Label text stages in the chain list with their words

Effect::label(values) names a stage in a list, defaulting to the title;
the text effect answers "Text (words)", and the chain rows are renamed
in place as params change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/core/effect.hpp

@@ -38,6 +38,13 @@ public:
     // use. An effect with no kind must declare no styled params.
     virtual std::string styleKind() const { return {}; }
 
+    // How a stage of this effect is named in a list of stages, given its
+    // values: the title unless the values say something more telling.
+    virtual std::string label(const ParamValues& values) const {
+        (void)values;
+        return title();
+    }
+
     virtual Image render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                          const ParamValues& values) const = 0;
 

src/effects/text.cpp

@@ -203,6 +203,22 @@ void TextEffect::loadBoxImage(const std::string& path, Image& image,
     alpha = cachedAlpha_;
 }
 
+std::string TextEffect::label(const ParamValues& values) const {
+    // Several lines read as one: each run of whitespace becomes a single space.
+    std::string words;
+    bool gap = false;
+    for (const char c : paramText(values, "text", "")) {
+        if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+            gap = !words.empty();
+            continue;
+        }
+        if (gap) words += ' ';
+        gap = false;
+        words += c;
+    }
+    return words.empty() ? title() : title() + " (" + words + ")";
+}
+
 Image TextEffect::render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                          const ParamValues& values) const {
     if (width < 1 || height < 1) throw EffectError("Canvas size must be at least 1x1 pixels.");

src/effects/text.hpp

@@ -30,6 +30,8 @@ public:
     const std::vector<ParamSpec>& params() const override;
     std::string styleKind() const override { return "text"; }
     bool needsSources() const override { return false; }
+    // "Text (Hello world)", so stages writing different words tell apart.
+    std::string label(const ParamValues& values) const override;
 
     Image render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                  const ParamValues& values) const override;

src/gui/window.cpp

@@ -1313,6 +1313,7 @@ void EffectorWindow::rebuildChainRows() {
     // Only the rows: the placeholder is a child of the list box as well, and
     // removing it would leave the empty list blank.
     while (auto* row = chainList_.get_row_at_index(0)) chainList_.remove(*row);
+    stageLabels_.clear();
 
     // The first stage that actually runs is the one handed the sources, which
     // is not stage 1 once stage 1 is switched off.
@@ -1343,8 +1344,8 @@ void EffectorWindow::rebuildChainRows() {
         });
         box->append(*check);
 
-        auto* label = Gtk::make_managed<Gtk::Label>(std::to_string(index + 1) + ". " +
+        auto* label = Gtk::make_managed<Gtk::Label>(stageLabel(i));
-                                                    stages_[i].effect->title());
+        stageLabels_.push_back(label);
         label->set_xalign(0.0F);
         label->set_hexpand(true);
         label->set_ellipsize(Pango::EllipsizeMode::END);
@@ -1418,8 +1419,17 @@ void EffectorWindow::onStageSelected() {
 
 // ------------------------------------------------------------ rendering ---
 
+std::string EffectorWindow::stageLabel(std::size_t index) const {
+    const ChainStage& stage = stages_[index];
+    return std::to_string(index + 1) + ". " + stage.effect->label(stageValues(stage, styles_));
+}
+
 void EffectorWindow::onParamChanged() {
     storeParams();
+    // A param can be what names the stage (the words of a text stage), and a
+    // styled one can rename every stage sharing the style.
+    for (std::size_t i = 0; i < stageLabels_.size() && i < stages_.size(); ++i)
+        stageLabels_[i]->set_text(stageLabel(i));
     requestRender();
 }
 

src/gui/window.hpp

@@ -95,6 +95,7 @@ private:
     // The check on a chain row: the stage stays where it is, and is skipped.
     void setStageEnabled(int index, bool enabled);
     void rebuildChainRows();
+    std::string stageLabel(std::size_t index) const;
     void selectStage(int index);
     void onStageSelected();
     Gtk::Widget& buildMainMenu();     // the header menu: new, open, save project
@@ -145,6 +146,8 @@ private:
     StyleSet styles_;
     int selectedStage_ = 0;
     bool suspendStageSelect_ = false;  // guards the rebuild of the chain rows
+    // The name label of each chain row, renamed in place as params change.
+    std::vector<Gtk::Label*> stageLabels_;
     Image result_;
     std::uint64_t seed_ = 0;
     std::string projectPath_;  // empty until the project has been saved once

tests/core_tests.cpp

@@ -857,6 +857,13 @@ int main() {
         // Like blur and overlay it needs no sources of its own, and the same
         // settings render the same bytes twice over.
         check(!TextEffect().needsSources(), "text can lead a chain");
+
+        // A text stage is named after its words, on one line.
+        check(TextEffect().label({{"text", std::string("  Two\nlines ")}}) == "Text (Two lines)",
+              "a text stage is labelled with its words");
+        check(TextEffect().label({{"text", std::string(" \n")}}) == "Text",
+              "a text stage with no words is labelled with the title alone");
+        check(effectByName("blur")->label({}) == "Blur", "other effects are labelled with their title");
         const auto alone = renderText({}, 200, 120, plain);
         check(alone.width() == 200 && countRed(alone, 0, 0, 200, 120) > 0,
               "without sources it draws on an empty canvas");