How to display python matplotlib graphs (png) with Chaquopy in Android Studio












2














So I use chaquopy to get simple python programs functioning in an old (jelly bean) tablet (I replace the example console app's main.py in the src directory). Not bad for a beginner's start and I'm very happy.



But now for a test I try to display a matplotlib graph like this:



import matplotlib.pyplot as plt
import matplotlib.image as mpimg
def main():

image = mpimg.imread("/storage/emulated/0/Documents/test.png")
plt.imshow(image)
plt.show()


The matplotlib library was installed from within android studio (albeit with a few missing elements, manual pip3 install and usage of local files). Now the build and program finish without errors, but there is no graph. Installation of pillow and use of other graph types no avail.



Can this be handled in python, or is a dive into android studio / java required?



Thanks for any advice










share|improve this question
























  • Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
    – mhsmith
    Nov 14 at 15:39










  • I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
    – Peter
    Nov 20 at 15:58










  • Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
    – mhsmith
    Nov 21 at 13:16
















2














So I use chaquopy to get simple python programs functioning in an old (jelly bean) tablet (I replace the example console app's main.py in the src directory). Not bad for a beginner's start and I'm very happy.



But now for a test I try to display a matplotlib graph like this:



import matplotlib.pyplot as plt
import matplotlib.image as mpimg
def main():

image = mpimg.imread("/storage/emulated/0/Documents/test.png")
plt.imshow(image)
plt.show()


The matplotlib library was installed from within android studio (albeit with a few missing elements, manual pip3 install and usage of local files). Now the build and program finish without errors, but there is no graph. Installation of pillow and use of other graph types no avail.



Can this be handled in python, or is a dive into android studio / java required?



Thanks for any advice










share|improve this question
























  • Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
    – mhsmith
    Nov 14 at 15:39










  • I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
    – Peter
    Nov 20 at 15:58










  • Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
    – mhsmith
    Nov 21 at 13:16














2












2








2







So I use chaquopy to get simple python programs functioning in an old (jelly bean) tablet (I replace the example console app's main.py in the src directory). Not bad for a beginner's start and I'm very happy.



But now for a test I try to display a matplotlib graph like this:



import matplotlib.pyplot as plt
import matplotlib.image as mpimg
def main():

image = mpimg.imread("/storage/emulated/0/Documents/test.png")
plt.imshow(image)
plt.show()


The matplotlib library was installed from within android studio (albeit with a few missing elements, manual pip3 install and usage of local files). Now the build and program finish without errors, but there is no graph. Installation of pillow and use of other graph types no avail.



Can this be handled in python, or is a dive into android studio / java required?



Thanks for any advice










share|improve this question















So I use chaquopy to get simple python programs functioning in an old (jelly bean) tablet (I replace the example console app's main.py in the src directory). Not bad for a beginner's start and I'm very happy.



But now for a test I try to display a matplotlib graph like this:



import matplotlib.pyplot as plt
import matplotlib.image as mpimg
def main():

image = mpimg.imread("/storage/emulated/0/Documents/test.png")
plt.imshow(image)
plt.show()


The matplotlib library was installed from within android studio (albeit with a few missing elements, manual pip3 install and usage of local files). Now the build and program finish without errors, but there is no graph. Installation of pillow and use of other graph types no avail.



Can this be handled in python, or is a dive into android studio / java required?



Thanks for any advice







android python matplotlib chaquopy






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 14 at 15:40









mhsmith

2,63012043




2,63012043










asked Nov 13 at 16:28









Peter

113




113












  • Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
    – mhsmith
    Nov 14 at 15:39










  • I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
    – Peter
    Nov 20 at 15:58










  • Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
    – mhsmith
    Nov 21 at 13:16


















  • Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
    – mhsmith
    Nov 14 at 15:39










  • I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
    – Peter
    Nov 20 at 15:58










  • Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
    – mhsmith
    Nov 21 at 13:16
















Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
– mhsmith
Nov 14 at 15:39




Installing matplotlib should be easy, so I'm concerned by "a few missing elements, manual pip3 install and usage of local files". If you had any problems here, please report them at the Chaquopy GitHub page.
– mhsmith
Nov 14 at 15:39












I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
– Peter
Nov 20 at 15:58




I unfortunately do not have the logs anymore, but I remember that even after a manual pip3 install of matplotlib, it was still necessary to install freetype (a dev version was suggested). So I now have both libfreetype6 and libfreetype6-dev installed.
– Peter
Nov 20 at 15:58












Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
– mhsmith
Nov 21 at 13:16




Chaquopy comes with its own copy of pip which installs into an isolated environment, so what you have installed on the build machine should make no difference.
– mhsmith
Nov 21 at 13:16












1 Answer
1






active

oldest

votes


















0














You'll have to include an ImageView in your app's layout, and then load the image file into it, as in this answer.



For an image which is generated dynamically by matplotlib, either save it to a file and then load from that file, or save it to a bytes object like this:



import io
bio = io.BytesIO()
plt.savefig(bio, format="png")
b = bio.getvalue()


... and then load that bytes object into the ImageView like in this app.






share|improve this answer





















  • OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
    – Peter
    Nov 20 at 15:40










  • @Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
    – mhsmith
    Nov 21 at 13:18













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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0














You'll have to include an ImageView in your app's layout, and then load the image file into it, as in this answer.



For an image which is generated dynamically by matplotlib, either save it to a file and then load from that file, or save it to a bytes object like this:



import io
bio = io.BytesIO()
plt.savefig(bio, format="png")
b = bio.getvalue()


... and then load that bytes object into the ImageView like in this app.






share|improve this answer





















  • OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
    – Peter
    Nov 20 at 15:40










  • @Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
    – mhsmith
    Nov 21 at 13:18


















0














You'll have to include an ImageView in your app's layout, and then load the image file into it, as in this answer.



For an image which is generated dynamically by matplotlib, either save it to a file and then load from that file, or save it to a bytes object like this:



import io
bio = io.BytesIO()
plt.savefig(bio, format="png")
b = bio.getvalue()


... and then load that bytes object into the ImageView like in this app.






share|improve this answer





















  • OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
    – Peter
    Nov 20 at 15:40










  • @Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
    – mhsmith
    Nov 21 at 13:18
















0












0








0






You'll have to include an ImageView in your app's layout, and then load the image file into it, as in this answer.



For an image which is generated dynamically by matplotlib, either save it to a file and then load from that file, or save it to a bytes object like this:



import io
bio = io.BytesIO()
plt.savefig(bio, format="png")
b = bio.getvalue()


... and then load that bytes object into the ImageView like in this app.






share|improve this answer












You'll have to include an ImageView in your app's layout, and then load the image file into it, as in this answer.



For an image which is generated dynamically by matplotlib, either save it to a file and then load from that file, or save it to a bytes object like this:



import io
bio = io.BytesIO()
plt.savefig(bio, format="png")
b = bio.getvalue()


... and then load that bytes object into the ImageView like in this app.







share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 14 at 15:38









mhsmith

2,63012043




2,63012043












  • OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
    – Peter
    Nov 20 at 15:40










  • @Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
    – mhsmith
    Nov 21 at 13:18




















  • OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
    – Peter
    Nov 20 at 15:40










  • @Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
    – mhsmith
    Nov 21 at 13:18


















OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
– Peter
Nov 20 at 15:40




OK, I managed to show a png graph using imagegeview. Thank you very much. I did not test the bytes object yet, but it will also show just an image. What I now realize is that I wanted to make use of the matplotlib plt.show() function, because then the graph is not passively displayed, but shown with zoom/pan functions. Would that be possible?
– Peter
Nov 20 at 15:40












@Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
– mhsmith
Nov 21 at 13:18






@Peter: It's not currently possible: it would require someone to write an Android front end for matplotlib.
– mhsmith
Nov 21 at 13:18




















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