A PDF's body puts each line of the page's text on a line of its own, not a heading and its paragraph run together with a space

MuPDF's text buffer joins the lines of one block with spaces, so a
typst page's heading and the text under it read as one line ("Page one
Hello normal PDF alpha."). The bridge now walks the structured text
itself, structure blocks included, and ends each line with a newline.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 27 insertions, 1 deletions

diff --git a/src/pdf_bridge.c b/src/pdf_bridge.c
index 6fdab46c..594db0f9 100644
--- a/src/pdf_bridge.c
+++ b/src/pdf_bridge.c
@@ -940,6 +940,31 @@ pardes_pdf_highlight_rows(
     return PARDES_PDF_OK;
 }
 
+/* A page's text, a line of it a line of the result: MuPDF's own buffer
+ * joins a block's lines with spaces, which ran a heading into the
+ * paragraph under it. Structure blocks are walked into. */
+static void
+pardes_append_stext_blocks(fz_context *ctx, fz_buffer *buffer, fz_stext_block *block)
+{
+    for (; block != NULL; block = block->next)
+    {
+        if (block->type == FZ_STEXT_BLOCK_STRUCT)
+        {
+            if (block->u.s.down != NULL)
+                pardes_append_stext_blocks(ctx, buffer, block->u.s.down->first_block);
+            continue;
+        }
+        if (block->type != FZ_STEXT_BLOCK_TEXT)
+            continue;
+        for (fz_stext_line *line = block->u.t.first_line; line != NULL; line = line->next)
+        {
+            for (fz_stext_char *ch = line->first_char; ch != NULL; ch = ch->next)
+                fz_append_rune(ctx, buffer, ch->c);
+            fz_append_byte(ctx, buffer, '\n');
+        }
+    }
+}
+
 int
 pardes_pdf_page_text(
     pardes_pdf_document *document,
@@ -961,7 +986,8 @@ pardes_pdf_page_text(
     fz_try(ctx)
     {
         pardes_pdf_cache_page(document, page_number, 1);
-        buffer = fz_new_buffer_from_stext_page(ctx, document->cached_text);
+        buffer = fz_new_buffer(ctx, 1024);
+        pardes_append_stext_blocks(ctx, buffer, document->cached_text->first_block);
         len = fz_buffer_storage(ctx, buffer, &data);
     }
     fz_catch(ctx)