Reportlab:如何在人像和风景之间切换？

Question

我正在使用reportlab从动态数据中自动生成pdf报告.由于内容有时太大而无法以纵向显示,因此我尝试切换到大型内容的横向.

以下是我的报告生成方式:

主功能 :

doc = DocTemplate(...)           //Doctemplate is a customed BaseDocTemplate class
array = []
some_data= "Here is some data displayed in portrait" 

array.append(Paragraph(some_data))

large_data = "this data is too large to be displayed in portrait"
array.append(Paragraph(large_data))

... // Some more data is added after this

doc.build(array, canvasmaker=NumberedCanvas)

我正在寻找的是一种能够在每一步从纵向切换到横向的方法,因为我不知道显示它所需的页数.我仍然是reportlab的新手,甚至还有一些python,所以我不知道如何正确地使用reportlab(PageTemplates,flowables)提供的解决方案,因为我在最后构建整个文档.

以下是本案例的其他有用类:

class DocTemplate(BaseDocTemplate, ):
def __init__(self, filename, **kw):
    apply(BaseDocTemplate.__init__, (self, filename), kw)
    f = Frame(2.6*cm, 2.8*cm, 16*cm, 22.7*cm, id='f')
    pt = PageTemplate('RectPage', [f], onPage=beforeDrawPage, onPageEnd=afterDrawPage)
    //beforeDrawPage and afterDrawPage fill the headers of the page (that also need to be in landscape)
    self.addPageTemplates(pt)

我想我会添加另一个页面模板或框架,但我不知道在数据附加阶段我如何从一个切换到另一个.

class NumberedCanvas(canvas.Canvas):
def __init__(self, *args, **kwargs):
    canvas.Canvas.__init__(self, *args, **kwargs)

    self._saved_page_states = []

def showPage(self):
    self._saved_page_states.append(dict(self.__dict__))
    self._startPage()

def save(self):
    """add page info to each page (page x of y)"""
    num_pages = len(self._saved_page_states)
    for state in self._saved_page_states:
        self.__dict__.update(state)
        self.draw_page_number(num_pages)
        canvas.Canvas.showPage(self)
    self.setTitle("Title")
    canvas.Canvas.save(self)
    self._doc.SaveToFile(self._filename, self)

def draw_page_number(self, page_count):
    self.setFont("Helvetica", 11)
    self.drawRightString(18.5*cm, 26.8*cm,
        "PAGE %d / %d" % (self._pageNumber, page_count))

我希望我没有忘记任何事情要清楚.

提前谢谢了.

Answer 1

使用pagesizes模块中已有的横向和纵向功能.

from reportlab.lib.pagesizes import letter, landscape
c = canvas.Canvas(file, pagesize=landscape(letter))

Answer 2

我终于找到了自己做的最佳方法:

我在DocTemplate中添加了一个带有横向设置的新PageTemplate,然后只使用了来自reportlab.platypus包的NextPageTemplate:

array.append(NextPageTemplate('landscape'))

为了回到肖像,我使用:

array.append(NextPageTemplate('portrait'))

这允许非常好的灵活性.

Answer 3

这是我在纵向和横向模式之间切换的方式,但我事先确定了哪个方向:

from reportlab.lib.pagesizes import letter, A4

lWidth, lHeight = letter

if orientation == 'landscape':
    canvas.setPageSize((lHeight, lWidth))
else:
    canvas.setPageSize((lWidth, lHeight))

Answer 4

doc=SimpleDocTemplate(..., pagesize=(A4[1],A4[0]))