Change the way that DrawText parses the next line to display, ready to
support multiline ellipsification etc. Rather than measuring the text each time we add a character and breaking once it is too long and WORDBREAK is enabled, we copy a whole text segment and then measure it; GetTextExtentPointEx is designed to tell us how much fitted. This may result in a little rescanning if wordbreak is enabled but will be well worth while when multiline path ellipsification is brought down into the NextLine function. Note also that the wordbreak calculation is a little more complete (e.g. including break-within-word for DT_EDITCONTROL).
This commit is contained in:
Bill Medland
Alexandre Julliard
parent
0e3c9d454b
commit
7af9098f6b
393
dlls/user/text.c
393
dlls/user/text.c
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@ -269,6 +269,192 @@ void TEXT_CopySansPrefix (int noprefix, WCHAR *d, int *len_d, const WCHAR *s, in
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}
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}
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/*********************************************************************
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* TEXT_WordBreak (static)
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*
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* Perform wordbreak processing on the given string
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*
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* Assumes that DT_WORDBREAK has been specified and not all the characters
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* fit. Note that this function should be called when the first character that
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* doesn't fit is a space or tab, so that it can swallow the space(s)
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*
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* Note that the Windows processing has some strange properties. In particular
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* leading and trailing spaces are not stripped except for the first space of a
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* line created by a wordbreak.
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*
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* Arguments
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* hdc [in] The handle to the DC that defines the font.
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* str [in/out] The string that needs to be broken.
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* max_str [in] The dimension of str (number of WCHAR).
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* len_str [in/out] The number of characters in str
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* width [in] The maximum width permitted
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* format [in] The format flags in effect
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* chars_fit [in] The maximum number of characters of str that are already
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* known to fit; chars_fit+1 is known not to fit.
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* chars_used [out] The number of characters of str that have been "used" and
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* do not need to be included in later text. For example this will
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* include any spaces that have been discarded from the start of
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* the next line.
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* size [out] The size of the returned text in logical coordinates
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*
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* Pedantic assumption - Assumes that the text length is monotonically
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* increasing with number of characters (i.e. no weird kernings)
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*
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* Algorithm
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*
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* Work back from the last character that did fit to either a space or the last
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* character of a word, whichever is met first.
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* If there was one or the first character didn't fit then
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* break the line after that character
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* and if the next character is a space then discard it.
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* Suppose there was none (and the first character did fit).
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* If Break Within Word is permitted
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* break the word after the last character that fits (there must be
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* at least one; none is caught earlier).
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* Otherwise
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* discard any trailing space.
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* include the whole word; it may be ellipsified later
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*
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* Break Within Word is permitted under a set of circumstances that are not
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* totally clear yet. Currently our best guess is:
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* If DT_EDITCONTROL is in effect and neither DT_WORD_ELLIPSIS nor
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* DT_PATH_ELLIPSIS is
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*/
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static void TEXT_WordBreak (HDC hdc, WCHAR *str, unsigned int max_str,
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unsigned int *len_str,
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int width, int format, unsigned int chars_fit,
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unsigned int *chars_used, SIZE *size)
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{
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WCHAR *p;
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int word_fits;
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assert (format & DT_WORDBREAK);
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assert (chars_fit < *len_str);
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/* Work back from the last character that did fit to either a space or the
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* last character of a word, whichever is met first.
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*/
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p = str + chars_fit; /* The character that doesn't fit */
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word_fits = TRUE;
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if (!chars_fit)
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; /* we pretend that it fits anyway */
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else if (*p == SPACE) /* chars_fit < *len_str so this is valid */
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p--; /* the word just fitted */
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else
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{
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while (p > str && *(--p) != SPACE)
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;
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word_fits = (p != str || *p == SPACE);
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}
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/* If there was one or the first character didn't fit then */
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if (word_fits)
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{
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/* break the line after that character */
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p++;
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*len_str = p - str;
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/* and if the next character is a space then discard it. */
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*chars_used = *len_str;
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if (*p == SPACE)
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(*chars_used)++;
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}
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/* Suppose there was none. */
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else
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{
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if ((format & (DT_EDITCONTROL | DT_WORD_ELLIPSIS | DT_PATH_ELLIPSIS)) ==
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DT_EDITCONTROL)
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{
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/* break the word after the last character that fits (there must be
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* at least one; none is caught earlier).
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*/
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*len_str = chars_fit;
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*chars_used = chars_fit;
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/* FIXME - possible error. Since the next character is now removed
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* this could make the text longer so that it no longer fits, and
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* so we need a loop to test and shrink.
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*/
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}
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/* Otherwise */
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else
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{
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/* discard any trailing space. */
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const WCHAR *e = str + *len_str;
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p = str + chars_fit;
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while (p < e && *p != SPACE)
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p++;
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*chars_used = p - str;
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if (p < e) /* i.e. loop failed because *p == SPACE */
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(*chars_used)++;
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/* include the whole word; it may be ellipsified later */
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*len_str = p - str;
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/* Possible optimisation; if DT_WORD_ELLIPSIS only use chars_fit+1
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* so that it will be too long
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*/
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}
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}
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/* Remeasure the string */
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GetTextExtentExPointW (hdc, str, *len_str, 0, NULL, NULL, size);
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}
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/*********************************************************************
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* TEXT_SkipChars
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*
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* Skip over the given number of characters, bearing in mind prefix
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* substitution and the fact that a character may take more than one
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* WCHAR (Unicode surrogates are two words long) (and there may have been
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* a trailing &)
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*
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* Parameters
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* new_count [out] The updated count
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* new_str [out] The updated pointer
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* start_count [in] The count of remaining characters corresponding to the
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* start of the string
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* start_str [in] The starting point of the string
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* max [in] The number of characters actually in this segment of the
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* string (the & counts)
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* n [in] The number of characters to skip (if prefix then
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* &c counts as one)
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* prefix [in] Apply prefix substitution
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*
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* Return Values
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* none
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*
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* Remarks
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* There must be at least n characters in the string
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* We need max because the "line" may have ended with a & followed by a tab
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* or newline etc. which we don't want to swallow
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*/
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static void TEXT_SkipChars (int *new_count, const WCHAR **new_str,
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int start_count, const WCHAR *start_str,
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int max, int n, int prefix)
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{
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/* This is specific to wide characters, MSDN doesn't say anything much
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* about Unicode surrogates yet and it isn't clear if _wcsinc will
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* correctly handle them so we'll just do this the easy way for now
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*/
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if (prefix)
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{
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const WCHAR *str_on_entry = start_str;
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assert (max >= n);
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max -= n;
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while (n--)
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if (*start_str++ == PREFIX && max--)
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start_str++;
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else;
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start_count -= (start_str - str_on_entry);
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}
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else
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{
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start_str += n;
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start_count -= n;
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}
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*new_str = start_str;
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*new_count = start_count;
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}
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/*********************************************************************
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* TEXT_Reprefix
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*
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@ -330,112 +516,121 @@ static int TEXT_Reprefix (const WCHAR *str, unsigned int n1, unsigned int n2,
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* len - dest buffer size in chars on input, copied length into dest on output.
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* width - maximum width of line in pixels.
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* format - format type passed to DrawText.
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* retsize - returned size of the line in pixels.
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*
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* Returns pointer to next char in str after end of the line
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* or NULL if end of str reached.
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*
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*/
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static const WCHAR *TEXT_NextLineW( HDC hdc, const WCHAR *str, int *count,
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WCHAR *dest, int *len, int width, WORD format)
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WCHAR *dest, int *len, int width, WORD format,
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SIZE *retsize)
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{
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int i = 0, j = 0;
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int plen = 0;
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int seg_plen; /* plen at the beginning of the current text segment */
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SIZE size;
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int wb_i = 0, wb_j = 0, wb_count = 0;
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int maxl = *len;
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int normal_char;
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int seg_j; /* j at the beginning of the current text segment */
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int seg_i, seg_count, seg_j;
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int max_seg_width;
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int num_fit;
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int word_broken;
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seg_j = j;
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seg_plen = plen;
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while (*count && j < maxl)
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{
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normal_char = 1;
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switch (str[i])
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{
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case CR:
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case LF:
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if (!(format & DT_SINGLELINE))
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{
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if ((*count > 1) && (((str[i] == CR) && (str[i+1] == LF)) ||
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((str[i] == LF) && (str[i+1] == CR))))
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{
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(*count)--;
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i++;
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}
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i++;
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*len = j;
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(*count)--;
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return (&str[i]);
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}
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/* else it's just another character */
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break;
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case PREFIX:
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if (!(format & DT_NOPREFIX) && *count > 1)
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{
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if (str[++i] == PREFIX)
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(*count)--; /* and treat it as just another character */
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else {
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prefix_offset = j;
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normal_char = 0; /* we are skipping the PREFIX itself */
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break;
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}
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}
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break;
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/* For each text segment in the line */
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case TAB:
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if (format & DT_EXPANDTABS)
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retsize->cy = 0;
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while (*count)
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{
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if ((format & DT_WORDBREAK))
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/* Skip any leading tabs */
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if (str[i] == TAB && (format & DT_EXPANDTABS))
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{
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wb_i = i+1;
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wb_j = j;
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wb_count = *count;
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plen = ((plen/tabwidth)+1)*tabwidth;
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seg_plen = plen;
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(*count)--; if (j < maxl) dest[j++] = str[i++]; else i++;
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while (*count && str[i] == TAB)
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{
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plen += tabwidth;
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(*count)--; if (j < maxl) dest[j++] = str[i++]; else i++;
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}
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}
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normal_char = 0;
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dest[j++] = str[i++];
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/* Now copy as far as the next tab or cr/lf or eos */
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seg_i = i;
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seg_count = *count;
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seg_j = j;
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while (*count &&
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(str[i] != TAB || !(format & DT_EXPANDTABS)) &&
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((str[i] != CR && str[i] != LF) || (format & DT_SINGLELINE)))
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{
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if (str[i] == PREFIX && !(format & DT_NOPREFIX) && *count > 1)
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{
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(*count)--, i++; /* Throw away the prefix itself */
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if (str[i] == PREFIX)
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{
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/* Swallow it before we see it again */
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(*count)--; if (j < maxl) dest[j++] = str[i++]; else i++;
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}
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else
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{
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prefix_offset = j;
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}
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}
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else
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{
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(*count)--; if (j < maxl) dest[j++] = str[i++]; else i++;
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}
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}
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/* Measure the whole text segment and possibly WordBreak it */
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max_seg_width = width - plen;
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GetTextExtentExPointW (hdc, dest + seg_j, j - seg_j, max_seg_width, &num_fit, NULL, &size);
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word_broken = 0;
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if (num_fit < j-seg_j && (format & DT_WORDBREAK))
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{
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const WCHAR *s;
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int chars_used;
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int j_in_seg = j-seg_j;
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TEXT_WordBreak (hdc, dest+seg_j, maxl-seg_j, &j_in_seg,
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max_seg_width, format, num_fit, &chars_used, &size);
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/* and correct the counts */
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j = seg_j + j_in_seg;
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TEXT_SkipChars (count, &s, seg_count, str+seg_i, i-seg_i,
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chars_used, !(format & DT_NOPREFIX));
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i = s - str;
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word_broken = 1;
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}
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plen += size.cx;
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if (size.cy > retsize->cy)
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retsize->cy = size.cy;
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if (word_broken)
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break;
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else if (!*count)
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break;
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else if (str[i] == CR || str[i] == LF)
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{
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count--, i++;
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if (count && (str[i] == CR || str[i] == LF) && str[i] != str[i-1])
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{
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count--, i++;
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}
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break;
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case SPACE:
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if ((format & DT_WORDBREAK))
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{
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wb_i = i+1;
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wb_j = j;
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wb_count = *count;
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}
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break;
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default:
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}
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if (normal_char)
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{
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dest[j++] = str[i++];
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if ((format & DT_WORDBREAK))
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{
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if (!GetTextExtentPointW(hdc, &dest[seg_j], j-seg_j, &size))
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return NULL;
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plen = seg_plen + size.cx;
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}
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}
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(*count)--;
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if ((format & DT_WORDBREAK) && plen > width && wb_j)
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{
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*len = wb_j;
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*count = wb_count - 1;
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return (&str[wb_i]);
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}
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/* else it was a Tab and we go around again */
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}
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retsize->cx = plen;
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*len = j;
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if (*count)
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return (&str[i]);
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else
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return NULL;
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}
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@ -476,39 +671,6 @@ static void TEXT_DrawUnderscore (HDC hdc, int x, int y, const WCHAR *str, int of
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DeleteObject (hpen);
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}
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/* We are only going to need this until we correct the measuring in
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* TEXT_NextLineW (coming soon)
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*/
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static int TEXT_TextExtent (HDC hdc, UINT flags, const WCHAR *line, int len, SIZE *size)
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{
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if ((flags & DT_EXPANDTABS))
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{
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SIZE tsize;
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const WCHAR *p;
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size->cx = 0;
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size->cy = 0;
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while (len)
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{
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p = line; while (p < line+len && *p != TAB) p++;
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if (!GetTextExtentPointW (hdc, line, p-line, &tsize)) return 0;
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size->cx += tsize.cx;
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if (tsize.cy > size->cy) size->cy = tsize.cy;
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len -= (p-line);
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line=p;
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if (len)
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{
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assert (*line == TAB);
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len--;
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line++;
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size->cx = ((size->cx/tabwidth)+1)*tabwidth;
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}
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}
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return 1;
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}
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else
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return GetTextExtentPointW(hdc, line, len, size);
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}
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/***********************************************************************
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* DrawTextExW (USER32.@)
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*
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@ -574,9 +736,8 @@ INT WINAPI DrawTextExW( HDC hdc, LPWSTR str, INT i_count,
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{
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prefix_offset = -1;
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len = MAX_STATIC_BUFFER;
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strPtr = TEXT_NextLineW(hdc, strPtr, &count, line, &len, width, flags);
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strPtr = TEXT_NextLineW(hdc, strPtr, &count, line, &len, width, flags, &size);
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if (!TEXT_TextExtent(hdc, flags, line, len, &size)) return 0;
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if (flags & DT_CENTER) x = (rect->left + rect->right -
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size.cx) / 2;
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else if (flags & DT_RIGHT) x = rect->right - size.cx;
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