Moving to the next Frame in ReportLab

In ReportLab, I have a Page Template made out of 2 vertical Frames. What I am trying to achieve here is - after putting some dynamic text onto the page (first frame), I would like to go to the top of the 2nd frame.

I've tried to achieve this by calculating the height of the text objects from the 1st frame and then inserting a Spacer with height equal to (doc.height - the weight of the text objects from the 1st frame). However, this is not working. This is the simplified code and its output.

   from reportlab.lib.pagesizes import A4, landscape
   from reportlab.lib.units import inch
   from reportlab.lib.styles import ParagraphStyle

   from reportlab.platypus import *

   if __name__ == "__main__":

       style_1 = ParagraphStyle(name='Stylo',
                              fontName='Helvetica',
                              fontSize=20,
                              leading=12)

       doc = BaseDocTemplate('test_spacer.pdf', showBoundary=1, 
                             pagesize=landscape(A4), topMargin=30,
                           bottomMargin=30,
                           leftMargin=30, rightMargin=30)

      frameCount = 2
      frameWidth = (doc.width) / frameCount
      frameHeight = doc.height - .05 * inch

      frames = []
      column = Frame(doc.leftMargin, doc.bottomMargin, 200, doc.height - .05* inch)
      frames.append(column)
      column = Frame(doc.leftMargin + 200, doc.bottomMargin, frameWidth - 200, doc.height - .05 * inch)
      frames.append(column)

      doc.addPageTemplates([PageTemplate(id='framess', frames=frames)])

      story = []

      for i, x in enumerate(['A', 'B', 'C']):

          text = x*10*(i+1)

          p1 = Paragraph(text, style_1)
          w, h1 = p1.wrap(200, doc.height)

          p2 = Paragraph(text*2, style_1)
          w, h2 = p2.wrap(200, doc.height)

          story.append(p1)
          story.append(p2)

          spac_height = ((doc.height) - (h1 + h2))
          story.append(Spacer(width=0, height=spac_height))

          story.append(Paragraph('This should be on the top of the 2nd Frame!' + x, style_1))

          story.append(PageBreak())

      doc.build(story)

Does anyone know what I am doing wrong here? Thanks!

I suggest you try using FrameBreak instead of a Spacer, as I think the break is a better solution to your issue.

Here is a modified version fo your code to show the result:

import random
from reportlab.lib.pagesizes import A4, landscape
from reportlab.lib.styles import ParagraphStyle
from reportlab.lib.units import inch
from reportlab.platypus import (
    BaseDocTemplate, PageTemplate, PageBreak, Frame, FrameBreak, Spacer, Paragraph,
)


if __name__ == "__main__":
    style_1 = ParagraphStyle(
        name='Stylo',
        fontName='Helvetica',
        fontSize=10,
        leading=12)
    doc = BaseDocTemplate(
        'test_spacer.pdf',
        showBoundary=1,
        pagesize=landscape(A4),
        topMargin=1*inch,
        bottomMargin=1*inch,
        leftMargin=1*inch,
        rightMargin=1*inch)

    frameCount = 2
    frameWidth = doc.width / frameCount
    frameHeight = doc.height - 0.05*inch

    frame_list = [
        Frame(
            x1=doc.leftMargin,
            y1=doc.bottomMargin,
            width=frameWidth,
            height=frameHeight),
        Frame(
            x1=doc.leftMargin + frameWidth,
            y1=doc.bottomMargin,
            width=frameWidth,
            height=frameHeight),
    ]
    doc.addPageTemplates([PageTemplate(id='frames', frames=frame_list), ])

    story = []
    for i, x in enumerate(['A', 'B', 'C']):
        # add text in first frame
        for _ in range(3):
            story.append(
                Paragraph(
                    x * random.randint(50, 100),
                    style_1))

        # jump to next frame
        story.append(FrameBreak())

        # add text in second frame
        story.append(
            Paragraph(
                'This should be on the top of the 2nd Frame! ' + x,
                style_1))

        story.append(PageBreak())

    doc.build(story)

It gives this output (this image only shows the first 2 pages):