Internals: Refactor: Moved all Columns code from imgui.cpp to imgui_widgets.cpp (#125)

Also moved NextColumn between BeginColumn and NextColumn which makes it easier to work on that code.

imgui.cpp

@@ -75,7 +75,6 @@ CODE
 // [SECTION] TOOLTIPS
 // [SECTION] POPUPS
 // [SECTION] KEYBOARD/GAMEPAD NAVIGATION
-// [SECTION] COLUMNS
 // [SECTION] DRAG AND DROP
 // [SECTION] LOGGING/CAPTURING
 // [SECTION] SETTINGS
@@ -8664,394 +8663,6 @@ void ImGui::NavUpdateWindowingList()
     PopStyleVar();
 }
 
-//-----------------------------------------------------------------------------
-// [SECTION] COLUMNS
-// In the current version, Columns are very weak. Needs to be replaced with a more full-featured system.
-//-----------------------------------------------------------------------------
-
-void ImGui::NextColumn()
-{
-    ImGuiWindow* window = GetCurrentWindow();
-    if (window->SkipItems || window->DC.CurrentColumns == NULL)
-        return;
-
-    ImGuiContext& g = *GImGui;
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-
-    if (columns->Count == 1)
-    {
-        window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
-        IM_ASSERT(columns->Current == 0);
-        return;
-    }
-
-    PopItemWidth();
-    PopClipRect();
-
-    columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
-    if (++columns->Current < columns->Count)
-    {
-        // Columns 1+ cancel out IndentX
-        // FIXME-COLUMNS: Unnecessary, could be locked?
-        window->DC.ColumnsOffset.x = GetColumnOffset(columns->Current) - window->DC.Indent.x + g.Style.ItemSpacing.x;
-        window->DrawList->ChannelsSetCurrent(columns->Current + 1);
-    }
-    else
-    {
-        // New row/line
-        window->DC.ColumnsOffset.x = 0.0f;
-        window->DrawList->ChannelsSetCurrent(1);
-        columns->Current = 0;
-        columns->LineMinY = columns->LineMaxY;
-    }
-    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
-    window->DC.CursorPos.y = columns->LineMinY;
-    window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
-    window->DC.CurrLineTextBaseOffset = 0.0f;
-
-    PushColumnClipRect(columns->Current);     // FIXME-COLUMNS: Could it be an overwrite?
-
-    // FIXME-COLUMNS: Share code with BeginColumns() - move code on columns setup.
-    float offset_0 = GetColumnOffset(columns->Current);
-    float offset_1 = GetColumnOffset(columns->Current + 1);
-    float width = offset_1 - offset_0;
-    PushItemWidth(width * 0.65f);
-    window->WorkRect.Max.x = window->Pos.x + offset_1 - window->WindowPadding.x;
-}
-
-int ImGui::GetColumnIndex()
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    return window->DC.CurrentColumns ? window->DC.CurrentColumns->Current : 0;
-}
-
-int ImGui::GetColumnsCount()
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    return window->DC.CurrentColumns ? window->DC.CurrentColumns->Count : 1;
-}
-
-static float OffsetNormToPixels(const ImGuiColumns* columns, float offset_norm)
-{
-    return offset_norm * (columns->OffMaxX - columns->OffMinX);
-}
-
-static float PixelsToOffsetNorm(const ImGuiColumns* columns, float offset)
-{
-    return offset / (columns->OffMaxX - columns->OffMinX);
-}
-
-static const float COLUMNS_HIT_RECT_HALF_WIDTH = 4.0f;
-
-static float GetDraggedColumnOffset(ImGuiColumns* columns, int column_index)
-{
-    // Active (dragged) column always follow mouse. The reason we need this is that dragging a column to the right edge of an auto-resizing
-    // window creates a feedback loop because we store normalized positions. So while dragging we enforce absolute positioning.
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = g.CurrentWindow;
-    IM_ASSERT(column_index > 0); // We are not supposed to drag column 0.
-    IM_ASSERT(g.ActiveId == columns->ID + ImGuiID(column_index));
-
-    float x = g.IO.MousePos.x - g.ActiveIdClickOffset.x + COLUMNS_HIT_RECT_HALF_WIDTH - window->Pos.x;
-    x = ImMax(x, ImGui::GetColumnOffset(column_index - 1) + g.Style.ColumnsMinSpacing);
-    if ((columns->Flags & ImGuiColumnsFlags_NoPreserveWidths))
-        x = ImMin(x, ImGui::GetColumnOffset(column_index + 1) - g.Style.ColumnsMinSpacing);
-
-    return x;
-}
-
-float ImGui::GetColumnOffset(int column_index)
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
-
-    if (column_index < 0)
-        column_index = columns->Current;
-    IM_ASSERT(column_index < columns->Columns.Size);
-
-    const float t = columns->Columns[column_index].OffsetNorm;
-    const float x_offset = ImLerp(columns->OffMinX, columns->OffMaxX, t);
-    return x_offset;
-}
-
-static float GetColumnWidthEx(ImGuiColumns* columns, int column_index, bool before_resize = false)
-{
-    if (column_index < 0)
-        column_index = columns->Current;
-
-    float offset_norm;
-    if (before_resize)
-        offset_norm = columns->Columns[column_index + 1].OffsetNormBeforeResize - columns->Columns[column_index].OffsetNormBeforeResize;
-    else
-        offset_norm = columns->Columns[column_index + 1].OffsetNorm - columns->Columns[column_index].OffsetNorm;
-    return OffsetNormToPixels(columns, offset_norm);
-}
-
-float ImGui::GetColumnWidth(int column_index)
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
-
-    if (column_index < 0)
-        column_index = columns->Current;
-    return OffsetNormToPixels(columns, columns->Columns[column_index + 1].OffsetNorm - columns->Columns[column_index].OffsetNorm);
-}
-
-void ImGui::SetColumnOffset(int column_index, float offset)
-{
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = g.CurrentWindow;
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
-
-    if (column_index < 0)
-        column_index = columns->Current;
-    IM_ASSERT(column_index < columns->Columns.Size);
-
-    const bool preserve_width = !(columns->Flags & ImGuiColumnsFlags_NoPreserveWidths) && (column_index < columns->Count-1);
-    const float width = preserve_width ? GetColumnWidthEx(columns, column_index, columns->IsBeingResized) : 0.0f;
-
-    if (!(columns->Flags & ImGuiColumnsFlags_NoForceWithinWindow))
-        offset = ImMin(offset, columns->OffMaxX - g.Style.ColumnsMinSpacing * (columns->Count - column_index));
-    columns->Columns[column_index].OffsetNorm = PixelsToOffsetNorm(columns, offset - columns->OffMinX);
-
-    if (preserve_width)
-        SetColumnOffset(column_index + 1, offset + ImMax(g.Style.ColumnsMinSpacing, width));
-}
-
-void ImGui::SetColumnWidth(int column_index, float width)
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
-
-    if (column_index < 0)
-        column_index = columns->Current;
-    SetColumnOffset(column_index + 1, GetColumnOffset(column_index) + width);
-}
-
-void ImGui::PushColumnClipRect(int column_index)
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    if (column_index < 0)
-        column_index = columns->Current;
-
-    ImGuiColumnData* column = &columns->Columns[column_index];
-    PushClipRect(column->ClipRect.Min, column->ClipRect.Max, false);
-}
-
-// Get into the columns background draw command (which is generally the same draw command as before we called BeginColumns)
-void ImGui::PushColumnsBackground()
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    window->DrawList->ChannelsSetCurrent(0);
-    int cmd_size = window->DrawList->CmdBuffer.Size;
-    PushClipRect(columns->HostClipRect.Min, columns->HostClipRect.Max, false); 
-    IM_UNUSED(cmd_size);
-    IM_ASSERT(cmd_size == window->DrawList->CmdBuffer.Size); // Being in channel 0 this should not have created an ImDrawCmd
-}
-
-void ImGui::PopColumnsBackground()
-{
-    ImGuiWindow* window = GetCurrentWindowRead();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    window->DrawList->ChannelsSetCurrent(columns->Current + 1);
-    PopClipRect();
-}
-
-ImGuiColumns* ImGui::FindOrCreateColumns(ImGuiWindow* window, ImGuiID id)
-{
-    // We have few columns per window so for now we don't need bother much with turning this into a faster lookup.
-    for (int n = 0; n < window->ColumnsStorage.Size; n++)
-        if (window->ColumnsStorage[n].ID == id)
-            return &window->ColumnsStorage[n];
-
-    window->ColumnsStorage.push_back(ImGuiColumns());
-    ImGuiColumns* columns = &window->ColumnsStorage.back();
-    columns->ID = id;
-    return columns;
-}
-
-ImGuiID ImGui::GetColumnsID(const char* str_id, int columns_count)
-{
-    ImGuiWindow* window = GetCurrentWindow();
-
-    // Differentiate column ID with an arbitrary prefix for cases where users name their columns set the same as another widget.
-    // In addition, when an identifier isn't explicitly provided we include the number of columns in the hash to make it uniquer.
-    PushID(0x11223347 + (str_id ? 0 : columns_count));
-    ImGuiID id = window->GetID(str_id ? str_id : "columns");
-    PopID();
-
-    return id;
-}
-
-void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlags flags)
-{
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = GetCurrentWindow();
-
-    IM_ASSERT(columns_count >= 1);
-    IM_ASSERT(window->DC.CurrentColumns == NULL); // Nested columns are currently not supported
-
-    // Acquire storage for the columns set
-    ImGuiID id = GetColumnsID(str_id, columns_count);
-    ImGuiColumns* columns = FindOrCreateColumns(window, id);
-    IM_ASSERT(columns->ID == id);
-    columns->Current = 0;
-    columns->Count = columns_count;
-    columns->Flags = flags;
-    window->DC.CurrentColumns = columns;
-
-    // Set state for first column
-    columns->OffMinX = window->DC.Indent.x - g.Style.ItemSpacing.x;
-    columns->OffMaxX = ImMax(window->WorkRect.Max.x - window->Pos.x, columns->OffMinX + 1.0f);
-    columns->HostCursorPosY = window->DC.CursorPos.y;
-    columns->HostCursorMaxPosX = window->DC.CursorMaxPos.x;
-    columns->HostClipRect = window->ClipRect;
-    columns->HostWorkRect = window->WorkRect;
-    columns->LineMinY = columns->LineMaxY = window->DC.CursorPos.y;
-    window->DC.ColumnsOffset.x = 0.0f;
-    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
-
-    // Clear data if columns count changed
-    if (columns->Columns.Size != 0 && columns->Columns.Size != columns_count + 1)
-        columns->Columns.resize(0);
-
-    // Initialize default widths
-    columns->IsFirstFrame = (columns->Columns.Size == 0);
-    if (columns->Columns.Size == 0)
-    {
-        columns->Columns.reserve(columns_count + 1);
-        for (int n = 0; n < columns_count + 1; n++)
-        {
-            ImGuiColumnData column;
-            column.OffsetNorm = n / (float)columns_count;
-            columns->Columns.push_back(column);
-        }
-    }
-
-    for (int n = 0; n < columns_count; n++)
-    {
-        // Compute clipping rectangle
-        ImGuiColumnData* column = &columns->Columns[n];
-        float clip_x1 = ImFloor(0.5f + window->Pos.x + GetColumnOffset(n));
-        float clip_x2 = ImFloor(0.5f + window->Pos.x + GetColumnOffset(n + 1) - 1.0f);
-        column->ClipRect = ImRect(clip_x1, -FLT_MAX, clip_x2, +FLT_MAX);
-        column->ClipRect.ClipWith(window->ClipRect);
-    }
-
-    if (columns->Count > 1)
-    {
-        window->DrawList->ChannelsSplit(1 + columns->Count);
-        window->DrawList->ChannelsSetCurrent(1);
-        PushColumnClipRect(0);
-    }
-
-    float offset_0 = GetColumnOffset(columns->Current);
-    float offset_1 = GetColumnOffset(columns->Current + 1);
-    float width = offset_1 - offset_0;
-    PushItemWidth(width * 0.65f);
-    window->WorkRect.Max.x = window->Pos.x + offset_1 - window->WindowPadding.x;
-}
-
-void ImGui::EndColumns()
-{
-    ImGuiContext& g = *GImGui;
-    ImGuiWindow* window = GetCurrentWindow();
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    IM_ASSERT(columns != NULL);
-
-    PopItemWidth();
-    if (columns->Count > 1)
-    {
-        PopClipRect();
-        window->DrawList->ChannelsMerge();
-    }
-
-    const ImGuiColumnsFlags flags = columns->Flags;
-    columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
-    window->DC.CursorPos.y = columns->LineMaxY;
-    if (!(flags & ImGuiColumnsFlags_GrowParentContentsSize))
-        window->DC.CursorMaxPos.x = columns->HostCursorMaxPosX;  // Restore cursor max pos, as columns don't grow parent
-
-    // Draw columns borders and handle resize
-    // The IsBeingResized flag ensure we preserve pre-resize columns width so back-and-forth are not lossy
-    bool is_being_resized = false;
-    if (!(flags & ImGuiColumnsFlags_NoBorder) && !window->SkipItems)
-    {
-        // We clip Y boundaries CPU side because very long triangles are mishandled by some GPU drivers.
-        const float y1 = ImMax(columns->HostCursorPosY, window->ClipRect.Min.y);
-        const float y2 = ImMin(window->DC.CursorPos.y, window->ClipRect.Max.y);
-        int dragging_column = -1;
-        for (int n = 1; n < columns->Count; n++)
-        {
-            ImGuiColumnData* column = &columns->Columns[n];
-            float x = window->Pos.x + GetColumnOffset(n);
-            const ImGuiID column_id = columns->ID + ImGuiID(n);
-            const float column_hit_hw = COLUMNS_HIT_RECT_HALF_WIDTH;
-            const ImRect column_hit_rect(ImVec2(x - column_hit_hw, y1), ImVec2(x + column_hit_hw, y2));
-            KeepAliveID(column_id);
-            if (IsClippedEx(column_hit_rect, column_id, false))
-                continue;
-
-            bool hovered = false, held = false;
-            if (!(flags & ImGuiColumnsFlags_NoResize))
-            {
-                ButtonBehavior(column_hit_rect, column_id, &hovered, &held);
-                if (hovered || held)
-                    g.MouseCursor = ImGuiMouseCursor_ResizeEW;
-                if (held && !(column->Flags & ImGuiColumnsFlags_NoResize))
-                    dragging_column = n;
-            }
-
-            // Draw column
-            const ImU32 col = GetColorU32(held ? ImGuiCol_SeparatorActive : hovered ? ImGuiCol_SeparatorHovered : ImGuiCol_Separator);
-            const float xi = (float)(int)x;
-            window->DrawList->AddLine(ImVec2(xi, y1 + 1.0f), ImVec2(xi, y2), col);
-        }
-
-        // Apply dragging after drawing the column lines, so our rendered lines are in sync with how items were displayed during the frame.
-        if (dragging_column != -1)
-        {
-            if (!columns->IsBeingResized)
-                for (int n = 0; n < columns->Count + 1; n++)
-                    columns->Columns[n].OffsetNormBeforeResize = columns->Columns[n].OffsetNorm;
-            columns->IsBeingResized = is_being_resized = true;
-            float x = GetDraggedColumnOffset(columns, dragging_column);
-            SetColumnOffset(dragging_column, x);
-        }
-    }
-    columns->IsBeingResized = is_being_resized;
-
-    window->WorkRect = columns->HostWorkRect;
-    window->DC.CurrentColumns = NULL;
-    window->DC.ColumnsOffset.x = 0.0f;
-    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
-}
-
-// [2018-03: This is currently the only public API, while we are working on making BeginColumns/EndColumns user-facing]
-void ImGui::Columns(int columns_count, const char* id, bool border)
-{
-    ImGuiWindow* window = GetCurrentWindow();
-    IM_ASSERT(columns_count >= 1);
-
-    ImGuiColumnsFlags flags = (border ? 0 : ImGuiColumnsFlags_NoBorder);
-    //flags |= ImGuiColumnsFlags_NoPreserveWidths; // NB: Legacy behavior
-    ImGuiColumns* columns = window->DC.CurrentColumns;
-    if (columns != NULL && columns->Count == columns_count && columns->Flags == flags)
-        return;
-
-    if (columns != NULL)
-        EndColumns();
-
-    if (columns_count != 1)
-        BeginColumns(id, columns_count, flags);
-}
-
 
 //-----------------------------------------------------------------------------
 // [SECTION] DRAG AND DROP
@@ -10072,7 +9683,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 return;
             ImGui::BulletText("Width: %.1f (MinX: %.1f, MaxX: %.1f)", columns->OffMaxX - columns->OffMinX, columns->OffMinX, columns->OffMaxX);
             for (int column_n = 0; column_n < columns->Columns.Size; column_n++)
-                ImGui::BulletText("Column %02d: OffsetNorm %.3f (= %.1f px)", column_n, columns->Columns[column_n].OffsetNorm, OffsetNormToPixels(columns, columns->Columns[column_n].OffsetNorm));
+                ImGui::BulletText("Column %02d: OffsetNorm %.3f (= %.1f px)", column_n, columns->Columns[column_n].OffsetNorm, GetColumnOffsetFromNorm(columns, columns->Columns[column_n].OffsetNorm));
             ImGui::TreePop();
         }
 

imgui_internal.h

@@ -1563,6 +1563,8 @@ namespace ImGui
     IMGUI_API void          PopColumnsBackground();
     IMGUI_API ImGuiID       GetColumnsID(const char* str_id, int count);
     IMGUI_API ImGuiColumns* FindOrCreateColumns(ImGuiWindow* window, ImGuiID id);
+    IMGUI_API float         GetColumnOffsetFromNorm(const ImGuiColumns* columns, float offset_norm);
+    IMGUI_API float         GetColumnNormFromOffset(const ImGuiColumns* columns, float offset);
 
     // Tab Bars
     IMGUI_API bool          BeginTabBarEx(ImGuiTabBar* tab_bar, const ImRect& bb, ImGuiTabBarFlags flags);

imgui_widgets.cpp

@@ -24,6 +24,7 @@ Index of this file:
 // [SECTION] Widgets: MenuItem, BeginMenu, EndMenu, etc.
 // [SECTION] Widgets: BeginTabBar, EndTabBar, etc.
 // [SECTION] Widgets: BeginTabItem, EndTabItem, etc.
+// [SECTION] Widgets: Columns, BeginColumns, EndColumns, etc.
 
 */
 
@@ -7088,3 +7089,409 @@ bool ImGui::TabItemLabelAndCloseButton(ImDrawList* draw_list, const ImRect& bb,
 
     return close_button_pressed;
 }
+
+
+//-------------------------------------------------------------------------
+// [SECTION] Widgets: Columns, BeginColumns, EndColumns, etc.
+// In the current version, Columns are very weak. Needs to be replaced with a more full-featured system.
+//-------------------------------------------------------------------------
+// - GetColumnIndex()
+// - GetColumnCount()
+// - GetColumnOffset()
+// - GetColumnWidth()
+// - SetColumnOffset()
+// - SetColumnWidth()
+// - PushColumnClipRect() [Internal]
+// - PushColumnsBackground() [Internal]
+// - PopColumnsBackground() [Internal]
+// - FindOrCreateColumns() [Internal]
+// - GetColumnsID() [Internal]
+// - BeginColumns()
+// - NextColumn()
+// - EndColumns()
+// - Columns()
+//-------------------------------------------------------------------------
+
+int ImGui::GetColumnIndex()
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    return window->DC.CurrentColumns ? window->DC.CurrentColumns->Current : 0;
+}
+
+int ImGui::GetColumnsCount()
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    return window->DC.CurrentColumns ? window->DC.CurrentColumns->Count : 1;
+}
+
+float ImGui::GetColumnOffsetFromNorm(const ImGuiColumns* columns, float offset_norm)
+{
+    return offset_norm * (columns->OffMaxX - columns->OffMinX);
+}
+
+float ImGui::GetColumnNormFromOffset(const ImGuiColumns* columns, float offset)
+{
+    return offset / (columns->OffMaxX - columns->OffMinX);
+}
+
+static const float COLUMNS_HIT_RECT_HALF_WIDTH = 4.0f;
+
+static float GetDraggedColumnOffset(ImGuiColumns* columns, int column_index)
+{
+    // Active (dragged) column always follow mouse. The reason we need this is that dragging a column to the right edge of an auto-resizing
+    // window creates a feedback loop because we store normalized positions. So while dragging we enforce absolute positioning.
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+    IM_ASSERT(column_index > 0); // We are not supposed to drag column 0.
+    IM_ASSERT(g.ActiveId == columns->ID + ImGuiID(column_index));
+
+    float x = g.IO.MousePos.x - g.ActiveIdClickOffset.x + COLUMNS_HIT_RECT_HALF_WIDTH - window->Pos.x;
+    x = ImMax(x, ImGui::GetColumnOffset(column_index - 1) + g.Style.ColumnsMinSpacing);
+    if ((columns->Flags & ImGuiColumnsFlags_NoPreserveWidths))
+        x = ImMin(x, ImGui::GetColumnOffset(column_index + 1) - g.Style.ColumnsMinSpacing);
+
+    return x;
+}
+
+float ImGui::GetColumnOffset(int column_index)
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    IM_ASSERT(columns != NULL);
+
+    if (column_index < 0)
+        column_index = columns->Current;
+    IM_ASSERT(column_index < columns->Columns.Size);
+
+    const float t = columns->Columns[column_index].OffsetNorm;
+    const float x_offset = ImLerp(columns->OffMinX, columns->OffMaxX, t);
+    return x_offset;
+}
+
+static float GetColumnWidthEx(ImGuiColumns* columns, int column_index, bool before_resize = false)
+{
+    if (column_index < 0)
+        column_index = columns->Current;
+
+    float offset_norm;
+    if (before_resize)
+        offset_norm = columns->Columns[column_index + 1].OffsetNormBeforeResize - columns->Columns[column_index].OffsetNormBeforeResize;
+    else
+        offset_norm = columns->Columns[column_index + 1].OffsetNorm - columns->Columns[column_index].OffsetNorm;
+    return ImGui::GetColumnOffsetFromNorm(columns, offset_norm);
+}
+
+float ImGui::GetColumnWidth(int column_index)
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    IM_ASSERT(columns != NULL);
+
+    if (column_index < 0)
+        column_index = columns->Current;
+    return GetColumnOffsetFromNorm(columns, columns->Columns[column_index + 1].OffsetNorm - columns->Columns[column_index].OffsetNorm);
+}
+
+void ImGui::SetColumnOffset(int column_index, float offset)
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    IM_ASSERT(columns != NULL);
+
+    if (column_index < 0)
+        column_index = columns->Current;
+    IM_ASSERT(column_index < columns->Columns.Size);
+
+    const bool preserve_width = !(columns->Flags & ImGuiColumnsFlags_NoPreserveWidths) && (column_index < columns->Count-1);
+    const float width = preserve_width ? GetColumnWidthEx(columns, column_index, columns->IsBeingResized) : 0.0f;
+
+    if (!(columns->Flags & ImGuiColumnsFlags_NoForceWithinWindow))
+        offset = ImMin(offset, columns->OffMaxX - g.Style.ColumnsMinSpacing * (columns->Count - column_index));
+    columns->Columns[column_index].OffsetNorm = GetColumnNormFromOffset(columns, offset - columns->OffMinX);
+
+    if (preserve_width)
+        SetColumnOffset(column_index + 1, offset + ImMax(g.Style.ColumnsMinSpacing, width));
+}
+
+void ImGui::SetColumnWidth(int column_index, float width)
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    IM_ASSERT(columns != NULL);
+
+    if (column_index < 0)
+        column_index = columns->Current;
+    SetColumnOffset(column_index + 1, GetColumnOffset(column_index) + width);
+}
+
+void ImGui::PushColumnClipRect(int column_index)
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    if (column_index < 0)
+        column_index = columns->Current;
+
+    ImGuiColumnData* column = &columns->Columns[column_index];
+    PushClipRect(column->ClipRect.Min, column->ClipRect.Max, false);
+}
+
+// Get into the columns background draw command (which is generally the same draw command as before we called BeginColumns)
+void ImGui::PushColumnsBackground()
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    window->DrawList->ChannelsSetCurrent(0);
+    int cmd_size = window->DrawList->CmdBuffer.Size;
+    PushClipRect(columns->HostClipRect.Min, columns->HostClipRect.Max, false); 
+    IM_UNUSED(cmd_size);
+    IM_ASSERT(cmd_size == window->DrawList->CmdBuffer.Size); // Being in channel 0 this should not have created an ImDrawCmd
+}
+
+void ImGui::PopColumnsBackground()
+{
+    ImGuiWindow* window = GetCurrentWindowRead();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    window->DrawList->ChannelsSetCurrent(columns->Current + 1);
+    PopClipRect();
+}
+
+ImGuiColumns* ImGui::FindOrCreateColumns(ImGuiWindow* window, ImGuiID id)
+{
+    // We have few columns per window so for now we don't need bother much with turning this into a faster lookup.
+    for (int n = 0; n < window->ColumnsStorage.Size; n++)
+        if (window->ColumnsStorage[n].ID == id)
+            return &window->ColumnsStorage[n];
+
+    window->ColumnsStorage.push_back(ImGuiColumns());
+    ImGuiColumns* columns = &window->ColumnsStorage.back();
+    columns->ID = id;
+    return columns;
+}
+
+ImGuiID ImGui::GetColumnsID(const char* str_id, int columns_count)
+{
+    ImGuiWindow* window = GetCurrentWindow();
+
+    // Differentiate column ID with an arbitrary prefix for cases where users name their columns set the same as another widget.
+    // In addition, when an identifier isn't explicitly provided we include the number of columns in the hash to make it uniquer.
+    PushID(0x11223347 + (str_id ? 0 : columns_count));
+    ImGuiID id = window->GetID(str_id ? str_id : "columns");
+    PopID();
+
+    return id;
+}
+
+void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlags flags)
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = GetCurrentWindow();
+
+    IM_ASSERT(columns_count >= 1);
+    IM_ASSERT(window->DC.CurrentColumns == NULL); // Nested columns are currently not supported
+
+    // Acquire storage for the columns set
+    ImGuiID id = GetColumnsID(str_id, columns_count);
+    ImGuiColumns* columns = FindOrCreateColumns(window, id);
+    IM_ASSERT(columns->ID == id);
+    columns->Current = 0;
+    columns->Count = columns_count;
+    columns->Flags = flags;
+    window->DC.CurrentColumns = columns;
+
+    // Set state for first column
+    columns->OffMinX = window->DC.Indent.x - g.Style.ItemSpacing.x;
+    columns->OffMaxX = ImMax(window->WorkRect.Max.x - window->Pos.x, columns->OffMinX + 1.0f);
+    columns->HostCursorPosY = window->DC.CursorPos.y;
+    columns->HostCursorMaxPosX = window->DC.CursorMaxPos.x;
+    columns->HostClipRect = window->ClipRect;
+    columns->HostWorkRect = window->WorkRect;
+    columns->LineMinY = columns->LineMaxY = window->DC.CursorPos.y;
+    window->DC.ColumnsOffset.x = 0.0f;
+    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
+
+    // Clear data if columns count changed
+    if (columns->Columns.Size != 0 && columns->Columns.Size != columns_count + 1)
+        columns->Columns.resize(0);
+
+    // Initialize default widths
+    columns->IsFirstFrame = (columns->Columns.Size == 0);
+    if (columns->Columns.Size == 0)
+    {
+        columns->Columns.reserve(columns_count + 1);
+        for (int n = 0; n < columns_count + 1; n++)
+        {
+            ImGuiColumnData column;
+            column.OffsetNorm = n / (float)columns_count;
+            columns->Columns.push_back(column);
+        }
+    }
+
+    for (int n = 0; n < columns_count; n++)
+    {
+        // Compute clipping rectangle
+        ImGuiColumnData* column = &columns->Columns[n];
+        float clip_x1 = ImFloor(0.5f + window->Pos.x + GetColumnOffset(n));
+        float clip_x2 = ImFloor(0.5f + window->Pos.x + GetColumnOffset(n + 1) - 1.0f);
+        column->ClipRect = ImRect(clip_x1, -FLT_MAX, clip_x2, +FLT_MAX);
+        column->ClipRect.ClipWith(window->ClipRect);
+    }
+
+    if (columns->Count > 1)
+    {
+        window->DrawList->ChannelsSplit(1 + columns->Count);
+        window->DrawList->ChannelsSetCurrent(1);
+        PushColumnClipRect(0);
+    }
+
+    float offset_0 = GetColumnOffset(columns->Current);
+    float offset_1 = GetColumnOffset(columns->Current + 1);
+    float width = offset_1 - offset_0;
+    PushItemWidth(width * 0.65f);
+    window->WorkRect.Max.x = window->Pos.x + offset_1 - window->WindowPadding.x;
+}
+
+void ImGui::NextColumn()
+{
+    ImGuiWindow* window = GetCurrentWindow();
+    if (window->SkipItems || window->DC.CurrentColumns == NULL)
+        return;
+
+    ImGuiContext& g = *GImGui;
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+
+    if (columns->Count == 1)
+    {
+        window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
+        IM_ASSERT(columns->Current == 0);
+        return;
+    }
+    PopItemWidth();
+    PopClipRect();
+
+    columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
+    if (++columns->Current < columns->Count)
+    {
+        // Columns 1+ cancel out IndentX
+        // FIXME-COLUMNS: Unnecessary, could be locked?
+        window->DC.ColumnsOffset.x = GetColumnOffset(columns->Current) - window->DC.Indent.x + g.Style.ItemSpacing.x;
+        window->DrawList->ChannelsSetCurrent(columns->Current + 1);
+    }
+    else
+    {
+        // New row/line
+        window->DC.ColumnsOffset.x = 0.0f;
+        window->DrawList->ChannelsSetCurrent(1);
+        columns->Current = 0;
+        columns->LineMinY = columns->LineMaxY;
+    }
+    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
+    window->DC.CursorPos.y = columns->LineMinY;
+    window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
+    window->DC.CurrLineTextBaseOffset = 0.0f;
+
+    PushColumnClipRect(columns->Current);     // FIXME-COLUMNS: Could it be an overwrite?
+
+    // FIXME-COLUMNS: Share code with BeginColumns() - move code on columns setup.
+    float offset_0 = GetColumnOffset(columns->Current);
+    float offset_1 = GetColumnOffset(columns->Current + 1);
+    float width = offset_1 - offset_0;
+    PushItemWidth(width * 0.65f);
+    window->WorkRect.Max.x = window->Pos.x + offset_1 - window->WindowPadding.x;
+}
+
+void ImGui::EndColumns()
+{
+    ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = GetCurrentWindow();
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    IM_ASSERT(columns != NULL);
+
+    PopItemWidth();
+    if (columns->Count > 1)
+    {
+        PopClipRect();
+        window->DrawList->ChannelsMerge();
+    }
+
+    const ImGuiColumnsFlags flags = columns->Flags;
+    columns->LineMaxY = ImMax(columns->LineMaxY, window->DC.CursorPos.y);
+    window->DC.CursorPos.y = columns->LineMaxY;
+    if (!(flags & ImGuiColumnsFlags_GrowParentContentsSize))
+        window->DC.CursorMaxPos.x = columns->HostCursorMaxPosX;  // Restore cursor max pos, as columns don't grow parent
+
+    // Draw columns borders and handle resize
+    // The IsBeingResized flag ensure we preserve pre-resize columns width so back-and-forth are not lossy
+    bool is_being_resized = false;
+    if (!(flags & ImGuiColumnsFlags_NoBorder) && !window->SkipItems)
+    {
+        // We clip Y boundaries CPU side because very long triangles are mishandled by some GPU drivers.
+        const float y1 = ImMax(columns->HostCursorPosY, window->ClipRect.Min.y);
+        const float y2 = ImMin(window->DC.CursorPos.y, window->ClipRect.Max.y);
+        int dragging_column = -1;
+        for (int n = 1; n < columns->Count; n++)
+        {
+            ImGuiColumnData* column = &columns->Columns[n];
+            float x = window->Pos.x + GetColumnOffset(n);
+            const ImGuiID column_id = columns->ID + ImGuiID(n);
+            const float column_hit_hw = COLUMNS_HIT_RECT_HALF_WIDTH;
+            const ImRect column_hit_rect(ImVec2(x - column_hit_hw, y1), ImVec2(x + column_hit_hw, y2));
+            KeepAliveID(column_id);
+            if (IsClippedEx(column_hit_rect, column_id, false))
+                continue;
+
+            bool hovered = false, held = false;
+            if (!(flags & ImGuiColumnsFlags_NoResize))
+            {
+                ButtonBehavior(column_hit_rect, column_id, &hovered, &held);
+                if (hovered || held)
+                    g.MouseCursor = ImGuiMouseCursor_ResizeEW;
+                if (held && !(column->Flags & ImGuiColumnsFlags_NoResize))
+                    dragging_column = n;
+            }
+
+            // Draw column
+            const ImU32 col = GetColorU32(held ? ImGuiCol_SeparatorActive : hovered ? ImGuiCol_SeparatorHovered : ImGuiCol_Separator);
+            const float xi = (float)(int)x;
+            window->DrawList->AddLine(ImVec2(xi, y1 + 1.0f), ImVec2(xi, y2), col);
+        }
+
+        // Apply dragging after drawing the column lines, so our rendered lines are in sync with how items were displayed during the frame.
+        if (dragging_column != -1)
+        {
+            if (!columns->IsBeingResized)
+                for (int n = 0; n < columns->Count + 1; n++)
+                    columns->Columns[n].OffsetNormBeforeResize = columns->Columns[n].OffsetNorm;
+            columns->IsBeingResized = is_being_resized = true;
+            float x = GetDraggedColumnOffset(columns, dragging_column);
+            SetColumnOffset(dragging_column, x);
+        }
+    }
+    columns->IsBeingResized = is_being_resized;
+
+    window->WorkRect = columns->HostWorkRect;
+    window->DC.CurrentColumns = NULL;
+    window->DC.ColumnsOffset.x = 0.0f;
+    window->DC.CursorPos.x = (float)(int)(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);
+}
+
+// [2018-03: This is currently the only public API, while we are working on making BeginColumns/EndColumns user-facing]
+void ImGui::Columns(int columns_count, const char* id, bool border)
+{
+    ImGuiWindow* window = GetCurrentWindow();
+    IM_ASSERT(columns_count >= 1);
+
+    ImGuiColumnsFlags flags = (border ? 0 : ImGuiColumnsFlags_NoBorder);
+    //flags |= ImGuiColumnsFlags_NoPreserveWidths; // NB: Legacy behavior
+    ImGuiColumns* columns = window->DC.CurrentColumns;
+    if (columns != NULL && columns->Count == columns_count && columns->Flags == flags)
+        return;
+
+    if (columns != NULL)
+        EndColumns();
+
+    if (columns_count != 1)
+        BeginColumns(id, columns_count, flags);
+}
+
+//-------------------------------------------------------------------------