Columns: Made GetColumnOffset() and GetColumnWidth() behave when there's no column set, consistently with other column functions + fixed Columns demo (#2683)

docs/CHANGELOG.txt

@@ -64,6 +64,8 @@ Other Changes:
 - Columns: Improved honoring alignment with various values of ItemSpacing.x and WindowPadding.x. (#125, #2666)
 - Word-wrapping: Fixed overzealous word-wrapping when glyph edge lands exactly on the limit. Because
   of this, auto-fitting exactly unwrapped text would make it wrap. (fixes initial 1.15 commit, 78645a7d).
+- Columns: Made GetColumnOffset() and GetColumnWidth() behave when there's no column set, consistently with
+  other column functions. (#2683)
 - Scrolling: Added SetScrollHereX(), SetScrollFromPosX() for completeness. (#1580) [@kevreco]
 - Style: Attenuated default opacity of ImGuiCol_Separator in Classic and Light styles.
 - Style: Added style.ColorButtonPosition (left/right, defaults to ImGuiDir_Right) to move the color button

imgui_demo.cpp

@@ -2593,7 +2593,9 @@ static void ShowDemoWindowColumns()
         static int columns_count = 4;
         const int lines_count = 3;
         ImGui::SetNextItemWidth(ImGui::GetFontSize() * 8);
-        ImGui::DragInt("##columns_count", &columns_count, 0.1f, 1, 10, "%d columns");
+        ImGui::DragInt("##columns_count", &columns_count, 0.1f, 2, 10, "%d columns");
+        if (columns_count < 2)
+            columns_count = 2;
         ImGui::SameLine();
         ImGui::Checkbox("horizontal", &h_borders);
         ImGui::SameLine();

imgui_widgets.cpp

@@ -7152,7 +7152,8 @@ float ImGui::GetColumnOffset(int column_index)
 {
     ImGuiWindow* window = GetCurrentWindowRead();
     ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
+    if (columns == NULL)
+        return 0.0f;
 
     if (column_index < 0)
         column_index = columns->Current;
@@ -7178,9 +7179,11 @@ static float GetColumnWidthEx(ImGuiColumns* columns, int column_index, bool befo
 
 float ImGui::GetColumnWidth(int column_index)
 {
-    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
     ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
+    if (columns == NULL)
+        return GetContentRegionAvail().x;
 
     if (column_index < 0)
         column_index = columns->Current;