Add multiline support for Text Shape.

Finish Enter/newline layout in GenerateTextJob, persist newlines and line gap in 3MF, and expose Line gap in the text tool UI.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: rhys100

src/libslic3r/Emboss.cpp

@@ -1475,9 +1475,16 @@ void Slic3r::Emboss::text2vshapes(EmbossShape &                emboss_shape,
             text_scales.emplace_back(real_scale);
         }
         cur_x = cursor.x() * standard_scale;
-        text_cursors.emplace_back(cur_x - last_x);
-        text_absolute_cursors.emplace_back(cur_x);
-        last_x = cur_x;
+        // After a line break cursor.x is reset; do not treat that as a negative advance into the previous line.
+        if (letter == '\n' || letter == '\r') {
+            text_cursors.emplace_back(0.f);
+            text_absolute_cursors.emplace_back(cur_x);
+            last_x = 0.f;
+        } else {
+            text_cursors.emplace_back(cur_x - last_x);
+            text_absolute_cursors.emplace_back(cur_x);
+            last_x = cur_x;
+        }
     }
     std::vector<Point> offset_xy;
     if (bfc_fn) {// support_backup_fonts
@@ -1487,11 +1494,13 @@ void Slic3r::Emboss::text2vshapes(EmbossShape &                emboss_shape,
     }
     std::vector<Vec2f> text_align_offsets;
     text_align_offsets.resize(text_scales.size());
-    for (int i = 0; i < text_scales.size(); i++) {
-        float x                  = (float) offset_xy[i][0] * standard_scale;
-        float y                  = (float) offset_xy[i][1] * standard_scale;
-        text_align_offsets[i][0] = x;
-        text_align_offsets[i][1] = y;
+    for (int i = 0; i < (int) text_scales.size(); i++) {
+        if (i < (int) offset_xy.size()) {
+            text_align_offsets[i][0] = (float) offset_xy[i][0] * standard_scale;
+            text_align_offsets[i][1] = (float) offset_xy[i][1] * standard_scale;
+        } else {
+            text_align_offsets[i] = Vec2f::Zero();
+        }
     }
     emboss_shape.text_align_offsets    = text_align_offsets;
     std::vector<float> no_use_text_scales;
@@ -2193,8 +2202,8 @@ void align_shape(ExPolygonsWithIds &shapes, std::vector<Point> &offset_xy, const
 
     // Speed up for left aligned text
     if (prop.align.first == FontProp::HorizontalAlign::left){
-        // already horizontaly aligned
-        offset_xy.emplace_back(Point(0, y_offset));
+        // already horizontaly aligned — still emit one offset per character for callers
+        offset_xy.assign(shapes.size(), Point(0, y_offset));
         for (ExPolygonsWithId& shape : shapes)
             for (ExPolygon &s : shape.expoly)
                 s.translate(Point(0, y_offset));
@@ -2216,9 +2225,11 @@ void align_shape(ExPolygonsWithIds &shapes, std::vector<Point> &offset_xy, const
     Point offset(
         get_align_x_offset(prop.align.first, shape_bb, get_line_bb(0)),
         y_offset);
+    offset_xy.reserve(shapes.size());
     for (size_t i = 0; i < shapes.size(); ++i) {
         wchar_t letter = text[i];
         if (letter == '\n'){
+            offset_xy.emplace_back(offset); // keep 1:1 with shapes/text for multiline
             offset.x() = get_align_x_offset(prop.align.first, shape_bb, get_line_bb(i + 1));
             continue;
         }
@@ -2272,9 +2283,11 @@ void align_shape(ExPolygonsWithIds &            shapes,
 
     // Align x line by line
     Point main_offset(get_align_x_offset(prop.align.first, shape_bb, get_line_bb(0)), main_y_offset);
+    offset_xy.reserve(shapes.size());
     for (size_t i = 0; i < shapes.size(); ++i) {
         wchar_t letter = text[i];
         if (letter == '\n') {//Enter the next line of text
+            offset_xy.emplace_back(main_offset); // keep 1:1 with shapes/text for multiline
             main_offset.x() = get_align_x_offset(prop.align.first, shape_bb, get_line_bb(i + 1));
             continue;
         }

src/libslic3r/Format/bbs_3mf.cpp

@@ -4979,6 +4979,10 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
             text_info.text_configuration.style.prop.boldness = bbs_get_attribute_value_float(attributes, num_attributes, BOLDNESS_ATTR);
             text_info.text_configuration.style.prop.skew     = bbs_get_attribute_value_float(attributes, num_attributes, SKEW_ATTR);
         }
+        if (bbs_has_attribute_value_int(attributes, num_attributes, LINE_GAP_ATTR))
+            text_info.text_configuration.style.prop.line_gap = bbs_get_attribute_value_int(attributes, num_attributes, LINE_GAP_ATTR);
+        if (bbs_has_attribute_value_int(attributes, num_attributes, CHAR_GAP_ATTR))
+            text_info.text_configuration.style.prop.char_gap = bbs_get_attribute_value_int(attributes, num_attributes, CHAR_GAP_ATTR);
         text_info.m_curr_font_idx = bbs_get_attribute_value_int(attributes, num_attributes, FONT_INDEX_ATTR);
 
         text_info.m_font_size = bbs_get_attribute_value_float(attributes, num_attributes, FONT_SIZE_ATTR);
@@ -8015,12 +8019,17 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
     void _add_text_info_to_archive(std::stringstream& stream, const TextInfo& text_info) {
         stream << "      <" << TEXT_INFO_TAG << " ";
 
-        stream << TEXT_ATTR << "=\"" << xml_escape(text_info.m_text) << "\" ";
+        // Preserve newlines/tabs in text attributes (XML attribute whitespace normalisation).
+        stream << TEXT_ATTR << "=\"" << xml_escape_double_quotes_attribute_value(text_info.m_text) << "\" ";
         stream << FONT_NAME_ATTR << "=\"" << xml_escape(text_info.m_font_name) << "\" ";
         stream << FONT_VERSION_ATTR << "=\"" << text_info.m_font_version << "\" ";
         stream << STYLE_NAME_ATTR << "=\"" << xml_escape_double_quotes_attribute_value(text_info.text_configuration.style.name) << "\" ";
         stream << BOLDNESS_ATTR << "=\"" << text_info.text_configuration.style.prop.boldness.value_or(0) << "\" ";
         stream << SKEW_ATTR << "=\"" << text_info.text_configuration.style.prop.skew.value_or(0) << "\" ";
+        if (text_info.text_configuration.style.prop.line_gap.has_value())
+            stream << LINE_GAP_ATTR << "=\"" << *text_info.text_configuration.style.prop.line_gap << "\" ";
+        if (text_info.text_configuration.style.prop.char_gap.has_value())
+            stream << CHAR_GAP_ATTR << "=\"" << *text_info.text_configuration.style.prop.char_gap << "\" ";
 
         stream << FONT_INDEX_ATTR << "=\"" << text_info.m_curr_font_idx << "\" ";
 

src/slic3r/GUI/Gizmos/GLGizmoText.cpp

@@ -1351,6 +1351,15 @@ std::unique_ptr<Emboss::DataBase> GLGizmoText::create_emboss_data_base(
     assert(style_manager.get_wx_font().IsOk());
     assert(style.path.compare(WxFontUtils::store_wxFont(style_manager.get_wx_font())) == 0);
 
+    // Multiline placement uses the Emboss 2D layout, so character spacing must live in FontProp.
+    // Single-line text still applies m_text_gap in GenerateTextJob::calc_position_points.
+    if (get_count_lines(text) > 1) {
+        if (std::abs(m_text_gap) > 1e-4f)
+            style.prop.char_gap = static_cast<int>(std::lround(m_text_gap));
+        else
+            style.prop.char_gap.reset();
+    }
+
     bool is_outside = (type == ModelVolumeType::MODEL_PART);
 
     // Cancel previous Job, when it is in process
@@ -2522,7 +2531,8 @@ bool GLGizmoText::set_height()
 
 void GLGizmoText::draw_text_input(int caption_width)
 {
-    bool allow_multi_line       = false;
+    // Enter creates a new line; Emboss::text2vshapes + GenerateTextJob baked layout consume '\n'.
+    bool allow_multi_line       = true;
     bool support_backup_fonts = GUI::wxGetApp().app_config->get_bool("support_backup_fonts");
     auto create_range_text_prep    = [&mng = m_style_manager, &text = m_text, &exist_unknown = m_text_contain_unknown_glyph, support_backup_fonts]() {
         if (text.empty()) { return std::string(); }
@@ -2983,6 +2993,34 @@ void GLGizmoText::draw_advanced(float caption_size, float slider_width, float sl
             m_need_update_text = true;
         }
     }
+
+    // Line gap (font points) — used by Emboss::get_line_height for multiline text.
+    std::optional<int> &line_gap = m_style_manager.get_font_prop().line_gap;
+    float               line_gap_value = static_cast<float>(line_gap.value_or(0));
+    const float         min_line_gap   = static_cast<float>(limits.line_gap.min);
+    const float         max_line_gap   = static_cast<float>(limits.line_gap.max);
+    ImGui::AlignTextToFramePadding();
+    m_imgui->text(_L("Line gap"));
+    ImGui::SameLine(caption_size + ad_space_size);
+    ImGui::PushItemWidth(slider_width);
+    if (m_imgui->bbl_slider_float_style("##text_line_gap", &line_gap_value, min_line_gap, max_line_gap, "%.0f", 1.0f, true)) {
+        if (std::abs(line_gap_value) < 0.5f)
+            line_gap.reset();
+        else
+            line_gap = static_cast<int>(std::lround(line_gap_value));
+    }
+    is_stop_sliding = m_imgui->get_last_slider_status().deactivated_after_edit;
+    if (is_stop_sliding)
+        m_need_update_text = true;
+    ImGui::SameLine(drag_left_width + ad_space_size);
+    ImGui::PushItemWidth(1.5 * slider_icon_width);
+    if (ImGui::BBLDragFloat("##text_line_gap_input", &line_gap_value, 1, min_line_gap, max_line_gap, "%.0f")) {
+        if (std::abs(line_gap_value) < 0.5f)
+            line_gap.reset();
+        else
+            line_gap = static_cast<int>(std::lround(line_gap_value));
+        m_need_update_text = true;
+    }
 }
 
 void GLGizmoText::init_font_name_texture()
@@ -3409,6 +3447,8 @@ TextInfo GLGizmoText::get_text_info()
     text_info.m_text_gap      = m_text_gap;
     text_info.m_surface_type  = m_surface_type;
     text_info.text_configuration = m_ui_text_configuration;
+    text_info.text_configuration.style.prop.line_gap = m_style_manager.get_font_prop().line_gap;
+    text_info.text_configuration.style.prop.char_gap = m_style_manager.get_font_prop().char_gap;
     text_info.m_font_version     = CUR_FONT_VERSION;
     return text_info;
 }
@@ -3446,6 +3486,8 @@ void GLGizmoText::load_from_text_info(const TextInfo &text_info)
     }
     m_custom_boldness          = text_info.text_configuration.style.prop.boldness.value_or(0.f);
     m_custom_skew              = text_info.text_configuration.style.prop.skew.value_or(0.f);
+    m_style_manager.get_font_prop().line_gap = text_info.text_configuration.style.prop.line_gap;
+    m_style_manager.get_font_prop().char_gap = text_info.text_configuration.style.prop.char_gap;
     if (is_text_changed) {
         process(true,std::nullopt,false);
     }

src/slic3r/GUI/Gizmos/GLGizmoText.hpp

@@ -27,8 +27,9 @@ enum class SLAGizmoEventType : unsigned char;
 //2.2 mean v2.2 bambu version(20250815) fix char gap of text
 // 2.3 mean v2.3 bambu version(20250826) add custom boldness and skew
 //2.5 mean v2.3 bambu version(20251130) fix text more accurate layout
+//2.6 mean multiline Text Shape (Enter / line breaks + line gap persistence)
 const std::string NEW_FONT_BEGIN_VERSION  = "2.0";
-const std::string CUR_FONT_VERSION        = "2.5";
+const std::string CUR_FONT_VERSION        = "2.6";
 class GLGizmoText : public GLGizmoBase
 {
 private: