Re: [matplotlib-devel] Re: Improved font manager

[John H. <jdh...@ac...>]

>>>>> "Paul" == Paul Barrett <ba...@st...> writes:


    Paul> This was an easy change to the font manager.  You should see
    Paul> it in CVS later today.

Great.

An unrelated bug I found in testing with one of my apps

In the font_manager

    def get_size_in_points(self, parent_size=None):
        """Convert text to point size"""
        if isinstance(self.__size, str):
            if   self.__size == 'larger':
                size = int(self.__parent_size*1.2)
            elif self.__size == 'smaller':
                size = int(self.__parent_size/1.2)
            else:
                defsize = fontManager.get_default_size()
                size = defsize*font_scalings[self.__size]
            return size
        else:
            return self.__size

I sometimes get key error on font_scalings[self.__size] when
self.__size is a number, eg 10.  From the code, it looks like you
intend self.__size to always be a relative size.  I did a temporary
workaround along the lines of

            else:
                try: size = float(self.__size)
                except ValueError:
                    defsize = fontManager.get_default_size()
                    size = defsize*font_scalings[self.__size]
            return size

but this hack may be masking another bug so I thought you'd want to
look into it.

    Paul> On a related issue, I noticed that the sizes of PS plots are
    Paul> different depending on which backend is used first.  If I
    Paul> send a plot directly to the PS backend, I get a nice plot
    Paul> (see the attachment simple_plot_PS.ps).  Whereas, if I first
    Paul> display the plot using TkAgg and then save it to PS, I get a
    Paul> plot that is much larger than the display area (see the
    Paul> attachment simple_plot.ps).  The text size in both plots
    Paul> appears to be the same size, this would indicate an
    Paul> incorrect scaling factor somewhere.

backend_tkagg needs to override FigureCanvasTkAgg.print_figure
following the lead of backend_gtkagg.  The critical point is that dpi
must be set to 72 for backend_ps.  Even though ps doesn't use DPI,
this value is used by the figure to compute the canvas size as
width*dpi and height*dpi, and this does affect backend_ps.

In FigureCanvaseGTKAgg.print_figure I save the orig dpi, set the
figure dpi to 72, print the figure, and then reset.  I do the same
with other figure properties (eg, background color, so you can have a
different color background for printing and GUI).

It should be mostly a cut and paste from backend_gtkagg.

JDH