Wednesday, December 31, 2014

Free Tools for Cropping PDFs

Every time I want to print some PDF documents, I'd like to put at least two pages of the PDF onto a single sheet to save papers. Now here comes the problem: many PDF documents have very large margins, and these empty spaces make the final printed content have very small font size, which is not comfortable for reading. Unlike Microsoft Word documents, which have many editors to reset the margin space for printing, most PDFs are not editable. But for PDFs, there are several free and open source tools for removing margins.

1. Briss 
A simple cross-platform application for cropping PDF files. A simple user interface lets you define exactly the crop-region by fitting a rectangle on the visually overlaid pages.

2. PDF Scissors

This one is very similar to Briss, you can see all pages together in stacked view to find the right content rectangle. It can also run online as a Java applet.

3. K2pdfopt
K2pdfopt optimizes PDF/DJVU files for mobile e-readers (e.g. the Kindle) and smartphones. It works well on multi-column PDF/DJVU files and can re-flow text even on scanned PDF files. It can also be used as a general PDF copying/cropping/re-sizing/OCR-ing manipulation tool. It can generate native or bitmapped PDF output, with an optional OCR layer. There are downloads for MS Windows, Mac OSX, and Linux.

Both Briss and PDF Scissors require Java. If you're using a public PC where Java is not available, you can try this one. K2pdfopt has many functions for converting PDF to view on e-readers, but for printing purpose conversions, all you need is to change the "Conversion Mode:" to "crop" and leave all other setting as default - the tool will remove the empty spaces automatically.


Thursday, December 11, 2014

Doom Turned 21, Play Doom Online!

Doom, Heretic and Hexen - Play the demo version of three remarkable FPS games based on id Software's first generation Doom engine in your browser! The games are ported to Flash by Newgrounds admin mike with Adobe Alchemy, using the original source code of the games.


And the open source Freedoom game assets running on PrBoom, compiled to HTML5 with Emscripten, runs in most browser, can be played at
Different from the Doom Triple Pack which uses orignial game code and offical assets, this game uses custom made game resources.

Finally, there is a PC emulator written in Java which can run unmodified Doom.exe in your browser: (require Java)

Links: (Doom Java port)

Thursday, December 4, 2014

Super Wolfenstein HD - Wolfenstein 3D Remake in HD with Realistic Physics

Super Wolfenstein 3D is a remake of the classic Wolfenstein 3D game by ID Software, in HD with realistic physics. It was made for the Indies VS PewDiePie jam using Unity.

Similar to Voxelstein 3D and MineCraft, the environment is fully destructible - you don't always need to use the doors, just dig holes and break the walls to find a shortcut to the new level.

The game can be downloaded at


Friday, November 21, 2014

TeamViewer - Remote Desktop Made Easy

TeamViewer is a software for remotely controlling any PC or Mac over the Internet. It supports Windows, Mac, Linux and Mobile (Android, iOS, Windows Phone 8 and Windows RT, even BlackBerry!). Just install and run the software on both devices, then you can use one to remote control the other via Internet using a pre-generated ID and password. What's more, the software is free for all non-commercial users!
I once tried to use the Windows remote desktop to control my computer through my laptop, but experience is rather frustrating - all that settings, user rights, firewall... Now with this software it just simplifies everything. Another great thing is it makes file transfer between computers comfortable - you can just "ctrl+C" (or right click -> copy) at one computer and "ctrl+V" (right click -> paste) at the other computer.

Official Site:


Monday, November 3, 2014

Google Opinion Rewards - Answer Surveys and Get Free Google Play Credits to Buy Anything on Google Play

Google Opinion Rewards is an app by Google itself which can help you to get free Google Play credits by doing some quick surveys. And you can use the earned credits to buy anthing you want on Google Play Store.

Install Google Opinion Rewards here:

How to Get a Fake IP Address of a Specific Country using Tor

First, you need to download the Tor Browser Bundle at and install.

Now go to the tor browser folder, e.g., "C:\Tor Browser\Browser\TorBrowser\Data\Tor", open the file "torrc-defaults" using notepad, find the following lines:
# If non-zero, try to write to disk less frequently than we would otherwise.
AvoidDiskWrites 1
# Where to send logging messages. Format is minSeverity[-maxSeverity]
Add the line of texts "ExitNodes (space) {CountryCode}" after the line "AvoidDiskWrites 1". For example,
where "{US}" is the coutry code for the IP address of the specific country you want to use. For example, {US} for United States, {PL} for Poland, {CN} for China. To find the country code of a specific country, you can use the table

Finally, Start Tor Browser -> Connect, you can go to to check your IP address and location.

To enable Flash Player in Tor Browser Bundle, press Alt key to show the menu, go to Tools - Add-ons (or Ctrl+Shift+A), Click Plugins, you should see the "Shockwave Flash ...", switch the setting "Never Activate" to "Ask to Activate" or "Always Activate".

Now you can view web page with flash, just click Activate Adobe Flash,then Allow and Remember or Allow Now.

If your plugins content are empty and there is no Shockwave Flash, that means Flash Player for FireFox is not installed in your system. Go to install Flash first and then restart Tor Browser and do the config again.

Note: For security reasons, manually set ExitNodes and Activate Flash Player and other scripts is not recommended. If you want to browse anonymously without the special need of using a country specific IP, it is better to use the default settings of Tor Browser.


Sunday, November 2, 2014

The Internet Arcade - Play Classic Arcade Games Online for Free

Provided by, now you can play 900 classic arcade (coin-operated) video games from the 1970s through to the 1990s for free with a web browser online. All games are emulated in JSMAME, the JavaScript port of the MESS emulator.

Play Now:

Wednesday, October 8, 2014

Free Commercial Goodies For Students!

Just grab these must have free stuffs while you're still a student!

GitHub's Student Developer Pack includes lots of tools for free, such as the Unreal game engine, cloud hosting and code repository service.

Unreal Engine 4 is free to use for colleges, universities and all students.

Google Drive for Education provides school and students unlimited online storage with individual files up to 5TB in size:

Free Microsoft Office 365 Education E1 for Students and Faculty:

Free SAS softwares:
SAS University Edition is a no-cost, packaged offering of core SAS software. It is available to students, professors, academic researchers and lifelong learners.
SAS OnDemand for Academics: SAS software in the cloud – for free!

Tuesday, August 5, 2014

Dell XPS 12 2-in-1 Convertible Ultrabook

It was once a hard choice between Dell XPS 12 and Asus Taichi 21. Now I think I prefer the former one. The configurations for both ultrabook are very similar, for example, both have 4GB memory, 128GB hard drive and Intel Core i5. I like that Asus Taichi has a Wacom stylus and double screens, which makes the choice harder. However, the prices and screen sizes for the two helped me to make the decision. The price for the 11.6 inch screen Asus Taichi 21 is almost the same as the 12.5 inch XPS 12 while the price for 13.3 inch Taichi 31 is much higher. 11.6 inch is a little smaller for a laptop but is all right for a tablet, so I think 12.5 inch is just the right size for a convertible ultrabook. Other advantages of XPS 12 over Taichi 21 and other competitors include much longer battery life, and the rather unique way to transform into a tablet.

Dell XPS 12 Official Site:


Notes: It's recommended to update to the latest BIOS to resolve the unable to wake from sleep problem.
Solve no wifi after wake from sleep problem:

Thursday, July 17, 2014

Nidhogg - An Interesting Sword Fighting Pixel Game

I like games with pixel art. The screen is usually simple and clean. This game is made of pure pixel art, even without shading. However, different from most pixel games, this one is a real time action - sword fighting game. The combat system is very additive and the fighting moves are vivid. The game won lots of rewards and is highly rated by many media. If you're a fun of pixels and sword fighting, you can't miss it!

Buy the game on Steam:
The Official Site:


Tuesday, July 15, 2014

InkCase - The Second Screen with E-ink Display for Your Phone

Last time I introduced you the device Yota Phone, which has double screens and one of the two is E-ink display. Actually, there is a phone accessory, called InkCase, can make your iPhone or Galaxy Note 2 as cool as Yota Phone. The protective case comes with a E-ink screen.

The Official Site:

Friday, June 27, 2014

Google Cardboard - DIY Your Virtual Reality Device with Your Smartphone

Want to own a VR device like Oculus Rift? Why not DIY your own for less than 20$? Released on this year's Google I/O, Cardboard is the low cost solution to VR DIY.
All you need is an Android smart phone, cardboard, two lenses, one magnet, two strips of velcro and one Rubber band. And All these things can be bought on Amazon.
You can find more details, the instructions for DIY and the Android App on the official site:

Google Play Apps for Cardboard VR:

Thursday, June 26, 2014

Puffin Web Browser - Browse Websites with Flash on iPad, iPhone and Android

Want to view websites with Flash and play Flash games on your iPad or iPhone? Try Puffin Web Browser! We all know IOS does not support Flash, however, Puffin Browser can run Flash on cloud so you can watch videos, play games, and tap into an endless sea of Flash content without the Adobe Flash Player Plugin. By the way, the browser's build-in theater mode and gamepad are very handy for playing Flash games. The free version gives your free Flash support from 8am to 4pm everyday. To enable unlimited Flash support, you can consider buying the full version.

App Store:
Google Play:

Official Site:

Android Browsers with Native Flash Support:

Saturday, June 21, 2014

PadFone - Smart Phone, Tablet, NoteBook, 3 in 1!

ASUS PadFone combines smart phone, tablet and notebook. It has a phone, a station and a dock. This device combines the top three electronic devices people use most, so at least can save you the trouble to transfer data among devices.
The official site:

Saturday, May 10, 2014

Fistful of Frags - Free 3D Western FPS Game

Fistful of Frags is a wild west themed multi-player first person shooter based on Source engine. The game has many game modes, advanced multiplayer bots for off-line practice and is free to play on PC/Mac/Linux. 

Install via Steam: steam://run/265630
Installer at ModDB:


Saturday, May 3, 2014

The Dark Mod - Standalone Thief-Inspired Game Mod Based on Doom 3 Engine Source Code

The Dark Mod, PC Gamer's 2013 Mod of the Year award winner, inspired by Thief series by Looking Glass Studios, based on the Doom 3 engine source code, is a first person view stealth game in a Gothic Steampunk world.
The Dark Mod includes creative new gameplay features, dozens of unique AI, and a complete set of custom art assets, allowing players and mappers alike to enjoy missions in a gothic steampunk universe. When you play The Dark Mod, you feel like you’re playing a gothic stealth game... there's nothing left that's recognizable from Doom 3.



Friday, May 2, 2014

Javascript PC Emulator - Linux in JavaScript

A very cool project by Fabrice Bellard, a Javascript PC emulator, which can even boot Linux. See Linux in JavaScript within your browser:

The Linux in the demo even contains a C compiler, an Emacs Clone and a small MS-DOS .COM launcher.

Thursday, April 24, 2014

Complete Linux Installer - Install Linux on Your Android Phones

With "Complete Linux Installer", you can install Linux operating systems such as Ubuntu, Debian, Backtrack, ArchLinux, openSUSE and Fedora on your Android phone or tablet. The installed Linux distribution will be almost fully functional as a standalone App of your phone - so it won't affect your phone's build-in system. With this Linux "App", you can download and use lots of Linux programmes such as FireFox, GIMP, Emacs, LyX, Octave and R with your phone.

The App is free and can be downloaded at:

Tutorial/Notes on how to use the App:

Official site of the App:

Sunday, April 13, 2014

One Device, Double Screen!

Yota phone has a very interesting feature - it has double screen on both sides. And what's more, one screen is LCD and the other is E-ink! LCD screen can be used as the normal screen and E-ink screen, which is used in Amazon Kindle, is most suitable for reading. For more details, check its official site:

This phone remind me of the ASUS Taichi ultrabook, which also has double screen. Another thing I like about this ultrabook is that it has a stylus pen.
See also EnTourage eDGe:

ZTE Zxon M:

Monday, April 7, 2014

Forbidden Arms - 2D Action Samurai Hack and Slash Game

In the game you play as a Japanese warrior with a legendary forbidden Samurai sword to slay ninjas. A nice game with lots of blood and violence.

Play the Game:

Sunday, April 6, 2014

.kkrieger - A 3D FPS Game in Just 96 KB

This is an old game from 2004, which uses only 97,280 bytes of disk space. However, it is 3D, complete and fully playable. The game use procedural generating techniques to create the most of the game content on the fly, so although the game executable itself is small, it can use a lot of your computer memory when it runs.

Download the game:

Friday, April 4, 2014

Metal Gear GB - A Metal Gear Solid Fun Made GameBoy-style Game

A Metal Gear Solid fun game with only 2-bit graphics. This game was made for Ludum Dare MiniLD50 jam within 10 days.

Move: Arrow Keys or WSAD
Start: Space
Button A: X or K 
Button B: Z or J
M: ?

Play the game:

Tuesday, April 1, 2014

Voxelstein 3D - the Wolfenstein 3D Inspired Game Made with Voxel

Voxelstein 3D is the open source & free game inspired by Wolfenstein 3D, but made with voxels. The game is based on the Voxlap engine by Ken Silverman, the author of the Build engine for the famous game Duke Nukem 3D. The Voxlap engine is also used in the commercial minecraft like FPS game - Ace of Spades.

This game featured fully destructible environment. You can blow up almost everything in the game, thanks to the voxel engine. If you're a fun of Wolfenstein 3D, or Duke Nukem 3D, or Voxels, you must try it.

The Voxelstein 3D Game:
The Blog for the Game:
The Voxlap Engine:

Monday, March 31, 2014

Play Android Games/APPs on PC & Mac

Want to play a mobile game on Android but don't have a (compatible) device? With BlueStacks App Player, you can install and run many Android games and APPs on your computer.
This software is a full feature emulator of Android phone for Windows/Mac and you can install Android App from Google Play or directly from a .apk file.
The App Player is free to use now since it is still in beta. Just click the link below to find the download for your Windows PC or Mac.

See also: