Currently, when we display a merge whose first parent is already present
in a column to the left of the merge commit, we display the first parent
as a vertical pipe `|` in the GRAPH_POST_MERGE line and then immediately
enter the GRAPH_COLLAPSING state. The first-parent line tracks to the
left and all the other parent lines follow it; this creates a "kink" in
those lines:
| *---.
| |\ \ \
|/ / / /
| | | *
This change tidies the display of such commits such that if the first
parent appears to the left of the merge, we render it as a `/` and the
second parent as a `|`. This reduces the horizontal and vertical space
needed to render the merge, and makes the resulting lines easier to
read.
| *-.
|/|\ \
| | | *
If the first parent is separated from the merge by several columns, a
horizontal line is drawn in a similar manner to how the GRAPH_COLLAPSING
state displays the line.
| | | *-.
| |_|/|\ \
|/| | | | *
This effect is applied to both "normal" two-parent merges, and to
octopus merges. It also reduces the vertical space needed for pre-commit
lines, as the merge occupies one less column than usual.
Before: After:
| * | *
| |\ | |\
| | \ | * \
| | \ |/|\ \
| *-. \
| |\ \ \
Signed-off-by: James Coglan <jcoglan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The commits following this one introduce a series of improvements to the
layout of graphs, tidying up a few edge cases, namely:
- merge whose first parent fuses with an existing column to the left
- merge whose last parent fuses with its immediate neighbor on the right
- edges that collapse to the left above and below a commit line
This test case exemplifies these cases and provides a motivating example
of the kind of history I'm aiming to clear up.
The first parent of merge E is the same as the parent of H, so those
edges fuse together.
* H
|
| *-. E
| |\ \
|/ / /
|
* B
We can "skew" the display of this merge so that it doesn't introduce
additional columns that immediately collapse:
* H
|
| * E
|/|\
|
* B
The last parent of E is D, the same as the parent of F which is the edge
to the right of the merge.
* F
|
\
*-. \ E
|\ \ \
/ / / /
| /
|/
* D
The two edges leading to D could be fused sooner: rather than expanding
the F edge around the merge and then letting the edges collapse, the F
edge could fuse with the E edge in the post-merge line:
* F
|
\
*-. | E
|\ \|
/ / /
|
* D
If this is combined with the "skew" effect above, we get a much cleaner
graph display for these edges:
* F
|
* | E
/|\|
|
* D
Finally, the edge leading from C to A appears jagged as it passes
through the commit line for B:
| * | C
| |/
* | B
|/
* A
This can be smoothed out so that such edges are easier to read:
| * | C
| |/
* / B
|/
* A
Signed-off-by: James Coglan <jcoglan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
