调整reportlab.platypus.Paragraph的大小是否可以流动？

Question

我有以下代码尝试调整reportlab Platypus flowable 文本的字体大小，直到它适合我给它的可用高度。但是我发现 Paragraph flowable 没有在递归的每个循环中保存其 style.fontSize 属性，并且 python baulks 具有无限递归。

def fits_space(w,h,aW,aH,p):
    """
    Determines if inputted text fits in the space given for a paragraph
    and if it doesn't, reduces the font-size until it does.

    """
    if w<=aW and h<=aH:
        # return font size to apply it to the para again
        print "final font_size: %d" % p.style.fontSize
        return p # now render the paragraph in the doctemplate
    else: 
        p.style.fontSize -= 1
        w,h = p.wrap(aW, aH)
        fits_space(w,h,aW,aH,p)

def renderPage(name, text):
    doc = SimpleDocTemplate("%s.pdf" % name)
    parts = []
    style = ParagraphStyle(name='fancy')
    style.fontSize = 150
    p = Paragraph(text, style)
    aW = PAGE_WIDTH-4*inch  # available width and height 
    aH = PAGE_HEIGHT-4*inch 
    w,h = p.wrap(aW, aH) # find required space
    p = fits_space(w,h,aW,aH,p) # recursively fit the font size to the text
    parts.append(p)
    doc.build(parts)

谁能告诉我为什么 - 在 fit_space() 函数中，在 else 子句中，当我调用 p.wrap(aW, aH) 时，输出的值与我将段落的 fontSize 减 1 之前的值相同吗？如果我减小字体大小，包裹的高度肯定会更小吗？

任何想法我哪里出错了？

更新 Nitzie 下面的代码几乎可以工作，在我的例子中，只需要在 style.leading 中添加一个调整大小：

def shrink_font_size(aW, aH, text, style):
    """Shrinks font size by using pdfmetrics to calculate the height
    of a paragraph, given the font name, size, and available width."""
    def break_lines(text, aW):
        # simpleSplit calculates how reportlab will break up the lines for
        # display in a paragraph, by using width/fontsize.
        return simpleSplit(text, style.fontName, style.fontSize, aW)

    def line_wrap(lines, style):
        # Get overall width of text by getting stringWidth of longest line
        width = stringWidth(max(lines), style.fontName, style.fontSize)
        # Paragraph height can be calculated via line spacing and number of lines.
        height = style.leading * len(lines)
        return width, height

    lines = break_lines(text, aW)
    width, height = line_wrap(lines, style)

    while height > aH or width > aW:
        style.fontSize -= 1
        style.leading -= 1 # do this if you're leading is based on the fontSize
        lines = break_lines(text, aW)
        width, height = line_wrap(lines, style)

TIA

Answer 1

由于某种原因，p.wrap 似乎并没有真正重新计算高度/宽度，一旦您在调用一次之后更改了字体大小。

我能够通过基于 ReportLab 的 stringWidth 和 splitLines 方法计算字体大小来获得工作版本。虽然这意味着它不再是递归的：

from reportlab.platypus import SimpleDocTemplate
from reportlab.lib.styles import ParagraphStyle
from reportlab.lib.units import inch
from reportlab.lib.pagesizes import A4
from reportlab.platypus import Paragraph
from reportlab.lib.utils import simpleSplit
from reportlab.pdfbase.pdfmetrics import stringWidth

def shrink_font_size(aW, aH, text, style):
    """Shrinks font size by using pdfmetrics to calculate the height
    of a paragraph, given the font name, size, and available width."""
    def break_lines(text, aW):
        # simpleSplit calculates how reportlab will break up the lines for
        # display in a paragraph, by using width/fontsize.
        return simpleSplit(text, style.fontName, style.fontSize, aW)

    def line_wrap(lines, style):
        # Get overall width of text by getting stringWidth of longest line
        width = stringWidth(max(lines), style.fontName, style.fontSize)
        # Paragraph height can be calculated via line spacing and number of lines.
        height = style.leading * len(lines)
        return width, height

    lines = break_lines(text, aW)
    width, height = line_wrap(lines, style)

    while height > aH or width > aW:
        style.fontSize -= 1
        lines = break_lines(text, aW)
        width, height = line_wrap(lines, style)


def renderPage(name, text):
    doc = SimpleDocTemplate("%s.pdf" % name)
    parts = []
    # Wasn't sure where PAGE_WIDTH and PAGE_HEIGHT came from for OP,
    # so I just used a standard A4 page measurement.
    PAGE_WIDTH, PAGE_HEIGHT = A4
    aW = PAGE_WIDTH - 4*inch  # available width and height 
    aH = PAGE_HEIGHT - 4*inch

    style = ParagraphStyle(name='fancy')
    style.fontSize = 200
    style.leading = 20
    shrink_font_size(aW, aH, text, style)

    p = Paragraph(text, style)
    parts.append(p)
    doc.build(parts)

if __name__ == "__main__":
    renderPage('test', '12345689019283382848248284 842828428529392381472754 842828428529392381472754 842828428529392381472754\n' * 10)