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MultiSelect: Demo: first-draft of user-side deletion idioms. 

(will need support from lib)
This commit is contained in:
ocornut 2023-06-02 14:22:13 +02:00
parent 387fc13894
commit 564dde0ee3
1 changed files with 157 additions and 11 deletions
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168
imgui_demo.cpp
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@ -605,7 +605,6 @@ void ImGui::ShowDemoWindow(bool* p_open)
ImGui::End();
}
static void ShowDemoWindowWidgets()
{
IMGUI_DEMO_MARKER("Widgets");
@ -2806,11 +2805,61 @@ struct ExampleSelection
if (ms_io->RequestSelectAll) { SelectAll(items_count); }
if (ms_io->RequestSetRange) { SetRange((int)(intptr_t)ms_io->RangeSrcItem, (int)(intptr_t)ms_io->RangeDstItem, ms_io->RangeSelected ? 1 : 0); }
}
// 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.
template<typename ITEM_TYPE>
int CalcNextFocusIdxForBeforeDeletion(ImGuiMultiSelectIO* ms_io, ImVector<ITEM_TYPE>& items)
{
// Return first unselected item after RangeSrcItem
for (int n = (int)(intptr_t)ms_io->RangeSrcItem + 1; n < items.Size; n++)
if (!GetSelected(n))
return n;
// Otherwise return last unselected item
for (int n = (int)(intptr_t)ms_io->RangeSrcItem - 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)
{
// This does two things:
// - (1) Update Items List (delete items from it)
// - (2) Convert the new focus index from old selection index (before deletion) to new selection index (after selection), and select it.
// FIXME: (2.3) if NavId is not selected, stay on same item -> facilitate persisting focus if ID change? (if ID is index-based) -> by setting focus again
// You are expected to handle both of those in user-space because Dear ImGui rightfully doesn't own items data nor selection data.
// This particular ExampleSelection case is designed to showcase maintaining selection-state separated from items-data.
IM_UNUSED(ms_io);
ImVector<ITEM_TYPE> new_items;
new_items.reserve(items.Size - SelectionSize);
int next_focus_idx_in_new_selection = -1;
for (int n = 0; n < items.Size; n++)
{
if (!GetSelected(n))
new_items.push_back(items[n]);
if (next_focus_idx_in_old_selection == n)
next_focus_idx_in_new_selection = new_items.Size - 1;
}
items.swap(new_items);
// Update selection
Clear();
if (next_focus_idx_in_new_selection != -1)
SetSelected(next_focus_idx_in_new_selection, true);
}
};
static void ShowDemoWindowMultiSelect()
{
IMGUI_DEMO_MARKER("Widgets/Selection State");
//ImGui::SetNextItemOpen(true, ImGuiCond_Once);
if (ImGui::TreeNode("Selection State"))
{
HelpMarker("Selections can be built under Selectable(), TreeNode() or other widgets. Selection state is owned by application code/data.");
@ -2896,7 +2945,77 @@ static void ShowDemoWindowMultiSelect()
ImGui::EndListBox();
}
ImGui::TreePop();
}
// Demonstrate holding/updating multi-selection data and using the BeginMultiSelect/EndMultiSelect API to support range-selection and clipping.
// SHIFT+Click w/ CTRL and other standard features are supported.
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 '
static ImVector<int> items;
static ExampleSelection selection;
ImGui::Text("Adding features:");
ImGui::BulletText("Dynamic list with Delete key support.");
// Initialize default list with 50 items + button to add more.
static int items_next_id = 0;
if (items_next_id == 0)
for (int n = 0; n < 50; n++)
items.push_back(items_next_id++);
ImGui::Text("Selection: %d/%d", selection.GetSize(), items.Size);
ImGui::SameLine();
if (ImGui::SmallButton("Add 20 items"))
for (int n = 0; n < 20; n++)
items.push_back(items_next_id++);
ImGui::Text("Selection size: %d/%d", selection.GetSize(), items.Size);
ImGui::Text("RangeRef: %d", selection.RangeRef);
// 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;
ImGuiMultiSelectIO* ms_io = ImGui::BeginMultiSelect(flags, (void*)(intptr_t)selection.RangeRef, selection.GetSelected(selection.RangeRef));
selection.ApplyRequests(ms_io, items.Size);
// 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.
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;
for (int n = 0; n < items.Size; n++)
{
const int item_id = items[n];
char label[64];
sprintf(label, "Object %05d: %s", item_id, random_names[item_id % IM_ARRAYSIZE(random_names)]);
bool item_is_selected = selection.GetSelected(n);
ImGui::SetNextItemSelectionData((void*)(intptr_t)n);
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);
}
// Apply multi-select requests
ms_io = ImGui::EndMultiSelect();
selection.RangeRef = (int)(intptr_t)ms_io->RangeSrcItem;
selection.ApplyRequests(ms_io, items.Size);
if (want_delete)
selection.ApplyDeletion(ms_io, items, next_focus_item_idx);
ImGui::EndListBox();
}
ImGui::TreePop();
}
@ -2939,6 +3058,7 @@ static void ShowDemoWindowMultiSelect()
// Advanced demonstration of BeginMultiSelect()
// - Showcase clipping.
// - Showcase deletion.
// - Showcase basic drag and drop.
// - Showcase TreeNode variant (note that tree node don't expand in the demo: supporting expanding tree nodes + clipping a separate thing).
// - Showcase using inside a table.
@ -2949,6 +3069,7 @@ static void ShowDemoWindowMultiSelect()
// Options
enum WidgetType { WidgetType_Selectable, WidgetType_TreeNode };
static bool use_clipper = true;
static bool use_deletion = true;
static bool use_drag_drop = true;
static bool show_in_table = false;
static bool show_color_button = false;
@ -2959,6 +3080,7 @@ static void ShowDemoWindowMultiSelect()
ImGui::SameLine();
if (ImGui::RadioButton("Tree nodes", widget_type == WidgetType_TreeNode)) { widget_type = WidgetType_TreeNode; }
ImGui::Checkbox("Enable clipper", &use_clipper);
ImGui::Checkbox("Enable deletion", &use_deletion);
ImGui::Checkbox("Enable drag & drop", &use_drag_drop);
ImGui::Checkbox("Show in a table", &show_in_table);
ImGui::Checkbox("Show color button", &show_color_button);
@ -2967,10 +3089,16 @@ static void ShowDemoWindowMultiSelect()
ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnEscape", &flags, ImGuiMultiSelectFlags_ClearOnEscape);
ImGui::CheckboxFlags("ImGuiMultiSelectFlags_ClearOnClickWindowVoid", &flags, ImGuiMultiSelectFlags_ClearOnClickWindowVoid);
const int ITEMS_COUNT = 1000;
// Initialize default list with 1000 items.
static ImVector<int> items;
static int items_next_id = 0;
if (items_next_id == 0) { for (int n = 0; n < 1000; n++) { items.push_back(items_next_id++); } }
static ExampleSelection selection;
ImGui::Text("Selection size: %d/%d", selection.GetSize(), ITEMS_COUNT);
ImGui::Text("Selection size: %d/%d", selection.GetSize(), items.Size);
const float items_height = (widget_type == WidgetType_TreeNode) ? ImGui::GetTextLineHeight() : ImGui::GetTextLineHeightWithSpacing();
ImGui::SetNextWindowContentSize(ImVec2(0.0f, items.Size * items_height));
if (ImGui::BeginListBox("##Basket", ImVec2(-FLT_MIN, ImGui::GetFontSize() * 20)))
{
ImVec2 color_button_sz(ImGui::GetFontSize(), ImGui::GetFontSize());
@ -2978,7 +3106,13 @@ static void ShowDemoWindowMultiSelect()
ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(ImGui::GetStyle().ItemSpacing.x, 0.0f));
ImGuiMultiSelectIO* ms_io = ImGui::BeginMultiSelect(flags, (void*)(intptr_t)selection.RangeRef, selection.GetSelected(selection.RangeRef));
selection.ApplyRequests(ms_io, ITEMS_COUNT);
selection.ApplyRequests(ms_io, items.Size);
// 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.
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 (show_in_table)
{
@ -2992,7 +3126,7 @@ static void ShowDemoWindowMultiSelect()
ImGuiListClipper clipper;
if (use_clipper)
clipper.Begin(ITEMS_COUNT);
clipper.Begin(items.Size);
while (!use_clipper || clipper.Step())
{
@ -3002,16 +3136,22 @@ static void ShowDemoWindowMultiSelect()
ms_io->RangeSrcPassedBy = true;
const int item_begin = use_clipper ? clipper.DisplayStart : 0;
const int item_end = use_clipper ? clipper.DisplayEnd : ITEMS_COUNT;
const int item_end = use_clipper ? clipper.DisplayEnd : items.Size;
for (int n = item_begin; n < item_end; n++)
{
if (show_in_table)
ImGui::TableNextColumn();
ImGui::PushID(n);
const char* category = random_names[n % IM_ARRAYSIZE(random_names)];
const int item_id = items[n];
const char* item_category = random_names[item_id % IM_ARRAYSIZE(random_names)];
char label[64];
sprintf(label, "Object %05d: %s", n, category);
sprintf(label, "Object %05d: %s", item_id, item_category);
// IMPORTANT: for deletion refocus to work we need object ID to be stable,
// aka not depend on their index in the list. Here we use our persistent item_id
// instead of index to build a unique ID that will persist.
// (If we used PushID(n) instead, focus wouldn't be restored correctly after deletion).
ImGui::PushID(item_id);
// Emit a color button, to test that Shift+LeftArrow landing on an item that is not part
// of the selection scope doesn't erroneously alter our selection (FIXME-TESTS: Add a test for that!).
@ -3027,6 +3167,8 @@ static void ShowDemoWindowMultiSelect()
if (widget_type == WidgetType_Selectable)
{
ImGui::Selectable(label, item_is_selected);
if (next_focus_item_idx == n)
ImGui::SetKeyboardFocusHere(-1); // FIXME-MULTISELECT: turn into a ms_io->RequestFocusIdx
if (use_drag_drop && ImGui::BeginDragDropSource())
{
ImGui::Text("(Dragging %d items)", selection.GetSize());
@ -3040,6 +3182,8 @@ static void ShowDemoWindowMultiSelect()
if (item_is_selected)
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
if (use_drag_drop && ImGui::BeginDragDropSource())
{
ImGui::Text("(Dragging %d items)", selection.GetSize());
@ -3063,7 +3207,7 @@ static void ShowDemoWindowMultiSelect()
ImGui::TableNextColumn();
ImGui::SetNextItemWidth(-FLT_MIN);
ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, ImVec2(0, 0));
ImGui::InputText("###NoLabel", (char*)(void*)category, strlen(category), ImGuiInputTextFlags_ReadOnly);
ImGui::InputText("###NoLabel", (char*)(void*)item_category, strlen(item_category), ImGuiInputTextFlags_ReadOnly);
ImGui::PopStyleVar();
}
@ -3083,7 +3227,9 @@ static void ShowDemoWindowMultiSelect()
// Apply multi-select requests
ms_io = ImGui::EndMultiSelect();
selection.RangeRef = (int)(intptr_t)ms_io->RangeSrcItem;
selection.ApplyRequests(ms_io, ITEMS_COUNT);
selection.ApplyRequests(ms_io, items.Size);
if (want_delete)
selection.ApplyDeletion(ms_io, items, next_focus_item_idx);
if (widget_type == WidgetType_TreeNode)
ImGui::PopStyleVar();