Drag and Drop: Added ImGuiDragDropFlags_SourceExtern to facilitate interfacing with WM_DROPFILES (#143)

This commit is contained in:
omar
2017-12-15 11:16:10 +01:00
parent 6effcf21d6
commit 0c6e260f73
2 changed files with 51 additions and 33 deletions

View File

@ -11220,50 +11220,67 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags, int mouse_button)
{
ImGuiContext& g = *GImGui;
ImGuiWindow* window = g.CurrentWindow;
if (g.IO.MouseDown[mouse_button] == false)
return false;
ImGuiID id = window->DC.LastItemId;
if (id == 0)
bool source_drag_active = false;
ImGuiID source_id = 0;
ImGuiID source_parent_id = 0;
if (!(flags & ImGuiDragDropFlags_SourceExtern))
{
// If you want to use BeginDragDropSource() on an item with no unique identifier for interaction, such as Text() or Image(), you need to:
// A) Read the explanation below, B) Use the ImGuiDragDropFlags_SourceAllowNullID flag, C) Swallow your programmer pride.
if (!(flags & ImGuiDragDropFlags_SourceAllowNullID))
{
IM_ASSERT(0);
source_id = window->DC.LastItemId;
if (source_id != 0 && g.ActiveId != source_id) // Early out for most common case
return false;
if (g.IO.MouseDown[mouse_button] == false)
return false;
}
// Magic fallback (=somehow reprehensible) to handle items with no assigned ID, e.g. Text(), Image()
// We build a throwaway ID based on current ID stack + relative AABB of items in window.
// THE IDENTIFIER WON'T SURVIVE ANY REPOSITIONING OF THE WIDGET, so if your widget moves your dragging operation will be canceled.
// We don't need to maintain/call ClearActiveID() as releasing the button will early out this function and trigger !ActiveIdIsAlive.
bool is_hovered = window->DC.LastItemRectHoveredRect;
if (!is_hovered && (g.ActiveId == 0 || g.ActiveIdWindow != window))
return false;
id = window->DC.LastItemId = window->GetIDFromRectangle(window->DC.LastItemRect);
if (is_hovered)
SetHoveredID(id);
if (is_hovered && g.IO.MouseClicked[mouse_button])
if (source_id == 0)
{
SetActiveID(id, window);
FocusWindow(window);
// If you want to use BeginDragDropSource() on an item with no unique identifier for interaction, such as Text() or Image(), you need to:
// A) Read the explanation below, B) Use the ImGuiDragDropFlags_SourceAllowNullID flag, C) Swallow your programmer pride.
if (!(flags & ImGuiDragDropFlags_SourceAllowNullID))
{
IM_ASSERT(0);
return false;
}
// Magic fallback (=somehow reprehensible) to handle items with no assigned ID, e.g. Text(), Image()
// We build a throwaway ID based on current ID stack + relative AABB of items in window.
// THE IDENTIFIER WON'T SURVIVE ANY REPOSITIONING OF THE WIDGET, so if your widget moves your dragging operation will be canceled.
// We don't need to maintain/call ClearActiveID() as releasing the button will early out this function and trigger !ActiveIdIsAlive.
bool is_hovered = window->DC.LastItemRectHoveredRect;
if (!is_hovered && (g.ActiveId == 0 || g.ActiveIdWindow != window))
return false;
source_id = window->DC.LastItemId = window->GetIDFromRectangle(window->DC.LastItemRect);
if (is_hovered)
SetHoveredID(source_id);
if (is_hovered && g.IO.MouseClicked[mouse_button])
{
SetActiveID(source_id, window);
FocusWindow(window);
}
if (g.ActiveId == source_id) // Allow the underlying widget to display/return hovered during the mouse release frame, else we would get a flicker.
g.ActiveIdAllowOverlap = is_hovered;
}
if (g.ActiveId == id) // Allow the underlying widget to display/return hovered during the mouse release frame, else we would get a flicker.
g.ActiveIdAllowOverlap = is_hovered;
if (g.ActiveId != source_id)
return false;
source_parent_id = window->IDStack.back();
source_drag_active = IsMouseDragging(mouse_button);
}
else
{
window = NULL;
source_id = ImHash("#SourceExtern", 0);
source_drag_active = true;
}
if (g.ActiveId != id)
return false;
if (IsMouseDragging(mouse_button))
if (source_drag_active)
{
if (!g.DragDropActive)
{
IM_ASSERT(id != 0);
IM_ASSERT(source_id != 0);
ClearDragDrop();
ImGuiPayload& payload = g.DragDropPayload;
payload.SourceId = id;
payload.SourceParentId = window->IDStack.back();
payload.SourceId = source_id;
payload.SourceParentId = source_parent_id;
g.DragDropActive = true;
g.DragDropSourceFlags = flags;
g.DragDropMouseButton = mouse_button;
@ -11279,7 +11296,7 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags, int mouse_button)
BeginTooltipEx(ImGuiWindowFlags_NoInputs);
}
if (!(flags & ImGuiDragDropFlags_SourceNoDisableHover))
if (!(flags & ImGuiDragDropFlags_SourceNoDisableHover) && !(flags & ImGuiDragDropFlags_SourceExtern))
window->DC.LastItemRectHoveredRect = false;
return true;
@ -11434,7 +11451,7 @@ const ImGuiPayload* ImGui::AcceptDragDropPayload(const char* type, ImGuiDragDrop
}
g.DragDropAcceptFrameCount = g.FrameCount;
payload.Delivery = was_accepted_previously && IsMouseReleased(g.DragDropMouseButton);
payload.Delivery = was_accepted_previously && !IsMouseDown(g.DragDropMouseButton); // For extern drag sources affecting os window focus, it's easier to just test !IsMouseDown() instead of IsMouseReleased()
if (!payload.Delivery && !(flags & ImGuiDragDropFlags_AcceptBeforeDelivery))
return NULL;