feat(editor): wrap text at a dragged width or the canvas edge

README.md

@@ -366,7 +366,7 @@ without reaching for the pointer.
 | `E` | Ellipse; shares the shape submenu and filled/hollow toggle |
 | `D` | Redact; press again to toggle randomized pixelation or solid redaction |
 | `X` | Cut out a band; drag to preview the crossed-out strip, then release to remove and collapse it |
-| `T` | Text on a cream readability pill, with Neucha as the default. Click for a one-line label, or drag a box to give it room for several lines: Enter moves to the next line while there is room and commits on the last one; `Shift+Enter` always adds a line; `Esc` commits too but keeps the label selected, so `Backspace` removes it; clicking away keeps the text; press T again to toggle the pill |
+| `T` | Text on a cream readability pill, with Neucha as the default. Click for a one-line label, or drag a box to give it room for several lines: Enter moves to the next line while there is room and commits on the last one; `Shift+Enter` always adds a line; `Esc` commits too but keeps the label selected, so `Backspace` removes it; long text wraps at the current canvas edge by default, while moving it or dragging its width handle beyond that edge expands the canvas; clicking away keeps the text; press T again to toggle the pill |
 | `Shift+T` | Cycle the next or selected text through Neucha, JetBrains Mono, and Inter Display |
 | `O` | Recognize and copy all text in the current image |
 | `B` | Cycle shadowed colors, window gray (shadowed and flat), and Off |

src/capture.cpp

@@ -1,4 +1,6 @@
 /** @fileoverview Captures, renders, saves, and shares screenshots. */
+#include <QTextLayout>
+#include <QTextOption>
 #include "capture.hpp"
 #include "output-config.hpp"
 #include "startup-timing.hpp"
@@ -67,13 +69,62 @@ QFont annotationTextFont(qreal size, TextFont textFont) {
   return font;
 }
 
-QRectF annotationTextBounds(const Annotation &annotation) {
+qreal annotationTextWrapWidth(const Annotation &annotation,
+                              qreal canvasWidth) {
+  if (annotation.textWidth > 0.0)
+    return annotation.textWidth;
+  if (canvasWidth <= 0.0)
+    return 0.0;
+  // Room left before the right edge. Narrower than this and the text would be
+  // wrapping to a sliver, so leave it on one line and let it run.
+  const qreal room = canvasWidth - annotation.start.x();
+  return room >= kMinimumTextWrapWidth ? room : 0.0;
+}
+
+QStringList annotationTextLines(const Annotation &annotation,
+                                qreal canvasWidth) {
+  const QStringList paragraphs = annotation.text.split('\n');
+  const qreal wrap = annotationTextWrapWidth(annotation, canvasWidth);
+  if (wrap <= 0.0)
+    return paragraphs;
+  QStringList lines;
+  for (const QString &paragraph : paragraphs) {
+    if (paragraph.isEmpty()) {
+      lines.push_back(paragraph);
+      continue;
+    }
+    QTextLayout layout(paragraph,
+                       annotationTextFont(annotation.size, annotation.textFont));
+    QTextOption option;
+    option.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
+    layout.setTextOption(option);
+    layout.beginLayout();
+    while (true) {
+      QTextLine line = layout.createLine();
+      if (!line.isValid())
+        break;
+      line.setLineWidth(wrap);
+      lines.push_back(paragraph.mid(line.textStart(), line.textLength()));
+    }
+    layout.endLayout();
+  }
+  return lines;
+}
+
+QRectF annotationTextBounds(const Annotation &annotation,
+                           qreal canvasWidth) {
   const QFontMetricsF metrics(
       annotationTextFont(annotation.size, annotation.textFont));
-  const QStringList lines = annotation.text.split('\n');
+  const QStringList lines = annotationTextLines(annotation, canvasWidth);
   qreal widestLine = 0.0;
-  for (const QString &line : lines)
-    widestLine = std::max(widestLine, metrics.horizontalAdvance(line));
+  for (const QString &line : lines) {
+    // QTextLayout excludes trailing wrap whitespace from naturalTextWidth;
+    // keep indentation, but match that painted width for the pill.
+    QString visible = line;
+    while (!visible.isEmpty() && visible.back().isSpace())
+      visible.chop(1);
+    widestLine = std::max(widestLine, metrics.horizontalAdvance(visible));
+  }
   const QRectF glyphs(
       annotation.start.x(), annotation.start.y() - metrics.ascent(),
       widestLine,
@@ -416,7 +467,8 @@ QVector<WindowTarget> parseWindows(const QByteArray &json,
   return result;
 }
 
-void drawAnnotation(QPainter &painter, const Annotation &annotation) {
+void drawAnnotation(QPainter &painter, const Annotation &annotation,
+                    qreal canvasWidth = 0.0) {
   // Redactions replace source pixels in renderCapture before ordinary vector
   // annotations are painted. They must never be approximated by a translucent
   // overlay here because that could leave recoverable source data in exports.
@@ -524,7 +576,7 @@ void drawAnnotation(QPainter &painter, const Annotation &annotation) {
   if (annotation.textBackground == TextBackground::Pill) {
     // A cream pill under the glyphs keeps text readable on any capture or
     // shape beneath it (the default text background).
-    const QRectF pill = annotationTextBounds(annotation);
+    const QRectF pill = annotationTextBounds(annotation, canvasWidth);
     const qreal radius = std::min(pill.height() / 4.0, 6.0);
     painter.setPen(Qt::NoPen);
     painter.setBrush(QColor(248, 245, 235));
@@ -534,7 +586,7 @@ void drawAnnotation(QPainter &painter, const Annotation &annotation) {
   painter.setPen(annotation.color);
   painter.setBrush(Qt::NoBrush);
   const QFontMetricsF metrics(font);
-  const QStringList lines = annotation.text.split('\n');
+  const QStringList lines = annotationTextLines(annotation, canvasWidth);
   if (annotation.textBackground == TextBackground::Outline) {
     // A white halo whatever the color: screenshots are mostly light UI, where
     // a dark halo reads as a drop shadow rather than a cut-out, and white
@@ -711,8 +763,9 @@ QRect pixelSelection(const CaptureData &capture, const QRectF &selection) {
 
 } // namespace
 
-void paintAnnotation(QPainter &painter, const Annotation &annotation) {
-  drawAnnotation(painter, annotation);
+void paintAnnotation(QPainter &painter, const Annotation &annotation,
+                     qreal canvasWidth) {
+  drawAnnotation(painter, annotation, canvasWidth);
 }
 
 QPainterPath spotlightPath(const Annotation &annotation) {
@@ -1680,6 +1733,8 @@ QJsonObject annotationToJson(const Annotation &annotation) {
   object.insert(QStringLiteral("color"),
                 annotation.color.name(QColor::HexArgb));
   object.insert(QStringLiteral("size"), annotation.size);
+  if (annotation.kind == Annotation::Kind::Text)
+    object.insert(QStringLiteral("textWidth"), annotation.textWidth);
   if (!annotation.text.isEmpty())
     object.insert(QStringLiteral("text"), annotation.text);
   if (annotation.kind == Annotation::Kind::Text)
@@ -1736,6 +1791,7 @@ bool annotationFromJson(const QJsonObject &object, Annotation &annotation,
   annotation.color = QColor(object.value(QStringLiteral("color")).toString());
   annotation.size = object.value(QStringLiteral("size")).toDouble(4.0);
   annotation.text = object.value(QStringLiteral("text")).toString();
+  annotation.textWidth = object.value(QStringLiteral("textWidth")).toDouble(0.0);
   annotation.textFont = textFontFromStyleName(
       object.value(QStringLiteral("textFont")).toString());
   annotation.number = object.value(QStringLiteral("number")).toInt();

src/capture.hpp

@@ -93,6 +93,8 @@ struct Annotation {
   /// Typeface is a layer property so reopened and duplicated labels keep it.
   TextFont textFont = TextFont::Neucha;
   quint64 id = 0;
+  /// Wrap width for text layers in image px; 0 leaves the layer unbounded.
+  qreal textWidth = 0.0;
 
   bool operator==(const Annotation &) const = default;
 };
@@ -166,7 +168,21 @@ enum class AnnotationLayer { Redaction, Default };
                                          bool includeWindows, QString &error);
 /** Bounds of a text layer's glyph box, or of its readability pill when it
  *  has one; `start` is the baseline origin. */
-[[nodiscard]] QRectF annotationTextBounds(const Annotation &annotation);
+/// Narrowest wrap width worth producing; below this a line would be a sliver,
+/// so the text stays on one line instead.
+inline constexpr qreal kMinimumTextWrapWidth = 48.0;
+/** Width a text layer wraps to: its own `textWidth`, else the room left
+ *  before an optional right edge (`canvasWidth`, 0 = unbounded). The editor
+ *  supplies that edge while typing, then stores an explicit width only when
+ *  the draft actually wrapped. */
+[[nodiscard]] qreal annotationTextWrapWidth(const Annotation &annotation,
+                                            qreal canvasWidth);
+/** The display lines of a text layer: hard newlines first, then each of those
+ *  word-wrapped to annotationTextWrapWidth(). */
+[[nodiscard]] QStringList annotationTextLines(const Annotation &annotation,
+                                              qreal canvasWidth = 0.0);
+[[nodiscard]] QRectF annotationTextBounds(const Annotation &annotation,
+                                          qreal canvasWidth = 0.0);
 /**
  * Pixel-aligned annotation space selected by `boundaryMode`. Grow contains
  * every painted extent, Frame stops at the normal backdrop frame, and Image
@@ -252,7 +268,8 @@ void describeFileCapture(CaptureData &capture, QImage image,
 [[nodiscard]] bool quickOutput(const QImage &image, QuickOutputMode mode,
                                QString &error);
 [[nodiscard]] bool copyTextToClipboard(const QString &text, QString &error);
-void paintAnnotation(QPainter &painter, const Annotation &annotation);
+void paintAnnotation(QPainter &painter, const Annotation &annotation,
+                     qreal canvasWidth = 0.0);
 [[nodiscard]] QPainterPath spotlightPath(const Annotation &annotation);
 void paintSpotlights(QPainter &painter, const QImage &source,
                      const QRectF &targetBounds, const QRectF &sourceRect,