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MultiSelect: Further simplication of user code to support Deletion.

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Provide standard RequestFocusItem storage.
This commit is contained in:
ocornut 2023-06-02 15:29:55 +02:00
parent df1eeb9a20
commit c0035705ca
3 changed files with 48 additions and 38 deletions
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7
imgui.h
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@ -2777,18 +2777,19 @@ struct ImGuiMultiSelectIO
bool RequestClear; // ms:w, app:r / / ms:w, app:r // 1. Request app/user to clear selection.
bool RequestSelectAll; // ms:w, app:r / / ms:w, app:r // 2. Request app/user to select all.
bool RequestSetRange; // / / ms:w, app:r // 3. Request app/user to select/unselect [RangeSrcItem..RangeDstItem] items, based on RangeSelected. In practice, only EndMultiSelect() request this, app code can read after BeginMultiSelect() and it will always be false.
void* RequestFocusItem; // app:w / app:r / app:r // (If using deletion) 4. Request user to focus item. This is actually only manipulated in user-space, but we provide storage to facilitate implemention of deletion idiom (see demo).
// STATE/ARGUMENTS ---------// BEGIN / LOOP / END
void* RangeSrcItem; // ms:w / app:r / ms:w, app:r // Begin: Last known SetNextItemSelectionUserData() value for RangeSrcItem. End: parameter from RequestSetRange request.
void* RangeDstItem; // / / ms:w, app:r // End: parameter from RequestSetRange request.
ImS8 RangeDirection; // / / ms:w, app:r // End: parameter from RequestSetRange request. +1 if RangeSrcItem came before RangeDstItem, -1 otherwise. Available as an indicator in case you cannot infer order from the void* values. If your void* values are storing indices you will never need this.
bool RangeSelected; // / / ms:w, app:r // End: parameter from RequestSetRange request. true = Select Range, false = Unselect Range.
bool RangeSrcPassedBy; // / ms:rw app:w / ms:r // (If using clipper) Need to be set by app/user if RangeSrcItem was part of the clipped set before submitting the visible items. Ignore if not clipping.
bool RangeSrcReset; // / app:w / ms:r // (If using deletion) Set before EndMultiSelect() to reset ResetSrcItem (e.g. if deleted selection).
bool RangeSrcReset; // app:w / app:w / ms:r // (If using deletion) Set before EndMultiSelect() to reset ResetSrcItem (e.g. if deleted selection).
bool NavIdSelected; // ms:w, app:r / / // (If using deletion) Last known selection state for NavId (if part of submitted items).
void* NavIdItem; // ms:w, app:r / / ms:w app:r // (If using deletion) Last known SetNextItemSelectionUserData() value for NavId (if part of submitted items)
void* NavIdItem; // ms:w, app:r / / // (If using deletion) Last known SetNextItemSelectionUserData() value for NavId (if part of submitted items).
ImGuiMultiSelectIO() { Clear(); }
void Clear() { memset(this, 0, sizeof(*this)); }
void Clear() { memset(this, 0, sizeof(*this)); RequestFocusItem = NavIdItem = RangeSrcItem = RangeDstItem = (void*)-1; }
};
//-----------------------------------------------------------------------------

77
imgui_demo.cpp
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@ -2814,32 +2814,38 @@ struct ExampleSelection
}
}
// Call after BeginMultiSelect()
// We cannot provide this logic in core Dear ImGui because we don't have access to selection data.
// Essentially this would be a ms_io->RequestNextFocusBeforeDeletion
// Important: This only works if the item ID are stable: aka not depend on their index, but on e.g. item id/ptr.
// Call after BeginMultiSelect().
// - Calculate and set ms_io->RequestFocusItem, which we will focus during the loop.
// - We cannot provide this logic in core Dear ImGui because we don't have access to selection data.
// - Essentially this would be a ms_io->RequestNextFocusBeforeDeletion
// - Important: This only works if the item ID are stable: aka not depend on their index, but on e.g. item id/ptr.
template<typename ITEM_TYPE>
int CalcNextFocusIdxForBeforeDeletion(ImGuiMultiSelectIO* ms_io, ImVector<ITEM_TYPE>& items)
int ApplyDeletionPreLoop(ImGuiMultiSelectIO* ms_io, ImVector<ITEM_TYPE>& items)
{
if (ms_io->NavIdSelected == false)
return (int)(intptr_t)ms_io->NavIdItem;
// If current item is not selected.
if (ms_io->NavIdSelected == false) // Here 'NavIdSelected' should be == to 'GetSelected(ms_io->NavIdData)'
{
ms_io->RangeSrcReset = true; // Request to recover RangeSrc from NavId next frame. Would be ok to reset even without the !NavIdSelected test but it would take an extra frame to recover RangeSrc when deleting a selected item.
return (int)(intptr_t)ms_io->NavIdItem; // Request to land on same item after deletion.
}
// Return first unselected item after RangeSrcItem
// If current item is selected: land on first unselected item after RangeSrc.
for (int n = (int)(intptr_t)ms_io->RangeSrcItem + 1; n < items.Size; n++)
if (!GetSelected(n))
return n;
// Otherwise return last unselected item
// If current item is selected: otherwise return last unselected item.
for (int n = IM_MIN((int)(intptr_t)ms_io->RangeSrcItem, items.Size) - 1; n >= 0; n--)
if (!GetSelected(n))
return n;
return -1;
}
// Call after EndMultiSelect()
// Apply deletion request + return index of item to refocus, if any.
template<typename ITEM_TYPE>
void ApplyDeletion(ImGuiMultiSelectIO* ms_io, ImVector<ITEM_TYPE>& items, int next_focus_idx_in_old_selection)
void ApplyDeletionPostLoop(ImGuiMultiSelectIO* ms_io, ImVector<ITEM_TYPE>& items)
{
// This does two things:
// - (1) Update Items List (delete items from it)
@ -2850,6 +2856,7 @@ struct ExampleSelection
IM_UNUSED(ms_io);
ImVector<ITEM_TYPE> new_items;
new_items.reserve(items.Size - SelectionSize);
int next_focus_idx_in_old_selection = (int)(intptr_t)ms_io->RequestFocusItem;
int next_focus_idx_in_new_selection = -1;
for (int n = 0; n < items.Size; n++)
{
@ -2861,9 +2868,8 @@ struct ExampleSelection
items.swap(new_items);
// Update selection
//IMGUI_DEBUG_LOG("ApplyDeletion(): next_focus_idx_in_new_selection = %d\n", next_focus_idx_in_new_selection);
Clear();
if (next_focus_idx_in_new_selection != -1)
if (next_focus_idx_in_new_selection != -1 && ms_io->NavIdSelected)
SetSelected(next_focus_idx_in_new_selection, true);
}
};
@ -2917,7 +2923,7 @@ static void ShowDemoWindowMultiSelect()
"Cauliflower", "Celery", "Celery Root", "Celcuce", "Chayote", "Celtuce", "Chayote", "Chinese Broccoli", "Corn", "Cucumber"
};
// Demonstrate holding/updating multi-selection data and using the BeginMultiSelect/EndMultiSelect API to support range-selection and clipping.
// Demonstrate holding/updating multi-selection data using the BeginMultiSelect/EndMultiSelect API.
// SHIFT+Click w/ CTRL and other standard features are supported.
IMGUI_DEMO_MARKER("Widgets/Selection State/Multiple Selection (full)");
//ImGui::SetNextItemOpen(true, ImGuiCond_Once);
@ -2958,13 +2964,19 @@ static void ShowDemoWindowMultiSelect()
ImGui::TreePop();
}
// Demonstrate holding/updating multi-selection data and using the BeginMultiSelect/EndMultiSelect API to support range-selection and clipping.
// Demonstrate holding/updating multi-selection data and using the BeginMultiSelect/EndMultiSelect API + support dynamic item list and deletion.
// SHIFT+Click w/ CTRL and other standard features are supported.
// In order to support Deletion without any glitches you need to:
// - (1) If items are submitted in their own scrolling area, submit contents size SetNextWindowContentSize() ahead of time to prevent one-frame readjustment of scrolling.
// - (2) Items needs to have persistent ID Stack identifier = ID needs to not depends on their index. PushID(index) = KO. PushID(item_id) = OK. This is in order to focus items reliably after a selection.
// - (3) BeginXXXX process
// - (4) Focus process
// - (5) EndXXXX process
IMGUI_DEMO_MARKER("Widgets/Selection State/Multiple Selection (full, with deletion)");
if (ImGui::TreeNode("Multiple Selection (full, with deletion)"))
{
// Intentionally separating items data from selection data!
// But you may decide to store selection data inside your item (aka '
// But you may decide to store selection data inside your item (aka intrusive storage).
static ImVector<int> items;
static ExampleSelection selection;
@ -2974,7 +2986,7 @@ static void ShowDemoWindowMultiSelect()
if (ImGui::IsItemHovered() && selection.GetSize() > 0)
selection.DebugTooltip();
// Initialize default list with 50 items + button to add more.
// Initialize default list with 50 items + button to add/remove items.
static int items_next_id = 0;
if (items_next_id == 0)
for (int n = 0; n < 50; n++)
@ -2983,9 +2995,10 @@ static void ShowDemoWindowMultiSelect()
ImGui::SameLine();
if (ImGui::SmallButton("Remove 20 items")) { for (int n = IM_MIN(20, items.Size); n > 0; n--) { selection.SetSelected(items.Size - 1, false); items.pop_back(); } } // This is to test
// Extra to support deletion: Submit scrolling range to avoid glitches on deletion
// (1) Extra to support deletion: Submit scrolling range to avoid glitches on deletion
const float items_height = ImGui::GetTextLineHeightWithSpacing();
ImGui::SetNextWindowContentSize(ImVec2(0.0f, items.Size * items_height));
if (ImGui::BeginListBox("##Basket", ImVec2(-FLT_MIN, ImGui::GetFontSize() * 20)))
{
ImGuiMultiSelectFlags flags = ImGuiMultiSelectFlags_ClearOnEscape;
@ -2994,11 +3007,11 @@ static void ShowDemoWindowMultiSelect()
// FIXME-MULTISELECT: Shortcut(). Hard to demo this? May be helpful to send a helper/optional "delete" signal.
// FIXME-MULTISELECT: may turn into 'ms_io->RequestDelete' -> need HasSelection passed.
// FIXME-MULTISELECT: Test with intermediary modal dialog.
// FIXME-MULTISELECT: If pressing Delete + another key we have slightly ambiguous behavior.
// FIXME-MULTISELECT: If pressing Delete + another key we have ambiguous behavior.
const bool want_delete = (selection.GetSize() > 0) && ImGui::IsWindowFocused() && ImGui::IsKeyPressed(ImGuiKey_Delete);
const int next_focus_item_idx = want_delete ? selection.CalcNextFocusIdxForBeforeDeletion(ms_io, items) : -1;
//if (want_delete) { IMGUI_DEBUG_LOG("next_focus_item_idx = %d\n", next_focus_item_idx); }
if (want_delete)
ms_io->RequestFocusItem = (void*)(intptr_t)selection.ApplyDeletionPreLoop(ms_io, items);
const int next_focus_item_idx = (int)(intptr_t)ms_io->RequestFocusItem;
for (int n = 0; n < items.Size; n++)
{
@ -3011,19 +3024,15 @@ static void ShowDemoWindowMultiSelect()
ImGui::Selectable(label, item_is_selected);
if (ImGui::IsItemToggledSelection())
selection.SetSelected(n, !item_is_selected);
// FIXME-MULTISELECT: turn into a ms_io->RequestFocusIdx
if (next_focus_item_idx == n)
ImGui::SetKeyboardFocusHere(-1); // FIXME-MULTISELECT: Need to avoid selection.
ImGui::SetKeyboardFocusHere(-1);
}
// Apply multi-select requests
if (want_delete && ms_io->NavIdSelected == false) // FIXME: would work without '&& !NavIdSelected' just take an extra frame to recover RangeSrc
ms_io->RangeSrcReset = true;
ms_io = ImGui::EndMultiSelect();
selection.ApplyRequests(ms_io, items.Size);
if (want_delete)
selection.ApplyDeletion(ms_io, items, ms_io->NavIdSelected ? next_focus_item_idx : -1);
selection.ApplyDeletionPostLoop(ms_io, items);
ImGui::EndListBox();
}
@ -3122,8 +3131,9 @@ static void ShowDemoWindowMultiSelect()
// FIXME-MULTISELECT: may turn into 'ms_io->RequestDelete' -> need HasSelection passed.
// FIXME-MULTISELECT: Test with intermediary modal dialog.
const bool want_delete = (selection.GetSize() > 0) && ImGui::IsWindowFocused() && ImGui::IsKeyPressed(ImGuiKey_Delete);
const int next_focus_item_idx = want_delete ? selection.CalcNextFocusIdxForBeforeDeletion(ms_io, items) : -1;
//if (want_delete) { IMGUI_DEBUG_LOG("next_focus_item_idx = %d\n", next_focus_item_idx); }
if (want_delete)
selection.ApplyDeletionPreLoop(ms_io, items);
const int next_focus_item_idx = (int)(intptr_t)ms_io->RequestFocusItem;
if (show_in_table)
{
@ -3183,7 +3193,8 @@ static void ShowDemoWindowMultiSelect()
{
ImGui::Selectable(label, item_is_selected);
if (next_focus_item_idx == n)
ImGui::SetKeyboardFocusHere(-1); // FIXME-MULTISELECT: turn into a ms_io->RequestFocusIdx
ImGui::SetKeyboardFocusHere(-1);
if (use_drag_drop && ImGui::BeginDragDropSource())
{
ImGui::Text("(Dragging %d items)", selection.GetSize());
@ -3198,7 +3209,7 @@ static void ShowDemoWindowMultiSelect()
tree_node_flags |= ImGuiTreeNodeFlags_Selected;
bool open = ImGui::TreeNodeEx(label, tree_node_flags);
if (next_focus_item_idx == n)
ImGui::SetKeyboardFocusHere(-1); // FIXME-MULTISELECT: turn into a ms_io->RequestFocusIdx
ImGui::SetKeyboardFocusHere(-1);
if (use_drag_drop && ImGui::BeginDragDropSource())
{
ImGui::Text("(Dragging %d items)", selection.GetSize());
@ -3246,12 +3257,10 @@ static void ShowDemoWindowMultiSelect()
}
// Apply multi-select requests
if (want_delete && ms_io->NavIdSelected == false)
ms_io->RangeSrcReset = true;
ms_io = ImGui::EndMultiSelect();
selection.ApplyRequests(ms_io, items.Size);
if (want_delete)
selection.ApplyDeletion(ms_io, items, ms_io->NavIdSelected ? next_focus_item_idx : -1);
selection.ApplyDeletionPostLoop(ms_io, items);
if (widget_type == WidgetType_TreeNode)
ImGui::PopStyleVar();

2
imgui_internal.h
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@ -1730,7 +1730,7 @@ struct IMGUI_API ImGuiMultiSelectTempData
//ImRect Rect; // Extent of selection scope between BeginMultiSelect() / EndMultiSelect(), used by ImGuiMultiSelectFlags_ClearOnClickRectVoid.
ImGuiMultiSelectTempData() { Clear(); }
void Clear() { memset(this, 0, sizeof(*this)); BeginIO.RangeSrcItem = EndIO.RangeSrcItem = BeginIO.RangeDstItem = EndIO.RangeDstItem = BeginIO.NavIdItem = EndIO.NavIdItem = (void*)-1; }
void Clear() { memset(this, 0, sizeof(*this)); BeginIO.Clear(); EndIO.Clear(); }
};
// Persistent storage for multi-select (as long as selection is alive)