ReportLab:在第一页的"正常"模板'第一'中可流动太大

Question

我使用ReportLab构建PDF.我的程序有MyDocTemplate(SimpleDocTemplate)两种方法类:beforePage(self)和afterPage(self)它的每一页上添加页眉和页脚(如PNG图像).还有一个MyDocStyle类描述ParagraphStyle.

主要方法如下:

TITLE = Paragraph(Title, MyDocStyle.h1)
TO = Paragraph(To, MyDocStyle.h2)
FROM = Paragraph(From, MyDocStyle.h2)
SUBJECT = Paragraph(Subject, MyDocStyle.h2)
LONG_PARAGRAPH = Paragraph(Text, MyDocStyle.h3)
...

Elements = [TITLE, TO, FROM, SUBJECT, LONG_PARAGRAPH, ...]
doc = MyDocTemplete('output.pdf', pagesize=A4, 
                     leftMargin=2*cm, rightMargin=2*cm,
                     topMargin=4*cm, bottomMargin=4*cm)
doc.build(Elements)

数据来自CSV文件和GUI.有时(取决于数据长度)我收到一个错误:

Flowable <Spacer at 0x2631120 frame=normal>...(1 x 5.66929133858) too large
on page 1 in frame 'normal'(469.88976378 x 603.118110236) of template 'First'

这个例外停止我的程序.对于我在MyDocStyle课堂上设置的简短段落,h2.keepWithNext = 1它并不是完美的解决方案.如果段落末尾与页面末尾(文本区域)"不一致",ReportLab会正确拆分长段.

我怎么处理它？

Answer 1

当ReportLab尝试将Spacer拆分为两页时,会发生此错误.似乎解决此问题的唯一方法是将您的Spacer包装到KeepTogether元素中:

elements.append(KeepTogether(Spacer(width, height)))

Answer 2

解决了。不要使用Spacer(例如Spacer(1, 0.2*cm)) 作为 的分隔符Paragraph。相反，定义spaceBefore和spaceAfterin ParagraphStyle，例如：

ParagraphStyle(name = 'Normal',
               fontName = "Verdana",
               fontSize = 11,
               leading = 15,
               alignment = TA_JUSTIFY,
               allowOrphans = 0,
               spaceBefore = 20,
               spaceAfter = 20,
               wordWrap = 1)