
     IMGUI_API void          Initialize(ImGuiContext* context);
     IMGUI_API void          Shutdown(ImGuiContext* context);    // Since 1.60 this is a _private_ function. You can call DestroyContext() to destroy the context created by CreateContext().
 
+    IMGUI_API void          NewFrameUpdateHoveredWindowAndCaptureFlags();
+
     IMGUI_API void                  MarkIniSettingsDirty();
     IMGUI_API ImGuiSettingsHandler* FindSettingsHandler(const char* type_name);
     IMGUI_API ImGuiWindowSettings*  FindWindowSettings(ImGuiID id);