ubuntu16.04 重新安装pcl的问题 libpcl-dev : Depends: libvtk6-dev but it is not going to be installed

环境 Ubuntu16.04 pcl 1.7

0.写在前面

同样是因为安装open3d*卸载了pcl(万恶的open3d)

1.问题

想要安装pcl

sudo apt-get install libpcl-dev

然而事情不是我想的这样

The following packages have unmet dependencies:
libpcl-dev : Depends: libvtk6-dev but it is not going to be installed
             Depends: libvtk6-qt-dev but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

继续安装libvtk6-dev又会提示依赖于别的库,一环套一环,如果你去尝试之后会发现最后是包的版本问题,像我这样子,其中一个包.

libfontconfig1-dev : Depends: libfontconfig1 (= 2.11.94-0ubuntu1) but 2.11.94-0ubuntu1.1 is to be installed

我需要一个2.11.94-0ubuntu1的,但是装的却是1.1的.
没错,我们需要降级!

(ps:这样子的问题之前也遇到过,现在写下来作为记录.)

2.解决方案

首选尝试

sudo apt-get install -f libpcl-dev

很遗憾,我没有修复成功,利用aptitude看看?

sudo apt-get install aptitude
sudo aptitude install libpcl-dev

终端给出了提示

The following packages have unmet dependencies:
 libpng16-devtools : Conflicts: libpng12-0-dev which is a virtual package, provided by:
                                 - libpng12-dev, but 1.2.54-1ubuntu1 is to be installed.
                     Conflicts: libpng12-dev but 1.2.54-1ubuntu1 is to be installed.
                     Conflicts: libpng3-dev which is a virtual package, provided by:
                                 - libpng12-dev, but 1.2.54-1ubuntu1 is to be installed.
 libpng16-dev : Conflicts: libpng12-0-dev which is a virtual package, provided by:
                            - libpng12-dev, but 1.2.54-1ubuntu1 is to be installed.
                Conflicts: libpng12-dev but 1.2.54-1ubuntu1 is to be installed.
                Conflicts: libpng3-dev which is a virtual package, provided by:
                            - libpng12-dev, but 1.2.54-1ubuntu1 is to be installed.
 libpng12-dev : Depends: libpng12-0 (= 1.2.54-1ubuntu1) but 1.2.54-1ubuntu1.1 is installed.
 libfontconfig1-dev : Depends: libfontconfig1 (= 2.11.94-0ubuntu1) but 2.11.94-0ubuntu1.1 is installed.
 libfreetype6-dev : Depends: libfreetype6 (= 2.6.1-0.1ubuntu2) but 2.6.1-0.1ubuntu2.4 is installed.
The following actions will resolve these dependencies:

      Keep the following packages at their current version:
1)      libfontconfig1-dev [Not Installed]                 
2)      libfreetype6-dev [Not Installed]                   
3)      libgdal-dev [Not Installed]                        
4)      libpcl-dev [Not Installed]                         
5)      libpng12-dev [Not Installed]                       
6)      libvtk6-dev [Not Installed]                        
7)      libvtk6-qt-dev [Not Installed]                     
8)      libxft-dev [Not Installed]                         
9)      tk-dev [Not Installed]                             
10)     tk8.6-dev [Not Installed]                          



Accept this solution? [Y/n/q/?]

我们需不需要保持现在的版本,你给我Not Installed?(之前我举的例子libfontconfig1就在其中)
当然选择n了.

Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Remove the following packages:                                             
1)     libpng16-dev                                                             
2)     libpng16-devtools                                                        

     Downgrade the following packages:                                          
3)     fontconfig-config [2.11.94-0ubuntu1.1 (now) -> 2.11.94-0ubuntu1 (xenial)]
4)     libfontconfig1 [2.11.94-0ubuntu1.1 (now) -> 2.11.94-0ubuntu1 (xenial)]   
5)     libfreetype6 [2.6.1-0.1ubuntu2.4 (now) -> 2.6.1-0.1ubuntu2 (xenial)]     
6)     libpng12-0 [1.2.54-1ubuntu1.1 (now) -> 1.2.54-1ubuntu1 (xenial)]         



Accept this solution? [Y/n/q/?]      

我们选择y
可以看到一些包可以被降级以满足安装pcl的需要,比如libfontconfig1
到此结束!