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authorMatthias Clasen <mclasen@redhat.com>2021-11-28 18:40:14 -0500
committerMatthias Clasen <mclasen@redhat.com>2021-11-29 08:12:11 -0500
commita6ed4ff80188bb0472891b08c421d3ca4c846315 (patch)
tree0161a56184dba742bb7f5b7bdc22cebed27d1ef2 /pango/pango-layout.c
parent60ae4ac4cf481e49f5ccbc4c97c95bb961620d61 (diff)
downloadpango-a6ed4ff80188bb0472891b08c421d3ca4c846315.tar.gz
layout: Implement tab alignments
Implement the other tab alignments by adjusting the tab width as we go. Based on an old patch by Itai Bar-Haim. This also includes a fix for the previously supported left tab alignment in the presence of indent. Fixes: #34
Diffstat (limited to 'pango/pango-layout.c')
-rw-r--r--pango/pango-layout.c258
1 files changed, 201 insertions, 57 deletions
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index ebdea36a..743f5d09 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -3262,6 +3262,7 @@ pango_layout_line_leaked (PangoLayoutLine *line)
*****************/
static void shape_tab (PangoLayoutLine *line,
+ ParaBreakState *state,
PangoItem *item,
PangoGlyphString *glyphs);
@@ -3367,54 +3368,54 @@ ensure_tab_width (PangoLayout *layout)
}
}
-/* For now we only need the tab position, we assume
- * all tabs are left-aligned.
- */
-static int
-get_tab_pos (PangoLayout *layout,
- int index,
- gboolean *is_default)
+static void
+get_tab_pos (PangoLayoutLine *line,
+ int index,
+ int *tab_pos,
+ PangoTabAlign *alignment,
+ gboolean *is_default)
{
- gint n_tabs;
+ PangoLayout *layout = line->layout;
+ int n_tabs;
gboolean in_pixels;
+ int offset = 0;
+
+ if (layout->alignment != PANGO_ALIGN_CENTER)
+ {
+ if (line->is_paragraph_start && layout->indent >= 0)
+ offset = layout->indent;
+ else if (!line->is_paragraph_start && layout->indent < 0)
+ offset = - layout->indent;
+ }
if (layout->tabs)
{
n_tabs = pango_tab_array_get_size (layout->tabs);
in_pixels = pango_tab_array_get_positions_in_pixels (layout->tabs);
- if (is_default)
- *is_default = FALSE;
+ *is_default = FALSE;
}
else
{
n_tabs = 0;
in_pixels = FALSE;
- if (is_default)
- *is_default = TRUE;
+ *is_default = TRUE;
}
if (index < n_tabs)
{
- gint pos = 0;
-
- pango_tab_array_get_tab (layout->tabs, index, NULL, &pos);
+ pango_tab_array_get_tab (layout->tabs, index, alignment, tab_pos);
if (in_pixels)
- return pos * PANGO_SCALE;
- else
- return pos;
+ *tab_pos *= PANGO_SCALE;
}
-
- if (n_tabs > 0)
+ else if (n_tabs > 0)
{
- /* Extrapolate tab position, repeating the last tab gap to
- * infinity.
- */
+ /* Extrapolate tab position, repeating the last tab gap to infinity. */
int last_pos = 0;
int next_to_last_pos = 0;
int tab_width;
- pango_tab_array_get_tab (layout->tabs, n_tabs - 1, NULL, &last_pos);
+ pango_tab_array_get_tab (layout->tabs, n_tabs - 1, alignment, &last_pos);
if (n_tabs > 1)
pango_tab_array_get_tab (layout->tabs, n_tabs - 2, NULL, &next_to_last_pos);
@@ -3428,22 +3429,19 @@ get_tab_pos (PangoLayout *layout,
}
if (last_pos > next_to_last_pos)
- {
- tab_width = last_pos - next_to_last_pos;
- }
+ tab_width = last_pos - next_to_last_pos;
else
- {
- tab_width = layout->tab_width;
- }
+ tab_width = layout->tab_width;
- return last_pos + tab_width * (index - n_tabs + 1);
+ *tab_pos = last_pos + tab_width * (index - n_tabs + 1);
}
else
{
- /* No tab array set, so use default tab width
- */
- return layout->tab_width * index;
+ /* No tab array set, so use default tab width */
+ *tab_pos = layout->tab_width * index;
}
+
+ *tab_pos -= offset;
}
static int
@@ -3460,7 +3458,7 @@ line_width (PangoLayoutLine *line)
{
PangoLayoutRun *run = l->data;
- for (i=0; i < run->glyphs->num_glyphs; i++)
+ for (i = 0; i < run->glyphs->num_glyphs; i++)
width += run->glyphs->glyphs[i].geometry.width;
}
@@ -3484,14 +3482,24 @@ showing_space (const PangoAnalysis *analysis)
return FALSE;
}
+static void break_state_set_last_tab (ParaBreakState *state,
+ PangoGlyphString *glyphs,
+ int width,
+ int tab_pos,
+ PangoTabAlign tab_align);
+
static void
shape_tab (PangoLayoutLine *line,
+ ParaBreakState *state,
PangoItem *item,
PangoGlyphString *glyphs)
{
int i, space_width;
+ int current_width;
+ int tab_pos;
+ PangoTabAlign tab_align;
- int current_width = line_width (line);
+ current_width = line_width (line);
pango_glyph_string_set_size (glyphs, 1);
@@ -3499,6 +3507,7 @@ shape_tab (PangoLayoutLine *line,
glyphs->glyphs[0].glyph = PANGO_GET_UNKNOWN_GLYPH ('\t');
else
glyphs->glyphs[0].glyph = PANGO_GLYPH_EMPTY;
+
glyphs->glyphs[0].geometry.x_offset = 0;
glyphs->glyphs[0].geometry.y_offset = 0;
glyphs->glyphs[0].attr.is_cluster_start = 1;
@@ -3509,22 +3518,28 @@ shape_tab (PangoLayoutLine *line,
ensure_tab_width (line->layout);
space_width = line->layout->tab_width / 8;
- for (i=0;;i++)
+ for (i = 0; ; i++)
{
gboolean is_default;
- int tab_pos = get_tab_pos (line->layout, i, &is_default);
+
+ get_tab_pos (line, i, &tab_pos, &tab_align, &is_default);
+
/* Make sure there is at least a space-width of space between
- * tab-aligned text and the text before it. However, only do
+ * tab-aligned text and the text before it. However, only do
* this if no tab array is set on the layout, ie. using default
- * tab positions. If use has set tab positions, respect it to
- * the pixel.
+ * tab positions. If the user has set tab positions, respect it
+ * to the pixel.
*/
if (tab_pos >= current_width + (is_default ? space_width : 1))
{
glyphs->glyphs[0].geometry.width = tab_pos - current_width;
+ g_debug ("shape_tab: tab %d, align %d, width %d\n",
+ i, tab_align, glyphs->glyphs[0].geometry.width);
break;
}
}
+
+ break_state_set_last_tab (state, glyphs, current_width, tab_pos, tab_align);
}
static inline gboolean
@@ -3608,12 +3623,65 @@ struct _ParaBreakState
int hyphen_width; /* How much space a hyphen will take */
GList *baseline_shifts;
+
+ PangoGlyphString *last_tab;
+ int last_tab_width;
+ int last_tab_pos;
+ PangoTabAlign last_tab_align;
};
+static void
+break_state_set_last_tab (ParaBreakState *state,
+ PangoGlyphString *glyphs,
+ int width,
+ int tab_pos,
+ PangoTabAlign tab_align)
+{
+
+ state->last_tab = glyphs;
+ state->last_tab_width = width;
+ state->last_tab_pos = tab_pos;
+ state->last_tab_align = tab_align;
+}
+
static gboolean
should_ellipsize_current_line (PangoLayout *layout,
ParaBreakState *state);
+static void
+get_decimal_prefix_width (PangoItem *item,
+ PangoGlyphString *glyphs,
+ const char *text,
+ int *width,
+ gboolean *found)
+{
+ PangoGlyphItem glyph_item = { item, glyphs, 0, 0, 0 };
+ int *log_widths;
+ int i;
+ const char *p;
+
+ log_widths = g_new (int, item->num_chars);
+
+ pango_glyph_item_get_logical_widths (&glyph_item, text, log_widths);
+
+ *width = 0;
+ *found = FALSE;
+
+ for (i = 0, p = text + item->offset; i < item->num_chars; i++, p = g_utf8_next_char (p))
+ {
+ if (g_utf8_get_char (p) == '.')
+ {
+ *width += log_widths[i] / 2;
+ *found = TRUE;
+ break;
+ }
+
+ *width += log_widths[i];
+ }
+
+ g_free (log_widths);
+}
+
static PangoGlyphString *
shape_run (PangoLayoutLine *line,
ParaBreakState *state,
@@ -3623,7 +3691,7 @@ shape_run (PangoLayoutLine *line,
PangoGlyphString *glyphs = pango_glyph_string_new ();
if (layout->text[item->offset] == '\t')
- shape_tab (line, item, glyphs);
+ shape_tab (line, state, item, glyphs);
else
{
PangoShapeFlags shape_flags = PANGO_SHAPE_NONE;
@@ -3661,6 +3729,33 @@ shape_run (PangoLayoutLine *line,
glyphs->glyphs[0].geometry.x_offset += space_left;
glyphs->glyphs[glyphs->num_glyphs - 1].geometry.width += space_right;
}
+
+ if (state->last_tab != NULL)
+ {
+ int w;
+
+ g_assert (state->last_tab->num_glyphs == 1);
+
+ /* Update the width of the current tab to position this run properly */
+
+ w = state->last_tab_pos - state->last_tab_width;
+
+ if (state->last_tab_align == PANGO_TAB_RIGHT)
+ w -= pango_glyph_string_get_width (glyphs);
+ else if (state->last_tab_align == PANGO_TAB_CENTER)
+ w -= pango_glyph_string_get_width (glyphs) / 2;
+ else if (state->last_tab_align == PANGO_TAB_DECIMAL)
+ {
+ int width;
+ gboolean found;
+
+ get_decimal_prefix_width (item, glyphs, layout->text, &width, &found);
+
+ w -= width;
+ }
+
+ state->last_tab->glyphs[0].geometry.width = MAX (w, 0);
+ }
}
return glyphs;
@@ -3681,19 +3776,45 @@ insert_run (PangoLayoutLine *line,
run->glyphs = glyphs;
else if (last_run && state->log_widths_offset == 0 &&
!(run_item->analysis.flags & PANGO_ANALYSIS_FLAG_NEED_HYPHEN))
- run->glyphs = state->glyphs;
+ {
+ run->glyphs = state->glyphs;
+ state->glyphs = NULL;
+ }
else
run->glyphs = shape_run (line, state, run_item);
- if (last_run)
+ if (last_run && state->glyphs)
{
- if (state->log_widths_offset > 0)
- pango_glyph_string_free (state->glyphs);
+ pango_glyph_string_free (state->glyphs);
state->glyphs = NULL;
}
line->runs = g_slist_prepend (line->runs, run);
line->length += run_item->length;
+
+ if (state->last_tab && run->glyphs != state->last_tab)
+ {
+ /* Adjust the tab position so placing further runs will continue to
+ * maintain the tab placement. In the case of decimal tabs, we are
+ * done once we've placed the run with the decimal point.
+ */
+
+ if (state->last_tab_align == PANGO_TAB_RIGHT)
+ state->last_tab_width += pango_glyph_string_get_width (run->glyphs);
+ else if (state->last_tab_align == PANGO_TAB_CENTER)
+ state->last_tab_width += pango_glyph_string_get_width (run->glyphs) / 2;
+ else if (state->last_tab_align == PANGO_TAB_DECIMAL)
+ {
+ int width;
+ gboolean found;
+
+ get_decimal_prefix_width (run->item, run->glyphs, line->layout->text, &width, &found);
+
+ state->last_tab_width += width;
+ if (found)
+ state->last_tab = NULL;
+ }
+ }
}
static gboolean
@@ -3801,6 +3922,15 @@ compute_log_widths (PangoLayout *layout,
pango_glyph_item_get_logical_widths (&glyph_item, layout->text, state->log_widths);
}
+static int
+tab_width_change (ParaBreakState *state)
+{
+ if (state->last_tab)
+ return state->last_tab->glyphs[0].geometry.width - (state->last_tab_pos - state->last_tab_width);
+
+ return 0;
+}
+
/* Tries to insert as much as possible of the item at the head of
* state->items onto @line. Five results are possible:
*
@@ -3916,7 +4046,6 @@ process_item (PangoLayout *layout,
if (state->remaining_width < 0 && !no_break_at_end) /* Wrapping off */
{
insert_run (line, state, item, NULL, TRUE);
-
DEBUG1 ("no wrapping, all-fit");
return BREAK_ALL_FIT;
}
@@ -3932,6 +4061,16 @@ process_item (PangoLayout *layout,
width += state->log_widths[state->log_widths_offset + i];
}
+ if (layout->text[item->offset] == '\t')
+ {
+ insert_run (line, state, item, NULL, TRUE);
+ state->remaining_width -= width;
+ state->remaining_width = MAX (state->remaining_width, 0);
+
+ DEBUG1 ("tab run, all-fit");
+ return BREAK_ALL_FIT;
+ }
+
if (!no_break_at_end &&
can_break_at (layout, state->start_offset + item->num_chars, wrap))
{
@@ -3946,31 +4085,32 @@ process_item (PangoLayout *layout,
else
extra_width = 0;
- if ((width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs)) &&
+ if ((width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs) ||
+ (state->last_tab && state->last_tab_align != PANGO_TAB_LEFT)) &&
!no_break_at_end)
{
+ PangoGlyphString *glyphs;
+
DEBUG1 ("%d + %d <= %d", width, extra_width, state->remaining_width);
- insert_run (line, state, item, NULL, FALSE);
+ glyphs = shape_run (line, state, item);
- width = pango_glyph_string_get_width (((PangoGlyphItem *)(line->runs->data))->glyphs);
+ width = pango_glyph_string_get_width (glyphs) + tab_width_change (state);
if (width + extra_width <= state->remaining_width || (item->num_chars == 1 && !line->runs))
{
+ insert_run (line, state, item, glyphs, TRUE);
+
state->remaining_width -= width;
state->remaining_width = MAX (state->remaining_width, 0);
- /* We passed last_run == FALSE to insert_run, so it did not do this */
- pango_glyph_string_free (state->glyphs);
- state->glyphs = NULL;
-
DEBUG1 ("early accept '%.*s', all-fit, remaining %d",
item->length, layout->text + item->offset,
state->remaining_width);
return BREAK_ALL_FIT;
}
- /* if it doesn't fit after shaping, revert and proceed to break the item */
- uninsert_run (line);
+ /* if it doesn't fit after shaping, discard and proceed to break the item */
+ pango_glyph_string_free (glyphs);
}
/*** From here on, we look for a way to break item ***/
@@ -4055,7 +4195,7 @@ retry_break:
glyphs = shape_run (line, state, new_item);
- new_break_width = pango_glyph_string_get_width (glyphs);
+ new_break_width = pango_glyph_string_get_width (glyphs) + tab_width_change (state);
if (num_chars > 0 &&
layout->log_attrs[state->start_offset + num_chars - 1].is_white)
@@ -4316,6 +4456,10 @@ process_line (PangoLayout *layout,
state->remaining_width = -1;
else
state->remaining_width = state->line_width;
+
+ state->last_tab = NULL;
+ state->last_tab_align = PANGO_TAB_LEFT;
+
DEBUG ("starting to fill line", line, state);
while (state->items)