Commit 8a02ff62 authored by Eli Zaretskii's avatar Eli Zaretskii
Browse files

(set_cursor_from_row): Fix and improve comments.

parent bde79dc0
......@@ -12316,16 +12316,18 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
struct glyph *glyph = row->glyphs[TEXT_AREA];
struct glyph *end = glyph + row->used[TEXT_AREA];
struct glyph *cursor = NULL;
/* The first glyph that starts a sequence of glyphs from string. */
/* The first glyph that starts a sequence of glyphs from a string
that is a value of a display property. */
struct glyph *string_start;
/* The X coordinate of string_start. */
int string_start_x;
/* The last known character position. */
/* The last known character position in row. */
int last_pos = MATRIX_ROW_START_CHARPOS (row) + delta;
/* The last known character position before string_start. */
int string_before_pos;
int x = row->x;
int cursor_x = x;
/* Last buffer position covered by an overlay. */
int cursor_from_overlay_pos = 0;
int pt_old = PT - delta;
......@@ -12353,11 +12355,15 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
string_start = NULL;
x += glyph->pixel_width;
++glyph;
/* If we are beyond the cursor position computed from the
last overlay seen, that overlay is not in effect for
current cursor position. Reset the cursor information
computed from that overlay. */
if (cursor_from_overlay_pos
&& last_pos >= cursor_from_overlay_pos)
{
cursor_from_overlay_pos = 0;
cursor = 0;
cursor = NULL;
}
}
else
......@@ -12368,7 +12374,7 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
string_start = glyph;
string_start_x = x;
}
/* Skip all glyphs from string. */
/* Skip all glyphs from a string. */
do
{
Lisp_Object cprop;
......@@ -12379,14 +12385,14 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
!NILP (cprop))
&& (pos = string_buffer_position (w, glyph->object,
string_before_pos),
(pos == 0 /* From overlay */
(pos == 0 /* from overlay */
|| pos == pt_old)))
{
/* Estimate overlay buffer position from the buffer
positions of the glyphs before and after the overlay.
Add 1 to last_pos so that if point corresponds to the
glyph right after the overlay, we still use a 'cursor'
property found in that overlay. */
/* Compute the first buffer position after the overlay.
If the `cursor' property tells us how many positions
are associated with the overlay, use that. Otherwise,
estimate from the buffer positions of the glyphs
before and after the overlay. */
cursor_from_overlay_pos = (pos ? 0 : last_pos
+ (INTEGERP (cprop) ? XINT (cprop) : 0));
cursor = glyph;
......@@ -12410,9 +12416,8 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
while (glyph > row->glyphs[TEXT_AREA]
&& (glyph - 1)->charpos == last_pos)
glyph--, x -= glyph->pixel_width;
/* That loop always goes one position too far,
including the glyph before the ellipsis.
So scan forward over that one. */
/* That loop always goes one position too far, including the
glyph before the ellipsis. So scan forward over that one. */
x += glyph->pixel_width;
glyph++;
}
......@@ -12433,8 +12438,8 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
x = string_start_x;
string = glyph->object;
pos = string_buffer_position (w, string, string_before_pos);
/* If STRING is from overlay, LAST_POS == 0. We skip such glyphs
because we always put cursor after overlay strings. */
/* If POS == 0, STRING is from overlay. We skip such glyphs
because we always put the cursor after overlay strings. */
while (pos == 0 && glyph < stop)
{
string = glyph->object;
......@@ -12461,8 +12466,8 @@ set_cursor_from_row (w, row, matrix, delta, delta_bytes, dy, dvpos)
}
}
/* If we reached the end of the line, and end was from a string,
cursor is not on this line. */
/* If we reached the end of the line, and END was from a string,
the cursor is not on this line. */
if (glyph == end && row->continued_p)
return 0;
}
......
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