[PATCH] Add "open Tex source file" support for evince

[Dongsheng Xing <homer xing yahoo com>]

Hello, everybody

The following patch add "open Tex source file" support for evince. It means that, if some person compiles a LaTeX source file by 
"latex --src-specials main.tex"
and she starts evince by 
"evince --editor='gedit +%l %f' main.dvi",
then when she double-clicked a characters in the page, "gedit" will open "main.tex" and jumps to the corresponding place.

This feature is also called "Inverse search", which is a feature of xdvi. See also http://xdvi.sourceforge.net/inverse-search.html

This patch is upon the svn trunk revision 3613.

Cheers,
Homer

Index: backend/dvi/dvi-document.c
===================================================================
--- backend/dvi/dvi-document.c	(revision 3613)
+++ backend/dvi/dvi-document.c	(working copy)
@@ -253,6 +253,102 @@
 	return info;
 }
 
+static void 
+dvi_open_tex_source (EvDocument *document,
+					int                  page, 
+					double               x,
+					double               y,
+					const gchar          *tex_editor)
+{
+	DviDocument *dvi_document = DVI_DOCUMENT (document);
+	DviContext *dvi = dvi_document->context;
+	DviTeXSrc *p, *found;
+	double dist, dist2;
+	GString *cmd_str;
+	gchar *cmd;
+	gint argc;
+	gchar **argv;
+	gboolean retval = FALSE;
+	GError *error = NULL;
+	const gchar *c;
+	gchar *path;
+	gchar *file;
+
+	if (!dvi->src)
+		return;
+
+	p = dvi->src;
+	found = dvi->src;
+
+	while (p) {
+		if (p->page < page)
+			found = p;
+		else if (p->page == page && p->y < y)
+			found = p;
+		else
+			break;
+		p = p->next;
+	}
+
+	dist = y - found->y;
+	p = found->next;
+	if (p) {
+		dist2 = p->y + (p->page - page - y);
+		if (dist2 < dist)
+			found = p;
+	}
+
+	cmd_str = g_string_new ("");
+	c = tex_editor;
+	while (*c) {
+		if (*c != '%')
+			g_string_append_c (cmd_str, *c);
+		else
+			switch (*(++c)) {
+				case '%':
+					g_string_append_c (cmd_str, '%');
+					break;
+				case 'l':
+					g_string_append_printf (cmd_str, "%d", found->line);
+					break;
+				case 'f':
+					if (found->source[0] == '/')
+						g_string_append (cmd_str, found->source);
+					else {
+						path = g_strdup (dvi_document->uri);
+						* (strrchr (path, '/')+1) = 0;
+						file = strrchr (found->source, '/');
+						if (!file)
+							file = found->source;
+						else
+							file++;
+						g_string_append (cmd_str, path);
+						g_string_append (cmd_str, file);
+						g_free(path);
+					}
+			}
+		c++;
+	}
+
+	cmd = g_string_free (cmd_str, FALSE);
+	g_shell_parse_argv (cmd, &argc, &argv, &error);
+	g_free (cmd);
+	
+	if (!error) {
+		retval = gdk_spawn_on_screen (gdk_screen_get_default (),
+					      NULL, argv, NULL,
+					      G_SPAWN_SEARCH_PATH,
+					      NULL, NULL, NULL,
+					      &error);
+		g_strfreev (argv);
+	}
+
+	if (error) {
+		g_warning ("Error launching '%s': %s\n", tex_editor, error->message);
+		g_error_free (error);
+	}
+}
+
 static void
 dvi_document_document_iface_init (EvDocumentIface *iface)
 {
@@ -262,6 +358,7 @@
 	iface->get_page_size = dvi_document_get_page_size;
 	iface->render = dvi_document_render;
 	iface->get_info = dvi_document_get_info;
+	iface->open_tex_source = dvi_open_tex_source;
 }
 
 static void
Index: backend/dvi/mdvi-lib/dviread.c
===================================================================
--- backend/dvi/mdvi-lib/dviread.c	(revision 3613)
+++ backend/dvi/mdvi-lib/dviread.c	(working copy)
@@ -911,6 +911,19 @@
 
 void	mdvi_destroy_context(DviContext *dvi)
 {
+	if(dvi->lasth) {
+		free(dvi->lasth);
+		free(dvi->lastv);
+	}
+	if(dvi->src) {
+		DviTeXSrc *p = dvi->src, *next;
+		do{
+			next = p->next;
+			free(p->source);
+			free(p);
+			p = next;
+		}while(p);
+	}
 	if(dvi->device.dev_destroy)
 		dvi->device.dev_destroy(dvi->device.device_data);
 	/* release all fonts */
Index: backend/dvi/mdvi-lib/mdvi.h
===================================================================
--- backend/dvi/mdvi-lib/mdvi.h	(revision 3613)
+++ backend/dvi/mdvi-lib/mdvi.h	(working copy)
@@ -38,6 +38,7 @@
 typedef struct _DviPageSpec *DviPageSpec;
 typedef struct _DviParams DviParams;
 typedef struct _DviBuffer DviBuffer;
+typedef struct _DviTeXSrc DviTeXSrc;
 typedef struct _DviContext DviContext;
 typedef struct _DviRange DviRange;
 typedef struct _DviColorPair DviColorPair;
@@ -357,7 +358,19 @@
 	Ulong	bg;
 };
 
+struct _DviTeXSrc {
+	char *source; /* TeX source */
+	int line; /* line number in TeX source */
+	int page; /* page number in DVI */
+	double x; /* horizontal position, 0~1 */
+	double y; /* vertical position, 0~1 */
+	struct _DviTeXSrc *next;
+};
+
 struct _DviContext {
+	int *lastv; /* last TeX src v position in a certain page */
+	int *lasth; /* last TeX src h position in a certain page */
+	struct _DviTeXSrc *src; /* linked list */
 	char	*filename;	/* name of the DVI file */
 	FILE	*in;		/* from here we read */
 	char	*fileid;	/* from preamble */
Index: backend/dvi/mdvi-lib/special.c
===================================================================
--- backend/dvi/mdvi-lib/special.c	(revision 3613)
+++ backend/dvi/mdvi-lib/special.c	(working copy)
@@ -46,6 +46,7 @@
 	void x __PROTO((DviContext *, const char *, const char *))
 
 static SPECIAL(sp_layer);
+static SPECIAL(sp_tex_src_special);
 extern SPECIAL(epsf_special);
 extern SPECIAL(do_color_special);
 
@@ -56,6 +57,7 @@
 	DviSpecialHandler handler;
 } builtins[] = {
 	{"Layers", "layer", NULL, sp_layer},
+	{"TexSource", "src", NULL, sp_tex_src_special},
 	{"EPSF", "psfile", NULL, epsf_special}
 };
 #define NSPECIALS	(sizeof(builtins) / sizeof(builtins[0]))
@@ -247,3 +249,80 @@
 	DEBUG((DBG_SPECIAL, "Layer level: %d\n", dvi->curr_layer));
 }
 
+static int compare(DviTeXSrc *a, DviTeXSrc *b)
+{
+	if (a->page < b->page)
+		return -1;
+	if (a->page > b->page)
+		return 1;
+	if (a->y < b->y)
+		return -1;
+	if (a->y > b->y)
+		return 1;
+	if (a->x < b->x)
+		return -1;
+	if (a->x > b->x)
+		return 1;
+	return 0;
+}
+
+static void insert(DviContext *dvi, char *source, int line, int page, double x, double y)
+{
+	DviTeXSrc *a = (DviTeXSrc *)malloc(sizeof(DviTeXSrc)), *p;
+	a->source = source;
+	a->line = line;
+	a->page = page;
+	a->x = x;
+	a->y = y;
+	a->next = 0;
+	if (dvi->src == 0){
+		dvi->src = a;
+	} else if (compare(a, dvi->src) < 0) {
+		a->next = dvi->src;
+		dvi->src = a;
+	} else {
+		p = dvi->src;
+		while (p->next) {
+			if (compare(a, p->next) < 0)
+				break;
+			p = p->next;
+		}
+		a->next = p->next;
+		p->next = a;
+	}
+}
+
+static int caninsert(DviContext *dvi, int page, int v, int h)
+{
+	if(!dvi->lastv){
+		dvi->lastv = (int *)malloc(sizeof(int) * dvi->npages);
+		memset(dvi->lastv, 0, sizeof(int) * dvi->npages);
+		dvi->lasth = (int *)malloc(sizeof(int) * dvi->npages);
+		memset(dvi->lasth, 0, sizeof(int) * dvi->npages);
+	}
+	if(v > dvi->lastv[dvi->currpage])
+		return 1;
+	if(v < dvi->lastv[dvi->currpage])
+		return 0;
+	if(h > dvi->lasth[dvi->currpage])
+		return 1;
+	return 0;
+}
+
+void	sp_tex_src_special(DviContext *dvi, const char *prefix, const char *arg)
+{
+	if(caninsert(dvi, dvi->currpage, dvi->pos.v, dvi->pos.h)){
+		double x = (double)(dvi->pos.h) / dvi->dvi_page_w;
+		double y = (double)(dvi->pos.v) / dvi->dvi_page_h;
+		int line = atoi(arg);
+		const char *source = arg;
+		while ('0' <= *source && *source <= '9')
+			source++;
+		source++;
+
+		insert(dvi, strdup (source), line, dvi->currpage, x, y);
+
+		dvi->lastv[dvi->currpage] = dvi->pos.v;
+		dvi->lasth[dvi->currpage] = dvi->pos.h;
+	}
+}
Index: libview/ev-view-private.h
===================================================================
--- libview/ev-view-private.h	(revision 3613)
+++ libview/ev-view-private.h	(working copy)
@@ -178,6 +178,8 @@
 	GtkWidget *goto_entry;
 
 	EvTransitionAnimation *animation;
+
+	gchar* tex_editor;
 };
 
 struct _EvViewClass {
Index: libview/ev-view.c
===================================================================
--- libview/ev-view.c	(revision 3613)
+++ libview/ev-view.c	(working copy)
@@ -133,6 +133,8 @@
 							      gint               *page,
 							      gint               *x_offset,
 							      gint               *y_offset);
+static int        find_page_contains                      (EvView             *view,
+							      EvPoint            *p);
 static gboolean  doc_point_to_view_point 		     (EvView             *view,
 				                              int                 page,
 							      EvPoint            *doc_point,
@@ -309,6 +311,9 @@
 static void       ev_view_presentation_transition_start      (EvView             *ev_view);
 static void       ev_view_presentation_transition_stop       (EvView             *ev_view);
 
+static void       ev_view_open_tex_source                  (EvView             *view,
+							     EvPoint        *p,
+							     int             page);
 
 G_DEFINE_TYPE (EvView, ev_view, GTK_TYPE_LAYOUT)
 
@@ -2634,7 +2639,19 @@
 			EvImage *image;
 			EvFormField *field;
 
-			if (EV_IS_SELECTION (view->document) && view->selection_info.selections) {
+			/* opens the corresponding TeX source */
+			if (event->type == GDK_2BUTTON_PRESS && 
+					ev_view_get_tex_editor(view) &&
+					(EV_DOCUMENT_GET_IFACE (view->document))->open_tex_source) {
+				EvPoint p;
+				int page;
+				p.x = event->x + view->scroll_x;
+				p.y = event->y + view->scroll_y;
+				if ((page = find_page_contains(view, &p)) != -1) {
+					ev_view_open_tex_source(view, &p, page);
+				}
+				return TRUE; /* Stop subsequence processing. */
+			}else if (EV_IS_SELECTION (view->document) && view->selection_info.selections) {
 				if (event->type == GDK_3BUTTON_PRESS) {
 					start_selection_for_event (view, event);
 				} else if (location_in_selected_text (view,
@@ -3735,6 +3752,11 @@
 {
 	EvView *view = EV_VIEW (object);
 
+	if (view->tex_editor) {
+		g_free (view->tex_editor);
+		view->tex_editor = NULL;
+	}
+
 	if (view->document) {
 		g_object_unref (view->document);
 		view->document = NULL;
@@ -4673,6 +4695,22 @@
 	return view->sizing_mode;
 }
 
+void
+ev_view_set_tex_editor (EvView *view, const gchar *tex_editor)
+{
+	g_return_if_fail (EV_IS_VIEW (view));
+
+	view->tex_editor = g_strdup(tex_editor);
+}
+
+const gchar*
+ev_view_get_tex_editor (EvView *view)
+{
+	g_return_val_if_fail (EV_IS_VIEW (view), 0);
+
+	return view->tex_editor;
+}
+
 gboolean
 ev_view_can_zoom_in (EvView *view)
 {
@@ -5209,6 +5247,56 @@
 		point->y < rectangle->y + rectangle->height;
 }
 
+static int
+find_page_contains (EvView  *view, EvPoint *p)
+{
+	int n_pages;
+	int start_page, end_page;
+	int i;
+	GdkRectangle page_area;
+	GtkBorder border;
+
+	n_pages = ev_page_cache_get_n_pages (view->page_cache);
+	if (view->continuous) {
+		start_page = 0;
+		end_page = n_pages;
+	} else if (view->dual_page) {
+		start_page = view->start_page;
+		end_page = view->end_page + 1;
+	} else {
+		start_page = view->current_page;
+		end_page = view->current_page + 1;
+	}
+
+	for (i = start_page; i < end_page; i++) {			
+		get_page_extents (view, i, &page_area, &border);
+		
+		if (page_area.x <= p->x &&
+			  page_area.y <= p->y &&
+			  p->x < page_area.x + page_area.width &&
+			  p->y < page_area.y + page_area.height)
+			return i;	
+	}
+
+	return -1;
+}
+
+static void 
+ev_view_open_tex_source(EvView *view, EvPoint *p, int page)
+{
+	GdkRectangle page_area;
+	GtkBorder border;
+
+	get_page_extents (view, page, &page_area, &border);
+	p->x = (p->x - page_area.x)/page_area.width;
+	p->y = (p->y - page_area.y)/page_area.height;
+	(EV_DOCUMENT_GET_IFACE (view->document))->open_tex_source(view->document,
+		page,
+		p->x,
+		p->y,
+		view->tex_editor);
+}
+
 static GList *
 compute_new_selection_text (EvView          *view,
 			    EvSelectionStyle style,
Index: libview/ev-view.h
===================================================================
--- libview/ev-view.h	(revision 3613)
+++ libview/ev-view.h	(working copy)
@@ -84,8 +84,10 @@
 void     	ev_view_set_sizing_mode	  (EvView         *view,
 					   EvSizingMode    mode);
 EvSizingMode	ev_view_get_sizing_mode	  (EvView         *view);
+void        ev_view_set_tex_editor	  (EvView         *view,
+					   const gchar *tex_editor);
+const gchar* ev_view_get_tex_editor	  (EvView         *view);
 
-
 /* Page size */
 gboolean	ev_view_can_zoom_in       (EvView         *view);
 void		ev_view_zoom_in		  (EvView         *view);
Index: libdocument/ev-document.h
===================================================================
--- libdocument/ev-document.h	(revision 3613)
+++ libdocument/ev-document.h	(working copy)
@@ -96,6 +96,11 @@
         cairo_surface_t * (* render)          (EvDocument      *document,
                                                EvRenderContext *rc);
         EvDocumentInfo *  (* get_info)        (EvDocument      *document);
+        void              (* open_tex_source) (EvDocument      *document,
+                                               int              page,
+                                               double           x,
+                                               double           y,
+                                               const gchar*     tex_editor);
 };
 
 GType            ev_document_get_type         (void) G_GNUC_CONST;
Index: shell/ev-application.c
===================================================================
--- shell/ev-application.c	(revision 3613)
+++ shell/ev-application.c	(working copy)
@@ -385,6 +385,18 @@
 	return value ? g_value_get_string (value) : NULL;
 }
 
+static const gchar *
+get_tex_editor_from_args (GHashTable *args)
+{
+	GValue *value = NULL;
+
+	g_assert (args != NULL);
+
+	value = g_hash_table_lookup (args, "tex_editor");
+
+	return value ? g_value_get_string (value) : NULL;
+}
+
 /**
  * ev_application_open_window:
  * @application: The instance of the application.
@@ -539,7 +551,7 @@
 		ev_stock_icons_add_icons_path_for_screen (screen);
 		gtk_window_set_screen (GTK_WINDOW (new_window), screen);
 	}
-
+	
 	/* We need to load uri before showing the window, so
 	   we can restore window size without flickering */	
 	ev_window_open_uri (new_window, uri, dest, mode, search_string);
@@ -581,14 +593,19 @@
 	EvWindowRunMode  mode = EV_WINDOW_MODE_NORMAL;
 	const gchar     *search_string = NULL;
 	GdkScreen       *screen = NULL;
+	const gchar     *tex_editor = NULL;
 
 	if (args) {
 		screen = get_screen_from_args (args);
 		dest = get_destination_from_args (args);
 		mode = get_window_run_mode_from_args (args);
 		search_string = get_find_string_from_args (args);
+		tex_editor = get_tex_editor_from_args (args);
 	}
-	
+
+	ev_metadata_manager_init();
+	ev_metadata_manager_set_string(uri, "tex_editor", tex_editor);
+
 	ev_application_open_uri_at_dest (application, uri, screen,
 					 dest, mode, search_string,
 					 timestamp);
Index: shell/ev-window.c
===================================================================
--- shell/ev-window.c	(revision 3613)
+++ shell/ev-window.c	(working copy)
@@ -1051,7 +1051,14 @@
 	GValue presentation = { 0, };
 	GValue fullscreen = { 0, };
 	GValue rotation = { 0, };
+	GValue tex_editor = { 0, };
 
+	/* TeX editor */
+	if (ev_metadata_manager_get (uri, "tex_editor", &tex_editor, FALSE)) {
+		ev_view_set_tex_editor (view, g_value_get_string(&tex_editor));
+		g_value_unset (&tex_editor);
+	}
+
 	/* Sizing mode */
 	if (ev_metadata_manager_get (uri, "sizing_mode", &sizing_mode, FALSE)) {
 		enum_value = g_enum_get_value_by_nick
@@ -1780,7 +1787,6 @@
 		    const gchar    *search_string)
 {
 	GFile *source_file;
-
 	ev_window->priv->in_reload = FALSE;
 	
 	if (ev_window->priv->uri &&
Index: shell/main.c
===================================================================
--- shell/main.c	(revision 3613)
+++ shell/main.c	(working copy)
@@ -49,6 +49,7 @@
 static gboolean presentation_mode = FALSE;
 static gboolean unlink_temp_file = FALSE;
 static gchar   *print_settings;
+static gchar   *tex_editor; 
 static const char **file_arguments = NULL;
 
 static gboolean
@@ -73,6 +74,7 @@
 	{ "unlink-tempfile", 'u', G_OPTION_FLAG_HIDDEN, G_OPTION_ARG_NONE, &unlink_temp_file, NULL, NULL },
 	{ "print-settings", 't', G_OPTION_FLAG_HIDDEN, G_OPTION_ARG_FILENAME, &print_settings, NULL, NULL },
 	{ "version", 0, G_OPTION_FLAG_NO_ARG | G_OPTION_FLAG_HIDDEN, G_OPTION_ARG_CALLBACK, option_version_cb, NULL, NULL },
+	{ "editor", 'e', 0, G_OPTION_ARG_STRING, &tex_editor, N_("A double-click in the evince window opens the corresponding TeX source"), N_("STRING")},
 	{ G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &file_arguments, NULL, N_("[FILE...]") },
 	{ NULL }
 };
@@ -210,6 +212,17 @@
 		ev_page_label = NULL;
 	}
 
+	if (tex_editor) {
+		value = g_new0 (GValue, 1);
+		g_value_init (value, G_TYPE_STRING);
+		g_value_set_string (value, tex_editor);
+
+		g_hash_table_insert (args, g_strdup ("tex_editor"), value);
+
+		g_free (tex_editor);
+		tex_editor = NULL;
+	}
+
 	if (fullscreen_mode)
 		mode = EV_WINDOW_MODE_FULLSCREEN;
 	else if (presentation_mode)