有什么方法可以获取reportlab中可流动段落的行数？ 我有一个很长的字符串，以不同的大小和字体打印。 我需要知道要用TA_JUSTIFY对齐方式打印整个段落要用多少行。
可以做到吗？
下面是我的示例python文件
import os
import sys
import string
import pprint
import imp
import tempfile
from reportlab.pdfgen import canvas
from reportlab.platypus import Preformatted, XPreformatted, Paragraph, Frame, Image, \
Table, TableStyle, Spacer
from reportlab.lib.enums import TA_LEFT, TA_RIGHT, TA_CENTER, TA_JUSTIFY
from reportlab.lib import styles
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.pagesizes import *
from reportlab.lib import colors
import reportlab.rl_config
# Import as may be needed if we require embedded true type fonts
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.lib.fonts import addMapping
from reportlab.graphics.barcode import code39, code128, code93
from reportlab.graphics.barcode import common
from reportlab.graphics.barcode import qr
from reportlab.graphics import renderPDF
from reportlab.graphics.shapes import Drawing
import string
import os
import imp
from reportlab.lib import colors
canv = canvas.Canvas('Output.pdf')
styles = getSampleStyleSheet()
parastyle = ParagraphStyle(name='Justify', alignment=TA_JUSTIFY)
parastyle.leading = 12
parastyle.fontSize = 11
styles.add(parastyle)
drawText = "The Avengers become divided, both over how to approach Loki and the revelation that S.H.I.E.L.D. plans to harness the Tesseract to develop weapons as a deterrent against hostile extraterrestrials. As the group argues, Barton and Loki's other possessed agents attack the Helicarrier, disabling one of its engines in flight and causing Banner to transform into the Hulk. Stark and Rogers work to restart the damaged engine, and Thor attempts to stop the Hulk's rampage. Romanoff reluctantly fights Barton, and knocks him unconscious, breaking Loki's mind control. Loki escapes after killing Coulson and ejecting Thor from the airship, while the Hulk falls to the ground after attacking a S.H.I.E.L.D. fighter jet. Fury uses Coulson's death to motivate the Avengers into working as a team. Stark and Rogers realize that for Loki, simply defeating them will not be enough; he needs to overpower them publicly to validate himself as ruler of Earth. Loki uses the Tesseract, in conjunction with a device Selvig built, to open a wormhole above Stark Tower to the Chitauri fleet in space, launching his invasion."
inch = INCH = 72
cm = CM = inch/2.54
mm = MM = cm/10
x=10*mm
y=240*mm
width=190*mm
height=10*mm
canv.saveState()
canv.translate(x,y)
canv.rotate(0)
canv.translate(-x,-y)
p = Paragraph(drawText, styles["Justify"])
p.wrapOn(canv, width, height)
p.drawOn(canv, x, y)
canv.showPage()
canv.save()
THis是当前输出 Output
我需要获取段落中打印的行数。 在我的示例中，我必须获得11。
如果我更改字体和字体大小，则必须相应地获取值。
答案 0 :(得分：0)
我认为这在Reportlab中目前根本不可能，因为可流动对象不直接“知道”内容。另请参见this exchange on the reportlab mailing list。
答案 1 :(得分：0)
我碰巧遇到了这个问题，同时也在寻找一些简单的方法来完成您要问的事情。不幸的是，我没有找到答案，所以我尝试将一些东西放在一起以使其正常工作。它不是很漂亮，但是可以！
我刚刚在您的canv.save（）方法调用之后添加了以下代码：
pixelRatio = 1.333333 # 1 point = 1.333333 pixels
# https://websemantics.uk/articles/font-size-conversion/
# http://www.endmemo.com/sconvert/pixelpoint.php#targetText=Pixel%E2%86%94Point%201%20Point,Twip%201%20Pixel%20%3D%2015%20Twip
fontLineHeight = styles["Justify"].fontSize * pixelRatio
boxWidth = width
boxHeight = height
boxLines = int(72/fontLineHeight)
boxLRBuffer = 0 # Adjust this to whatever inside margin/padding you have in your box
boxPixelCapacity = boxWidth * boxLines - boxLRBuffer # Total pixels in the box
# A list to hold the lines of text
textLines = []
# A pointer to indicate which character is being evaluated
position = len(drawText)
# Make a copy of the original string so as to not modify it
tempString = drawText
# This is a dummy string used to test the width of the string
testString1 = tempString
# Another dummy string to hold what is not being split into a line
# testString2 will be build going backwards from the last character
# to the character right after the line split
testString2 = ''
# Boolean flag to get out of the while loop
done = False
while not done:
# Use pdfmetrics to get the line width in points based upon the fontName and fontSize used
if pdfmetrics.stringWidth(testString1, styles["Justify"].fontName, styles["Justify"].fontSize, 'utf8') > boxWidth-boxLRBuffer*2:
# Since the line is too long, move backwards through the string until an appropriate size is found
# by decreasing the pointer position. Spaces also take space.
position -= 1
if position >= 0:
#since the the pointer has not reached the beginning of testString1
testString1 = testString1[:position] # remove the last character from testString1
testString2 = tempString[position:] # add the next character to testString2 for later use
# Since testString1 now fits within the stringWidth
# it must be checked to see if this is the last line
# being processed.
elif testString1 == testString2:
# This must be the last line since it equals testString2
textLines.append(testString2.strip())
break
# This is not the last line of text, so now work backwards in
# the string to find a space so the line can be split
elif ' ' in testString1:
while testString1[position:] != ' ' and position >= 0:
testString1 = testString1[:position]
testString2 = tempString[position:]
position -= 1
if len(testString1):
textLines.append(testString1.strip())
else:
textLines.append(testString2.strip())
break
tempString = tempString[position:].strip()
testString1 = tempString
position = len(tempString)
elif testString1 == "":
# It's done
break
else:
# The text does not exceed the stringWidth
textLines.append(testString1)
# testString2 must be checked and if empty then it's done
if testString2 == "":
done = True
else:
tempString = tempString[position:].strip()
testString1 = tempString
position = len(tempString)
print(len(textLines))
我愿意提出一些建议以使此代码更好或更简化。