[reportlab-users] Fwd: ReportLab problems with CJK

[Robin Becker]

I've created a small example using roman alphabet and that seems to indicate 
that you're right. However, your fix allows the loop to be much cheaper so I 
rewrote as


> 		if endLine:

> 			extraSpace = maxWidth - widthUsed

> 			if not lineBreak:

> 				#This is the most important of the Japanese typography rules.

> 				#if next character cannot start a line, wrap it up to this line so it hangs

> 				#in the right margin. We won't do two or more though - that's unlikely and

> 				#would result in growing ugliness.

> 				#otherwise we need to push the character back

> 				#and increase the extra space

> 				#bug fix contributed by Alexander Vasilenko <alexs.vasilenko at gmail.com>

> 				if u not in ALL_CANNOT_START:

> 					i -= 1

> 					extraSpace += w

> 			lines.append(makeCJKParaLine(U[lineStartPos:i],extraSpace,calcBounds))

> 			try:

> 				maxWidth = maxWidths[len(lines)]

> 			except IndexError:

> 				maxWidth = maxWidths[-1]  # use the last one

>

> 			lineStartPos = i

> 			widthUsed = 0


which seems to work with this example

from reportlab.lib import textsplit
textsplit.ALL_CANNOT_START += u'M'
from reportlab.pdfgen.canvas import Canvas
from reportlab.platypus.paragraph import Paragraph
from reportlab.lib.styles import ParagraphStyle
from reportlab.pdfbase import pdfmetrics
from reportlab.lib.enums import TA_LEFT


sty = ParagraphStyle('A')
sty.fontSize = 15
sty.leading = sty.fontSize*1.2
sty.fontName = 'Courier'
sty.alignment = TA_LEFT
sty.wordWrap = 'CJK'
p0=Paragraph('ABCDEFGHIJKLMN',sty)
p1=Paragraph('AB<font color="red">C</font>DEFGHIJKLMN',sty)

aW = pdfmetrics.stringWidth('ABCD','Courier',15)
p0.wrap(aW,1000000)
p1.wrap(aW,1000000)

canv = Canvas('tcjk.pdf')
p0.drawOn(canv,72,canv._pagesize[1]-72)
p1.drawOn(canv,72,canv._pagesize[1]-172)
canv.showPage()
canv.save()


On 16/02/2011 15:33, Alexandr Vasilenko wrote:

> Hi Robin,

>

> Unfortunately, I don't read/speak Japanese too. Just was fixing a bug with

> overlapped characters.

> I think i -= 1 should be added, because on that step the last character is

> out of width already, and extraSpace is corrected by extraSpace += w

> operation (this mean removing the latest character). But pointer wasn't

> changed (i variable is a pointer in this case)

>

> Image we have ABCD  cjk characters, each has width=5, let maxwidth=12.

> If you'll use such example you will see that is will be splitted as:

> ABC  (total width=15 instead of maxwidth=12)

> D

> instread of:

> AB (total width=10, which is good)

> CD

>

> I hope that described clearly the issue.

>

> Regards,

> Alex

>.......

-- 
Robin Becker