Re: [Matplotlib-users] Save a plot background
Hrafnkell Pálsson wrote:
> Any chance of further help?
> John?
>
> Hrafnkell
>
Hrafnkell: I'm pretty sure this is a fundamental limitation of
canvas.restore_region - everything gets draw on top of it.
If I recall correctly, you'd like to save the map with coastlines drawn,
and just redraw contours on it. If you're reusing a Basemap instance,
I'd be surprised if the time spent redrawing the coastlines is all that
significant. Are you? Creating the coastline polygons in map
projection coordinates is the most expensive operation, but that is done
when the Basemap instance is created.
Another option would be to just remove the contours from the figure,
then redraw the new ones and re-save the figure, i.e.
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
# create new figure
fig=plt.figure()
# setup of of mollweide Basemap.
m = Basemap(resolution='c',projection='moll',lon_0=0)
# draw some contours.
x, y = m(lons, lats) # get map projection coords of lat/lon grid
CS = m.contour(x,y,data,15,linewidths=0.5,colors='k')
# draw coastlines and projection limb.
m.drawcoastlines()
m.drawmapboundary()
# save figure with contours.
plt.savefig('fig1.png')
# remove contours, save figure again.
for coll in CS.collections:
coll.remove()
plt.savefig('fig2.png')
# draw contours again, this time red, save figure a third time.
CS = m.contour(x,y,data,15,linewidths=0.5,colors='r')
plt.savefig('fig3.png')
HTH,
-Jeff
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Re: [Matplotlib-users] Save a plot background
Any chance of further help? John? Hrafnkell -- View this message in context: http://www.nabble.com/Save-a-plot-background-tp20519596p20771515.html Sent from the matplotlib - users mailing list archive at Nabble.com. - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
Hrafnkell Pálsson wrote:
> Jeff Whitaker wrote:
>
>> Hrafnkell:
>>
>> Had some time this morning, so I used John's method to create a working
>> Basemap example:
>>
>> import matplotlib
>> matplotlib.use('Agg')
>> from mpl_toolkits.basemap import Basemap
>> import matplotlib.pyplot as plt
>>
>> # this example shows how to save a map background and
>> # reuse it in another figure.
>>
>> # make sure we have all the same properties on all figs
>> figprops = dict(figsize=(8,6), dpi=100, facecolor='white')
>>
>> # generate the first figure.
>> fig1 = plt.figure(1,**figprops)
>> ax1 = fig1.add_subplot(111)
>> # create basemap instance, plot coastlines.
>> map = Basemap(projection='moll',lon_0=0)
>> map.drawcoastlines()
>> map.drawmapboundary(fill_color='aqua')
>> map.fillcontinents(color='coral',lake_color='aqua')
>> fig1.canvas.draw()
>> background = fig1.canvas.copy_from_bbox(fig1.bbox)
>> fig1.savefig('figure1.png', dpi=100)
>>
>>
>> # generate the second figure, re-using the background
>> # from figure 1.
>> fig2 = plt.figure(2,frameon=False,**figprops)
>> ax2 = fig2.add_subplot(111, frameon=False, xticks=[], yticks=[])
>> # restore previous background.
>> fig2.canvas.restore_region(background)
>> # draw parallels and meridians on existing background.
>> map.drawparallels(range(-90,90,30))
>> map.drawmeridians(range(-180,180,60))
>> fig2.savefig('figure2.png', dpi=100)
>>
>>
>> I've added this to the basemap examples directory as save_background.py
>>
>> HTH,
>>
>> -Jeff
>>
>>
>
> There's still one snag.
> Using your example I could restore the background.
> But it turns out everything is plotted over the background; so if my
> background consist only of the coastline and then I do a filled contour plot
> after restoring it the coastline disappears under the filled contours (by
> using the alpha keyword to contourf I could see the coastline beneath).
>
> Had I plotted the coastline into the figure instead of restoring it this
> would not have happened.
>
> Is there any way of avoiding this?
>
> Hrafnkell
>
>
>
>
Hrafnkell:
I see your point, but I don't see any obvious solution. Perhaps someone with
more knowledge of matplotlib internals (John?) can answer.
-Jeff
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Re: [Matplotlib-users] Save a plot background
Jeff Whitaker wrote:
>
> Hrafnkell:
>
> Had some time this morning, so I used John's method to create a working
> Basemap example:
>
> import matplotlib
> matplotlib.use('Agg')
> from mpl_toolkits.basemap import Basemap
> import matplotlib.pyplot as plt
>
> # this example shows how to save a map background and
> # reuse it in another figure.
>
> # make sure we have all the same properties on all figs
> figprops = dict(figsize=(8,6), dpi=100, facecolor='white')
>
> # generate the first figure.
> fig1 = plt.figure(1,**figprops)
> ax1 = fig1.add_subplot(111)
> # create basemap instance, plot coastlines.
> map = Basemap(projection='moll',lon_0=0)
> map.drawcoastlines()
> map.drawmapboundary(fill_color='aqua')
> map.fillcontinents(color='coral',lake_color='aqua')
> fig1.canvas.draw()
> background = fig1.canvas.copy_from_bbox(fig1.bbox)
> fig1.savefig('figure1.png', dpi=100)
>
>
> # generate the second figure, re-using the background
> # from figure 1.
> fig2 = plt.figure(2,frameon=False,**figprops)
> ax2 = fig2.add_subplot(111, frameon=False, xticks=[], yticks=[])
> # restore previous background.
> fig2.canvas.restore_region(background)
> # draw parallels and meridians on existing background.
> map.drawparallels(range(-90,90,30))
> map.drawmeridians(range(-180,180,60))
> fig2.savefig('figure2.png', dpi=100)
>
>
> I've added this to the basemap examples directory as save_background.py
>
> HTH,
>
> -Jeff
>
There's still one snag.
Using your example I could restore the background.
But it turns out everything is plotted over the background; so if my
background consist only of the coastline and then I do a filled contour plot
after restoring it the coastline disappears under the filled contours (by
using the alpha keyword to contourf I could see the coastline beneath).
Had I plotted the coastline into the figure instead of restoring it this
would not have happened.
Is there any way of avoiding this?
Hrafnkell
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Re: [Matplotlib-users] Save a plot background
Hrafnkell Pálsson wrote:
>
>
>> This will turn off the rendering of both the background rectangle as
>> well as all the ticks and their associated labels, ticklines and
>> gridlines. Perhaps Jeff can advise you vis-a-vis the basemap api what
>> the equivalent is
>>
>>
>
> Ok, I tested your example and see what you mean.
> But if I understood you correctly this won't allow me to retain the
> watermark and the dots I've used for marking cities.
> It would be nice if I could retain the whole background, if it wouldn't
> matter whether I retrieved the background or actually plotted it.
> But even just avoiding plotting the coastline every time would save a lot of
> time.
>
>
>
>
>> Perhaps Jeff can advise you vis-a-vis the basemap api what
>> the equivalent is
>>
>>
>
> Could you, Jeff, give me a nudge in the right direction? I've read through
> the basemap documentation but didn't notice anything that might help.
>
> Hrafnkell
>
Hrafnkell:
Had some time this morning, so I used John's method to create a working Basemap
example:
import matplotlib
matplotlib.use('Agg')
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
# this example shows how to save a map background and
# reuse it in another figure.
# make sure we have all the same properties on all figs
figprops = dict(figsize=(8,6), dpi=100, facecolor='white')
# generate the first figure.
fig1 = plt.figure(1,**figprops)
ax1 = fig1.add_subplot(111)
# create basemap instance, plot coastlines.
map = Basemap(projection='moll',lon_0=0)
map.drawcoastlines()
map.drawmapboundary(fill_color='aqua')
map.fillcontinents(color='coral',lake_color='aqua')
fig1.canvas.draw()
background = fig1.canvas.copy_from_bbox(fig1.bbox)
fig1.savefig('figure1.png', dpi=100)
# generate the second figure, re-using the background
# from figure 1.
fig2 = plt.figure(2,frameon=False,**figprops)
ax2 = fig2.add_subplot(111, frameon=False, xticks=[], yticks=[])
# restore previous background.
fig2.canvas.restore_region(background)
# draw parallels and meridians on existing background.
map.drawparallels(range(-90,90,30))
map.drawmeridians(range(-180,180,60))
fig2.savefig('figure2.png', dpi=100)
I've added this to the basemap examples directory as save_background.py
HTH,
-Jeff
--
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Re: [Matplotlib-users] Save a plot background
Hrafnkell Pálsson wrote: > > >> This will turn off the rendering of both the background rectangle as >> well as all the ticks and their associated labels, ticklines and >> gridlines. Perhaps Jeff can advise you vis-a-vis the basemap api what >> the equivalent is >> >> > > Ok, I tested your example and see what you mean. > But if I understood you correctly this won't allow me to retain the > watermark and the dots I've used for marking cities. > It would be nice if I could retain the whole background, if it wouldn't > matter whether I retrieved the background or actually plotted it. > But even just avoiding plotting the coastline every time would save a lot of > time. > > > > >> Perhaps Jeff can advise you vis-a-vis the basemap api what >> the equivalent is >> >> > > Could you, Jeff, give me a nudge in the right direction? I've read through > the basemap documentation but didn't notice anything that might help. > > Hrafnkell > Hrafnkell: You can go by the example John gave, using figure and axes instance methods. Basemap just draws stuff on the current figure and axes instances. Are you recreating the Basemap instance every time you generate a plot? If the projection isn't changing, you can save a lot of overhead by re-using a single Basemap instance. You can even pickle it to a file for use in another script. -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX: (303)497-6449 NOAA/OAR/PSD R/PSD1Email : [EMAIL PROTECTED] 325 BroadwayOffice : Skaggs Research Cntr 1D-113 Boulder, CO, USA 80303-3328 Web: http://tinyurl.com/5telg - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
> This will turn off the rendering of both the background rectangle as > well as all the ticks and their associated labels, ticklines and > gridlines. Perhaps Jeff can advise you vis-a-vis the basemap api what > the equivalent is > Ok, I tested your example and see what you mean. But if I understood you correctly this won't allow me to retain the watermark and the dots I've used for marking cities. It would be nice if I could retain the whole background, if it wouldn't matter whether I retrieved the background or actually plotted it. But even just avoiding plotting the coastline every time would save a lot of time. > Perhaps Jeff can advise you vis-a-vis the basemap api what > the equivalent is > Could you, Jeff, give me a nudge in the right direction? I've read through the basemap documentation but didn't notice anything that might help. Hrafnkell -- View this message in context: http://www.nabble.com/Save-a-plot-background-tp20519596p20582574.html Sent from the matplotlib - users mailing list archive at Nabble.com. - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
John Hunter wrote: > On Tue, Nov 18, 2008 at 9:41 AM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote: > >> Ok, I tried your last suggestion and sure enough it worked. >> But it turns out to solve only half of my problem. I'd like to be able to >> restore the background (using the Agg backend) and then use it further, i.e. >> plot on it, without it disappearing. >> >> Elaborating on my real use case, what I want to do is to make a Basemap >> instance, plot the coastlines and other things that are constant in time >> (put marker on the maps for cities, watermark the figure, draw meridians and >> parallels and so on) and save that as a background. >> I would then restore this background and plot "the weather" (open and filled >> contours, quivers and barbs) onto it. I typically have data for some dozens >> of timesteps, so I'd be restoring the background many times. Each time I'd >> > > This should work fine as long as you make the figure frame and axes > frame invisible. Basically, you need to create the figure background, > and the axes background with all the grid lines, tick labels, > coastlines, etc, save it, and then for the new figure make sure all > the stuff you have saved is turned off. I am not a basemap user, but > I know all this stuff is ultimately exposed. Eg for a plain vanilla > axes, you would do > > > fig1 = figure(frameon=False) > ax1 = fig1.add_subplot(111) > > > fig = figure(frameon=False) > ax = fig.add_subplot(111, frameon=false, xticks=[], yticks=[]) > fig.canvas.restore_region(background) > > > This will turn off the rendering of both the background rectangle as > well as all the ticks and their associated labels, ticklines and > gridlines. Perhaps Jeff can advise you vis-a-vis the basemap api what > the equivalent is > > > Don't see why this wouldn't work fine with basemap, as long as you don't call the drawmapboundary method (which will set the axes frame on). -Jeff -- Jeffrey S. Whitaker Phone : (303)497-6313 Meteorologist FAX: (303)497-6449 NOAA/OAR/PSD R/PSD1Email : [EMAIL PROTECTED] 325 BroadwayOffice : Skaggs Research Cntr 1D-113 Boulder, CO, USA 80303-3328 Web: http://tinyurl.com/5telg - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
On Tue, Nov 18, 2008 at 9:41 AM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote: > > Ok, I tried your last suggestion and sure enough it worked. > But it turns out to solve only half of my problem. I'd like to be able to > restore the background (using the Agg backend) and then use it further, i.e. > plot on it, without it disappearing. > > Elaborating on my real use case, what I want to do is to make a Basemap > instance, plot the coastlines and other things that are constant in time > (put marker on the maps for cities, watermark the figure, draw meridians and > parallels and so on) and save that as a background. > I would then restore this background and plot "the weather" (open and filled > contours, quivers and barbs) onto it. I typically have data for some dozens > of timesteps, so I'd be restoring the background many times. Each time I'd This should work fine as long as you make the figure frame and axes frame invisible. Basically, you need to create the figure background, and the axes background with all the grid lines, tick labels, coastlines, etc, save it, and then for the new figure make sure all the stuff you have saved is turned off. I am not a basemap user, but I know all this stuff is ultimately exposed. Eg for a plain vanilla axes, you would do fig1 = figure(frameon=False) ax1 = fig1.add_subplot(111) fig = figure(frameon=False) ax = fig.add_subplot(111, frameon=false, xticks=[], yticks=[]) fig.canvas.restore_region(background) This will turn off the rendering of both the background rectangle as well as all the ticks and their associated labels, ticklines and gridlines. Perhaps Jeff can advise you vis-a-vis the basemap api what the equivalent is - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
Ok, I tried your last suggestion and sure enough it worked.
But it turns out to solve only half of my problem. I'd like to be able to
restore the background (using the Agg backend) and then use it further, i.e.
plot on it, without it disappearing.
Elaborating on my real use case, what I want to do is to make a Basemap
instance, plot the coastlines and other things that are constant in time
(put marker on the maps for cities, watermark the figure, draw meridians and
parallels and so on) and save that as a background.
I would then restore this background and plot "the weather" (open and filled
contours, quivers and barbs) onto it. I typically have data for some dozens
of timesteps, so I'd be restoring the background many times. Each time I'd
plot a particular weather (corresponding to a particular timestep) onto the
background I'd save that figure, so in the end I have some dozens of
figures.
Sliding the slider beneath the pictures at http://www.belgingur.is
http://www.belgingur.is should give a good idea of what I mean (notice that
the website is also in English).
A somewhat simplified example of what I'd like to do (but it catches the
essence of it) follows.
The problem that arises is that when I try to plot onto the background it
disappears and only what I tried to plot onto it remains. So figure2.png
contains the coastline of Iceland while figure3.png contains only the
quivers, the coastline has disappeared.
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import numpy
from mpl_toolkits.basemap import Basemap
plt.close('all')
basemap = Basemap(llcrnrlat=62.8,
llcrnrlon=-24.8,
urcrnrlat=66.7,
urcrnrlon=-12.4,
lat_0=65.0,
lon_0=-19.5)
# make sure we have all the same properties on all figs
figprops = dict(figsize=(8,6), dpi=100, facecolor='white')
fig1 = plt.figure(1, **figprops)
basemap.drawcoastlines()
fig1.canvas.draw()
background = fig1.canvas.copy_from_bbox(fig1.bbox)
# turn the frame off or it will overwrite the background
fig2 = plt.figure(2, frameon=False, **figprops)
fig2.canvas.restore_region(background)
fig2.savefig('figure2.png', dpi=100)
# turn the frame off or it will overwrite the background
fig3 = plt.figure(3, frameon=False, **figprops)
fig3.canvas.restore_region(background)
# create a lon-lat grid for plotting quivers
n, m = 10, 5
latitudes = numpy.resize(numpy.linspace(63.5, 65.0, n), (n, m))
longitudes = numpy.transpose(numpy.resize(numpy.linspace(-22, -14, n),(n,
m)))
x, y = basemap(longitudes, latitudes)
# create the u and v components of the quivers
u = numpy.resize([5], (n, m))
v = numpy.resize([5], (n, m))
# since keyword ax is not supplied the current axes instance is used, i.e.
the axes of fig3
basemap.quiver(x, y, u, v)
fig3.savefig('figure3.png', dpi=100)
Hrafnkell
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Re: [Matplotlib-users] Save a plot background
On Mon, Nov 17, 2008 at 8:05 AM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote:
>
> Hi
>
> I tried you suggestions but it didn't work out for me.
> In the following code I try to save the axes and the grid from figure1 into
> buffer and then restore it on figure2 but figure2.png turns out to be of an
> empty canvas.
>
OK, ever since Jae-Joon clued me into to the importance of the savefig
call, I realized there is a fairly easy solution for your problem.
The problem you are having is that savefig is redrawing the "figure
frame" which is essentially just filling the rectangular background of
the figure canvas. This is obscuring the background you are trying to
restore. SO just turn the frame off, and your background will be
revealed in its place. Here is the example code:
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
plt.close('all')
# make sure we have all the same properties on all figs
figprops = dict(figsize=(8,6), dpi=100, facecolor='white')
fig1 = plt.figure(1, **figprops)
ax1 = fig1.add_subplot(111)
ax1.grid()
fig1.canvas.draw()
background = fig1.canvas.copy_from_bbox(fig1.bbox)
fig1.savefig('figure1.png', dpi=100)
# turn the frame off or it will overwrite the background
fig2 = plt.figure(2, frameon=False, **figprops)
fig2.canvas.restore_region(background)
fig2.savefig('figure2.png', dpi=100)
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Re: [Matplotlib-users] Save a plot background
On Mon, Nov 17, 2008 at 1:50 PM, Jae-Joon Lee <[EMAIL PROTECTED]> wrote: > I think the savefig() command calls draw() internally, doesn't it? Ahh yes. The copy_from_bbox / restore_region was conceived as an aid to animation and I don't think I've used it in the context of savefig where none of the artists are involved in the restored region. Ie, in a typical animation use case, you draw the axes, background and ticks, store the region, and then animate a line on top of it. When you go to savefig, the axes background is redrawn because the associated artists already reside in the figure, along with the line in its final state. It should be fairly easy to expose the agg BufferRegion object in the artist API, so you could grab a buffer region from one canvas, bless it as an artist, and add it to the figure or another figure, with the x and y location attrs exposed so it could be easily moved. In this case you would get the zorder for free. This would help some, and would certainly address the case at hand, but the really big win would probably be something more like the chaco model, where each zorder is rendered onto a different rendering buffer, with a fairly straight-forward way to just re-render certain planes. This would certainly be harder. Could you elaborate a bit on your use case, which will help me in thinking about how this should be done? JDH - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Save a plot background
I think the savefig() command calls draw() internally, doesn't it?
So, I guess the restore_region() command comes before the draw() call,
i.e., it has no effect for the saved figure.
One way I can think of is to save the agg buffer without redrawing it.
It seems work.
---
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
fig1 = plt.figure(1)
ax1 = fig1.add_subplot(111)
ax1.grid()
fig1.canvas.draw()
background = fig1.canvas.copy_from_bbox(ax1.bbox)
fig1.savefig('figure1.png')
from matplotlib import _png
from matplotlib.cbook import is_string_like
def print_png(fig, filename_or_obj):
canvas = fig.canvas
renderer = canvas.get_renderer()
if is_string_like(filename_or_obj):
filename_or_obj = file(filename_or_obj, 'wb')
_png.write_png(renderer._renderer.buffer_rgba(0, 0),
renderer.width, renderer.height,
filename_or_obj, canvas.figure.dpi)
fig1.clf()
fig1.canvas.restore_region(background)
print_png(fig1, 'figure2.png')
---
Somehow, the copy_from_bbox() needs to be called before the savefig().
This is just a quick hacky solution.
But I think it would be nice if we have this kind of functionality in
the mpl, ideally with zorder support. For example,
> ax1.add_background(background, zroder=2)
And, restore_region(background) is called within the draw() method
(with correct zorder).
Just a thought.
IHTH,
-JJ
On Mon, Nov 17, 2008 at 12:37 PM, John Hunter <[EMAIL PROTECTED]> wrote:
> On Mon, Nov 17, 2008 at 8:05 AM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote:
>>
>> Hi
>>
>> I tried you suggestions but it didn't work out for me.
>> In the following code I try to save the axes and the grid from figure1 into
>> buffer and then restore it on figure2 but figure2.png turns out to be of an
>> empty canvas.
>>
>> #!/usr/bin/env /opt/python/bin/python
>> # encoding: utf-8
>> import matplotlib
>> if not matplotlib.get_backend()=='agg':
>>matplotlib.use('Agg')
>> import pylab
>>
>> figure1 = pylab.figure(1)
>> axes1 = pylab.gca()
>> axes1.grid()
>> canvas1 = axes1.figure.canvas
>> background = canvas1.copy_from_bbox(axes1.bbox)
>> figure1.savefig('figure1.png')
>
> The only problem I could see with your code is that you need to force
> a draw before copying the background. But when I added the draw, and
> then further simplified to reuse the same canvas, I still am not
> seeing the restored region. I will need to do further digging to see
> what is going wrong, but the problem appears both on the maintenance
> branch and the trunk. Here is my modified test script:
>
>import matplotlib
>matplotlib.use('Agg')
>
>import matplotlib.pyplot as plt
>
>fig1 = plt.figure(1)
>ax1 = fig1.add_subplot(111)
>ax1.grid()
>fig1.canvas.draw()
>fig1.savefig('figure1.png')
>background = fig1.canvas.copy_from_bbox(ax1.bbox)
>
>fig1.clf()
>
>
>#figure2 = pylab.figure(2)
>#canvas2 = figure2.canvas
>fig1.canvas.restore_region(background)
>fig1.savefig('figure2.png')
>
>
> JDH
>
> -
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Re: [Matplotlib-users] Save a plot background
On Mon, Nov 17, 2008 at 8:05 AM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote:
>
> Hi
>
> I tried you suggestions but it didn't work out for me.
> In the following code I try to save the axes and the grid from figure1 into
> buffer and then restore it on figure2 but figure2.png turns out to be of an
> empty canvas.
>
> #!/usr/bin/env /opt/python/bin/python
> # encoding: utf-8
> import matplotlib
> if not matplotlib.get_backend()=='agg':
>matplotlib.use('Agg')
> import pylab
>
> figure1 = pylab.figure(1)
> axes1 = pylab.gca()
> axes1.grid()
> canvas1 = axes1.figure.canvas
> background = canvas1.copy_from_bbox(axes1.bbox)
> figure1.savefig('figure1.png')
The only problem I could see with your code is that you need to force
a draw before copying the background. But when I added the draw, and
then further simplified to reuse the same canvas, I still am not
seeing the restored region. I will need to do further digging to see
what is going wrong, but the problem appears both on the maintenance
branch and the trunk. Here is my modified test script:
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
fig1 = plt.figure(1)
ax1 = fig1.add_subplot(111)
ax1.grid()
fig1.canvas.draw()
fig1.savefig('figure1.png')
background = fig1.canvas.copy_from_bbox(ax1.bbox)
fig1.clf()
#figure2 = pylab.figure(2)
#canvas2 = figure2.canvas
fig1.canvas.restore_region(background)
fig1.savefig('figure2.png')
JDH
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Re: [Matplotlib-users] Save a plot background
Hi
I tried you suggestions but it didn't work out for me.
In the following code I try to save the axes and the grid from figure1 into
buffer and then restore it on figure2 but figure2.png turns out to be of an
empty canvas.
#!/usr/bin/env /opt/python/bin/python
# encoding: utf-8
import matplotlib
if not matplotlib.get_backend()=='agg':
matplotlib.use('Agg')
import pylab
figure1 = pylab.figure(1)
axes1 = pylab.gca()
axes1.grid()
canvas1 = axes1.figure.canvas
background = canvas1.copy_from_bbox(axes1.bbox)
figure1.savefig('figure1.png')
figure2 = pylab.figure(2)
canvas2 = figure2.canvas
canvas2.restore_region(background)
figure2.savefig('figure2.png')
Thanks for your efforts,
Hrafnkell
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Re: [Matplotlib-users] Save a plot background
On Sat, Nov 15, 2008 at 3:23 PM, Hrafnkell Pálsson <[EMAIL PROTECTED]> wrote: > > Hi > I haven't managed to save a plot background into buffer to be able to > restore it later. > I use matplotlib to draw weather maps (see www.belgingur.is), and though the > weather constantly changes the outlines of the countries are the same for > every picture. > Currently I plot the coastlines anew for every picture, which is kinda *not > smart*. Have you tried the "copy from bbox" / "restore_region" methods. Draw just what you want to save, and use "copy_from_bbox". Later when you want to plot something new, do a "restore_region" onto a clean canvas and then plot the new stuff on top: * background = canvas.copy_from_bbox(ax.bbox) - copy the region in ax.bbox into a pixel buffer and return it in an object type of your choosing. bbox is a matplotlib BBox instance from the transforms module. background is not used by the matplotlib frontend, but it stores it and passes it back to the backend in the restore_region method. You will probably want to store not only the pixel buffer but the rectangular region of the canvas from whence it came in the background object. * canvas.restore_region(background) - restore the region copied above to the canvas. * canvas.blit(bbox) - transfer the pixel buffer in region bounded by bbox to the canvas. Search the examples for "copy_from_bbox" on the web site http://matplotlib.sourceforge.net/search.html If you are still having troubles, let me know and I can give more help. JDH - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
