glib: Expose inline attributes of structure elements

Allows obtaining inline text attributes from structure elements. The text
is divived into "spans", which are groups of consecutive glyphs that share
their attributes. Each one of those is represented by a PopplerTextSpan,
which gives information about the text font and color, and the link target
for links. The list of PopplerTextSpans is created lazily when first used.

https://bugs.freedesktop.org/show_bug.cgi?id=64821

4 files changed, 297 insertions, 1 deletions

diff --git a/glib/poppler-structure-element.cc b/glib/poppler-structure-element.cc
index 6b8778c1..39dfd519 100644
--- a/glib/poppler-structure-element.cc
+++ b/glib/poppler-structure-element.cc
@@ -661,3 +661,272 @@ poppler_structure_element_iter_get_child (PopplerStructureElementIter *parent)
 
   return NULL;
 }
+
+
+struct _PopplerTextSpan {
+  gchar *text;
+  gchar *font_name;
+  guint  flags;
+  PopplerColor color;
+};
+
+POPPLER_DEFINE_BOXED_TYPE (PopplerTextSpan,
+                           poppler_text_span,
+                           poppler_text_span_copy,
+                           poppler_text_span_free)
+
+enum {
+  POPPLER_TEXT_SPAN_FIXED_WIDTH = (1 << 0),
+  POPPLER_TEXT_SPAN_SERIF       = (1 << 1),
+  POPPLER_TEXT_SPAN_ITALIC      = (1 << 2),
+  POPPLER_TEXT_SPAN_BOLD        = (1 << 3),
+};
+
+static PopplerTextSpan *
+text_span_poppler_text_span (const TextSpan& span)
+{
+    PopplerTextSpan *new_span = g_slice_new0 (PopplerTextSpan);
+    if (GooString *text = span.getText ())
+      new_span->text = _poppler_goo_string_to_utf8 (text);
+
+    new_span->color.red = colToDbl (span.getColor ().r) * 65535;
+    new_span->color.green = colToDbl (span.getColor ().g) * 65535;
+    new_span->color.blue = colToDbl (span.getColor ().b) * 65535;
+
+    if (span.getFont ())
+      {
+        // GfxFont sometimes does not have a family name but there
+        // is always a font name that can be used as fallback.
+        GooString *font_name = span.getFont ()->getFamily ();
+        if (font_name == NULL)
+          font_name = span.getFont ()->getName ();
+
+        new_span->font_name = _poppler_goo_string_to_utf8 (font_name);
+        if (span.getFont ()->isFixedWidth ())
+          new_span->flags |= POPPLER_TEXT_SPAN_FIXED_WIDTH;
+        if (span.getFont ()->isSerif ())
+            new_span->flags |= POPPLER_TEXT_SPAN_SERIF;
+        if (span.getFont ()->isItalic ())
+            new_span->flags |= POPPLER_TEXT_SPAN_ITALIC;
+        if (span.getFont ()->isBold ())
+            new_span->flags |= POPPLER_TEXT_SPAN_BOLD;
+
+        /* isBold() can return false for some fonts whose weight is heavy */
+        switch (span.getFont ()->getWeight ())
+          {
+          case GfxFont::W500:
+          case GfxFont::W600:
+          case GfxFont::W700:
+          case GfxFont::W800:
+          case GfxFont::W900:
+            new_span->flags |= POPPLER_TEXT_SPAN_BOLD;
+          default:
+            break;
+          }
+      }
+
+    return new_span;
+}
+
+/**
+ * poppler_text_span_copy:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Makes a copy of a text span.
+ *
+ * Return value: (transfer full): A new #PopplerTextSpan
+ *
+ * Since: 0.26
+ */
+PopplerTextSpan *
+poppler_text_span_copy (PopplerTextSpan *poppler_text_span)
+{
+  PopplerTextSpan *new_span;
+
+  g_return_val_if_fail (poppler_text_span != NULL, NULL);
+
+  new_span = g_slice_dup (PopplerTextSpan, poppler_text_span);
+  new_span->text = g_strdup (poppler_text_span->text);
+  if (poppler_text_span->font_name)
+    new_span->font_name = g_strdup (poppler_text_span->font_name);
+  return new_span;
+}
+
+/**
+ * poppler_text_span_free:
+ * @poppler_text_span: A #PopplerTextSpan
+ *
+ * Frees a text span.
+ *
+ * Since: 0.26
+ */
+void
+poppler_text_span_free (PopplerTextSpan *poppler_text_span)
+{
+  if (G_UNLIKELY (poppler_text_span == NULL))
+    return;
+
+  g_free (poppler_text_span->text);
+  g_free (poppler_text_span->font_name);
+  g_slice_free (PopplerTextSpan, poppler_text_span);
+}
+
+/**
+ * poppler_text_span_is_fixed_width_font:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Check wether a text span is meant to be rendered using a fixed-width font.
+ *
+ * Return value: Whether the span uses a fixed-width font.
+ *
+ * Since: 0.26
+ */
+gboolean
+poppler_text_span_is_fixed_width_font (PopplerTextSpan *poppler_text_span)
+{
+  g_return_val_if_fail (poppler_text_span != NULL, FALSE);
+
+  return (poppler_text_span->flags & POPPLER_TEXT_SPAN_FIXED_WIDTH);
+}
+
+/**
+ * poppler_text_span_is_serif_font:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Check whether a text span is meant to be rendered using a serif font.
+ *
+ * Return value: Whether the span uses a serif font.
+ *
+ * Since: 0.26
+ */
+gboolean
+poppler_text_span_is_serif_font (PopplerTextSpan *poppler_text_span)
+{
+  g_return_val_if_fail (poppler_text_span != NULL, FALSE);
+
+  return (poppler_text_span->flags & POPPLER_TEXT_SPAN_SERIF);
+}
+
+/**
+ * poppler_text_span_is_bold_font:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Check whether a text span is meant to be rendered using a bold font.
+ *
+ * Return value: Whether the span uses bold font.
+ *
+ * Since: 0.26
+ */
+gboolean
+poppler_text_span_is_bold_font (PopplerTextSpan *poppler_text_span)
+{
+  g_return_val_if_fail (poppler_text_span != NULL, FALSE);
+
+  return (poppler_text_span->flags & POPPLER_TEXT_SPAN_BOLD);
+}
+
+/**
+ * poppler_text_span_get_color:
+ * @poppler_text_span: a #PopplerTextSpan
+ * @color: (out): a return location for a #PopplerColor
+ *
+ * Obtains the color in which the text is to be rendered.
+ *
+ * Since: 0.26
+ */
+void
+poppler_text_span_get_color (PopplerTextSpan *poppler_text_span,
+                             PopplerColor *color)
+{
+  g_return_if_fail (poppler_text_span != NULL);
+  g_return_if_fail (color != NULL);
+
+  *color = poppler_text_span->color;
+}
+
+/**
+ * poppler_text_span_get_text:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Obtains the text contained in the span.
+ *
+ * Return value: (transfer none): A string.
+ *
+ * Since: 0.26
+ */
+const gchar *
+poppler_text_span_get_text (PopplerTextSpan *poppler_text_span)
+{
+  g_return_val_if_fail (poppler_text_span != NULL, NULL);
+
+  return poppler_text_span->text;
+}
+
+/**
+ * poppler_text_span_get_font_name:
+ * @poppler_text_span: a #PopplerTextSpan
+ *
+ * Obtains the name of the font in which the span is to be rendered.
+ *
+ * Return value: (transfer none): A string containing the font name, or
+ *   %NULL if a font is not defined.
+ *
+ * Since: 0.26
+ */
+const gchar *
+poppler_text_span_get_font_name (PopplerTextSpan *poppler_text_span)
+{
+  g_return_val_if_fail (poppler_text_span != NULL, NULL);
+
+  return poppler_text_span->font_name;
+}
+
+
+/**
+ * poppler_structure_element_get_text_spans:
+ * @poppler_structure_element: A #PopplerStructureElement
+ * @n_text_spans: (out): A pointer to the location where the number of elements in
+ *    the returned array will be stored.
+ *
+ * Obtains the text enclosed by an element, as an array of #PopplerTextSpan
+ * structures. Each item in the list is a piece of text which share the same
+ * attributes, plus its attributes. The following example shows how to
+ * obtain and free the text spans of an element:
+ *
+ * <informalexample><programlisting>
+ * guint i, n_spans;
+ * PopplerTextSpan **text_spans =
+ *    poppler_structure_element_get_text_spans (element, &n_spans);
+ * /<!-- -->* Use the text spans *<!-- -->/
+ * for (i = 0; i < n_spans; i++)
+ *    poppler_text_span_free (text_spans[i]);
+ * g_free (text_spans);
+ * </programlisting></informalexample>
+ *
+ * Return value: (transfer full) (array length=n_text_spans) (element-type PopplerTextSpan):
+ *    An array of #PopplerTextSpan elments.
+ *
+ * Since: 0.26
+ */
+PopplerTextSpan **
+poppler_structure_element_get_text_spans (PopplerStructureElement *poppler_structure_element,
+                                          guint                   *n_text_spans)
+{
+  g_return_val_if_fail (POPPLER_IS_STRUCTURE_ELEMENT (poppler_structure_element), NULL);
+  g_return_val_if_fail (n_text_spans != NULL, NULL);
+  g_return_val_if_fail (poppler_structure_element->elem != NULL, NULL);
+
+  if (!poppler_structure_element->elem->isContent ())
+    return NULL;
+
+  const TextSpanArray spans(poppler_structure_element->elem->getTextSpans ());
+  PopplerTextSpan **text_spans = g_new0 (PopplerTextSpan*, spans.size ());
+
+  size_t i = 0;
+  for (TextSpanArray::const_iterator s = spans.begin (); s != spans.end (); ++s)
+    text_spans[i++] = text_span_poppler_text_span (*s);
+
+  *n_text_spans = spans.size ();
+
+  return text_spans;
+}
diff --git a/glib/poppler-structure-element.h b/glib/poppler-structure-element.h
index a5ac04b5..7ba5d561 100644
--- a/glib/poppler-structure-element.h
+++ b/glib/poppler-structure-element.h
@@ -82,7 +82,6 @@ typedef enum {
   POPPLER_STRUCTURE_ELEMENT_FORM,
 } PopplerStructureElementKind;
 
-
 GType                        poppler_structure_element_get_type                   (void) G_GNUC_CONST;
 PopplerStructureElementKind  poppler_structure_element_get_kind                   (PopplerStructureElement  *poppler_structure_element);
 gint                         poppler_structure_element_get_page                   (PopplerStructureElement  *poppler_structure_element);
@@ -97,6 +96,8 @@ gchar                       *poppler_structure_element_get_text
                                                                                    gboolean                  recursive);
 gchar                       *poppler_structure_element_get_alt_text               (PopplerStructureElement  *poppler_structure_element);
 gchar                       *poppler_structure_element_get_actual_text            (PopplerStructureElement  *poppler_structure_element);
+PopplerTextSpan            **poppler_structure_element_get_text_spans             (PopplerStructureElement  *poppler_structure_element,
+                                                                                   guint                    *n_text_spans);
 
 #define POPPLER_TYPE_STRUCTURE_ELEMENT_ITER                                       (poppler_structure_element_iter_get_type ())
 GType                        poppler_structure_element_iter_get_type              (void) G_GNUC_CONST;
@@ -107,6 +108,19 @@ PopplerStructureElement     *poppler_structure_element_iter_get_element
 gboolean                     poppler_structure_element_iter_next                  (PopplerStructureElementIter *iter);
 void                         poppler_structure_element_iter_free                  (PopplerStructureElementIter *iter);
 
+#define POPPLER_TYPE_TEXT_SPAN                                                    (poppler_text_span_get_type ())
+GType                        poppler_text_span_get_type                           (void) G_GNUC_CONST;
+PopplerTextSpan             *poppler_text_span_copy                               (PopplerTextSpan *poppler_text_span);
+void                         poppler_text_span_free                               (PopplerTextSpan *poppler_text_span);
+gboolean                     poppler_text_span_is_fixed_width_font                (PopplerTextSpan *poppler_text_span);
+gboolean                     poppler_text_span_is_serif_font                      (PopplerTextSpan *poppler_text_span);
+gboolean                     poppler_text_span_is_bold_font                       (PopplerTextSpan *poppler_text_span);
+gboolean                     poppler_text_span_is_link                            (PopplerTextSpan *poppler_text_span);
+void                         poppler_text_span_get_color                          (PopplerTextSpan *poppler_text_span,
+                                                                                   PopplerColor    *color);
+const gchar                 *poppler_text_span_get_text                           (PopplerTextSpan *poppler_text_span);
+const gchar                 *poppler_text_span_get_font_name                      (PopplerTextSpan *poppler_text_span);
+
 G_END_DECLS
 
 #endif /* !__POPPLER_STRUCTURE_ELEMENT_H__ */
diff --git a/glib/poppler.h b/glib/poppler.h
index 1da2af13..f5c95630 100644
--- a/glib/poppler.h
+++ b/glib/poppler.h
@@ -210,6 +210,7 @@ typedef struct _PopplerAnnotSquare         PopplerAnnotSquare;
 typedef struct _PopplerQuadrilateral       PopplerQuadrilateral;
 typedef struct _PopplerStructureElement    PopplerStructureElement;
 typedef struct _PopplerStructureElementIter PopplerStructureElementIter;
+typedef struct _PopplerTextSpan            PopplerTextSpan;
 
 typedef enum
 {
diff --git a/glib/reference/poppler-sections.txt b/glib/reference/poppler-sections.txt
index fff370b2..719b708f 100644
--- a/glib/reference/poppler-sections.txt
+++ b/glib/reference/poppler-sections.txt
@@ -590,6 +590,7 @@ poppler_movie_get_type
 PopplerStructureElement
 PopplerStructureElementKind
 PopplerStructureElementIter
+PopplerTextSpan
 poppler_structure_element_iter_new
 poppler_structure_element_iter_next
 poppler_structure_element_iter_copy
@@ -608,6 +609,15 @@ poppler_structure_element_get_language
 poppler_structure_element_get_text
 poppler_structure_element_get_alt_text
 poppler_structure_element_get_actual_text
+poppler_structure_element_get_text_spans
+poppler_text_span_copy
+poppler_text_span_free
+poppler_text_span_is_fixed_width_font
+poppler_text_span_is_serif_font
+poppler_text_span_is_bold_font
+poppler_text_span_get_color
+poppler_text_span_get_text
+poppler_text_span_get_font_name
 
 <SUBSECTION Standard>
 POPPLER_STRUCTURE_ELEMENT
@@ -618,7 +628,9 @@ POPPLER_TYPE_STRUCTURE_ELEMENT_KIND
 
 <SUBSECTION Private>
 poppler_structure_element_get_type
+poppler_structure_element_kind_get_type
 poppler_structure_element_iter_get_type
+poppler_text_span_get_type
 </SECTION>
 
 <SECTION>