Fix #631 crossing branch lines have the wrong color

doc/tigrc.5.adoc

@@ -460,8 +460,13 @@ author::
 	  sizing content, up to this limit.
 
 commit-title::
-	- 'graph' (mixed) [no|v2|v1]: Whether to show the revision graph in the
-	  main view on start-up. "v1" refers to the old graph rendering, which
+	- 'graph' (mixed) [no|v2|v2-horizontal-crossover|v1]:
+	  Whether to show the revision graph in the main view on start-up.
+	  "v2" refers to the newer graph rendering where a vertical path is placed over a horizontal path,
+	  but the horizontal path is miscolored.
+	  "v2-horizontal-crossover" refers to the newer graph rendering where a horizontal path is placed over a vertical path,
+	  and the horizontal path is correctly colored.
+	  "v1" refers to the old graph rendering, which
 	  is less accurate but faster and thus recommended in large
 	  repositories.  See also the 'line-graphics' options.
 	- 'refs' (bool): Whether to show references (branches, tags, and

include/tig/types.h

@@ -82,6 +82,7 @@ bool map_enum_do(const struct enum_map_entry *map, size_t map_size, int *value,
 #define GRAPH_DISPLAY_ENUM(_) \
 	_(GRAPH_DISPLAY, NO), \
 	_(GRAPH_DISPLAY, V2), \
+	_(GRAPH_DISPLAY, V2_HORIZONTAL_CROSSOVER), \
 	_(GRAPH_DISPLAY, V1)
 
 #define DATE_ENUM(_) \

src/graph-v2.c

@@ -695,7 +695,6 @@ graph_generate_symbols(struct graph_v2 *graph, struct graph_canvas *canvas)
 	for (pos = 0; pos < row->size; pos++) {
 		struct graph_column *column = &row->columns[pos];
 		struct graph_symbol *symbol = &column->symbol;
-		const char *id = next_row->columns[pos].id;
 
 		symbol->commit            = (pos == graph->position);
 		symbol->boundary          = (pos == graph->position && next_row->columns[pos].symbol.boundary);
@@ -723,10 +722,8 @@ graph_generate_symbols(struct graph_v2 *graph, struct graph_canvas *canvas)
 		symbol->new_column        = new_column(row, prev_row, pos);
 		symbol->empty             = (!graph_column_has_commit(&row->columns[pos]));
 
-		if (graph_column_has_commit(column)) {
-			id = column->id;
-		}
-		symbol->color = get_color(graph, id);
+		// Do initial assignment of symbol colors
+		symbol->color = get_color(graph, column->id ? column->id : next_row->columns[pos].id);
 
 		graph_canvas_append_symbol(graph, canvas, symbol);
 	}
@@ -1085,6 +1082,15 @@ graph_symbol_to_utf8(const struct graph_symbol *symbol)
 	return "  ";
 }
 
+static const char *
+graph_symbol_to_utf8_horiz(const struct graph_symbol *symbol)
+{
+	return
+	  graph_symbol_cross_over(symbol)           ? "──"
+	: graph_symbol_turn_down_cross_over(symbol) ? " ╭"
+	: graph_symbol_to_utf8(symbol);
+}
+
 static const chtype *
 graph_symbol_to_chtype(const struct graph_symbol *symbol)
 {
@@ -1156,6 +1162,16 @@ graph_symbol_to_chtype(const struct graph_symbol *symbol)
 	return graphics;
 }
 
+static const chtype *
+graph_symbol_to_chtype_horiz(const struct graph_symbol *symbol)
+{
+	static chtype graphics[2];
+	return
+	  graph_symbol_cross_over(symbol)           ? (graphics[0] = ACS_HLINE, graphics[1] = ACS_HLINE,    graphics)
+	: graph_symbol_turn_down_cross_over(symbol) ? (graphics[0] = ' ',       graphics[1] = ACS_ULCORNER, graphics)
+	: graph_symbol_to_chtype(symbol);
+}
+
 static const char *
 graph_symbol_to_ascii(const struct graph_symbol *symbol)
 {
@@ -1208,6 +1224,33 @@ graph_symbol_to_ascii(const struct graph_symbol *symbol)
 	return "  ";
 }
 
+static const char *
+graph_symbol_to_ascii_horiz(const struct graph_symbol *symbol)
+{
+	return
+	  graph_symbol_cross_over(symbol)           ? "--"
+	: graph_symbol_turn_down_cross_over(symbol) ? " ."
+	: graph_symbol_to_ascii(symbol);
+}
+
+/* Re-color the symbols array of the given graph_canvas
+ * so that horizontal cross-over symbols are properly colored
+ */
+static void
+graph_symbol_recolor(const struct graph_canvas *canvas)
+{
+	struct graph_symbol *sy = &canvas->symbols[canvas->size - 1];
+	size_t merge_c = 0;
+	int i;
+
+	for (i = canvas->size - 1; i >= 0; i--, sy--) {
+		if (graph_symbol_merge(sy) || graph_symbol_turn_left(sy))
+			if (!merge_c) merge_c = sy->color;
+		if (graph_symbol_cross_over(sy))
+			sy->color = merge_c;
+	}
+}
+
 static void
 graph_foreach_symbol(const struct graph *graph, const struct graph_canvas *canvas,
 		     graph_symbol_iterator_fn fn, void *data)
@@ -1223,8 +1266,16 @@ graph_foreach_symbol(const struct graph *graph, const struct graph_canvas *canva
 	}
 }
 
+static void
+graph_foreach_symbol_horiz(const struct graph *graph, const struct graph_canvas *canvas,
+		     graph_symbol_iterator_fn fn, void *data)
+{
+	graph_symbol_recolor(canvas);
+	graph_foreach_symbol(graph, canvas, fn, data);
+}
+
 struct graph *
-init_graph_v2(void)
+init_graph_v2(bool crossover)
 {
 	struct graph_v2 *graph = calloc(1, sizeof(*graph));
 	struct graph *api;
@@ -1240,10 +1291,10 @@ init_graph_v2(void)
 	api->add_parent = graph_add_parent;
 	api->is_merge = graph_is_merge;
 	api->render_parents = graph_render_parents;
-	api->foreach_symbol = graph_foreach_symbol;
-	api->symbol_to_ascii = graph_symbol_to_ascii;
-	api->symbol_to_utf8 = graph_symbol_to_utf8;
-	api->symbol_to_chtype = graph_symbol_to_chtype;
+	api->foreach_symbol   = crossover ? graph_foreach_symbol_horiz   : graph_foreach_symbol   ;
+	api->symbol_to_ascii  = crossover ? graph_symbol_to_ascii_horiz  : graph_symbol_to_ascii  ;
+	api->symbol_to_utf8   = crossover ? graph_symbol_to_utf8_horiz   : graph_symbol_to_utf8   ;
+	api->symbol_to_chtype = crossover ? graph_symbol_to_chtype_horiz : graph_symbol_to_chtype ;
 
 	return api;
 }

src/graph.c

@@ -15,15 +15,17 @@
 #include "tig/graph.h"
 
 struct graph *init_graph_v1(void);
-struct graph *init_graph_v2(void);
+struct graph *init_graph_v2(bool);
 
 struct graph *
 init_graph(enum graph_display display)
 {
 	if (display == GRAPH_DISPLAY_V1)
 		return init_graph_v1();
 	if (display == GRAPH_DISPLAY_V2)
-		return init_graph_v2();
+		return init_graph_v2(false);
+	if (display == GRAPH_DISPLAY_V2_HORIZONTAL_CROSSOVER)
+		return init_graph_v2(true);
 	return NULL;
 }
 

test/main/default-test

@@ -22,6 +22,7 @@ steps '
 	:save-display main-no-refs.screen
 	:toggle commit-title-graph
 	:toggle commit-title-graph
+	:toggle commit-title-graph
 	:save-display main-no-graph.screen
 
 	:957f2b368e6fa5c0757f36b1441e32729ee5e9c7