graph API: Use horizontal lines for more compact graphs

Use horizontal lines instead of long diagonal lines during the
collapsing state of graph rendering.  For example what used to be:

    | | | | |
    | | | |/
    | | |/|
    | |/| |
    |/| | |
    | | | |

is now

    | | | | |
    | |_|_|/
    |/| | |
    | | | |

This results in more compact and legible graphs.

Signed-off-by: Allan Caffee <allan.caffee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Allan Caffee 2009-04-21 08:47:01 -04:00 committed by Junio C Hamano
parent 66996ecc28
commit eaf158f8bd
2 changed files with 49 additions and 19 deletions

62
graph.c
View File

@ -47,20 +47,6 @@ static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
* - Limit the number of columns, similar to the way gitk does.
* If we reach more than a specified number of columns, omit
* sections of some columns.
*
* - The output during the GRAPH_PRE_COMMIT and GRAPH_COLLAPSING states
* could be made more compact by printing horizontal lines, instead of
* long diagonal lines. For example, during collapsing, something like
* this: instead of this:
* | | | | | | | | | |
* | |_|_|/ | | | |/
* |/| | | | | |/|
* | | | | | |/| |
* |/| | |
* | | | |
*
* If there are several parallel diagonal lines, they will need to be
* replaced with horizontal lines on subsequent rows.
*/
struct column {
@ -982,6 +968,9 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
{
int i;
int *tmp_mapping;
short used_horizontal = 0;
int horizontal_edge = -1;
int horizontal_edge_target = -1;
/*
* Clear out the new_mapping array
@ -1019,6 +1008,23 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
* Move to the left by one
*/
graph->new_mapping[i - 1] = target;
/*
* If there isn't already an edge moving horizontally
* select this one.
*/
if (horizontal_edge == -1) {
int j;
horizontal_edge = i;
horizontal_edge_target = target;
/*
* The variable target is the index of the graph
* column, and therefore target*2+3 is the
* actual screen column of the first horizontal
* line.
*/
for (j = (target * 2)+3; j < (i - 2); j += 2)
graph->new_mapping[j] = target;
}
} else if (graph->new_mapping[i - 1] == target) {
/*
* There is a branch line to our left
@ -1039,10 +1045,21 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
*
* The space just to the left of this
* branch should always be empty.
*
* The branch to the left of that space
* should be our eventual target.
*/
assert(graph->new_mapping[i - 1] > target);
assert(graph->new_mapping[i - 2] < 0);
assert(graph->new_mapping[i - 3] == target);
graph->new_mapping[i - 2] = target;
/*
* Mark this branch as the horizontal edge to
* prevent any other edges from moving
* horizontally.
*/
if (horizontal_edge == -1)
horizontal_edge = i;
}
}
@ -1061,8 +1078,23 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
strbuf_addch(sb, ' ');
else if (target * 2 == i)
strbuf_write_column(sb, &graph->new_columns[target], '|');
else
else if (target == horizontal_edge_target &&
i != horizontal_edge - 1) {
/*
* Set the mappings for all but the
* first segment to -1 so that they
* won't continue into the next line.
*/
if (i != (target * 2)+3)
graph->new_mapping[i] = -1;
used_horizontal = 1;
strbuf_write_column(sb, &graph->new_columns[target], '_');
} else {
if (used_horizontal && i < horizontal_edge)
graph->new_mapping[i] = -1;
strbuf_write_column(sb, &graph->new_columns[target], '/');
}
}
graph_pad_horizontally(graph, sb, graph->mapping_size);

View File

@ -298,14 +298,12 @@ cat > expect <<\EOF
* | | | Merge branch 'side'
|\ \ \ \
| * | | | side-2
| | | |/
| | |/|
| | |_|/
| |/| |
| * | | side-1
* | | | Second
* | | | sixth
| | |/
| |/|
| |_|/
|/| |
* | | fifth
* | | fourth