# 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('') # Default font
self._reset() # Prepare for new line
#
# 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, lines):
self.vspacepixels(int(lines * self.d.lineheight()))
#
# Add vertical space given in pixels.
#
def vspacepixels(self, dv):
self.flush()
self.v = self.v + dv
#
# 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, stdwinq
from stdwinevents import *
try:
import mac
# Mac font assignments:
font1 = 'times', '', 12
font2 = 'times', 'b', 14
except ImportError:
# 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 = stdwinq.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(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)
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