Re: GtkPrintOperation and margins

[Ivan Baldo <ibaldo adinet com uy>]

 Hello Ian.
I don't use GTK 2.10 yet but AFAIK when you are producing a Postscript 
file you do everything with a resolution of 72dpi, that is, in Adobe 
point units (1pt = 1/72 inches); so, you position everything with 72dpi 
precision, though, when you embed a bitmap image, that image will use 
whatever DPI the printer has; I think with Cairo thats called the 
"fallback resolution".
My hope is that GTK sets a correctly configured Cairo context with the 
correct fallback resolution suitable for the printer but with a 
resolution of 72dpi for positioning and text.
You may change the Cairo Current Transformation Matrix (CTM) to scale 
everything by 1/72 so that you work with inches, that should be far more 
intuitive and easy.
The Postscript interpreter will correctly render the curves, segments, 
fonts, etc. with the dpi of the printer and the images will be stored 
with the dpi of the printer.
So, maybe this isn't a bug but a misunderstanding, I didn't read the GTK 
2.10 documentation about printing yet though maybe it can be improved.
It would be nice for someone more experienced in this topic to confirm this.
HTH, bye! :)



El 30/11/06 16:55, Ian Puleston escribi� Another bug that I noticed whilst working on this is that I initially tried
> to work in pixels rather than inches, so I tried to extract the print margin
> size in pixels by:
>
>     margin = gtk_page_setup_get_top_margin(pageSetup, GTK_UNIT_PIXEL);
>
> And with a 1" top margin this returned the value 72. With a 300dpi printer
> that should have returned 300 - it has actually returned the point size
> rather than pixel size (as if I'd called it with GTK_UNIT_POINT).
>
> I will submit a bug report on this too if thats not already been done.
>
>
>
>
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