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MultiSelect: ImGuiSelectionBasicStorage: added GetNextSelectedItem() to abstract selection storage from user. Amend Assets Browser demo to handle drag and drop correctly.

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ocornut 2024-06-11 17:14:00 +02:00
parent c3d7aa252b
commit e1fd25051e
3 changed files with 61 additions and 25 deletions
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34
imgui.h
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@ -2817,35 +2817,39 @@ struct ImGuiSelectionRequest
// Optional helper to store multi-selection state + apply multi-selection requests.
// - Used by our demos and provided as a convenience to easily implement basic multi-selection.
// - Iterate selection with 'void* it = NULL; while (ImGuiId id = selection.GetNextSelectedItem(&it)) { ... }'
// Or you can check 'if (Contains(id)) { ... }' for each possible object if their number is not too high to iterate.
// - USING THIS IS NOT MANDATORY. This is only a helper and not a required API.
// To store a multi-selection, in your application you could:
// - A) Use this helper as a convenience. We use our simple key->value ImGuiStorage as a std::set<ImGuiID> replacement.
// - B) Use your own external storage: e.g. std::set<MyObjectId>, std::vector<MyObjectId>, interval trees, etc.
// - C) Use intrusively stored selection (e.g. 'bool IsSelected' inside objects). Cannot have multiple views over same objects.
// - Use this helper as a convenience. We use our simple key->value ImGuiStorage as a std::set<ImGuiID> replacement.
// - Use your own external storage: e.g. std::set<MyObjectId>, std::vector<MyObjectId>, interval trees, intrusively stored selection etc.
// In ImGuiSelectionBasicStorage we:
// - always use indices in the multi-selection API (passed to SetNextItemSelectionUserData(), retrieved in ImGuiMultiSelectIO)
// - use the AdapterIndexToStorageId() indirection layer to abstract how persistent selection data is derived from an index.
// - use decently optimized logic to allow queries and insertion of very large selection sets.
// - do not preserve selection order.
// Many combinations are possible depending on how you prefer to store your items and how you prefer to store your selection.
// Large applications are likely to eventually want to get rid of this indirection layer and do their own thing.
// See https://github.com/ocornut/imgui/wiki/Multi-Select for details and pseudo-code using this helper.
struct ImGuiSelectionBasicStorage
{
// Members
ImGuiStorage Storage; // [Internal] Selection set. Think of this as similar to e.g. std::set<ImGuiID>
ImGuiStorage _Storage; // [Internal] Selection set. Think of this as similar to e.g. std::set<ImGuiID>. Prefer not accessing directly: iterate with GetNextSelectedItem().
int Size; // Number of selected items (== number of 1 in the Storage), maintained by this helper.
void* UserData; // User data for use by adapter function // e.g. selection.UserData = (void*)my_items;
ImGuiID (*AdapterIndexToStorageId)(ImGuiSelectionBasicStorage* self, int idx); // e.g. selection.AdapterIndexToStorageId = [](ImGuiSelectionBasicStorage* self, int idx) { return ((MyItems**)self->UserData)[idx]->ID; };
// Methods: apply selection requests coming from BeginMultiSelect() and EndMultiSelect() functions. Uses 'items_count' passed to BeginMultiSelect()
IMGUI_API void ApplyRequests(ImGuiMultiSelectIO* ms_io);
// Methods
IMGUI_API void ApplyRequests(ImGuiMultiSelectIO* ms_io);// Apply selection requests coming from BeginMultiSelect() and EndMultiSelect() functions. It uses 'items_count' passed to BeginMultiSelect()
IMGUI_API ImGuiID GetNextSelectedItem(void** opaque_it); // Iterate selection with 'void* it = NULL; while (ImGuiId id = selection.GetNextSelectedItem(&it)) { ... }'
bool Contains(ImGuiID id) const { return _Storage.GetInt(id, 0) != 0; } // Query if an item id is in selection.
ImGuiID GetStorageIdFromIndex(int idx) { return AdapterIndexToStorageId(this, idx); } // Convert index to item id based on provided adapter.
// Methods: selection storage
ImGuiSelectionBasicStorage() { Size = 0; UserData = NULL; AdapterIndexToStorageId = [](ImGuiSelectionBasicStorage*, int idx) { return (ImGuiID)idx; }; }
void Clear() { Storage.Data.resize(0); Size = 0; }
void Swap(ImGuiSelectionBasicStorage& r) { Storage.Data.swap(r.Storage.Data); int lhs_size = Size; Size = r.Size; r.Size = lhs_size; }
bool Contains(ImGuiID id) const { return Storage.GetInt(id, 0) != 0; }
void SetItemSelected(ImGuiID id, bool v) { int* p_int = Storage.GetIntRef(id, 0); if (v && *p_int == 0) { *p_int = 1; Size++; } else if (!v && *p_int != 0) { *p_int = 0; Size--; } }
ImGuiID GetStorageIdFromIndex(int idx) { return AdapterIndexToStorageId(this, idx); }
// [Internal, rarely called directly by end-user]
ImGuiSelectionBasicStorage() { Size = 0; UserData = NULL; AdapterIndexToStorageId = [](ImGuiSelectionBasicStorage*, int idx) { return (ImGuiID)idx; }; }
void Clear() { _Storage.Data.resize(0); Size = 0; }
void Swap(ImGuiSelectionBasicStorage& r) { _Storage.Data.swap(r._Storage.Data); int lhs_size = Size; Size = r.Size; r.Size = lhs_size; }
void SetItemSelected(ImGuiID id, bool v) { int* p_int = _Storage.GetIntRef(id, 0); if (v && *p_int == 0) { *p_int = 1; Size++; } else if (!v && *p_int != 0) { *p_int = 0; Size--; } }
};
// Optional helper to apply multi-selection requests to existing randomly accessible storage.
@ -2857,8 +2861,8 @@ struct ImGuiSelectionExternalStorage
void (*AdapterSetItemSelected)(ImGuiSelectionExternalStorage* self, int idx, bool selected); // e.g. AdapterSetItemSelected = [](ImGuiSelectionExternalStorage* self, int idx, bool selected) { ((MyItems**)self->UserData)[idx]->Selected = selected; }
// Methods
ImGuiSelectionExternalStorage() { UserData = NULL; AdapterSetItemSelected = NULL; }
IMGUI_API void ApplyRequests(ImGuiMultiSelectIO* ms_io); // Generic function, using AdapterSetItemSelected()
ImGuiSelectionExternalStorage() { UserData = NULL; AdapterSetItemSelected = NULL; }
IMGUI_API void ApplyRequests(ImGuiMultiSelectIO* ms_io); // Generic function, using AdapterSetItemSelected()
};
//-----------------------------------------------------------------------------