Apparently the screen resolution is not set to 72 dpi on every platform we support.

Discussion: https://groups.google.com/forum/?fromgroups#!topic/phantomjs/YQIyxLWhmr0.

Related pull request: https://github.com/ariya/phantomjs/pull/286.

Rescheduled to 1.8.

I agree that we should provide a consistent default value of 72 for resolution (DPI) fonts, PDFs, etc. across all supported platforms. However, I also think we should provide the user with a mechanism to set their own choice DPI, as mentioned by other users in comments on the Pull Request and in forum discussions, e.g. https://groups.google.com/forum/m/?fromgroups#!topic/phantomjs/V9EU0UdT1cg

Rescheduled to 1.9.

I found that all we need is to implement physicalSize() for our minimalistic QPlatformScreen implementation. Because it was not implemented, the default 100 dpi was used and that causes the inconsistency.

It's more complicated on Windows because Qt just uses the values from GetDeviceCaps and LOGPIXELSX/LOGPIXELSY. According to http://stackoverflow.com/questions/645352/is-the-number-of-pixels-per-inch-standard-on-all-windows-pc-displays-logpixels, the return values could be anything from 88, 96, 120, and maybe even more variations on the future Windows version.

I think nothing we can do about Windows for the near future. Hence, I plan to change the issue title to only cover OS X and Linux.

Linux: Ensure we use 72 dpi. https://github.com/ariya/phantomjs/commit/3f42fb230f

Filed Issue #934 to pursue fixing this for Windows in the future.

Still not fixed for me :( For some reason I still have different pdf outputs from mac os x version and from linux version

What about PNG output? The PDF output relies on the print engine which may have some slight differences.

With the 72 dpi change I have committed, QWebFrame::print gives zoomFactorX and zoomFactorY both to 1.

Here is a test script I used:;

var page = require('webpage').create(); page.content = '

Hello

The PDF results can be seen in the attachment, as well as the comparison screenshot.

try this:

var page = require('webpage').create();

page.paperSize = { format: 'A4', margin: "1cm", };

page.content = "Test"; page.render("out.pdf"); phantom.exit();

out.1.6-linux-mypatch obtained with the force dpi=72 patch added to phantomjs 1.6 (https://github.com/ariya/phantomjs/pull/286)

Did you try with version 1.8? Unfortunately, this one did not make it to 1.8. It will be part of 1.9, meanwhile you need to build it yourself.

Issue 750 has been merged into this issue.

This issue has been moved to GitHub: https://github.com/ariya/phantomjs/issues/10659