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/* Pango
* glyphstring.c:
*
* Copyright (C) 1999 Red Hat Software
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <glib.h>
#include "pango-glyph.h"
#include "pango-font.h"
#include "pango-impl-utils.h"
/**
* pango_glyph_string_new:
*
* Create a new #PangoGlyphString.
*
* Return value: the newly allocated #PangoGlyphString, which
* should be freed with pango_glyph_string_free().
*/
PangoGlyphString *
pango_glyph_string_new (void)
{
PangoGlyphString *string = g_slice_new (PangoGlyphString);
string->num_glyphs = 0;
string->space = 0;
string->glyphs = NULL;
string->log_clusters = NULL;
return string;
}
/**
* pango_glyph_string_set_size:
* @string: a #PangoGlyphString.
* @new_len: the new length of the string.
*
* Resize a glyph string to the given length.
*/
void
pango_glyph_string_set_size (PangoGlyphString *string, gint new_len)
{
g_return_if_fail (new_len >= 0);
while (new_len > string->space)
{
if (string->space == 0)
{
string->space = 4;
}
else
{
const guint max_space =
MIN (G_MAXINT, G_MAXSIZE / MAX (sizeof(PangoGlyphInfo), sizeof(gint)));
guint more_space = (guint)string->space * 2;
if (more_space > max_space)
{
more_space = max_space;
if ((guint)new_len > max_space)
{
g_error ("%s: failed to allocate glyph string of length %i\n",
G_STRLOC, new_len);
}
}
string->space = more_space;
}
}
string->glyphs = g_realloc (string->glyphs, string->space * sizeof (PangoGlyphInfo));
string->log_clusters = g_realloc (string->log_clusters, string->space * sizeof (gint));
string->num_glyphs = new_len;
}
G_DEFINE_BOXED_TYPE (PangoGlyphString, pango_glyph_string,
pango_glyph_string_copy,
pango_glyph_string_free);
/**
* pango_glyph_string_copy:
* @string: (nullable): a #PangoGlyphString, may be %NULL
*
* Copy a glyph string and associated storage.
*
* Return value: (nullable): the newly allocated #PangoGlyphString,
* which should be freed with pango_glyph_string_free(),
* or %NULL if @string was %NULL.
*/
PangoGlyphString *
pango_glyph_string_copy (PangoGlyphString *string)
{
PangoGlyphString *new_string;
if (string == NULL)
return NULL;
new_string = g_slice_new (PangoGlyphString);
*new_string = *string;
new_string->glyphs = g_memdup (string->glyphs,
string->space * sizeof (PangoGlyphInfo));
new_string->log_clusters = g_memdup (string->log_clusters,
string->space * sizeof (gint));
return new_string;
}
/**
* pango_glyph_string_free:
* @string: (nullable): a #PangoGlyphString, may be %NULL
*
* Free a glyph string and associated storage.
*/
void
pango_glyph_string_free (PangoGlyphString *string)
{
if (string == NULL)
return;
g_free (string->glyphs);
g_free (string->log_clusters);
g_slice_free (PangoGlyphString, string);
}
/**
* pango_glyph_string_extents_range:
* @glyphs: a #PangoGlyphString
* @start: start index
* @end: end index (the range is the set of bytes with
indices such that start <= index < end)
* @font: a #PangoFont
* @ink_rect: (out caller-allocates) (optional): rectangle used to
* store the extents of the glyph string range as drawn or
* %NULL to indicate that the result is not needed.
* @logical_rect: (out caller-allocates) (optional): rectangle used to
* store the logical extents of the glyph string range or
* %NULL to indicate that the result is not needed.
*
* Computes the extents of a sub-portion of a glyph string. The extents are
* relative to the start of the glyph string range (the origin of their
* coordinate system is at the start of the range, not at the start of the entire
* glyph string).
**/
void
pango_glyph_string_extents_range (PangoGlyphString *glyphs,
int start,
int end,
PangoFont *font,
PangoRectangle *ink_rect,
PangoRectangle *logical_rect)
{
int x_pos = 0;
int i;
/* Note that the handling of empty rectangles for ink
* and logical rectangles is different. A zero-height ink
* rectangle makes no contribution to the overall ink rect,
* while a zero-height logical rect still reserves horizontal
* width. Also, we may return zero-width, positive height
* logical rectangles, while we'll never do that for the
* ink rect.
*/
g_return_if_fail (start <= end);
if (G_UNLIKELY (!ink_rect && !logical_rect))
return;
if (ink_rect)
{
ink_rect->x = 0;
ink_rect->y = 0;
ink_rect->width = 0;
ink_rect->height = 0;
}
if (logical_rect)
{
logical_rect->x = 0;
logical_rect->y = 0;
logical_rect->width = 0;
logical_rect->height = 0;
}
for (i = start; i < end; i++)
{
PangoRectangle glyph_ink;
PangoRectangle glyph_logical;
PangoGlyphGeometry *geometry = &glyphs->glyphs[i].geometry;
pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph,
ink_rect ? &glyph_ink : NULL,
logical_rect ? &glyph_logical : NULL);
if (ink_rect && glyph_ink.width != 0 && glyph_ink.height != 0)
{
if (ink_rect->width == 0 || ink_rect->height == 0)
{
ink_rect->x = x_pos + glyph_ink.x + geometry->x_offset;
ink_rect->width = glyph_ink.width;
ink_rect->y = glyph_ink.y + geometry->y_offset;
ink_rect->height = glyph_ink.height;
}
else
{
int new_x, new_y;
new_x = MIN (ink_rect->x, x_pos + glyph_ink.x + geometry->x_offset);
ink_rect->width = MAX (ink_rect->x + ink_rect->width,
x_pos + glyph_ink.x + glyph_ink.width + geometry->x_offset) - new_x;
ink_rect->x = new_x;
new_y = MIN (ink_rect->y, glyph_ink.y + geometry->y_offset);
ink_rect->height = MAX (ink_rect->y + ink_rect->height,
glyph_ink.y + glyph_ink.height + geometry->y_offset) - new_y;
ink_rect->y = new_y;
}
}
if (logical_rect)
{
logical_rect->width += geometry->width;
if (i == start)
{
logical_rect->y = glyph_logical.y;
logical_rect->height = glyph_logical.height;
}
else
{
int new_y = MIN (logical_rect->y, glyph_logical.y);
logical_rect->height = MAX (logical_rect->y + logical_rect->height,
glyph_logical.y + glyph_logical.height) - new_y;
logical_rect->y = new_y;
}
}
x_pos += geometry->width;
}
}
/**
* pango_glyph_string_extents:
* @glyphs: a #PangoGlyphString
* @font: a #PangoFont
* @ink_rect: (out) (allow-none): rectangle used to store the extents of the glyph string
* as drawn or %NULL to indicate that the result is not needed.
* @logical_rect: (out) (allow-none): rectangle used to store the logical extents of the
* glyph string or %NULL to indicate that the result is not needed.
*
* Compute the logical and ink extents of a glyph string. See the documentation
* for pango_font_get_glyph_extents() for details about the interpretation
* of the rectangles.
*/
void
pango_glyph_string_extents (PangoGlyphString *glyphs,
PangoFont *font,
PangoRectangle *ink_rect,
PangoRectangle *logical_rect)
{
pango_glyph_string_extents_range (glyphs, 0, glyphs->num_glyphs,
font, ink_rect, logical_rect);
}
/**
* pango_glyph_string_get_width:
* @glyphs: a #PangoGlyphString
*
* Computes the logical width of the glyph string as can also be computed
* using pango_glyph_string_extents(). However, since this only computes the
* width, it's much faster. This is in fact only a convenience function that
* computes the sum of geometry.width for each glyph in the @glyphs.
*
* Return value: the logical width of the glyph string.
*
* Since: 1.14
*/
int
pango_glyph_string_get_width (PangoGlyphString *glyphs)
{
int i;
int width = 0;
for (i = 0; i < glyphs->num_glyphs; i++)
width += glyphs->glyphs[i].geometry.width;
return width;
}
/**
* pango_glyph_string_get_logical_widths:
* @glyphs: a #PangoGlyphString
* @text: the text corresponding to the glyphs
* @length: the length of @text, in bytes
* @embedding_level: the embedding level of the string
* @logical_widths: (array): an array whose length is the number of
* characters in text (equal to g_utf8_strlen (text,
* length) unless text has NUL bytes) to be filled in
* with the resulting character widths.
*
* Given a #PangoGlyphString resulting from pango_shape() and the corresponding
* text, determine the screen width corresponding to each character. When
* multiple characters compose a single cluster, the width of the entire
* cluster is divided equally among the characters.
*
* See also pango_glyph_item_get_logical_widths().
**/
void
pango_glyph_string_get_logical_widths (PangoGlyphString *glyphs,
const char *text,
int length,
int embedding_level,
int *logical_widths)
{
/* Build a PangoGlyphItem and call the other API */
PangoItem item = {0, length, pango_utf8_strlen (text, length),
{NULL, NULL, NULL,
embedding_level, PANGO_GRAVITY_AUTO, 0,
PANGO_SCRIPT_UNKNOWN, NULL,
NULL}};
PangoGlyphItem glyph_item = {&item, glyphs};
pango_glyph_item_get_logical_widths (&glyph_item, text, logical_widths);
}
/* The initial implementation here is script independent,
* but it might actually need to be virtualized into the
* rendering modules. Otherwise, we probably will end up
* enforcing unnatural cursor behavior for some languages.
*
* The only distinction that Uniscript makes is whether
* cursor positioning is allowed within clusters or not.
*/
/**
* pango_glyph_string_index_to_x:
* @glyphs: the glyphs return from pango_shape()
* @text: the text for the run
* @length: the number of bytes (not characters) in @text.
* @analysis: the analysis information return from pango_itemize()
* @index_: the byte index within @text
* @trailing: whether we should compute the result for the beginning (%FALSE)
* or end (%TRUE) of the character.
* @x_pos: (out): location to store result
*
* Converts from character position to x position. (X position
* is measured from the left edge of the run). Character positions
* are computed by dividing up each cluster into equal portions.
*/
void
pango_glyph_string_index_to_x (PangoGlyphString *glyphs,
char *text,
int length,
PangoAnalysis *analysis,
int index,
gboolean trailing,
int *x_pos)
{
int i;
int start_xpos = 0;
int end_xpos = 0;
int width = 0;
int start_index = -1;
int end_index = -1;
int cluster_chars = 0;
int cluster_offset = 0;
char *p;
g_return_if_fail (glyphs != NULL);
g_return_if_fail (length >= 0);
g_return_if_fail (length == 0 || text != NULL);
if (!x_pos) /* Allow the user to do the useless */
return;
if (glyphs->num_glyphs == 0)
{
*x_pos = 0;
return;
}
/* Calculate the starting and ending character positions
* and x positions for the cluster
*/
if (analysis->level % 2) /* Right to left */
{
for (i = glyphs->num_glyphs - 1; i >= 0; i--)
width += glyphs->glyphs[i].geometry.width;
for (i = glyphs->num_glyphs - 1; i >= 0; i--)
{
if (glyphs->log_clusters[i] > index)
{
end_index = glyphs->log_clusters[i];
end_xpos = width;
break;
}
if (glyphs->log_clusters[i] != start_index)
{
start_index = glyphs->log_clusters[i];
start_xpos = width;
}
width -= glyphs->glyphs[i].geometry.width;
}
}
else /* Left to right */
{
for (i = 0; i < glyphs->num_glyphs; i++)
{
if (glyphs->log_clusters[i] > index)
{
end_index = glyphs->log_clusters[i];
end_xpos = width;
break;
}
if (glyphs->log_clusters[i] != start_index)
{
start_index = glyphs->log_clusters[i];
start_xpos = width;
}
width += glyphs->glyphs[i].geometry.width;
}
}
if (end_index == -1)
{
end_index = length;
end_xpos = (analysis->level % 2) ? 0 : width;
}
/* Calculate offset of character within cluster */
p = text + start_index;
while (p < text + end_index)
{
if (p < text + index)
cluster_offset++;
cluster_chars++;
p = g_utf8_next_char (p);
}
if (trailing)
cluster_offset += 1;
if (G_UNLIKELY (!cluster_chars)) /* pedantic */
{
*x_pos = start_xpos;
return;
}
*x_pos = ((cluster_chars - cluster_offset) * start_xpos +
cluster_offset * end_xpos) / cluster_chars;
}
/**
* pango_glyph_string_x_to_index:
* @glyphs: the glyphs returned from pango_shape()
* @text: the text for the run
* @length: the number of bytes (not characters) in text.
* @analysis: the analysis information return from pango_itemize()
* @x_pos: the x offset (in Pango units)
* @index_: (out): location to store calculated byte index within @text
* @trailing: (out): location to store a boolean indicating
* whether the user clicked on the leading or trailing
* edge of the character.
*
* Convert from x offset to character position. Character positions
* are computed by dividing up each cluster into equal portions.
* In scripts where positioning within a cluster is not allowed
* (such as Thai), the returned value may not be a valid cursor
* position; the caller must combine the result with the logical
* attributes for the text to compute the valid cursor position.
*/
void
pango_glyph_string_x_to_index (PangoGlyphString *glyphs,
char *text,
int length,
PangoAnalysis *analysis,
int x_pos,
int *index,
gboolean *trailing)
{
int i;
int start_xpos = 0;
int end_xpos = 0;
int width = 0;
int start_index = -1;
int end_index = -1;
int cluster_chars = 0;
char *p;
gboolean found = FALSE;
/* Find the cluster containing the position */
width = 0;
if (analysis->level % 2) /* Right to left */
{
for (i = glyphs->num_glyphs - 1; i >= 0; i--)
width += glyphs->glyphs[i].geometry.width;
for (i = glyphs->num_glyphs - 1; i >= 0; i--)
{
if (glyphs->log_clusters[i] != start_index)
{
if (found)
{
end_index = glyphs->log_clusters[i];
end_xpos = width;
break;
}
else
{
start_index = glyphs->log_clusters[i];
start_xpos = width;
}
}
width -= glyphs->glyphs[i].geometry.width;
if (width <= x_pos && x_pos < width + glyphs->glyphs[i].geometry.width)
found = TRUE;
}
}
else /* Left to right */
{
for (i = 0; i < glyphs->num_glyphs; i++)
{
if (glyphs->log_clusters[i] != start_index)
{
if (found)
{
end_index = glyphs->log_clusters[i];
end_xpos = width;
break;
}
else
{
start_index = glyphs->log_clusters[i];
start_xpos = width;
}
}
if (width <= x_pos && x_pos < width + glyphs->glyphs[i].geometry.width)
found = TRUE;
width += glyphs->glyphs[i].geometry.width;
}
}
if (end_index == -1)
{
end_index = length;
end_xpos = (analysis->level % 2) ? 0 : width;
}
/* Calculate number of chars within cluster */
p = text + start_index;
while (p < text + end_index)
{
p = g_utf8_next_char (p);
cluster_chars++;
}
if (start_xpos == end_xpos)
{
if (index)
*index = start_index;
if (trailing)
*trailing = FALSE;
}
else
{
double cp = ((double)(x_pos - start_xpos) * cluster_chars) / (end_xpos - start_xpos);
/* LTR and right-to-left have to be handled separately
* here because of the edge condition when we are exactly
* at a pixel boundary; end_xpos goes with the next
* character for LTR, with the previous character for RTL.
*/
if (start_xpos < end_xpos) /* Left-to-right */
{
if (index)
{
char *p = text + start_index;
int i = 0;
while (i + 1 <= cp)
{
p = g_utf8_next_char (p);
i++;
}
*index = (p - text);
}
if (trailing)
*trailing = (cp - (int)cp >= 0.5) ? TRUE : FALSE;
}
else /* Right-to-left */
{
if (index)
{
char *p = text + start_index;
int i = 0;
while (i + 1 < cp)
{
p = g_utf8_next_char (p);
i++;
}
*index = (p - text);
}
if (trailing)
{
double cp_flip = cluster_chars - cp;
*trailing = (cp_flip - (int)cp_flip >= 0.5) ? FALSE : TRUE;
}
}
}
}
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