programming – Page 6 – Silveira Neto

Compiling Inkscape

Published by Silveira on 2008-08-04

Inkscape running

Inkscape is a Open Source vector graphics editor that works with SVG (Scalable Vector Graphics) format, Inkscape works with transparency, gradients, node editing, pattern fills, PNG export, and more. It also runs on Linux, Windows and OSX, those three are officially supported, but also runs in a broad list of Operational Systems. Is a software that I work daily and frequently is featured here in my blog.

You can download Inkscape or directly install it via some package system like Apt:

sudo apt-get install inskcape

But sometimes we need some special feature that is not available yet in the repositories or we want gain speed by having special binaries for our platforms or we want to help developing a new feature. In those cases we need to compile the software by ourself.

Those tips are valid for Ubuntu 8.04 but some part of them can be applied in others distributions. The Inkscape compiled here is the version 0.46+devel so newest versions can have compiling procedures slightly different.

Getting sources via APT.The easiest way to compile Inkscape on Ubuntu is

sudo su
apt-get build-dep inkscape
apt-get source inkscape
cd inkscape
./autogen.sh
./configure
make
make install

This will get a version of inkscape, compile it and install. If the first step doesn’t work well, you can try install all necessary packages by yourself using:

sudo apt-get install autotools-dev fakeroot dh-make build-essential autoconf automake intltool libglib2.0-dev libpng12-dev libgc-dev libfreetype6-dev liblcms1-dev libgtkmm-2.4-dev libxslt1-dev libboost-dev libpopt-dev libgsl0ldbl libgsl0-dev libgsl0-dbg libgnome-vfsmm-2.6-dev libssl-dev libmagick++9-dev libwpg-dev

Getting sources via SVN. The recipe I showed above will compile a stable version of Inkscape but not the last version of Inkscape. For that we need to grab the source directly from the Subversion repositories and so compile it.

At your home folder:

sudo apt-get install subversion
svn checkout https://inkscape.svn.sourceforge.net/svnroot/inkscape/inkscape/trunk inkscape

A alternative way to subversion is getting sources from here. Those are tarballs built every hour after someone change something in the development repositories. Download a tarball, and decompress it on your home folder.

Install all tools we need to compile Inkscape, this should fits:

sudo apt-get install autotools-dev fakeroot dh-make build-essential autoconf automake intltool libglib2.0-dev libpng12-dev libgc-dev libfreetype6-dev liblcms1-dev libgtkmm-2.4-dev libxslt1-dev libboost-dev libpopt-dev libgsl0ldbl libgsl0-dev libgsl0-dbg libgnome-vfsmm-2.6-dev libssl-dev libmagick++9-dev libwpg-dev

Enter in the directory with the Inkscape source and do:

./autogen.sh
mkdir build
cd build
../configure
make
sudo make install

In both cases, grabbing sources via svn or via apt, or can set the place where the software will be installed so it not cause conflicts with you already installed version of Inkscape. You can do that replacing the ./configure step with something like:

./configure –prefix=/home/yourname/inkscape

If you had some trouble in one of those steps, consider reading some of those other tutorials:

ps: thanks guys from the inkscape-devel@lists.sourceforge.net specially heathenx.

Ruby: A Simple Example of Meta Programming

Published by Silveira on 2008-03-26

A really cool piece of code I read today in the book Ruby on Rails: Up and Running.

class Talker
  def method_missing(method)
     if method.to_s =~ /say_/
       puts $'
     end
  end
end

t = Talker.new

t.say_hello
t.say_something
t.say_goodbye

And running

$ ruby Talker.rb
hello
something
goodbye

But why do that when we have parameters? Because you can do some methods really dynamic with a clear semantic, just looking for them you know are they are doing.

Java assertion to prevent time travelers

Published by Silveira on 2008-03-23

Creative Commons photo by jekemp

public class PreventTimeTravelers {
    public static void main(String args[]){
        long startTime = System.currentTimeMillis();
        long endTime = System.currentTimeMillis();
        assert endTime >= startTime: "We came back in time!";
    }
}

Please do not execute this code in a time machine.

NumberFormatException Example

Published by Silveira on 2008-03-21

NumberFormatException: Thrown to indicate that the application has attempted to convert a string to one of the numeric types, but that the string does not have the appropriate format.

An simple example:

public class SummationExample {
    public static void main(String args[]){
        int sum = 0;
        for(String arg: args){
            System.out.println("+" + arg);
            sum += Integer.parseInt(arg);
        }
        System.out.println("= " + sum);
    }
}

$ javac SummationExample.java
$ java SummationExample 1 2 3 4 5
+1
+2
+3
+4
+5
= 15

but

$ java SummationExample 1 2 3 4 five
+1
+2
+3
+4
+five
Exception in thread “main” java.lang.NumberFormatException: For input string: “five”
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:447)
at java.lang.Integer.parseInt(Integer.java:497)
at SummationExample.main(SummationExample.java:6)

public class SummationExample {
    public static void main(String args[]){
        int sum = 0;
        for(String arg: args){
            try {
                sum += Integer.parseInt(arg);
                System.out.println("+" + arg);
            } catch (NumberFormatException e) {
                // nothing
            }
        }
        System.out.println("= " + sum);
    }
}

now

$ javac BetterSummationExample.java
$ java BetterSummationExample 1 2 3 4 5
+1
+2
+3
+4
+5
= 15

and also

$ java BetterSummationExample 1 2 3 4 five
+1
+2
+3
+4
= 10

Java Duke animated gif waving

Pointers to functions in C++

Published by Silveira on 2008-03-16

I need to implements some codes in C++. Just remembering some concepts like pointers to functions.

A simple example:

#include <stdlib.h>
#include <iostream>

using namespace std;

double evalFunction(double (*f)(double), double param){
    return f(param);
}

double function(double x){
    return x/2;
}

int main(int argc, char** argv) {
    cout << function(5.0) << endl;
    cout << evalFunction(function, 5.0) << endl;
    return (EXIT_SUCCESS);
}

Java, listing system properties

Published by Silveira on 2008-03-10

This code prints out your system properties.

import java.util.Properties;

public class PropertiesLister{
   public static void main (String args[]){
       Properties props = System.getProperties();
       props.list(System.out);
   }
}

In the machine I’m writing right now:

— listing properties —
java.runtime.name=Java(TM) SE Runtime Environment
sun.boot.library.path=/usr/lib/jvm/java-6-sun-1.6.0.00/jre/…
java.vm.version=1.6.0-b105
java.vm.vendor=Sun Microsystems Inc.
java.vendor.url=http://java.sun.com/
path.separator=:
java.vm.name=Java HotSpot(TM) Server VM
file.encoding.pkg=sun.io
user.country=BR
sun.java.launcher=SUN_STANDARD
sun.os.patch.level=unknown
java.vm.specification.name=Java Virtual Machine Specification
user.dir=/tmp
java.runtime.version=1.6.0-b105
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment
java.endorsed.dirs=/usr/lib/jvm/java-6-sun-1.6.0.00/jre/…
os.arch=i386
java.io.tmpdir=/tmp
line.separator=

java.vm.specification.vendor=Sun Microsystems Inc.
os.name=Linux
sun.jnu.encoding=UTF-8
java.library.path=/usr/lib/jvm/java-6-sun-1.6.0.00/jre/…
java.specification.name=Java Platform API Specification
java.class.version=50.0
sun.management.compiler=HotSpot Server Compiler
os.version=2.6.20-16-generic
user.home=/home/export/silveira
user.timezone=
java.awt.printerjob=sun.print.PSPrinterJob
file.encoding=UTF-8
java.specification.version=1.6
user.name=silveira
java.class.path=.
java.vm.specification.version=1.0
sun.arch.data.model=32
java.home=/usr/lib/jvm/java-6-sun-1.6.0.00/jre
java.specification.vendor=Sun Microsystems Inc.
user.language=pt
java.vm.info=mixed mode
java.version=1.6.0
java.ext.dirs=/usr/lib/jvm/java-6-sun-1.6.0.00/jre/…
sun.boot.class.path=/usr/lib/jvm/java-6-sun-1.6.0.00/jre/…
java.vendor=Sun Microsystems Inc.
file.separator=/
java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport…
sun.cpu.endian=little
sun.io.unicode.encoding=UnicodeLittle
sun.cpu.isalist=

Try out at your home. 🙂

JavaFX: Side-scrolling

Published by Silveira on 2008-02-20

An side-scrolling game attempt.

an plane

I used two images, this mountain background made with Gimp (xcf sources here) and that ship above made with Inkscape (svg sources here).

[youtube]5F4STuluSiM[/youtube]

import javafx.ui.*;
import javafx.ui.canvas.*;

var scroll;
scroll = [1..800] dur 60000 linear continue if true;

var mountains = Clip{
    transform: bind translate(-scroll,0)
    shape: Rect {x:bind scroll, y:0, width:400, height:200}
    content: [ImageView {
            transform: translate(0,0)
            image: Image { url: "http://silveiraneto.net/downloads/mountains.png"}
        },
        ImageView {
            transform: translate(800,0)
            image: Image { url: "http://silveiraneto.net/downloads/mountains.png"}
        }
    ]
};

var h = 50;

var ship = ImageView {
    cursor: HAND
    transform: bind translate(0,h)
    image: Image { url: "http://silveiraneto.net/downloads/jfx_plane.png"}
    onMouseDragged: operation(e) {
        h += e.localDragTranslation.y;
    }
};

Canvas {
    content: [mountains, ship]
}

Tag: programming