Re: [Matplotlib-users] Pixel placement of text

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

>>>>> "Eric" == Eric Firing <ef...@ha...> writes:

    Eric> I think that what you want to do requires something like the
    Eric> mechanism in QuiverKey: a derived artist with a draw method
    Eric> that figures out at draw time where to put the text; I don't
    Eric> think there is any other way to handle zooming while keeping
    Eric> the screen separation from a data point fixed.

You can do this using offsets -- see
matplotlib.axis.XTick._get_text1.  This is how tick labeling is done
(a point offset from an x location in data coords and a y location in
axis coords).  Here is an example -- you have to copy the default data
transform so that the offset doesn't affect the figure data

from matplotlib.transforms import Value, translation_transform,blend_xy_sep_transform
from pylab import figure, show

fig = figure()
ax = fig.add_subplot(111)
points = 7
pad = fig.dpi*Value(points/72.0)
# poor man's copy
trans = blend_xy_sep_transform(ax.transData, ax.transData)

# to the left and above
offset = translation_transform(Value(-1)*pad, pad)
trans.set_offset( (0,0), offset)

ax.plot([1,2,3])

t = ax.text(1,2, 'hi', transform=trans)

show()