Merge branch 'pangolayout'

10 files changed, 231 insertions, 103 deletions

diff --git a/src/frame.c b/src/frame.c
index 3699b74..3713277 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -64,6 +64,9 @@ struct _paragraph
 	PangoLayout     *layout;
 	size_t           offset_last;
 
+	/* For anything other than PARA_TYPE_TEXT */
+	SCBlock         *scblock;
+
 	/* For PARA_TYPE_IMAGE */
 	char            *filename;
 	double           image_w;
@@ -288,7 +291,8 @@ void wrap_paragraph(Paragraph *para, PangoContext *pc, double w)
 	/* Allocate the complete text */
 	text = malloc(total_len+1);
 	if ( text == NULL ) {
-		fprintf(stderr, "Couldn't allocate combined text\n");
+		fprintf(stderr, "Couldn't allocate combined text (%lli)\n",
+		       (long long int)total_len);
 		return;
 	}
 
@@ -388,7 +392,37 @@ static Paragraph *create_paragraph(struct frame *fr)
 }
 
 
-void add_callback_para(struct frame *fr, double w, double h,
+/* Create a new paragraph in 'fr' just after paragraph 'pos' */
+static Paragraph *insert_paragraph(struct frame *fr, int pos)
+{
+	Paragraph **paras_new;
+	Paragraph *pnew;
+	int i;
+
+	if ( pos >= fr->n_paras ) {
+		fprintf(stderr, "insert_paragraph(): pos too high!\n");
+		return NULL;
+	}
+
+	paras_new = realloc(fr->paras, (fr->n_paras+1)*sizeof(Paragraph *));
+	if ( paras_new == NULL ) return NULL;
+
+	pnew = calloc(1, sizeof(struct _paragraph));
+	if ( pnew == NULL ) return NULL;
+
+	fr->paras = paras_new;
+	fr->n_paras ++;
+
+	for ( i=fr->n_paras-1; i>pos; i-- ) {
+		fr->paras[i] = fr->paras[i-1];
+	}
+	fr->paras[pos+1] = pnew;
+
+	return pnew;
+}
+
+
+void add_callback_para(struct frame *fr, SCBlock *bl, double w, double h,
                        SCCallbackDrawFunc draw_func,
                        SCCallbackClickFunc click_func, void *bvp,
                        void *vp)
@@ -402,6 +436,7 @@ void add_callback_para(struct frame *fr, double w, double h,
 	}
 
 	pnew->type = PARA_TYPE_CALLBACK;
+	pnew->scblock = bl;
 	pnew->cb_w = w;
 	pnew->cb_h = h;
 	pnew->draw_func = draw_func;
@@ -413,7 +448,7 @@ void add_callback_para(struct frame *fr, double w, double h,
 }
 
 
-void add_image_para(struct frame *fr, const char *filename,
+void add_image_para(struct frame *fr, SCBlock *scblock, const char *filename,
                     double w, double h, int editable)
 {
 	Paragraph *pnew;
@@ -425,6 +460,7 @@ void add_image_para(struct frame *fr, const char *filename,
 	}
 
 	pnew->type = PARA_TYPE_IMAGE;
+	pnew->scblock = scblock;
 	pnew->filename = strdup(filename);
 	pnew->image_w = w;
 	pnew->image_h = h;
@@ -798,18 +834,43 @@ void delete_text_in_paragraph(Paragraph *para, size_t offs1, size_t offs2)
 }
 
 
-static void split_text_paragraph(struct frame *fr, int pn, int pos,
-                                 PangoContext *pc)
+static __attribute__((unused)) void show_para(Paragraph *p)
+{
+	int i;
+	printf("Paragraph %p\n", p);
+	printf("%i runs:\n", p->n_runs);
+	for ( i=0; i<p->n_runs; i++ ) {
+		printf("  Run %2i: para offs %lli, SCBlock %p offs %lli, len "
+		       "%lli %s\n", i, (long long int)p->runs[i].para_offs_bytes,
+		       p->runs[i].scblock,
+		       (long long int)p->runs[i].scblock_offs_bytes,
+		       (long long int)p->runs[i].len_bytes,
+		       pango_font_description_to_string(p->runs[i].fontdesc));
+	}
+}
+
+
+static char *s_strdup(const char *a)
+{
+	if ( a == NULL ) return NULL;
+	return strdup(a);
+}
+
+
+static SCBlock *split_text_paragraph(struct frame *fr, int pn, size_t pos,
+                                     PangoContext *pc)
 {
 	Paragraph *pnew;
-	int i, j;
+	int i;
+	size_t offs, run_offs;
 	int run;
 	Paragraph *para = fr->paras[pn];
+	struct text_run *rr;
 
 	pnew = insert_paragraph(fr, pn);
 	if ( pnew == NULL ) {
 		fprintf(stderr, "Failed to insert paragraph\n");
-		return;
+		return NULL;
 	}
 
 	/* Determine which run the cursor is in */
@@ -821,34 +882,67 @@ static void split_text_paragraph(struct frame *fr, int pn, int pos,
 	pnew->runs = malloc(pnew->n_runs * sizeof(struct text_run));
 	if ( pnew->runs == NULL ) {
 		fprintf(stderr, "Failed to allocate runs.\n");
-		return; /* Badness is coming */
-	}
+		return NULL; /* Badness is coming */
+	}
+
+	/* First run of the new paragraph contains the leftover text */
+	rr = &para->runs[run];
+	pnew->runs[0].scblock = rr->scblock;
+	run_offs = pos - rr->para_offs_bytes;
+	pnew->runs[0].scblock_offs_bytes = rr->scblock_offs_bytes + run_offs;
+	pnew->runs[0].para_offs_bytes = 0;
+	pnew->runs[0].len_bytes = rr->len_bytes - run_offs;
+	pnew->runs[0].col[0] = rr->col[0];
+	pnew->runs[0].col[1] = rr->col[1];
+	pnew->runs[0].col[2] = rr->col[2];
+	pnew->runs[0].col[3] = rr->col[3];
+	pnew->runs[0].fontdesc = pango_font_description_copy(rr->fontdesc);
+	pnew->n_runs = 1;
+
+	/* All later runs just get moved to the new paragraph */
+	offs = pnew->runs[0].len_bytes;
+	for ( i=run+1; i<para->n_runs; i++ ) {
+		pnew->runs[pnew->n_runs] = para->runs[i];
+		pnew->runs[pnew->n_runs].para_offs_bytes = offs;
+		pnew->n_runs++;
+		offs += rr->len_bytes;
+	}
+
+	/* Truncate the first paragraph at the appropriate position */
+	rr->len_bytes = run_offs;
+	para->n_runs = run+1;
 
-	/* If the position is right at the start of a run, the whole run
-	 * gets moved to the next paragraph */
-	if ( para->runs[run].para_offs_bytes ) {
+	/* If the first and second paragraphs have the same SCBlock, split it */
+	if ( rr->scblock == pnew->runs[0].scblock ) {
+		size_t sc_offs;
+		sc_offs = rr->scblock_offs_bytes + run_offs;
+		pnew->runs[0].scblock = sc_block_split(rr->scblock, sc_offs);
+		pnew->runs[0].scblock_offs_bytes = 0;
 	}
 
-	j = 0;
-	for ( i=run; i<para->n_runs; i++ ) {
-		pnew->runs[j++] = para->runs[i];
-	}
+	/* Add a newline after the end of the first paragraph's SC */
+	sc_block_append(rr->scblock, s_strdup(sc_block_name(rr->scblock)),
+	                             s_strdup(sc_block_options(rr->scblock)),
+	                             strdup("\n"), NULL);
 
+	pnew->open = para->open;
 	para->open = 0;
-	para->n_runs = run+1;
 
 	wrap_paragraph(para, pc, fr->w);
 	wrap_paragraph(pnew, pc, fr->w);
+
+	return sc_block_next(rr->scblock);
 }
 
 
-void split_paragraph(struct frame *fr, int pn, int pos, PangoContext *pc)
+SCBlock *split_paragraph(struct frame *fr, int pn, size_t pos, PangoContext *pc)
 {
 	Paragraph *para = fr->paras[pn];
 
 	if ( para->type == PARA_TYPE_TEXT ) {
-		split_text_paragraph(fr, pn, pos, pc);
+		return split_text_paragraph(fr, pn, pos, pc);
 	} else {
 		/* Other types can't be split */
+		return NULL;
 	}
 }
diff --git a/src/frame.h b/src/frame.h
index d6d171c..2941411 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -115,12 +115,14 @@ extern void add_run(Paragraph *para, SCBlock *scblock, size_t offs_bytes,
                     size_t len_bytes, PangoFontDescription *fdesc,
                     double col[4]);
 
-extern void add_callback_para(struct frame *fr, double w, double h,
+extern void add_callback_para(struct frame *fr, SCBlock *scblock,
+                              double w, double h,
                               SCCallbackDrawFunc draw_func,
                               SCCallbackClickFunc click_func, void *bvp,
                               void *vp);
 
-extern void add_image_para(struct frame *fr, const char *filename,
+extern void add_image_para(struct frame *fr, SCBlock *scblock,
+                           const char *filename,
                            double w, double h, int editable);
 
 extern void wrap_paragraph(Paragraph *para, PangoContext *pc, double w);
@@ -150,4 +152,7 @@ extern void insert_text_in_paragraph(Paragraph *para, size_t offs,
 extern void delete_text_in_paragraph(Paragraph *para,
                                      size_t offs1, size_t offs2);
 
+extern SCBlock *split_paragraph(struct frame *fr, int pn, size_t pos,
+                                PangoContext *pc);
+
 #endif	/* FRAME_H */
diff --git a/src/narrative_window.c b/src/narrative_window.c
index 6e09d71..5a352f7 100644
--- a/src/narrative_window.c
+++ b/src/narrative_window.c
@@ -139,41 +139,36 @@ static void exportpdf_sig(GSimpleAction *action, GVariant *parameter,
 }
 
 
-static void open_slidesorter_sig(GSimpleAction *action, GVariant *parameter, gpointer vp)
+static void open_slidesorter_sig(GSimpleAction *action, GVariant *parameter,
+                                 gpointer vp)
 {
 }
 
 
-static void delete_frame_sig(GSimpleAction *action, GVariant *parameter, gpointer vp)
+static void delete_frame_sig(GSimpleAction *action, GVariant *parameter,
+                             gpointer vp)
 {
 }
 
 
-static void add_slide_sig(GSimpleAction *action, GVariant *parameter, gpointer vp)
+static void add_slide_sig(GSimpleAction *action, GVariant *parameter,
+                          gpointer vp)
 {
-	int n_slides;
-	SCBlock *block;
 	SCBlock *nsblock;
 	NarrativeWindow *nw = vp;
 
-	/* Link it into the SC structure */
-	nsblock = sc_parse("\\slide{}");
-	insert_scblock(nsblock, nw->sceditor);
-
-	/* Iterate over blocks of presentation, counting \slides, until
-	 * we reach the block we just added */
-	block = nw->p->scblocks;
-	n_slides = 0;
-	while ( block != NULL ) {
-		const char *n = sc_block_name(block);
-		if ( n == NULL ) goto next;
-		if ( strcmp(n, "slide") == 0 ) {
-			if ( block == nsblock ) break;
-			n_slides++;
-		}
-next:
-		block = sc_block_next(block);
+	/* Split the current paragraph */
+	nsblock = split_paragraph_at_cursor(nw->sceditor);
+
+	/* Link the new SCBlock in */
+	if ( nsblock != NULL ) {
+		sc_block_append(nsblock, "slide", NULL, NULL, NULL);
+	} else {
+		fprintf(stderr, "Failed to split paragraph\n");
 	}
+
+	sc_editor_set_scblock(nw->sceditor,
+	                      sc_editor_get_scblock(nw->sceditor));
 }
 
 
diff --git a/src/presentation.c b/src/presentation.c
index 60c27f8..266535c 100644
--- a/src/presentation.c
+++ b/src/presentation.c
@@ -164,9 +164,15 @@ static char *fgets_long(FILE *fh, size_t *lp)
 
 		r = fgetc(fh);
 		if ( r == EOF ) {
-			free(line);
-			*lp = 0;
-			return NULL;
+			if ( l == 0 ) {
+				free(line);
+				*lp = 0;
+				return NULL;
+			} else {
+				line[l++] = '\0';
+				*lp = l;
+				return line;
+			}
 		}
 
 		line[l++] = r;
diff --git a/src/sc_editor.c b/src/sc_editor.c
index 5549c54..e54e60a 100644
--- a/src/sc_editor.c
+++ b/src/sc_editor.c
@@ -555,38 +555,13 @@ static gboolean draw_sig(GtkWidget *da, cairo_t *cr, SCEditor *e)
 }
 
 
-void insert_scblock(SCBlock *scblock, SCEditor *e)
+SCBlock *split_paragraph_at_cursor(SCEditor *e)
 {
-#if 0
-	/* FIXME: Insert "scblock" at the cursor */
-	int sln, sbx, sps;
-	struct wrap_box *sbox;
-	struct frame *fr = e->cursor_frame;
-
-	if ( fr == NULL ) return;
-
-	/* If this is, say, the top level frame, do nothing */
-	if ( fr->boxes == NULL ) return;
-
-	sln = e->cursor_line;
-	sbx = e->cursor_box;
-	sps = e->cursor_pos;
-	sbox = bv_box(e->cursor_frame->lines[sln].boxes, sbx);
-
-	sc_insert_block(sbox->scblock, sps+sbox->offs_char, scblock);
-
-	fr->empty = 0;
-
-	full_rerender(e); /* FIXME: No need for full */
-
-	//fixup_cursor(e);
-	//advance_cursor(e);
-	//sc_editor_redraw(e);
-#endif
+	return split_paragraph(e->cursor_frame, e->cursor_para,
+	                       e->cursor_pos+e->cursor_trail, e->pc);
 }
 
 
-
 static void insert_text(char *t, SCEditor *e)
 {
 	Paragraph *para;
@@ -838,6 +813,13 @@ static void check_paragraph(struct frame *fr, PangoContext *pc,
 {
 	if ( fr->n_paras > 0 ) return;
 	Paragraph *para = last_open_para(fr);
+
+	/* We are creating the first paragraph.  It uses the last SCBlock
+	 * in the chain */
+	while ( sc_block_next(scblocks) != NULL ) {
+		scblocks = sc_block_next(scblocks);
+	}
+
 	add_run(para, scblocks, 0, 0, fr->fontdesc, fr->col);
 	wrap_paragraph(para, pc, fr->w - fr->pad_l - fr->pad_r);
 }
@@ -923,12 +905,18 @@ static gboolean button_press_sig(GtkWidget *da, GdkEventButton *event,
 
 	} else {
 
-		/* Selected top new frame, no immediate dragging */
+		/* Clicked an existing frame, no immediate dragging */
 		e->drag_status = DRAG_STATUS_NONE;
 		e->drag_reason = DRAG_REASON_NONE;
 		e->selection = clicked;
 		e->cursor_frame = clicked;
-		check_paragraph(e->cursor_frame, e->pc, e->scblocks);
+		if ( clicked == e->top ) {
+			show_sc_block(clicked->scblocks, ")>");
+			check_paragraph(e->cursor_frame, e->pc, clicked->scblocks);
+		} else {
+			check_paragraph(e->cursor_frame, e->pc,
+			                sc_block_child(clicked->scblocks));
+		}
 		find_cursor(clicked, x-clicked->x, y-clicked->y,
 		            &e->cursor_para, &e->cursor_pos, &e->cursor_trail);
 
@@ -1545,7 +1533,6 @@ SCEditor *sc_editor_new(SCBlock *scblocks, SCBlock **stylesheets,
 {
 	SCEditor *sceditor;
 	GtkTargetEntry targets[1];
-	GError *err;
 
 	sceditor = g_object_new(SC_TYPE_EDITOR, NULL);
 
@@ -1567,12 +1554,7 @@ SCEditor *sc_editor_new(SCBlock *scblocks, SCBlock **stylesheets,
 
 	sceditor->stylesheets = copy_ss_list(stylesheets);
 
-	err = NULL;
-	sceditor->bg_pixbuf = gdk_pixbuf_new_from_file(DATADIR"/colloquium/sky.png", &err);
-	if ( sceditor->bg_pixbuf == NULL ) {
-		fprintf(stderr, "Failed to load background: %s\n",
-		        err->message);
-	}
+	sceditor->bg_pixbuf = NULL;
 
 	gtk_widget_set_size_request(GTK_WIDGET(sceditor),
 	                            sceditor->w, sceditor->h);
diff --git a/src/sc_editor.h b/src/sc_editor.h
index 594f344..5e54cde 100644
--- a/src/sc_editor.h
+++ b/src/sc_editor.h
@@ -177,8 +177,8 @@ extern void sc_editor_set_min_border(SCEditor *e, double min_border);
 extern void sc_editor_set_top_frame_editable(SCEditor *e,
                                              int top_frame_editable);
 extern void sc_editor_set_callbacks(SCEditor *e, SCCallbackList *cbl);
-extern void insert_scblock(SCBlock *scblock, SCEditor *e);
 extern void sc_editor_delete_selected_frame(SCEditor *e);
 extern void sc_editor_remove_cursor(SCEditor *e);
+extern SCBlock *split_paragraph_at_cursor(SCEditor *e);
 
 #endif	/* SC_EDITOR_H */
diff --git a/src/sc_interp.c b/src/sc_interp.c
index 9899a95..993cb9e 100644
--- a/src/sc_interp.c
+++ b/src/sc_interp.c
@@ -216,7 +216,7 @@ static void do_callback(SCInterpreter *scin, SCBlock *bl, const char *name)
 		if ( strcmp(cbl->names[i], name) != 0 ) continue;
 		r = cbl->box_funcs[i](scin, bl, &w, &h, &bvp, cbl->vps[i]);
 		if ( !r ) return;
-		add_callback_para(sc_interp_get_frame(scin), w, h,
+		add_callback_para(sc_interp_get_frame(scin), bl, w, h,
 		                  cbl->draw_funcs[i], cbl->click_funcs[i],
 		                  bvp, cbl->vps[i]);
 
@@ -262,6 +262,21 @@ int sc_interp_get_height(SCInterpreter *scin)
 }
 
 
+static void set_frame_default_style(struct frame *fr, SCInterpreter *scin)
+{
+	if ( fr == NULL ) return;
+
+	if ( fr->fontdesc != NULL ) {
+		pango_font_description_free(fr->fontdesc);
+	}
+	fr->fontdesc = pango_font_description_copy(sc_interp_get_fontdesc(scin));
+	fr->col[0] = sc_interp_get_fgcol(scin)[0];
+	fr->col[1] = sc_interp_get_fgcol(scin)[1];
+	fr->col[2] = sc_interp_get_fgcol(scin)[2];
+	fr->col[3] = sc_interp_get_fgcol(scin)[3];
+}
+
+
 static void update_font(SCInterpreter *scin)
 {
 	PangoFontMetrics *metrics;
@@ -279,6 +294,7 @@ static void update_font(SCInterpreter *scin)
 	st->ascent = pango_font_metrics_get_ascent(metrics);
 	st->height = st->ascent + pango_font_metrics_get_descent(metrics);
 	pango_font_metrics_unref(metrics);
+	set_frame_default_style(sc_interp_get_frame(scin), scin);
 }
 
 
@@ -380,6 +396,7 @@ static void set_colour(SCInterpreter *scin, const char *colour)
 	st->col[1] = col.green;
 	st->col[2] = col.blue;
 	st->col[3] = col.alpha;
+	set_frame_default_style(sc_interp_get_frame(scin), scin);
 }
 
 
@@ -545,6 +562,7 @@ SCInterpreter *sc_interp_new(PangoContext *pc, PangoLanguage *lang,
 		return NULL;
 	}
 	st->macro_contents = NULL;
+	st->fr = NULL;
 
 	scin->lang = lang;
 
@@ -883,7 +901,7 @@ static int check_outputs(SCBlock *bl, SCInterpreter *scin)
 		if ( parse_image_options(options, sc_interp_get_frame(scin),
 		                         &w, &h, &filename) == 0 )
 		{
-			add_image_para(sc_interp_get_frame(scin),
+			add_image_para(sc_interp_get_frame(scin), bl,
 			               filename, w, h, 1);
 			free(filename);
 		} else {
@@ -907,11 +925,7 @@ static int check_outputs(SCBlock *bl, SCInterpreter *scin)
 			return 1;
 		}
 
-		fr->fontdesc = pango_font_description_copy(sc_interp_get_fontdesc(scin));
-		fr->col[0] = sc_interp_get_fgcol(scin)[0];
-		fr->col[1] = sc_interp_get_fgcol(scin)[1];
-		fr->col[2] = sc_interp_get_fgcol(scin)[2];
-		fr->col[3] = sc_interp_get_fgcol(scin)[3];
+		set_frame_default_style(fr, scin);
 
 		parse_frame_options(fr, sc_interp_get_frame(scin),
 			            options);
diff --git a/src/sc_parse.c b/src/sc_parse.c
index 95b5c76..c8eea6f 100644
--- a/src/sc_parse.c
+++ b/src/sc_parse.c
@@ -41,7 +41,6 @@ struct _scblock
 	char *contents;
 
 	SCBlock *next;
-	SCBlock *prev;
 	SCBlock *child;
 };
 
@@ -103,11 +102,9 @@ SCBlock *sc_block_append(SCBlock *bl, char *name, char *opt, char *contents,
 	bln->child = NULL;
 	bln->next = NULL;
 
-	if ( bl == NULL ) {
-		bln->prev = NULL;
-	} else {
+	if ( bl != NULL ) {
+		bln->next = bl->next;
 		bl->next = bln;
-		bln->prev = bl;
 	}
 
 	if ( (blfp != NULL) && (*blfp == NULL) ) {
@@ -128,6 +125,7 @@ SCBlock *sc_block_append_end(SCBlock *bl, char *name, char *opt, char *contents)
 	if ( bln == NULL ) return NULL;
 
 	while ( bl->next != NULL ) {
+		bln->next = bl->next;
 		bl = bl->next;
 	};
 
@@ -162,11 +160,6 @@ SCBlock *sc_block_append_inside(SCBlock *parent,
 	bln->child = NULL;
 	bln->next = NULL;
 
-	if ( bl == NULL ) {
-		bln->prev = NULL;
-	} else {
-		bln->prev = bl;
-	}
 	*ptr = bln;
 
 	return bln;
@@ -668,3 +661,34 @@ SCBlock *sc_block_copy(const SCBlock *bl)
 
 	return first_copy;
 }
+
+
+static char *s_strdup(const char *a)
+{
+	if ( a == NULL ) return NULL;
+	return strdup(a);
+}
+
+
+SCBlock *sc_block_split(SCBlock *bl, size_t pos)
+{
+	SCBlock *n = sc_block_new();
+
+	if ( bl->child != NULL ) {
+		fprintf(stderr, "Splitting a block with a child!\n");
+		return NULL;
+	}
+
+	/* Second block */
+	n->name = s_strdup(bl->name);
+	n->options = s_strdup(bl->options);
+	n->contents = strdup(bl->contents+pos);
+
+	/* Truncate the first block */
+	bl->contents[pos] = '\0';
+
+	n->next = bl->next;
+	bl->next = n;
+
+	return n;
+}
diff --git a/src/sc_parse.h b/src/sc_parse.h
index 94bab30..dad797b 100644
--- a/src/sc_parse.h
+++ b/src/sc_parse.h
@@ -1,7 +1,7 @@
 /*
  * sc_parse.h
  *
- * Copyright © 2013-2015 Thomas White <taw@bitwiz.org.uk>
+ * Copyright © 2013-2016 Thomas White <taw@bitwiz.org.uk>
  *
  * This file is part of Colloquium.
  *
@@ -66,6 +66,7 @@ extern void sc_block_set_contents(SCBlock *bl, char *con);
 extern void sc_insert_text(SCBlock *b1, size_t o1, const char *t);
 extern void sc_insert_block(SCBlock *b1, int o1, SCBlock *ins);
 extern void sc_delete_text(SCBlock *b1, int o1, SCBlock *b2, int o2);
+extern SCBlock *sc_block_split(SCBlock *bl, size_t pos);
 
 extern void show_sc_blocks(const SCBlock *bl);
 extern void show_sc_block(const SCBlock *bl, const char *prefix);
diff --git a/src/slide_window.c b/src/slide_window.c
index b232e58..659c0bd 100644
--- a/src/slide_window.c
+++ b/src/slide_window.c
@@ -533,6 +533,7 @@ SlideWindow *slide_window_open(struct presentation *p, SCBlock *scblocks)
 	SlideWindow *sw;
 	SCBlock *stylesheets[2];
 	GtkWidget *image;
+	SCBlock *ch;
 
 	sw = calloc(1, sizeof(SlideWindow));
 	if ( sw == NULL ) return NULL;
@@ -610,7 +611,13 @@ SlideWindow *slide_window_open(struct presentation *p, SCBlock *scblocks)
 	                               "win.last");
 	stylesheets[0] = p->stylesheet;
 	stylesheets[1] = NULL;
-	sw->sceditor = sc_editor_new(sc_block_child(scblocks), stylesheets, p->lang);
+
+	ch = sc_block_child(scblocks);
+	if ( ch == NULL ) {
+		ch = sc_block_append_inside(scblocks, NULL, NULL, "");
+	}
+
+	sw->sceditor = sc_editor_new(ch, stylesheets, p->lang);
 	scroll = gtk_scrolled_window_new(NULL, NULL);
 	gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll),
 	                               GTK_POLICY_AUTOMATIC,