InputText: Fixed undo/redo state corruption when editing buffer in user callback. (#4947, #4949)
diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
index 707d06f..5d146da 100644
--- a/imgui_widgets.cpp
+++ b/imgui_widgets.cpp
@@ -3929,6 +3929,48 @@
return true;
}
+static inline void InputTextUpdateUndoStateAfterUserCallback(ImGuiInputTextState *state, const char *new_buf) {
+ // Find the shortest single replacement we can make to get the new text
+ // from the old text.
+ ImWchar *old_buf = state->TextW.Data;
+ int old_length = state->CurLenW;
+ int new_length = ImTextCountCharsFromUtf8(new_buf, NULL);
+ int shorter_length = ImMin(old_length, new_length);
+
+ int where = 0;
+ while (where < shorter_length) {
+ unsigned int b;
+ ImTextCharFromUtf8(&b, new_buf + where, NULL);
+ if (old_buf[where] != b)
+ break;
+
+ where += 1;
+ }
+
+ int old_last_diff = old_length - 1;
+ int new_last_diff = new_length - 1;
+ while (old_last_diff >= where && new_last_diff >= 0) {
+ unsigned int b;
+ ImTextCharFromUtf8(&b, new_buf + new_last_diff, NULL);
+ if (old_buf[old_last_diff] != b)
+ break;
+
+ old_last_diff -= 1;
+ new_last_diff -= 1;
+ }
+
+ int insert_len = new_last_diff - where + 1;
+ int delete_len = old_last_diff - where + 1;
+
+ if (insert_len > 0 || delete_len > 0) {
+ STB_TEXTEDIT_CHARTYPE *p = stb_text_createundo(&state->Stb.undostate, where, delete_len, insert_len);
+ if (p) {
+ for (int i=0; i < delete_len; ++i)
+ p[i] = ImStb::STB_TEXTEDIT_GETCHAR(state, where + i);
+ }
+ }
+}
+
// Edit a string of text
// - buf_size account for the zero-terminator, so a buf_size of 6 can hold "Hello" but not "Hello!".
// This is so we can easily call InputText() on static arrays using ARRAYSIZE() and to match
@@ -4516,6 +4558,7 @@
if (buf_dirty)
{
IM_ASSERT(callback_data.BufTextLen == (int)strlen(callback_data.Buf)); // You need to maintain BufTextLen if you change the text!
+ InputTextUpdateUndoStateAfterUserCallback(state, callback_data.Buf);
if (callback_data.BufTextLen > backup_current_text_length && is_resizable)
state->TextW.resize(state->TextW.Size + (callback_data.BufTextLen - backup_current_text_length));
state->CurLenW = ImTextStrFromUtf8(state->TextW.Data, state->TextW.Size, callback_data.Buf, NULL);
