ReportLab：如何在画布上居中一张图片

Question

ReportLab：如何在画布上居中一张图片

4

在这里尝试居中一张图片。现在，我能够将图片相对于x轴居中，但我无法将实际图片居中在该点上。相反，它会从页面的中心开始显示图片。

from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.pagesizes import letter
from reportlab.lib.units import inch
from reportlab.lib.units import mm
from reportlab.platypus import Image
from reportlab.lib.enums import TA_JUSTIFY
from reportlab.lib.utils import ImageReader
from reportlab.pdfgen import canvas

Width, Height = letter
styles = getSampleStyleSheet()
Title = "Comparison Index"
pageinfo = "platypus example"
BTRLogo = 'BTALogo.png'
PartnerLogo = 'PartnerLogo.png'
ClientLogo = 'ClientLogo.png'
Graph1 = 'PlanOffered.jpg'



# Define the fixed features of the first page of the document
def myFirstPage(canvas, doc):
    canvas.saveState()

    canvas.setFillColorCMYK(0.68, 0.44, 0, 0.41)
    canvas.setFontSize(22)
    canvas.setFont('Helvetica-Bold', 36)
    canvas.drawString(40, 670, 'Health & Welfare')

    canvas.setFont('Helvetica-Bold', 24)
    canvas.drawString(40, 625, 'Benchmark Comparison Report')

    canvas.setFont('Helvetica', 16)
    canvas.drawString(40, 550, 'Prepared for:')
    canvas.drawString(40, 400, 'Prepared on:') #INSERY DYNAMIC DATE****

    canvas.drawImage(BTRLogo,480,18,width=100,height=66.62,mask='auto') 
    #Logo is measured and good to go

    canvas.drawImage(PartnerLogo, 10, Height/5, width=Width/1.2, 
    preserveAspectRatio=True, mask='auto') #MAKE SURE IMAGE IS DYNAMIC AND HAS MAX SETS

    canvas.setStrokeColorCMYK(0.68,0.44,0,0.41)
    canvas.setLineWidth(7)
    canvas.line(40,112,570,112)



# Since we want pages after the first to look different from the first we define an alternate layout for
# the fixed features of the other pages.
# Note that the two functions use the pdfgen level canvas operations to paint the annotations for the pages.
def myLaterPages(canvas, doc):
    canvas.saveState()
    canvas.setFont('Times-Roman', 23)
    page_num = canvas.getPageNumber()
    text = "Page #%s" % page_num
    canvas.drawRightString(200 * mm, 20 * mm, text)
    canvas.restoreState()

def myThirdPages(canvas, doc):
    canvas.saveState()
    canvas.setFont('Times-Roman', 9)
    canvas.drawString(inch, 0.75 * inch, "Page %d %s")
    canvas.restoreState()

# Create a story and build the document
def createMultiPage():

    doc = SimpleDocTemplate("Comparison Index.pdf", pagesize=letter, rightMargin=72, leftMargin=72, topMargin=72, bottomMargin=18)
    style = styles["Normal"]
    styles.add(ParagraphStyle(name='Justify', alignment=TA_JUSTIFY))

    Story = [Spacer(1, 2 * inch)]

    doc.build(Story, onFirstPage=myFirstPage, onLaterPages=myLaterPages)

if __name__ == "__main__":
    createMultiPage()

所以，最终我需要确保我的图像在x轴上居中。具体来说，只有PartnerLogo需要这样做。此标志需要位于画布线的正上方并居中。请帮忙！

- Julian Olivares

1个回答

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原文链接

- Kyle Heuton · Accepted Answer

您有几个选项。如果您只想将图像居中于您的行上方，而该行的位置是固定的，则可以根据该行的位置绘制图像：

line_x_start = 40
line_width = 530
line_y = 112

canvas.setStrokeColorCMYK(0.68,0.44,0,0.41)
canvas.setLineWidth(7)
canvas.line(line_x_start, line_y,
            line_x_start+line_width, line_y)

canvas.drawImage(PartnerLogo, line_x_start, line_y, width=line_width, 
                 preserveAspectRatio=True, mask='auto')

如果你想让标志比线的完整宽度更小，可以从line_x_start +一些缓冲开始图像，并设置width=line_width-某些缓冲*2 此外，在 drawImage 的文档中，有一个选项可以将图像锚定在边界框的中心，因此你可以这样做：

canvas.drawImage(PartnerLogo, line_x_start, line_y, width=line_width, 
                 preserveAspectRatio=True, mask='auto', anchor='c')