Ubuntu: Install java 7 source (openjdk-7-source)

sudo apt-get install openjdk-7-source

The src.zip that is going to be installed by this command can be found: /usr/lib/jvm/java-7-openjdk-i386 or
/usr/lib/jvm/java-7-openjdk-common

Arch Linux: xfce 4.10 panel freezes

From time to time the xfce 4.10 panel freezes. Instead of restarting or logging out, one can just kill it and it should restartkillall -9 xfce4-panel

ImageJ: Import source code into Eclipse and git version control

ImageJ is a public domain Java image processing program inspired by NIH Image for the Macintosh. It runs, either as an online applet or as a downloadable application, on any computer with a Java 1.4 or later virtual machine. Downloadable distributions are available for Windows, Mac OS, Mac OS X and Linux.

Since it is open sourced it can be modified and extended. It normally comes with ant build.xml but I usually work with Eclipse and Git, thus I wanted to work with the source files in this environment.

I will show how to add ImageJ source code into Eclipse and with Git support. The steps below where executed in Xubuntu 13.04.

1. Download the source code and unpack

The ImageJ source code is here. At the moment of writing, the latest version is ij147v-src.zip I usually download to ~/Downloads folder. To unpack it use the following:cd ~/Downloads/
unzip ij147v-src.zipThis will create a folder named source in ~/Downloads.

2. Create new Java Project in Eclipse

Create new Java Project in your default workspace. Usually the folder is set by Eclipse as ~/workspace. Its important to select "Use project folder as root for sources and class files" because in a moment we will import the ImageJ source into it.

Arch Linux: Error about msvcr100.dll.wctomb_s in wine 1.6-rc5 when starting Path of Exile.

Sorry, just writing from memory. I had wine 1.6-rc5 on a Arch Linux x64, though wine was set as 32-bit wine environment, i.e. withWINEARCH=win32 winecfgI had problem running Path of Exile client (Client.exe). It was something about unimplemented function msvcr100.dll.wctomb_s. The fix for me was to install Microsoft Visual C++ 2010 winetricks vcrun2010However, this may require you to first install msxml3.

avcon: change frame, resize ogv obtained from RecordMyDesktop

avconv -i test.ogv -r 10 -s 1280x720 -q 1 output.ogvr is frames per second, s is the new size and q is quality, from 1(worse) to 32(best).

Matlab: How to check if structure has any fields

	% To check if struct has any fields,
	% fieldnames function can use that return cell with
	% strings representing fields names if any
	%
	s = struct();
	if numel(fieldnames(s)) == 0
	disp('No fields');
	end
	s = struct([]);
	if numel(fieldnames(s)) == 0
	disp('No fields');
	end
	s = struct();

view raw test.m hosted with ❤ by GitHub

Matlab: Click mouse points on an image

	classdef GuiImagePointClicker < handle
	%GuiImagePointClicker Point selection on an image with the ability
	% to delete points using backspace.
	%
	%
	% EXAMPLE
	% I = load('gatlin');
	% mygui = GuiImagePointClicker(I.X./max(I.X(:)));
	% mygui.x
	% mygui.y
	%
	properties(SetAccess = private)
	x = [];
	y = [];
	I = [];
	imh = 0;
	fh = 0;
	ptHandles = [];
	end
	methods
	function obj = GuiImagePointClicker(I)
	obj.init();
	obj.I = I;
	obj.getPoints();
	end
	function init(obj)
	obj.I = [];
	obj.x = [];
	obj.y = [];
	obj.imh = 0;
	obj.fh = 0;
	obj.ptHandles = [];
	end
	function getPoints(obj)
	% show image
	obj.fh = figure();
	obj.imh = imshow(obj.I);
	hold on;
	fprintf(1, ['\n\nPress mouse to put points.\n', ...
	'Enter on the figure to finish and backspace to ', ...
	'remove last point.\n\n']);
	% set callback function for keyboard press
	set(obj.fh, 'KeyPressFcn', ...
	@(s,e) obj.callback_keyPressFcn(s,e) );
	% set callback function for mouse press
	set(obj.imh, 'ButtonDownFcn', ...
	@(s,e) obj.callback_mousePressFcn(s,e) );
	end
	function callback_mousePressFcn(obj, hObject, ~)
	% get position of mouse click
	imaxis = get(hObject,'parent');
	point = get(imaxis,'currentpoint');
	x = point(1,1);
	y = point(1,2);
	% save it
	obj.x(end + 1) = x;
	obj.y(end + 1) = y;
	% show the click points
	obj.showPoints();
	end
	function callback_keyPressFcn(obj, hObject, evnt)
	pressedKey = evnt.Key;
	switch pressedKey
	case 'backspace'
	obj.deleteOnePoint();
	case 'return'
	obj.closeFigure();
	end
	end
	function deleteOnePoint(obj)
	numPoints = numel(obj.x);
	if numPoints < 1
	disp('No points to delete');
	return;
	end
	% remove last point
	obj.x(end) = [];
	obj.y(end) = [];
	% redraw points
	obj.showPoints();
	end
	function closeFigure(obj)
	disp('finished.');
	close(obj.fh);
	end
	function showPoints(obj)
	%first delete all points and than redraw them
	arrayfun(@delete, obj.ptHandles);
	obj.ptHandles = [];
	% redraw points
	for pi = 1:numel(obj.x)
	x = obj.x(pi);
	y = obj.y(pi);
	ph = plot(x, y, 'or', ...
	'MarkerFaceColor', 'red', ...
	'MarkerSize', 6);
	obj.ptHandles(end+1) = ph;
	end
	end
	end
	end

view raw GuiImagePointClicker.m hosted with ❤ by GitHub

Matlab: deal - assign values in vector into variables

	function varargout = mydeal(varargin)
	% Assign values in vector into variables.
	%
	% EXAMPLE 1
	% [a,b,c] = mydeal([1,2,3]);
	% EXAMPLE 2
	% some_vector = [1,2,3];
	% [a,b,c] = mydeal(some_vector);
	%
	% %results in a=1, b=2, c=3;
	%
	assert(nargout == numel(varargin{1}), 'Different number of in and out arguments');
	for i = 1:nargout
	varargout{i} = varargin{1}(i);
	end

view raw mydeal.m hosted with ❤ by GitHub

Mex files in Matlab for linux: failed to map segment from shared object: Operation not permitted

This happens when you have no permissions to execute given file or library. In my case it was happening because I was trying to run mex files using Matlab for linux that were located in NTFS partition. Often the partition is mounted in linux without exec arguments. To fix it, I edited my /etc/fstab file and aded exec argument to the line responsible for mounting NTFS partition:

UUID=F4B664646C02A51D /mnt/c ntfs users,defaults,exec 0 0

Problems with libstdc++.so.6 when compiling mex files in Matlab 2013a x64 on Xubuntu 13.04 x64

Problem compiling mex files in Matlab 2013a x64 on Linux (Xubuntu 13.04 x64):/usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus: /usr/local/MATLAB/R2013a/sys/os/glnxa64/libstdc++.so.6: version `GLIBCXX_3.4.15' not found (required by /usr/lib/x86_64-linux-gnu/libppl_c.so.4) /usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus: /usr/local/MATLAB/R2013a/sys/os/glnxa64/libstdc++.so.6: version `GLIBCXX_3.4.15' not found (required by /usr/lib/x86_64-linux-gnu/libppl.so.12)

The problem was that Matlab was linking libstdc++.so.6 (located in /usr/local/MATLAB/R2013a/sys/os/glnxa64) to the file it provides, i.e. libstdc++.so.6.0.13 (located in /usr/local/MATLAB/R2013a/sys/os/glnxa64).

This is the old version of libstdc++, and xubuntu has newer version, i.e. libstdc++.so.6.0.17 (located in /usr/lib/x86_64-linux-gnu).

Thus, I solved this problem by changing the symbolic link in Matlab to point to the new version:cd /usr/local/MATLAB/R2013a/sys/os/glnxa64
sudo mv libstdc++.so.6 libstdc++.so.6_org
sudo ln -s /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.17 libstdc++.so.6