Re: Dimensions in pixels of a draw Area to obtain a plot on a A4 paper

[Nicola Fontana <ntd entidi it>]

Il Sat, 21 Apr 2018 04:01:21 +0200 arkkimede <arkkimede gmail com> scrisse:

> HI!
> I've realized an App with GTK3 and the library CAIRO to plot results of
> measurements.
> I use the function "cairo_surface_write_to_png" to obtain a png file that I
> put on a paper of format A4 (with usual resolution of 300dpi) to generate
> reports.
> Consider also that preliminary plot are observed on a screen with
> resolution 1920x1080.
>
> The question is:
>
> Could you advice me dimensions in pixels of the draw area in order to
> obtain png file to plot on A4 paper and see (more or less) similar pictures
> on the screen
> (or different dimensions for the plot on png and dimensions for the plot on
> screen)?

Hi,

the PNG backend must not be used for serious applications. From
the doc [1]:

    It is a toy API. It only offers very simple support for
    reading and writing PNG files, which is sufficient for testing
    and demonstration purposes.

So my advice is "use the PDF backend".

[1] https://cairographics.org/manual/cairo-PNG-Support.html

Ciao.
-- 
Nicola