16.04 - How to install packages when dependency is already installed from PPA?

I'm trying to install libgdal-dev:

sudo apt-get install libgdal-dev

But it has unmet dependencies: Depends: libpng-dev

Which itself cannot be installed because:

libpng12-dev : Depends: libpng12-0 (= 1.2.54-1ubuntu1.1) but 1.2.54-5x0~ppa is to be installed

This package is installed from a ppa:

dpkg -s libpng12-0 | grep ^Maintainer
Maintainer: Otto Meier 

(via)

I want to keep that ppa as it provides GIMP 2.9.

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Question:

• How can I install libpng12-dev and libgdal-dev (maybe ignoring or manually changing certain dependencies) ?




• or generally: How to install packages when dependency is already installed in another version from PPA ?

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(Hint: Installing GIMP with Snap is neither preferred nor possible)

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What I tried:

I installed libpng12-dev ignoring libpng12-0 dependecy
(via):

apt download libpng12-dev
sudo dpkg --ignore-depends=libpng12-0 -i libpng12-dev_1.2.54-1ubuntu1.1_amd64.deb

This worked.
Also, libgdal-dev still had unmnet dependencies, so I did the same:

sudo apt install libgdal-dev
sudo dpkg --ignore-depends=libpng12-0 -i libgdal-dev_2.2.2+dfsg-1~xenial1_amd64.deb #png12-dev_1.2.54-1ubuntu1.1_amd64.deb

dpkg: dependency problems prevent configuration of libgdal-dev:
 libgdal-dev depends on libarmadillo-dev; however:
  Package libarmadillo-dev is not installed.
 libgdal-dev depends on libcurl4-gnutls-dev | libcurl-ssl-dev; however:

  Package libcurl4-gnutls-dev is not installed.
  Package libcurl-ssl-dev is not installed.
 libgdal-dev depends on libdap-dev; however:
  Package libdap-dev is not installed.
 libgdal-dev depends on libepsilon-dev; however:
  Package libepsilon-dev is not installed.
 libgdal-dev depends on libfreexl-dev; however:
  Package libfreexl-dev is not installed.
 libgdal-dev depends on libfyba-dev; however:
  Package libfyba-dev is not installed.

 libgdal-dev depends on libgeos-dev; however:
  Package libgeos-dev is not installed.
 libgdal-dev depends on libgeotiff-dev; however:
  Package libgeotiff-dev is not installed.
 libgdal-dev depends on libgif-dev; however:
  Package libgif-dev is not installed.
 libgdal-dev depends on libhdf4-alt-dev; however:
  Package libhdf4-alt-dev is not installed

So, I stopped here and fixed the situation again:

sudo dpkg -r libgdal-dev
sudo dpkg -r libpng12-dev