font.c

winNT技术操作系统,国外开放的原代码和LIUX一样

    if (len_ellipsis > max_len) len_ellipsis = max_len;
    if (*len_str > max_len - len_ellipsis)
        *len_str = max_len - len_ellipsis;

    /* First do a quick binary search to get an upper bound for *len_str. */
    if (*len_str > 0 &&
        GetTextExtentExPointW(hdc, str, *len_str, width, NULL, NULL, size) &&
        size->cx > width)
    {
        for (lo = 0, hi = *len_str; lo < hi; )
        {
            mid = (lo + hi) / 2;
            if (!GetTextExtentExPointW(hdc, str, mid, width, NULL, NULL, size))
                break;
            if (size->cx > width)
                hi = mid;
            else
                lo = mid + 1;
        }
        *len_str = hi;
    }
    /* Now this should take only a couple iterations at most. */
    for ( ; ; )
    {
        wcsncpy (str + *len_str, ELLIPSISW, len_ellipsis);

        if (!GetTextExtentExPointW (hdc, str, *len_str + len_ellipsis, width,
                                    NULL, NULL, size)) break;

        if (!*len_str || size->cx <= width) break;

        (*len_str)--;
    }
    *len_ellip = len_ellipsis;
    *len_before = *len_str;
    *len_str += len_ellipsis;

    if (modstr)
    {
        wcsncpy (modstr, str, *len_str);
        *(str+*len_str) = '\0';
    }
}

/*********************************************************************
 *                      TEXT_PathEllipsify (static)
 *
 * Add an ellipsis to the provided string in order to make it fit within
 * the width.  The ellipsis is added as specified for the DT_PATH_ELLIPSIS
 * flag.
 *
 * See Also TEXT_Ellipsify
 *
 * Arguments
 *   hdc        [in] The handle to the DC that defines the font.
 *   str        [in/out] The string that needs to be modified
 *   max_str    [in] The dimension of str (number of WCHAR).
 *   len_str    [in/out] The number of characters in str
 *   width      [in] The maximum width permitted (in logical coordinates)
 *   size       [out] The dimensions of the text
 *   modstr     [out] The modified form of the string, to be returned to the
 *                    calling program.  It is assumed that the caller has
 *                    made sufficient space available so we don't need to
 *                    know the size of the space.  This pointer may be NULL if
 *                    the modified string is not required.
 *   pellip     [out] The ellipsification results
 *
 * For now we will simply use three dots rather than worrying about whether
 * the font contains an explicit ellipsis character.
 *
 * The following applies, I think to Win95.  We will need to extend it for
 * Win98 which can have both path and end ellipsis at the same time (e.g.
 *  C:\MyLongFileName.Txt becomes ...\MyLongFileN...)
 *
 * The resulting string consists of as much as possible of the following:
 * 1. The ellipsis itself
 * 2. The last \ or / of the string (if any)
 * 3. Everything after the last \ or / of the string (if any) or the whole
 *    string if there is no / or \.  I believe that under Win95 this would
 *    include everything even though some might be clipped off the end whereas
 *    under Win98 that might be ellipsified too.
 *    Yet to be investigated is whether this would include wordbreaking if the
 *    filename is more than 1 word and splitting if DT_EDITCONTROL was in
 *    effect.  (If DT_EDITCONTROL is in effect then on occasions text will be
 *    broken within words).
 * 4. All the stuff before the / or \, which is placed before the ellipsis.
 */
static void TEXT_PathEllipsify (HDC hdc, WCHAR *str, unsigned int max_len,
                                unsigned int *len_str, int width, SIZE *size,
                                WCHAR *modstr, ellipsis_data *pellip)
{
    unsigned int len_ellipsis;
    int len_trailing;
    int len_under;
    WCHAR *lastBkSlash, *lastFwdSlash, *lastSlash;

    len_ellipsis = wcslen (ELLIPSISW);
    if (!max_len) return;
    if (len_ellipsis >= max_len) len_ellipsis = max_len - 1;
    if (*len_str + len_ellipsis >= max_len)
        *len_str = max_len - len_ellipsis-1;
        /* Hopefully this will never happen, otherwise it would probably lose
         * the wrong character
         */
    str[*len_str] = '\0'; /* to simplify things */

    lastBkSlash  = wcsrchr (str, BACK_SLASH);
    lastFwdSlash = wcsrchr (str, FORWARD_SLASH);
    lastSlash = lastBkSlash > lastFwdSlash ? lastBkSlash : lastFwdSlash;
    if (!lastSlash) lastSlash = str;
    len_trailing = *len_str - (lastSlash - str);

    /* overlap-safe movement to the right */
    memmove (lastSlash+len_ellipsis, lastSlash, len_trailing * sizeof(WCHAR));
    wcsncpy (lastSlash, ELLIPSISW, len_ellipsis);
    len_trailing += len_ellipsis;
    /* From this point on lastSlash actually points to the ellipsis in front
     * of the last slash and len_trailing includes the ellipsis
     */

    len_under = 0;
    for ( ; ; )
    {
        if (!GetTextExtentExPointW (hdc, str, *len_str + len_ellipsis, width,
                                    NULL, NULL, size)) break;

        if (lastSlash == str || size->cx <= width) break;

        /* overlap-safe movement to the left */
        memmove (lastSlash-1, lastSlash, len_trailing * sizeof(WCHAR));
        lastSlash--;
        len_under++;

        assert (*len_str);
        (*len_str)--;
    }
    pellip->before = lastSlash-str;
    pellip->len = len_ellipsis;
    pellip->under = len_under;
    pellip->after = len_trailing - len_ellipsis;
    *len_str += len_ellipsis;

    if (modstr)
    {
        wcsncpy (modstr, str, *len_str);
        *(str+*len_str) = '\0';
    }
}

/*********************************************************************
 *                      TEXT_WordBreak (static)
 *
 *  Perform wordbreak processing on the given string
 *
 * Assumes that DT_WORDBREAK has been specified and not all the characters
 * fit.  Note that this function should even be called when the first character
 * that doesn't fit is known to be a space or tab, so that it can swallow them.
 *
 * Note that the Windows processing has some strange properties.
 * 1. If the text is left-justified and there is room for some of the spaces
 *    that follow the last word on the line then those that fit are included on
 *    the line.
 * 2. If the text is centred or right-justified and there is room for some of
 *    the spaces that follow the last word on the line then all but one of those
 *    that fit are included on the line.
 * 3. (Reasonable behaviour) If the word breaking causes a space to be the first
 *    character of a new line it will be skipped.
 *
 * Arguments
 *   hdc        [in] The handle to the DC that defines the font.
 *   str        [in/out] The string that needs to be broken.
 *   max_str    [in] The dimension of str (number of WCHAR).
 *   len_str    [in/out] The number of characters in str
 *   width      [in] The maximum width permitted
 *   format     [in] The format flags in effect
 *   chars_fit  [in] The maximum number of characters of str that are already
 *              known to fit; chars_fit+1 is known not to fit.
 *   chars_used [out] The number of characters of str that have been "used" and
 *              do not need to be included in later text.  For example this will
 *              include any spaces that have been discarded from the start of
 *              the next line.
 *   size       [out] The size of the returned text in logical coordinates
 *
 * Pedantic assumption - Assumes that the text length is monotonically
 * increasing with number of characters (i.e. no weird kernings)
 *
 * Algorithm
 *
 * Work back from the last character that did fit to either a space or the last
 * character of a word, whichever is met first.
 * If there was one or the first character didn't fit then
 *     If the text is centred or right justified and that one character was a
 *     space then break the line before that character
 *     Otherwise break the line after that character
 *     and if the next character is a space then discard it.
 * Suppose there was none (and the first character did fit).
 *     If Break Within Word is permitted
 *         break the word after the last character that fits (there must be
 *         at least one; none is caught earlier).
 *     Otherwise
 *         discard any trailing space.
 *         include the whole word; it may be ellipsified later
 *
 * Break Within Word is permitted under a set of circumstances that are not
 * totally clear yet.  Currently our best guess is:
 *     If DT_EDITCONTROL is in effect and neither DT_WORD_ELLIPSIS nor
 *     DT_PATH_ELLIPSIS is
 */

static void TEXT_WordBreak (HDC hdc, WCHAR *str, unsigned int max_str,
                            unsigned int *len_str,
                            int width, int format, unsigned int chars_fit,
                            unsigned int *chars_used, SIZE *size)
{
    WCHAR *p;
    int word_fits;
    assert (format & DT_WORDBREAK);
    assert (chars_fit < *len_str);

    /* Work back from the last character that did fit to either a space or the
     * last character of a word, whichever is met first.
     */
    p = str + chars_fit; /* The character that doesn't fit */
    word_fits = TRUE;
    if (!chars_fit)
        ; /* we pretend that it fits anyway */
    else if (*p == SPACE) /* chars_fit < *len_str so this is valid */
        p--; /* the word just fitted */
    else
    {
        while (p > str && *(--p) != SPACE)
            ;
        word_fits = (p != str || *p == SPACE);
    }
    /* If there was one or the first character didn't fit then */
    if (word_fits)
    {
        int next_is_space;
        /* break the line before/after that character */
        if (!(format & (DT_RIGHT | DT_CENTER)) || *p != SPACE)
            p++;
        next_is_space = (unsigned int) (p - str) < *len_str && *p == SPACE;
        *len_str = p - str;
        /* and if the next character is a space then discard it. */
        *chars_used = *len_str;
        if (next_is_space)
            (*chars_used)++;
    }
    /* Suppose there was none. */
    else
    {
        if ((format & (DT_EDITCONTROL | DT_WORD_ELLIPSIS | DT_PATH_ELLIPSIS)) ==
            DT_EDITCONTROL)
        {
            /* break the word after the last character that fits (there must be
             * at least one; none is caught earlier).
             */
            *len_str = chars_fit;
            *chars_used = chars_fit;

            /* FIXME - possible error.  Since the next character is now removed
             * this could make the text longer so that it no longer fits, and
             * so we need a loop to test and shrink.
             */
        }
        /* Otherwise */
        else
        {
            /* discard any trailing space. */
            const WCHAR *e = str + *len_str;
            p = str + chars_fit;
            while (p < e && *p != SPACE)
                p++;
            *chars_used = p - str;
            if (p < e) /* i.e. loop failed because *p == SPACE */
                (*chars_used)++;

            /* include the whole word; it may be ellipsified later */
            *len_str = p - str;
            /* Possible optimisation; if DT_WORD_ELLIPSIS only use chars_fit+1
             * so that it will be too long
             */
        }
    }
    /* Remeasure the string */
    GetTextExtentExPointW (hdc, str, *len_str, 0, NULL, NULL, size);
}

/*********************************************************************
 *                      TEXT_SkipChars
 *
 *  Skip over the given number of characters, bearing in mind prefix
 *  substitution and the fact that a character may take more than one
 *  WCHAR (Unicode surrogates are two words long) (and there may have been
 *  a trailing &)
 *
 * Parameters
 *   new_count  [out] The updated count
 *   new_str    [out] The updated pointer
 *   start_count [in] The count of remaining characters corresponding to the
 *                    start of the string
 *   start_str  [in] The starting point of the string
 *   max        [in] The number of characters actually in this segment of the
 *                   string (the & counts)
 *   n          [in] The number of characters to skip (if prefix then
 *                   &c counts as one)
 *   prefix     [in] Apply prefix substitution
 *
 * Return Values
 *   none
 *
 * Remarks
 *   There must be at least n characters in the string
 *   We need max because the "line" may have ended with a & followed by a tab
 *   or newline etc. which we don't want to swallow
 */

static void TEXT_SkipChars (int *new_count, const WCHAR **new_str,
                            int start_count, const WCHAR *start_str,
                            int max, int n, int prefix)
{
    /* This is specific to wide characters, MSDN doesn't say anything much
     * about Unicode surrogates yet and it isn't clear if _wcsinc will
     * correctly handle them so we'll just do this the easy way for now
     */

    if (prefix)
    {