diff options
Diffstat (limited to 'Lib/stdwin')
| -rwxr-xr-x | Lib/stdwin/formatter.py | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/Lib/stdwin/formatter.py b/Lib/stdwin/formatter.py new file mode 100755 index 0000000..9bfbe6b --- /dev/null +++ b/Lib/stdwin/formatter.py @@ -0,0 +1,204 @@ +# A class to help applications that do fancy text formatting. +# You create an instance each time you must redraw the window. +# Set the initial left, top and right coordinates; +# then feed it words, font changes and vertical movements. +# +# This class should eventually be extended to support much fancier +# formatting, along the lines of TeX; for now, a very simple model +# is sufficient. +# +class formatter(): + # + # Initialize a formatter instance. + # Pass the window's drawing object, and left, top, right + # coordinates of the drawing space as arguments. + # + def init(self, (d, left, top, right)): + self.d = d # Drawing object + self.left = left # Left margin + self.right = right # Right margin + self.v = top # Top of current line + self.center = 0 + self.justify = 1 + self.setfont('') # Current font + self._reset() # Prepare for new line + return self + # + # Reset for start of fresh line. + # + def _reset(self): + self.boxes = [] # Boxes and glue still to be output + self.sum_width = 0 # Total width of boxes + self.sum_space = 0 # Total space between boxes + self.sum_stretch = 0 # Total stretch for space between boxes + self.max_ascent = 0 # Max ascent of current line + self.max_descent = 0 # Max descent of current line + self.avail_width = self.right - self.left + self.hang_indent = 0 + # + # Set the current font, and compute some values from it. + # + def setfont(self, font): + self.font = font + self.d.setfont(font) + self.font_space = self.d.textwidth(' ') + self.font_ascent = self.d.baseline() + self.font_descent = self.d.lineheight() - self.font_ascent + # + # Add a word to the list of boxes; first flush if line is full. + # Space and stretch factors are expressed in fractions + # of the current font's space width. + # (Two variations: one without, one with explicit stretch factor.) + # + def addword(self, (word, spacefactor)): + self.addwordstretch(word, spacefactor, spacefactor) + # + def addwordstretch(self, (word, spacefactor, stretchfactor)): + width = self.d.textwidth(word) + if width > self.avail_width: + self._flush(1) + space = int(float(self.font_space) * float(spacefactor)) + stretch = int(float(self.font_space) * float(stretchfactor)) + box = (self.font, word, width, space, stretch) + self.boxes.append(box) + self.sum_width = self.sum_width + width + self.sum_space = self.sum_space + space + self.sum_stretch = self.sum_stretch + stretch + self.max_ascent = max(self.font_ascent, self.max_ascent) + self.max_descent = max(self.font_descent, self.max_descent) + self.avail_width = self.avail_width - width - space + # + # Flush current line and start a new one. + # Flushing twice is harmless (i.e. does not introduce a blank line). + # (Two versions: the internal one has a parameter for justification.) + # + def flush(self): + self._flush(0) + # + def _flush(self, justify): + if not self.boxes: + return + # + # Compute amount of stretch needed. + # + if justify and self.justify or self.center: + # + # Compute extra space to fill; + # this is avail_width plus glue from last box. + # Also compute available stretch. + # + last_box = self.boxes[len(self.boxes)-1] + font, word, width, space, stretch = last_box + tot_extra = self.avail_width + space + tot_stretch = self.sum_stretch - stretch + else: + tot_extra = tot_stretch = 0 + # + # Output the boxes. + # + baseline = self.v + self.max_ascent + h = self.left + self.hang_indent + if self.center: + h = h + tot_extra / 2 + tot_extra = tot_stretch = 0 + for font, word, width, space, stretch in self.boxes: + self.d.setfont(font) + v = baseline - self.d.baseline() + self.d.text((h, v), word) + h = h + width + space + if tot_extra > 0 and tot_stretch > 0: + extra = stretch * tot_extra / tot_stretch + h = h + extra + tot_extra = tot_extra - extra + tot_stretch = tot_stretch - stretch + # + # Prepare for next line. + # + self.v = baseline + self.max_descent + self.d.setfont(self.font) + self._reset() + # + # Add vertical space; first flush. + # Vertical space is expressed in fractions of the current + # font's line height. + # + def vspace(self, dy): + self.flush() + dy = int(float(dy) * float(self.d.lineheight())) + self.v = self.v + dy + # + # Set temporary (hanging) indent, for paragraph start. + # First flush. + # + def tempindent(self, space): + self.flush() + hang = int(float(self.font_space) * float(space)) + self.hang_indent = hang + self.avail_width = self.avail_width - hang + # + # Add (permanent) left indentation. First flush. + # + def addleftindent(self, space): + self.flush() + self.left = self.left \ + + int(float(self.font_space) * float(space)) + self._reset() + # + + +# Test procedure +# +def test(): + import stdwin + from stdwinevents import * + try: + import mac + # Mac font assignments: + font1 = 'times', '', 12 + font2 = 'times', 'b', 14 + except NameError: + # X11R4 font assignments + font1 = '*times-medium-r-*-120-*' + font2 = '*times-bold-r-*-140-*' + words = \ + ['The','quick','brown','fox','jumps','over','the','lazy','dog.'] + words = words * 2 + stage = 0 + stages = [(0,0,'ragged'), (1,0,'justified'), (0,1,'centered')] + justify, center, title = stages[stage] + stdwin.setdefwinsize(300,200) + w = stdwin.open(title) + winsize = w.getwinsize() + while 1: + type, window, detail = stdwin.getevent() + if type = WE_CLOSE: + break + elif type = WE_SIZE: + newsize = w.getwinsize() + if newsize <> winsize: + w.change((0,0), winsize) + winsize = newsize + w.change((0,0), winsize) + elif type = WE_MOUSE_DOWN: + stage = (stage + 1) % len(stages) + justify, center, title = stages[stage] + w.settitle(title) + w.change((0, 0), (1000, 1000)) + elif type = WE_DRAW: + width, height = winsize + f = formatter().init(w.begindrawing(), 0, 0, width) + f.center = center + f.justify = justify + if not center: + f.tempindent(5) + for font in font1, font2, font1: + f.setfont(font) + for word in words: + space = 1 + (word[-1:] = '.') + f.addword(word, space) + if center and space > 1: + f.flush() + f.flush() + height = f.v + del f + w.setdocsize(0, height) |