// performance penalty, but requires a little more work on the code. If you only have a few hundreds elements in your possible selection set,
// you may as well not bother with clipping, as the cost should be negligible (as least on Dear ImGui side).
// If you are not sure, always start without clipping and you can work your way to the more optimized version afterwards.
// - The void* RangeSrc/RangeDst value represent a selectable object. They are the values you pass to SetNextItemSelectionUserData().
// - The void* RangeSrcItem/RangeDstItem value represent a selectable object. They are the value you pass to SetNextItemSelectionUserData().
// Most likely you will want to store an index here.
// Storing an integer index is the easiest thing to do, as SetRange requests will give you two end points and you will need to interpolate
// between them to honor range selection. But the code never assume that sortable integers are used (you may store pointers to your object,
// and then from the pointer have your own way of iterating from RangeSrc to RangeDst).
// and then from the pointer have your own way of iterating from RangeSrcItem to RangeDstItem).
// Usage flow:
// Begin
// 1) Call BeginMultiSelect() with the last saved value of ->RangeSrc and its selection state.
// 1) Call BeginMultiSelect() with the last saved value of ->RangeSrcItem and its selection state.
// It is because you need to pass its selection state (and you own selection) that we don't store this value in Dear ImGui.
// (For the initial frame or when resetting your selection state: you may use the value for your first item or a "null" value that matches the type stored in your void*).
// 2) Honor Clear/SelectAll/SetRange requests by updating your selection data. (Only required if you are using a clipper in step 4: but you can use same code as step 6 anyway.)
// Loop
// 3) Set RangeSrcPassedBy=true if the RangeSrc item is part of the items clipped before the first submitted/visible item. [Only required if you are using a clipper in step 4]
// 3) Set RangeSrcPassedBy=true if the RangeSrcItem item is part of the items clipped before the first submitted/visible item. [Only required if you are using a clipper in step 4]
// This is because for range-selection we need to know if we are currently "inside" or "outside" the range.
// If you are using integer indices everywhere, this is easy to compute: if (clipper.DisplayStart > (int)data->RangeSrc) { data->RangeSrcPassedBy = true; }
// If you are using integer indices everywhere, this is easy to compute: if (clipper.DisplayStart > (int)data->RangeSrcItem) { data->RangeSrcPassedBy = true; }
// 4) Submit your items with SetNextItemSelectionUserData() + Selectable()/TreeNode() calls.
// Call IsItemToggledSelection() to query if the selection state has been toggled, if you need the info immediately for your display (before EndMultiSelect()).
// When cannot provide a "IsItemSelected()" value because we need to consider clipped/unprocessed items, this is why we return a "Toggled" event instead.
// End
// 5) Call EndMultiSelect(). Save the value of ->RangeSrc for the next frame (you may convert the value in a format that is safe for persistance)
// 5) Call EndMultiSelect(). Save the value of ->RangeSrcItem for the next frame (you may convert the value in a format that is safe for persistance)
// 6) Honor Clear/SelectAll/SetRange requests by updating your selection data. Always process them in this order (as you will receive Clear+SetRange request simultaneously)
// If you submit all items (no clipper), Step 2 and 3 and will be handled by Selectable() on a per-item basis.
structImGuiMultiSelectIO
@ -2786,12 +2786,12 @@ struct ImGuiMultiSelectIO
// // BEGIN / LOOP / END
boolRequestClear;// ms:w, app:r / / ms:w, app:r // 1. Request user to clear selection (processed by app code)
boolRequestSelectAll;// ms:w, app:r / / ms:w, app:r // 2. Request user to select all (processed by app code)
boolRequestSetRange;// / / ms:w, app:r // 3. Request user to alter selection in the [RangeSrc..RangeDst] range using RangeValue. In practice, only EndMultiSelect() request this, app code can read after BeginMultiSelect() and it will always be false.
void*RangeSrc;// ms:w / app:r / ms:w, app:r // Begin: Last known RangeSrc value. End: parameter from RequestSetRange request.
ImS8RangeDirection;// / / ms:w, app:r // End: parameter from RequestSetRange request. +1 if RangeSrc came before RangeDst, -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.
boolRequestSetRange;// / / ms:w, app:r // 3. Request user to alter selection in the [RangeSrcItem..RangeDstItem] range using RangeValue. In practice, only EndMultiSelect() request this, app code can read after BeginMultiSelect() and it will always be false.
void*RangeSrcItem;// ms:w / app:r / ms:w, app:r // Begin: Last known SetNextItemSelectionData() value for RangeSrcItem value. End: parameter from RequestSetRange request.
ImS8RangeDirection;// / / 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.
boolRangeSrcPassedBy;// / ms:rw app:w / ms:r // (If using a clipper) Need to be set by user if RangeSrc was part of the clipped set before submitting the visible items. Ignore if not clipping.
boolRangeSrcPassedBy;// / ms:rw app:w / ms:r // (If using a clipper) Need to be set by user if RangeSrcItem was part of the clipped set before submitting the visible items. Ignore if not clipping.
ImGuiMultiSelectIOEndIO;// Requests are set during the loop and returned by EndMultiSelect().
boolIsFocused;// Set if currently focusing the selection scope (any item of the selection). May be used if you have custom shortcut associated to selection.
boolIsSetRange;// Set by BeginMultiSelect() when using Shift+Navigation. Because scrolling may be affected we can't afford a frame of lag with Shift+Navigation.
boolSetRangeDstPassedBy;// Set by the the item that matches NavJustMovedToId when IsSetRange is set.
boolRangeDstPassedBy;// Set by the item that matches NavJustMovedToId when IsSetRange is set.
//ImRect Rect; // Extent of selection scope between BeginMultiSelect() / EndMultiSelect(), used by ImGuiMultiSelectFlags_ClearOnClickRectVoid.
ocornut
1 year ago