Make behavior of horizontal scrolling configurable

Requested by bill lam.

diff --git a/NEWS b/NEWS
index e52130cb340ed738a176dfd289c5ce7674cc1b79..7bd288942eaa18190c09080e604ed0fa1e4e7f6b 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,9 @@ Improvements:
  - Colors for 256-capable terminals can be specified as colorN.
  - Entering a number in the prompt will jump to that line number.
  - Handle core.worktree by setting GIT_DIR and GIT_WORK_TREE.
+ - Make behavior of horizontal scrolling configurable by setting the
+   'horizontal-scroll' variable to a number or a percentage. Defaults to
+   scrolling 50% of the view width.
 
 Bug fixes:
 

diff --git a/tig.c b/tig.c
index 2b2607bdc9828f6ba4a13db944d78c50e50214c0..705e3ddbe5e96b91eb16b28c5d7848f82b60bfa9 100644 (file)
--- a/tig.c
+++ b/tig.c
@@ -109,7 +109,6 @@ static size_t utf8_length(const char **string, size_t col, int *width, size_t ma
 
 /* The default interval between line numbers. */
 #define NUMBER_INTERVAL        5
-#define SCROLL_INTERVAL        1
 
 #define TAB_SIZE       8
 
@@ -863,6 +862,7 @@ static bool opt_line_graphics               = TRUE;
 static bool opt_rev_graph              = FALSE;
 static bool opt_show_refs              = TRUE;
 static int opt_num_interval            = NUMBER_INTERVAL;
+static double opt_hscroll              = 0.50;
 static int opt_tab_size                        = TAB_SIZE;
 static int opt_author_cols             = AUTHOR_COLS-1;
 static char opt_path[SIZEOF_STR]       = "";
@@ -1384,6 +1384,27 @@ static const struct enum_map attr_map[] = {
 
 #define set_attribute(attr, name)      map_enum(attr, attr_map, name)
 
+static int parse_step(double *opt, const char *arg)
+{
+       *opt = atoi(arg);
+       if (!strchr(arg, '%'))
+               return OK;
+
+       /* "Shift down" so 100% and 1 does not conflict. */
+       *opt = (*opt - 1) / 100;
+       if (*opt >= 1.0) {
+               *opt = 0.99;
+               config_msg = "Step value larger than 100%";
+               return ERR;
+       }
+       if (*opt < 0.0) {
+               *opt = 1;
+               config_msg = "Invalid step value";
+               return ERR;
+       }
+       return OK;
+}
+
 static int
 parse_int(int *opt, const char *arg, int min, int max)
 {
@@ -1513,6 +1534,9 @@ option_set_command(int argc, const char *argv[])
        if (!strcmp(argv[0], "author-width"))
                return parse_int(&opt_author_cols, argv[2], 0, 1024);
 
+       if (!strcmp(argv[0], "horizontal-scroll"))
+               return parse_step(&opt_hscroll, argv[2]);
+
        if (!strcmp(argv[0], "tab-size"))
                return parse_int(&opt_tab_size, argv[2], 1, 1024);
 
@@ -2285,6 +2309,15 @@ goto_view_line(struct view *view, unsigned long offset, unsigned long lineno)
        return FALSE;
 }
 
+static int
+apply_step(double step, int value)
+{
+       if (step >= 1)
+               return (int) step;
+       value *= step + 0.01;
+       return value ? value : 1;
+}
+
 /* Scrolling backend */
 static void
 do_scroll_view(struct view *view, int lines)
@@ -2346,10 +2379,10 @@ scroll_view(struct view *view, enum request request)
                        report("Cannot scroll beyond the first column");
                        return;
                }
-               if (view->yoffset <= SCROLL_INTERVAL)
+               if (view->yoffset <= apply_step(opt_hscroll, view->width))
                        view->yoffset = 0;
                else
-                       view->yoffset -= SCROLL_INTERVAL;
+                       view->yoffset -= apply_step(opt_hscroll, view->width);
                redraw_view_from(view, 0);
                report("");
                return;
@@ -2358,7 +2391,9 @@ scroll_view(struct view *view, enum request request)
                        report("Cannot scroll beyond the last column");
                        return;
                }
-               view->yoffset += SCROLL_INTERVAL;
+               view->yoffset += apply_step(opt_hscroll, view->width);
+               if (view->yoffset > view->width)
+                       view->yoffset = view->width;
                redraw_view(view);
                report("");
                return;

diff --git a/tigrc.5.txt b/tigrc.5.txt
index d0e8c9118cf07251cd71721c59e27911334f0e74..59149acf78bb3cd9e74e538af1eac00ec6678ecd 100644 (file)
--- a/tigrc.5.txt
+++ b/tigrc.5.txt
@@ -51,6 +51,7 @@ set show-refs = yes           # Show references?
 set show-line-numbers = no     # Show line numbers?
 set line-number-interval = 5   # Interval between line numbers
 set commit-encoding = "UTF-8"  # Commit encoding
+set horizontal-scroll = 33%    # Scroll 33% of the view width
 --------------------------------------------------------------------------
 
 Or in the git configuration files:
@@ -63,7 +64,7 @@ Or in the git configuration files:
        tab-size = 8            # Number of spaces per tab
 --------------------------------------------------------------------------
 
-The type of variables are either bool, int, and string.
+The type of variables are either bool, int, string, or mixed.
 
 Valid bool values::
 
@@ -78,6 +79,11 @@ Valid string values::
 
        A string of characters. Optionally, use either ' or " as delimiters.
 
+Valid mixed values::
+
+       These values are composites of the above types. The valid values are
+       specified in the description.
+
 Variables
 ~~~~~~~~~
 
@@ -111,6 +117,14 @@ The following variables can be set:
 
        Number of spaces per tab. The default is 8 spaces.
 
+'horizontal-scroll' (mixed)::
+
+       Interval to scroll horizontally in each step. Can be specified either
+       as the number of columns, e.g. '5', or as a percentage of the view
+       width, e.g. '33%', where the maximum is 100%. For percentages it is
+       always ensured that at least one column is scrolled. The default is to
+       scroll '50%' of the view width.
+
 'commit-encoding' (string)::
 
        The encoding used for commits. The default is UTF-8. Not this option