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POCreate PDF with (resized) PNG images using Pycairo - rescaling Surface issue
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copied!<p>I have som PNG image links that I want to download, "convert to thumbnails" and save to PDF using Python and Cairo.</p> <p>Now, I have a working code, but I don't know how to control image size on paper. Is there a way to resize a PyCairo Surface to the dimensions I want (which happens to be smaller than the original)? I want the original pixels to be "shrinked" to a higher resolution (on paper).</p> <p>Also, I tried <code>Image.rescale()</code> function from PIL, but it gives me back a 20x20 pixel output (out of a 200x200 pixel original image, which is not the banner example on the code). What I want is a 200x200 pixel image plotted inside a 20x20 mm square on paper (instead of a 200x200 mm square as I am getting now)</p> <p>My current code is:</p> <pre><code>#!/usr/bin/python import cairo, urllib, StringIO, Image # could I do it without Image module? paper_width = 210 paper_height = 297 margin = 20 point_to_milimeter = 72/25.4 pdfname = "out.pdf" pdf = cairo.PDFSurface(pdfname , paper_width*point_to_milimeter, paper_height*point_to_milimeter) cr = cairo.Context(pdf) cr.scale(point_to_milimeter, point_to_milimeter) f=urllib.urlopen("http://cairographics.org/cairo-banner.png") i=StringIO.StringIO(f.read()) im=Image.open(i) # are these StringIO operations really necessary? imagebuffer = StringIO.StringIO() im.save(imagebuffer, format="PNG") imagebuffer.seek(0) imagesurface = cairo.ImageSurface.create_from_png(imagebuffer) ### EDIT: best answer from Jeremy, and an alternate answer from mine: best_answer = True # put false to use my own alternate answer if best_answer: cr.save() cr.scale(0.5, 0.5) cr.set_source_surface(imagesurface, margin, margin) cr.paint() cr.restore() else: cr.set_source_surface(imagesurface, margin, margin) pattern = cr.get_source() scalematrix = cairo.Matrix() # this can also be used to shear, rotate, etc. scalematrix.scale(2,2) # matrix numbers seem to be the opposite - the greater the number, the smaller the source scalematrix.translate(-margin,-margin) # this is necessary, don't ask me why - negative values!! pattern.set_matrix(scalematrix) cr.paint() pdf.show_page() </code></pre> <p>Note that the beautiful Cairo banner does not even fit the page... The ideal result would be that I could control the width and height of this image in user space units (milimeters, in this case), to create a nice header image, for example.</p> <p>Thanks for reading and for any help or comment!!</p>

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