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Fix predict_text_width by using xcb_query_text_extents 

This fixes ticket #173, at least for the rendering errors.
I don’t really know why I implemented predict_text_width like it
was before (querying the whole table and pulling out information
one by one). Maybe I have overlooked xcb_query_text_extents. In
any case, it works better now.
This commit is contained in:
Michael Stapelberg 2010-03-10 23:27:24 +01:00
parent 593bff5ffd
commit a70f4353b7
1 changed files with 14 additions and 69 deletions
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83
src/xcb.c
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@ -294,85 +294,30 @@ void cached_pixmap_prepare(xcb_connection_t *conn, struct Cached_Pixmap *pixmap)
}
/*
* Returns the xcb_charinfo_t for the given character (specified by row and
* column in the lookup table) if existing, otherwise the minimum bounds.
*
*/
static xcb_charinfo_t *get_charinfo(int col, int row, xcb_query_font_reply_t *font_info,
xcb_charinfo_t *table, bool dont_fallback) {
xcb_charinfo_t *result;
/* Bounds checking */
if (row < font_info->min_byte1 || row > font_info->max_byte1 ||
col < font_info->min_char_or_byte2 || col > font_info->max_char_or_byte2)
return NULL;
/* If we don’t have a table to lookup the infos per character, return the
* minimum bounds */
if (table == NULL)
return &font_info->min_bounds;
result = &table[((row - font_info->min_byte1) *
(font_info->max_char_or_byte2 - font_info->min_char_or_byte2 + 1)) +
(col - font_info->min_char_or_byte2)];
/* If the character has an entry in the table, return it */
if (result->character_width != 0 ||
(result->right_side_bearing |
result->left_side_bearing |
result->ascent |
result->descent) != 0)
return result;
/* Otherwise, get the default character and return its charinfo */
if (dont_fallback)
return NULL;
return get_charinfo((font_info->default_char >> 8),
(font_info->default_char & 0xFF),
font_info,
table,
true);
}
/*
* Calculate the width of the given text (16-bit characters, UCS) with given
* real length (amount of glyphs) using the given font.
* Query the width of the given text (16-bit characters, UCS) with given real
* length (amount of glyphs) using the given font.
*
*/
int predict_text_width(xcb_connection_t *conn, const char *font_pattern, char *text, int length) {
xcb_query_font_reply_t *font_info;
xcb_charinfo_t *table;
xcb_generic_error_t *error;
int i, width = 0;
i3Font *font = load_font(conn, font_pattern);
font_info = xcb_query_font_reply(conn, xcb_query_font(conn, font->id), &error);
if (error != NULL) {
fprintf(stderr, "ERROR: query font (X error code %d)\n", error->error_code);
xcb_query_text_extents_cookie_t cookie;
xcb_query_text_extents_reply_t *reply;
xcb_generic_error_t *error;
int width;
cookie = xcb_query_text_extents(conn, font->id, length, (xcb_char2b_t*)text);
if ((reply = xcb_query_text_extents_reply(conn, cookie, &error)) == NULL) {
ELOG("Could not get text extents (X error code %d)\n",
error->error_code);
/* We return the rather safe guess of 7 pixels, because a
* rendering error is better than a crash. Plus, the user will
* see the error on his stderr. */
* see the error in his log. */
return 7;
}
/* If no per-char info is available for this font, we use the default */
if (xcb_query_font_char_infos_length(font_info) == 0) {
DLOG("Falling back on default char_width of %d pixels\n", font_info->max_bounds.character_width);
return (font_info->max_bounds.character_width * length);
}
table = xcb_query_font_char_infos(font_info);
for (i = 0; i < 2 * length; i += 2) {
xcb_charinfo_t *info = get_charinfo(text[i+1], text[i], font_info, table, false);
if (info == NULL)
continue;
width += info->character_width;
}
free(font_info);
width = reply->overall_width;
free(reply);
return width;
}