Xeve - About code and problems

Fix for Latex4CorelDraw with CorelDraw 2017

May 19, 2018 0 comments Article Uncategorized nspo

I was not able to make the official build of Latex4CorelDraw work with CorelDraw 2017 (and Windows 10). The ‘Latex’ Docker window was always empty. The solution was to recompile it with Visual Studio 2017 Community. Read More

Convert dSPACE ControlDesk measurement to MATLAB timeseries that can be used in Simulink

May 11, 2018 0 comments Article Uncategorized nspo

dSPACE ControlDesk can export measurements to mdf4 files or mat files
mat file exports can be converted to timeseries with this MATLAB script
The timeseries can then be imported into Simulink with the ‘From Workspace’ blog
Multiple signals can be imported at once

Example output:

>> import_dspace_mat_to_simulink_ts
--Imported dSPACE mat file 
C:\Users\Nicolai\Nextcloud\foo.mat
into workspace variable dsp_ts
--Time: 0.000000 s to 42.399572 s, 423980 steps
--2 variables are in dsp_ts:
 'In1' 'In1_1'

>> import_dspace_mat_to_simulink_ts

--Imported dSPACE mat file

C:\Users\Nicolai\Nextcloud\foo.mat

into workspace variable dsp_ts

--Time: 0.000000 s to 42.399572 s, 423980 steps

--2 variables are in dsp_ts:

'In1' 'In1_1'

Robust sync between Android phone and Linux computer

April 22, 2018 0 comments Article Uncategorized nspo

I already tried quite a few methods to reliably sync data (e.g. backups) between my Android phone and a Linux computer. Most were not good, some were horrible (MTP…). I just tried one that has proven to be the best, by far: installing an SSH server on the phone and then syncing with rsync. I Read More

Django DetailView with pagination for related objects

March 31, 2018 0 comments Article Uncategorized nspo

This is an example of a DetailView of a User that can have a paginated list of Purchases:

from django.views.generic.detail import DetailView
from django.core import paginator

@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')
class UserDetailView(DetailView):
    model = User
    template_name = "user_detail.html"
    purchases_paginate_by = 5

    def get_context_data(self, **kwargs):
        context = super(UserDetailView, self).get_context_data(**kwargs)

        purchases_page = self.request.GET.get("purchases_page")
        purchases = self.object.get_purchases().filter()
        purchases_paginator = paginator.Paginator(purchases, self.purchases_paginate_by)
        # Catch invalid page numbers
        try:
            purchases_page_obj = purchases_paginator.page(purchases_page)
        except (paginator.PageNotAnInteger, paginator.EmptyPage):
            purchases_page_obj = purchases_paginator.page(1)

        context["purchases_page_obj"] = purchases_page_obj
        return context

from django.views.generic.detail import DetailView

from django.core import paginator

@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')

class UserDetailView(DetailView):

model = User

template_name = "user_detail.html"

purchases_paginate_by = 5

def get_context_data(self, **kwargs):

context = super(UserDetailView, self).get_context_data(**kwargs)

purchases_page = self.request.GET.get("purchases_page")

purchases = self.object.get_purchases().filter()

purchases_paginator = paginator.Paginator(purchases, self.purchases_paginate_by)

# Catch invalid page numbers

try:

purchases_page_obj = purchases_paginator.page(purchases_page)

except (paginator.PageNotAnInteger, paginator.EmptyPage):

purchases_page_obj = purchases_paginator.page(1)

context["purchases_page_obj"] = purchases_page_obj

return context

In the template file, the pagination needs to done similar to the following example (using django-bootstrap3):

{% bootstrap_pagination purchases_page_obj extra=request.GET.urlencode parameter_name="purchases_page" %}

1	{% bootstrap_pagination purchases_page_obj extra=request.GET.urlencode parameter_name="purchases_page" %}

Github gist Read More

Export object_list of a django-filters FilterView to CSV

March 31, 2018 0 comments Article Uncategorized nspo

This is a simple way to allow users to export the data they have just filtered using django-filter as CSV.

# Normal View (has a link to export view and keeps GET parameters)
@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')
class PaymentListView(FilterView):
    filterset_class = filters.PaymentFilter
    template_name = "barsys/userarea/payment_list.html"
    paginate_by = 10

# Export View
@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')
class PaymentExportView(FilterView):
    filterset_class = filters.PaymentFilter

    def render_to_response(self, context, **response_kwargs):
        # Could use timezone.now(), but that makes the string much longer
        filename = "{}-export.csv".format(datetime.datetime.now().replace(microsecond=0).isoformat())

        response = HttpResponse(content_type='text/csv')
        response['Content-Disposition'] = 'attachment; filename="{}"'.format(filename)

        writer = csv.writer(response)
        writer.writerow(['created', 'email', 'display_name'])

        for obj in self.object_list:
            writer.writerow([obj.created_date, obj.user.email, obj.user.display_name])

        return response

# Normal View (has a link to export view and keeps GET parameters)

@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')

class PaymentListView(FilterView):

filterset_class = filters.PaymentFilter

template_name = "barsys/userarea/payment_list.html"

paginate_by = 10

# Export View

@method_decorator(staff_member_required(login_url='user_login'), name='dispatch')

class PaymentExportView(FilterView):

filterset_class = filters.PaymentFilter

def render_to_response(self, context, **response_kwargs):

# Could use timezone.now(), but that makes the string much longer

filename = "{}-export.csv".format(datetime.datetime.now().replace(microsecond=0).isoformat())

response = HttpResponse(content_type='text/csv')

response['Content-Disposition'] = 'attachment; filename="{}"'.format(filename)

writer = csv.writer(response)

writer.writerow(['created', 'email', 'display_name'])

for obj in self.object_list:

writer.writerow([obj.created_date, obj.user.email, obj.user.display_name])

return response

Github gist Read More

Running multiple Django projects on one Apache instance with mod_wsgi

March 31, 2018 0 comments Article Uncategorized nspo

I did not yet find a page with a concise but complete description of how to run multiple Django instances/projects on one server with Apache. This method is similar to the one in the Django docs, but the docs version does not run the Django instance in a daemon process, therefore it does not work Read More

Analytical convolution integral (Analytische Faltung) with Matlab and Maple

September 10, 2015 0 comments Article Uncategorized nspo

With $\sigma(t) = Heaviside(t)$ and $\delta(t) = Dirac(t)$
Function 1 (e.g. input signal/Eingangssignal):
$u(t) = \sigma(t-1) - \sigma(t-4)$

Function 2 (e.g. impulse response/Stoßantwort):
$g(t) = -\frac{1}{RC}\exp(-\frac{t}{RC})\sigma(t) + \delta(t)$ Read More

Automatically convert videos in Powerpoint file (pptx) to a different format

September 2, 2015 0 comments Article Uncategorized nspo

I have been trying to convert a lot of embedded videos in pptx files to a different format lately due to compatibility issues on some systems, but have not found an easy and fast way – so I wrote this bash script.

The goal was to have a pptx with videos that can be played using Powerpoint 2010 or later on Windows as well as OS X without plugins. That seems to only be the case for MPG videos (mpeg1video codec).

To convert videos in a presentation

make sure that ffmpeg and a zip/unzip application is installed (ffmpeg can easily be replaced by avconv, but avconv somehow could not convert some files that were no problem for ffmpeg during my tests)
download the bash file and make it executable
edit the options at the beginning of the file, if you want to (mainly video output format and bitrate)
Change to the directory with the pptx file(s) and start the conversion with /path/to/pptx_video_convert.sh myPresentation.pptx
Check if everything worked by looking at myPresentation_converted.pptx or the logs

< Read More

3D printed Arduino Nano case

August 7, 2015 0 comments Article Uncategorized nspo

I put a a practical Arduino Nano case on Thingiverse.

It can be downloaded here: https://www.thingiverse.com/thing:959057 Read More

Oneplus One touchscreen bug fix

June 4, 2015 0 comments Article Uncategorized nspo

There is a very common touchscreen bug with the Oneplus One that can only be partly/temporarily fixed by a reboot and shows in several ways:

Touchscreen less responsive at all times
Touches are often not recognized (apparently triggered by heat)
Ghost touches (apparently triggered by heat)

Although this seems to be in some way related to the hardware (because I could easily reproduce it by making it warmer), a new touchscreen firmware was published recently in the CyanogenMod 12.1 repository that seems to work arround the problem somehow. I can attest that installing the new firmware fixed the problem on two Oneplus Ones that I tried it on. Battery life is noticably worse though, but this is said to be fixed with some changes that were committed to the CM12.1 repository on June 2. Read More