path: root/Lib/lib-old/Para.py

# Text formatting abstractions
# Note -- this module is obsolete, it's too slow anyway


# Oft-used type object
Int = type(0)


# Represent a paragraph.  This is a list of words with associated
# font and size information, plus indents and justification for the
# entire paragraph.
# Once the words have been added to a paragraph, it can be laid out
# for different line widths.  Once laid out, it can be rendered at
# different screen locations.  Once rendered, it can be queried
# for mouse hits, and parts of the text can be highlighted
class Para:
    #
    def __init__(self):
        self.words = [] # The words
        self.just = 'l' # Justification: 'l', 'r', 'lr' or 'c'
        self.indent_left = self.indent_right = self.indent_hang = 0
        # Final lay-out parameters, may change
        self.left = self.top = self.right = self.bottom = \
                self.width = self.height = self.lines = None
    #
    # Add a word, computing size information for it.
    # Words may also be added manually by appending to self.words
    # Each word should be a 7-tuple:
    # (font, text, width, space, stretch, ascent, descent)
    def addword(self, d, font, text, space, stretch):
        if font is not None:
            d.setfont(font)
        width = d.textwidth(text)
        ascent = d.baseline()
        descent = d.lineheight() - ascent
        spw = d.textwidth(' ')
        space = space * spw
        stretch = stretch * spw
        tuple = (font, text, width, space, stretch, ascent, descent)
        self.words.append(tuple)
    #
    # Hooks to begin and end anchors -- insert numbers in the word list!
    def bgn_anchor(self, id):
        self.words.append(id)
    #
    def end_anchor(self, id):
        self.words.append(0)
    #
    # Return the total length (width) of the text added so far, in pixels
    def getlength(self):
        total = 0
        for word in self.words:
            if type(word) is not Int:
                total = total + word[2] + word[3]
        return total
    #
    # Tab to a given position (relative to the current left indent):
    # remove all stretch, add fixed space up to the new indent.
    # If the current position is already at the tab stop,
    # don't add any new space (but still remove the stretch)
    def tabto(self, tab):
        total = 0
        as, de = 1, 0
        for i in range(len(self.words)):
            word = self.words[i]
            if type(word) is Int: continue
            (fo, te, wi, sp, st, as, de) = word
            self.words[i] = (fo, te, wi, sp, 0, as, de)
            total = total + wi + sp
        if total < tab:
            self.words.append((None, '', 0, tab-total, 0, as, de))
    #
    # Make a hanging tag: tab to hang, increment indent_left by hang,
    # and reset indent_hang to -hang
    def makehangingtag(self, hang):
        self.tabto(hang)
        self.indent_left = self.indent_left + hang
        self.indent_hang = -hang
    #
    # Decide where the line breaks will be given some screen width
    def layout(self, linewidth):
        self.width = linewidth
        height = 0
        self.lines = lines = []
        avail1 = self.width - self.indent_left - self.indent_right
        avail = avail1 - self.indent_hang
        words = self.words
        i = 0
        n = len(words)
        lastfont = None
        while i < n:
            firstfont = lastfont
            charcount = 0
            width = 0
            stretch = 0
            ascent = 0
            descent = 0
            lsp = 0
            j = i
            while i < n:
                word = words[i]
                if type(word) is Int:
                    if word > 0 and width >= avail:
                        break
                    i = i+1
                    continue
                fo, te, wi, sp, st, as, de = word
                if width + wi > avail and width > 0 and wi > 0:
                    break
                if fo is not None:
                    lastfont = fo
                    if width == 0:
                        firstfont = fo
                charcount = charcount + len(te) + (sp > 0)
                width = width + wi + sp
                lsp = sp
                stretch = stretch + st
                lst = st
                ascent = max(ascent, as)
                descent = max(descent, de)
                i = i+1
            while i > j and type(words[i-1]) is Int and \
                    words[i-1] > 0: i = i-1
            width = width - lsp
            if i < n:
                stretch = stretch - lst
            else:
                stretch = 0
            tuple = i-j, firstfont, charcount, width, stretch, \
                    ascent, descent
            lines.append(tuple)
            height = height + ascent + descent
            avail = avail1
        self.height = height
    #
    # Call a function for all words in a line
    def visit(self, wordfunc, anchorfunc):
        avail1 = self.width - self.indent_left - self.indent_right
        avail = avail1 - self.indent_hang
        v = self.top
        i = 0
        for tuple in self.lines:
            wordcount, firstfont, charcount, width, stretch, \
                    ascent, descent = tuple
            h = self.left + self.indent_left
            if i == 0: h = h + self.indent_hang
            extra = 0
            if self.just == 'r': h = h + avail - width
            elif self.just == 'c': h = h + (avail - width) / 2
            elif self.just == 'lr' and stretch > 0:
                extra = avail - width
            v2 = v + ascent + descent
            for j in range(i, i+wordcount):
                word = self.words[j]
                if type(word) is Int:
                    ok = anchorfunc(self, tuple, word, \
                                    h, v)
                    if ok is not None: return ok
                    continue
                fo, te, wi, sp, st, as, de = word
                if extra > 0 and stretch > 0:
                    ex = extra * st / stretch
                    extra = extra - ex
                    stretch = stretch - st
                else:
                    ex = 0
                h2 = h + wi + sp + ex
                ok = wordfunc(self, tuple, word, h, v, \
                        h2, v2, (j==i), (j==i+wordcount-1))
                if ok is not None: return ok
                h = h2
            v = v2
            i = i + wordcount
            avail = avail1
    #
    # Render a paragraph in "drawing object" d, using the rectangle
    # given by (left, top, right) with an unspecified bottom.
    # Return the computed bottom of the text.
    def render(self, d, left, top, right):
        if self.width != right-left:
            self.layout(right-left)
        self.left = left
        self.top = top
        self.right = right
        self.bottom = self.top + self.height
        self.anchorid = 0
        try:
            self.d = d
            self.visit(self.__class__._renderword, \
                       self.__class__._renderanchor)
        finally:
            self.d = None
        return self.bottom
    #
    def _renderword(self, tuple, word, h, v, h2, v2, isfirst, islast):
        if word[0] is not None: self.d.setfont(word[0])
        baseline = v + tuple[5]
        self.d.text((h, baseline - word[5]), word[1])
        if self.anchorid > 0:
            self.d.line((h, baseline+2), (h2, baseline+2))
    #
    def _renderanchor(self, tuple, word, h, v):
        self.anchorid = word
    #
    # Return which anchor(s) was hit by the mouse
    def hitcheck(self, mouseh, mousev):
        self.mouseh = mouseh
        self.mousev = mousev
        self.anchorid = 0
        self.hits = []
        self.visit(self.__class__._hitcheckword, \
                   self.__class__._hitcheckanchor)
        return self.hits
    #
    def _hitcheckword(self, tuple, word, h, v, h2, v2, isfirst, islast):
        if self.anchorid > 0 and h <= self.mouseh <= h2 and \
                v <= self.mousev <= v2:
            self.hits.append(self.anchorid)
    #
    def _hitcheckanchor(self, tuple, word, h, v):
        self.anchorid = word
    #
    # Return whether the given anchor id is present
    def hasanchor(self, id):
        return id in self.words or -id in self.words
    #
    # Extract the raw text from the word list, substituting one space
    # for non-empty inter-word space, and terminating with '\n'
    def extract(self):
        text = ''
        for w in self.words:
            if type(w) is not Int:
                word = w[1]
                if w[3]: word = word + ' '
                text = text + word
        return text + '\n'
    #
    # Return which character position was hit by the mouse, as
    # an offset in the entire text as returned by extract().
    # Return None if the mouse was not in this paragraph
    def whereis(self, d, mouseh, mousev):
        if mousev < self.top or mousev > self.bottom:
            return None
        self.mouseh = mouseh
        self.mousev = mousev
        self.lastfont = None
        self.charcount = 0
        try:
            self.d = d
            return self.visit(self.__class__._whereisword, \
                              self.__class__._whereisanchor)
        finally:
            self.d = None
    #
    def _whereisword(self, tuple, word, h1, v1, h2, v2, isfirst, islast):
        fo, te, wi, sp, st, as, de = word
        if fo is not None: self.lastfont = fo
        h = h1
        if isfirst: h1 = 0
        if islast: h2 = 999999
        if not (v1 <= self.mousev <= v2 and h1 <= self.mouseh <= h2):
            self.charcount = self.charcount + len(te) + (sp > 0)
            return
        if self.lastfont is not None:
            self.d.setfont(self.lastfont)
        cc = 0
        for c in te:
            cw = self.d.textwidth(c)
            if self.mouseh <= h + cw/2:
                return self.charcount + cc
            cc = cc+1
            h = h+cw
        self.charcount = self.charcount + cc
        if self.mouseh <= (h+h2) / 2:
            return self.charcount
        else:
            return self.charcount + 1
    #
    def _whereisanchor(self, tuple, word, h, v):
        pass
    #
    # Return screen position corresponding to position in paragraph.
    # Return tuple (h, vtop, vbaseline, vbottom).
    # This is more or less the inverse of whereis()
    def screenpos(self, d, pos):
        if pos < 0:
            ascent, descent = self.lines[0][5:7]
            return self.left, self.top, self.top + ascent, \
                    self.top + ascent + descent
        self.pos = pos
        self.lastfont = None
        try:
            self.d = d
            ok = self.visit(self.__class__._screenposword, \
                            self.__class__._screenposanchor)
        finally:
            self.d = None
        if ok is None:
            ascent, descent = self.lines[-1][5:7]
            ok = self.right, self.bottom - ascent - descent, \
                    self.bottom - descent, self.bottom
        return ok
    #
    def _screenposword(self, tuple, word, h1, v1, h2, v2, isfirst, islast):
        fo, te, wi, sp, st, as, de = word
        if fo is not None: self.lastfont = fo
        cc = len(te) + (sp > 0)
        if self.pos > cc:
            self.pos = self.pos - cc
            return
        if self.pos < cc:
            self.d.setfont(self.lastfont)
            h = h1 + self.d.textwidth(te[:self.pos])
        else:
            h = h2
        ascent, descent = tuple[5:7]
        return h, v1, v1+ascent, v2
    #
    def _screenposanchor(self, tuple, word, h, v):
        pass
    #
    # Invert the stretch of text between pos1 and pos2.
    # If pos1 is None, the beginning is implied;
    # if pos2 is None, the end is implied.
    # Undoes its own effect when called again with the same arguments
    def invert(self, d, pos1, pos2):
        if pos1 is None:
            pos1 = self.left, self.top, self.top, self.top
        else:
            pos1 = self.screenpos(d, pos1)
        if pos2 is None:
            pos2 = self.right, self.bottom,self.bottom,self.bottom
        else:
            pos2 = self.screenpos(d, pos2)
        h1, top1, baseline1, bottom1 = pos1
        h2, top2, baseline2, bottom2 = pos2
        if bottom1 <= top2:
            d.invert((h1, top1), (self.right, bottom1))
            h1 = self.left
            if bottom1 < top2:
                d.invert((h1, bottom1), (self.right, top2))
            top1, bottom1 = top2, bottom2
        d.invert((h1, top1), (h2, bottom2))