Virtual and real life!

New blog at wordpress

2009-04-04T03:59:00.000-07:00

Well I got tired of the sick editing interface of blogger and hence moved my blog to wordpress. From now on you can follow my updates in the following url
http://krishnaggk.wordpress.com

Code Less Create More

2009-02-25T11:00:00.000-08:00

Interesting! I unintentionally discovered a commercial app with the punch line "Code Less Create More" which almost matches to that of Qt. (Previously it was an exact match ;) )

I love this catchy phrase and this was one of the motivating factor for me to try Qt :D

The funnier part is I discovered this app after watching zack's talk on accelerating graphics which inspired me too look for cool opengl apps and I was driven back to where I started from!!

MakeStatus plasmoid: Code uploaded

2009-01-26T10:38:00.000-08:00

Hi, in my previous blog I introduced the new plasmoid I wrote as a means of learning experience.

I got some good suggestions like pastebin integration, KJob based implementation etc.. Really thanks for such good ideas :)

However I have not yet thought of implementing them as I just started learning some basics. It will take quite some time to master plasma and then actually dive into kde internals.

Anyways, I have decided to use code.google.com to host the plasmoid as of now. I thought of uploading code in kde svn playground but then I was confused on where exactly to import the 'makeinvoker' program code.

I have done a couple of changes since my last blog

First of all I have notify-enabled the makeinvoker program which informs the completion of the make invocation along with number of errors/warnings.
Secondly, a rather minor impacted change, converted makeinvoker program from qtcore app to kapp so that I can use notifications :)

Here is a screenshot:
Here are some meta-info about MakeStatus

Project url:	http://code.google.com/p/makestatus/
SVN (anonymous) :	svn checkout http://makestatus.googlecode.com/svn/trunk/ makestatus-read-only
Tarball(~13kB):	http://makestatus.googlecode.com/files/makestatus-0_0_1.tar.gz

I hope this plasmoid will be of some use to others as well :) I appreciate your feedback :)

MakeStatus: A new plasmoid for developers!

2009-01-20T02:24:00.000-08:00

I always wanted to develop a plasmoid ever since kde4.0 but I wasn't getting any ideas which had enough driving force in them. Finally, about 2 days back, I got an idea which was the result of "scratch your own itch"!

Let me introduce the functionality of this plasmoid, which served as learning means to me.

Usually we developers keep building from sources quite often. Many a times we do multiple builds in the background. Its quite annoying to monitor the progress staring at the screen. Others start some other work only to realize that the build has completed long time back.
Some smart people invoke echo -e '\a' immediately after make invocation to alert them.

However, wouldn't it be cool to have sneak-peak of the progress somewhere in the panel or as applet on the desktop ?

Especially, cmake has a wonderful method of saying the progress in percentile. So the visualization could really be made simple.

I used this as a use-case and developed a simple data-engine based plasmoid which is made up of following three components.

The data-engine, which has a dbus-interface to add, remove make source and also set the progress for an already added make-source.
The plasmoid, which at the moment is just a simple visualization, which displays the total progress of all builds.
The makeinvoker, which is a simple stand-alone qt-core based program that wraps around make and parses the output of make for progress information. As soon as it finds the progress information, it relays this information to the data-engine using a dbus-call. Also the makeinvoker prints out both the stdout and stderr of the make process to its stdout and stderr.

Here is snapshot of the applet in work

Armed with Techbase, I could grasp the basics quite fast. I really love the architecture of plasma - its flexible, intuitive yet powerful :)
However the codebase of MakeStatus isn't as clean since I am newbie to plasmoids, data-engines and D-Bus. It will take some time to shape up the code.

Some more ideas that can be implemented are:

Notification mechanism to indicate completion of make job (probably with error/warning clue as well if any)
Ability to pause/resume make
Display all make jobs with their progress in an extender when clicked.

As of now there is an issue bugging me and I am afraid there isn't an easy solution for it. The issue is, the "coloring of the output text" by cmake based Makefiles don't work. I don't know how I can read stdout from a QProcess and also forward the same to parent process with coloring. Any help is appreciated :)

Also I somehow could not get data-engine d-bus connection to exist standalone as I wanted. I tried

QDBusConnection::connectToBus(QDBusConnection::SessionBus, "org.MakeStatusEngine")

but somehow that created the connection at ":1.125". I really don't know much dbus - so will resolve this later (or may be I'll get help soon ).
The dbus interface path currently lies in the connection "org.kde.plasma"

BTW, for non cmake based Makefiles there is currently no way to display the progress information. For these build systems, the progress is either 0% or 100% (yeah, its binary in nature ;) )

Thats all I had to say. Any feedback is appreciated. Infact I'd love to listen to many more ideas that can be incorporated into this plasmoid.

Metalinks (contd)

2009-01-10T12:53:00.000-08:00

My previous post turned out to be very messy with updations because of my confusions. Hence I am doing a new post.

Metalink is a protocol which allows to embed several links for a given file. The links can be bittorent, ftp, http. Metalink enabled clients can use all these links to download segments of files from different sources.

aria2 is one such client. It is a special download utility which is really fast. Its power lies in ability to handle multiple connections from multiple sources simultaneously.

Opensuse has adopted such goodness already. All its iso's and rpm's also come with metalinks, which means people can download opensuse faster.

This sweetness is also being adopted in libzypp as well by providing a download handler using aria. However the default handler is curl for opensuse 11. zypper can be made to use aria by setting the environment variable as follows
ZYPP_ARIA2C=1

Now here comes the part, where I am confused.
Looking at the invocation of aria by the zypper (ps aux |grep aria) it seems libzypp instructs aria to download from direct rpm link and not its metalink. The metalink for each rpm file can be seen in html pages of repos (look to right of each rpm link in http://download.opensuse.org/distribution/11.1/repo/oss/suse/noarch/)
According to my testing, zypper is quite slow even while using aria for downloading which suggests its not using metalink.
So, somebody please confirm whether libzypp-aria integration uses metalinks to download rpm files or not.

Meanwhile I tried a manual download of several rpm metalinks and this was really fast. I could get a stable download rate of 80+kbps.

So I decided to work out some python magic to extract metalinks of packages to be downloaded from zypper output and then feed those metalinks to aria2c. The script is messy, but it did increase download speed. More importantly it served my purpose of maximizing bandwidth exploiting in the free download hours.

It certainly is a good idea for zypper to use metalinks rather than direct rpm links if its using aria. However this might already be the case as I am unsure. If it isn't, may be it can be done as summer of code project as well :)

So, I hope to have cleared up the confusion I set up in my previous post.

I will end with a question. Is there a way to get openSuSE factory KDE packages as an ISO which is available through torrents/metalink ?

Opensuse and metalinks

2009-01-10T10:40:00.000-08:00

Finally the time to try opensuse on my dell notebook had come. Previously I had Kubuntu 8.04 which was affected by the infamous hard-drive killer bug. So i thought of giving opensuse a shot after my exams and here i did it.

Actually I had downloaded the installer cd for 11.1-rc-x86_64 during my exams so, installed it right away. Almost everything was fine, except for the wifi. Dell inspiron 1525 comes with broadcom card and I had to install the 64bit driver for it. Thankfully I found this link with ease and hence got wifi working as well.

Very soon, I also compiled kdelibs, kdebase, kdesdk, kdepimlibs and kdeplasma-addons and was happy using the trunk kde as my main desktop environment. Desktop effects were descent though I was getting only 57 FPS in glxgears. However, I was running a mix and match kde4 apps from trunk and 4.1.3. Because of this there were some problems like

Akregator's menu and icons were absent when run through trunk KDE environment.
Setting the KDEHOME variable meant kde3 apps would also use kde4's home directory.
Yakuake's prompt used to hang whenever I did tab completetion for the first time in the session

These annoyances drove me to go for stability and hence I switched back to KDE 4.1.3. I wasn't satisfied still as I wanted something which was "latest" and yet somewhat "stable". So I chose to use factory packages for KDE.

The annoyances aggravated once I started the update with KDE factory repos enabled..

First of all, the download was really slow (about 2 kbps!) And also the update required me to monitor it because, either download.opensuse.org or the mirror used to fail and zypper used to hang on stdin asking me to abort/retry every 10 minutes. I took some patience and completed the update.

After the update, I ran into one more problem. KDM won't authenticate me at all, no matter what!! I tried xdm, but I guess I had done an unclean update because of which kde 4.1 didn't work for me. I was forced to use trunk KDE compiled by me, but again there were too many crashes. I think I had by mistake, enabled/disabled repos in between update (when download had failed).

All these left me with no choice, but to reinstall a clean opensuse. I did that but I haven't installed packages nor updated it yet. This is because I am tired of 2 kbps. Also I can't download all time as I have already amassed quite a hefty download and will be paying more for internet usage. The only way I can update is to make use of 2am to 8am free download time by my ISP(BSNL).

I also tried using different mirrors for the repos, yet the speed wasn't impressive. Some research led me to the wonder called METALINKS

Continued here.

Update: I apologize for updations because of my confusions. To clear the things, here is a new post which describes the metalink and its adoption by openSuSE. I have removed those parts from this blog.

Foss.in 2008

2008-12-04T23:05:00.000-08:00

Its been about 5 days since foss.in 2008 got over and I couldn't blog about it as I was busy with exam.
As I mentioned before, I only got to attend the first day (25th Nov) for my first ever foss.in.

Day-1

I made sure to attend the keynote, and hence reached the venue pretty early. After getting the delegate card, I headed inside only to meet a bunch of KDE folks who had gathered there - Pradeepto, Sharan, Adriaan, Madhusudan, Santosh Vattam and few more friends of Madhu and Santosh.

Adriaan gave us the cool KDE tags and that added up like a topping to my already cool summer of code t-shirt :D

Most of us then headed to the formal inauguration where Atul introduced the focus of foss.in 2008 - "Show me the code (i.e get work done)" in a funnier fashion. He had an apple in his hand which he regarded as the only low hanging fruit @ foss.in which he gladly ate it off :)

Harald then took over the dais to address the keynote where he spoke about "Doing Embedded Linux Right".
The funnier instance was, I took exactly the whole keynote session to configure network on my laptop, and to succeed I had to switch between Vista and Kubuntu to get help and try the same.

After the keynote, I found it more appropriate to socialize than to attend further talks. So i headed to the KDE(4 ;)) booth where we setup the awesome KDE4 pillar posters (Thanks Wade, Kamal and others for the lovely posters!!)

I joined Kamal, Santosh at the booth explaining people about KDE. We were giving away KDE handbooks and Kubuntu-Interprid remix live Cd's. The cd's got over soon, so we had to replace kubuntu with fedora 9 which Kushal had got with him.

Here is pic of the booth (oops forgot to take pic after hanging pillar posters :( )

The KDE handbook deserves lot of credits. I heartily thank Madhusudan, Santosh Vattam and their gang, Pradeepto, Kamal and others for coming with such a lovely piece of work.
Here are a couple of snapshots from my canon.

1) Making the official release ;)

2) The front page of handbook

3) The back page of handbook (bug fixed by me : Added Kushal Das in credits :D )

Well, the time passed by fast and I had to leave early as I had to catch up a train to Hyderabad. So we all barged into Adriaan's "hack room" and requested him to pose for us. We had a good chat with Ade and I was really inspired by his ability to motivate and encourage folks to contribute for FLOSS. The kde4-solaris port info which he gave was really some good knowledge which we wouldn't have known otherwise (as we hardly use solaris)

Posing with Ade

I was a bit late, so bid a bye to all the friendly floss folks and then quickly left the premises in my two wheeler.
More pictures from my canon at my picasa.

For better coverage of other days of foss.in as well, check out kushal's blog.

Foss.in taught me a lesson by embarrassing me for not contributing in the recent days. I didn't code a single line @ foss.in either as I really had less time and chose to socialize than to code, which means I failed this year's focus :(
However I am motivated positively enough to bounce back after my exams (31st Dec is my last exam)

FOSS.IN 2008 and posters!

2008-11-19T11:02:00.000-08:00

The D-Day is fast approaching.. FOSS.IN-2008 is all set to begin on November 25th with keynote from noted linux hacker - Harald Welte. The detailed schedule is out as well.

Foss.in is very special to us as it also marks the anniversary of kde.in. My hearty congratulations to one and all involved in upbringing kde.in.

And to celebrate this with pride, our own Kamaleshwar Morjwal has gifted us with stunning posters depicting pillars of KDE. [You rock Kamaleshwar!] Here is one of my favorite.

You can find the other splendid posters done by Kamaleshwar here. For a sneak peak you can also look at Pradeepto's blog.

Ironically, this is going to be my first ever foss.in even though I am residing in Bangalore for the last 14 years and given that IISC is only about 25 km from my house!!
Sadly I am not 100% sure of attending this event completely either due to another college commitment(research project presentation) which is scheduled during same occasion as of foss.in in Hyderabad. This is probably heights of being unlucky and lucky at the same time.

I am really thrilled to experience the atmosphere of huge foss event. I hope to make it on the first day atleast, especially to the "excited states of plasma" workout.

If you are interested to drop in to foss.in, register fast at http://foss.in/register/delegate-registration

Hope to see you guys :)

Busy days

2008-10-20T10:46:00.000-07:00

Its been quite a long time since I blogged (and also made good progress with umbrello after soc). The main reason is university. I have been on very tight schedule since college started.

We have operating system, system software, Formal Language & Automata Theory, Computer Networks-1, DBMS and Software Engineering courses this semester. Whew.. Though all of them are interesting, we require lot of effort to actually understand them in depth.

Of late, I and two of my friends are working on an interesting research project related to music and image processing.

And guess what - we are using Qt for almost everything required! I am really happy with introducing open source development tools (qt, g++, gdb, svn..) to my team mates as those tools are rarely known to anyone in college.

I have done various small projects like snake game, youtube cache downloader, simple image viewer using Qt in very little span of time to assist their understandings and fine tune my skills.

Recently my patch for Akregator- click on tray icon bug was accepted and I am happy on this small accomplishment :)

What bothers me these days is, I am simply not able to do any umbrello work - which is bad. I really need to work on my schedule, skip unimportant tasks and use the time wisely on umbrello. I plan to merge my soc-branch into trunk soon for KDE 4.2. This needs descent amount of work and so, I will certainly make good use of Diwali holidays :)

I wonder how days become busy all of a sudden! Ofcourse I ensure that I do allocate time for enjoyment :)

Hopefully my next blog will be about the succesful merge.

Update: Forgot to mention an important news. My article about my soc-umbrello accomplishment was published in the recent commit digest. I am thankful to Danny for making this happen :)

GSoC: Last week, new beginning!

2008-08-12T05:48:00.000-07:00

Well, GSoC is almost ending now officially. I am amazed how the time passed so fast.
All and all, it has really been a very nice experience. I have learnt so much and I am really thankful to Google and KDE. Especially I should thank my mentor Riddell, because I always end up doing different than what I communicate with him and he bears that :)

One important lesson I have learnt is how crucial execution of planning is. To be honest, I over planned most of the time and my execution of the plan was haphazard. This can be attributed to gsoc-08 being my first time-tested and planned project.
But importantly I have been productive (atleast in my terms ;) ) and also probably the saying "Aim for sky, you will land up on stars" has worked for me.

So here is the progress report I posted about 12 days before to the mailing list :)
In addition to the above report

I implemented an expander box item to hide/show the attributes and operations of a Class. Here are the screen shots.

I ported many more widgets, only 2 more remaining now. ( one point, but more work )
I implemented constraints for some widgets like - horizontal only movement, vertical only movement, resizable only in one dimension..

Now comes the part regarding the "new beginning".

Firstly I have to prepare my branch for being merged into trunk. This is quite a lot of work as you can see the following with still some work left!

gopala@gopala-desktop:~/Desktop/srcUmbrello$ svn diff svn://anonsvn.kde.org/home/kde/branches/work/soc-umbrello -r800853:845810 > b.diff

gopala@gopala-desktop:~/Desktop/srcUmbrello$ du --si b.diff
2.4M b.diff

gopala@gopala-desktop:~/Desktop/srcUmbrello$ cat b.diff |grep "^[-+][^-+]" |wc -l
44170

Next I have to do longer term plan with the other umbrello folks and work on it!

On another note, looks like aKademy as usual is a grand success. It would have been nice to be part of it. I hope to make into it sometime :)

GSoC: Couldn't resist posting!

2008-08-07T11:59:00.000-07:00

Its been quite a long time since my last post though I was busy working.
I am happy that my work is paying dividends

My idea of the framework classes to handle text inside the UML objects seems to be working nice. All these days I was busy porting all the UML widget-objects to new GraphicsView based classes and also using the TextItems classes. There has been many small behavioral improvements like lesser jitters. Still some work is left before it can be merged to trunk.

I now have 4 classes to be ported and after that I need to provide UI for the gradient selection, add hovering mechanism (just need to set a flag ) and then implement inplace editing (i.e double click an entry on widget-object's text and edit it there itself)

Here are the two pictures which displays prettier umbrello

I hope Umbrello to be more prettier, powerful and very flexible UML open source tool

kde.in monsoon hackathon

2008-07-15T11:12:00.000-07:00

Hello guys,
I am glad to inform about the successful hackathon we had in India during the last weekend. Apologies for the late report as there was a last exam bugging me.

The hackathon was mainly hosted by Geodesic office at Bangalore and sponsored by FOSS.IN. I am really thankful to Atul Chitnis and Shreyas for providing us with an excellent workspace to hack on. The arrangements rocked!

The hackathon involved Pradeepto(kdepim), Sharan(kexi), Tejas(kopete), Akarsh(kstars), Shashank(panoramio/marble), and me(umbrello).

Day 1:
We started of pretty well. Tejas was kind enough to drop us to the workspace ( I cannot forget the number of U-turns we took to find pradeepto :D ). We met for lunch at about 1:30 pm and started off with introduction chat. Kushal joined us as well. Kushal being camera ninja, took a few pics of us but unfortunately we couldn't have him further as he had to leave for Pune.

After a few moments, we started of with building stuff. All the soc students - me, Akarsh and Shashank were using the desktops set up over there and the rest of them were updating the kde sources on their notebooks.
Shreyas started adding some fun, by twittering the tidbits of what we were talking and doing. Pradeepto being smart to utilize build time, held a discussion about foss.in topics related to kde amongst us.

At about 5 pm, everyone had kde svn running and by then Tejas had taken the lead with the first commit of the hackathon - bonjour to knetwork/kopete which is likely to be released with KDE 4.2. Pradeepto then made a release of kdepim called 'Monsoon in Bangalore'. I ported the BoxWidget to set of framework classes I had written. Shashank was working on his cool Panoramio support to Marble. Then we had a nice dinner in Nandini restaurant and probably Akarsh was the only person to hack even during the night :P (others were tired of travel)

Day 2
This was quite productive day. Codewise there were bug fixes by Tejas, Akarsh, Sharan(helped Tejas) and me porting a few UML digrams widgets to the GV framework. Shashank continued his hack on the Panoramio support with download queue to Panoramio JavaScriptObjectNotation.

But the best part was, knowledge transfer that happened during the day.

Sharan gave really a nice motivating talk on how to use "XEmacs + kdesdk emacs scripts" productively.
Pradeepto gave a brief on how Test based development can be effectively used with qt/kde. Infact he demoed us and cleared our doubts. He also gaveus lot of information about EBN and how krazy works. Akarsh seems to have gotten krazy with krazy fixes in kstars code ;) His conjunction tool in kstars rocks!
Pradeepto also explained on how we can increase our productivity with the scripts written by David Faure and it really rocks!
Tejas explained the advantages of Yakuake.

Also during the tea break, we discussed on how FOSS can be imbibed in the people. We discussed various positive effects of FOSS and how many people have been benefited by it. The FOSS stories inspired me and I guess others as well!

Day 3
I couldn't attend this day, as I had to study for the *postponed* exam :-(
So you can read Akarsh's blog about day 3.
Well I could make a couple of commits from home which fixed some bugs in my previous commits, did a few merges as well. Here a screenshot depicting the work done by me during hackathon.

Overall I am really happy to be part of such a nice event. This was my first ever foss event and I learnt about foss in more detail. The attendees are my first ever FOSS friends :-) Infact a better word for the event is FOSSathon!

So thank you folks for such an awesome event. I thank Atul once again for sponsoring us and making this event a grand success!!
Yay!

GSoC: Mission merge!

2008-07-08T14:41:00.000-07:00

Hi folks!

Now that all but one exams are over, I started again with the soc.
The first thing I did was, to stabilize some classes which I was talking about before.

Then I suddenly remembered that I hadn't merged the changes in trunk into my branch. A quick

svnmerge avail -b

listed about 23 or so entries, thanks to my exams.
I was bit skeptical whether to do the merge or simply ignore them. I asked my mentor Riddell, and he told me it would be good if i could periodically keep merging.

So, the mission started. Since I had already modified many files I had to be careful while merging.
svnmerge proved extremely useful. Thanks to pradeepto for pointing me about this in the beginning of the soc itself :-)

Finally I am done with all the merges. I worked big time from 9pm to 3:30am (about 25 commits) :-) Don't be daunted by the numbers though as I committed one after the other to avoid messing it up.

Further plans are to port all the UML widgets to the new framework of classes I have written. I could port datatype widget in just about 5 minutes!
Hopefully I can finish this phase fast so that I can concentrate on adding more functionalities.

Expect more updates soon!

GSoc: Hovering and tooltip effect for umbrello.

2008-07-02T03:36:00.000-07:00

After some work yesterday, I found some 2 hrs of time again which i used to port the enum widget to new class. The results are simply amazing :)
Hover and tooltips work for the text on the widgets now!

Now the uml-widget contents aren't painted by single item, instead the texts are split into multiple text items. In future, a user should be able to edit the text by double clicking on any text inside widget and edit it with validation support. This will surely improve the user experience of umbrello. :-)

I can't wait to port other uml-widgets :p

BTW I started using neon and it really rocks. I will be able to free about 8 GB space on my hard drive ;)
Thanks a lot to the neon team :)

Refracturing umbrello

2008-07-01T11:06:00.000-07:00

I have been busy lately with exams as I indicated before. As a result I have not been able to spend quality time on umbrello, but hopefully I can get in full swing from this Saturday (penultimate exam, last exam is on 15th)

Meanwhile I decided to do some ground work preparation before I start properly with my soc project again. So i started with merging my new deepest base classes with the existing one. Since there are various style issues, i am bit confused and so decided to retain two versions of each function that is used. This huge modification ( fracturing ;) ) in the root resulted in lot of time.
Getting umbrello build again was nightmare but fortunately I succeeded in it :)

Of course i now broke all uml widget drawing, they leave marks on scene and there are some crashes. But thats ok because I will anyway implement each and every widget carefully from ground up. Also a positive being, the resizing using all the 8 handles work for most of the widgets without any single change to their resizing code.

I also added some utility methods to save brush(any kind including gradients) to xmi and retrieve the same.

That said, I now have setup the flexible base classes and have somehow managed to replace the parts of "root" of huge tree with new ones. I sometimes feel I was overbrave, but this challenge is fun :-) My whole holiday fun this time will be coding, coding, coding.... :-)

I also by chance spotted this beautiful architecture diagram and it serves as motivation to me with respect to achieving such nice things with umbrello. May be amarok will in future be able to produce beautiful diagrams with umbrello as well ;)

Now I need to sleep so that I can wake up early and study Microprocessors.
Wish me luck!

Umbrello : More improvements follow!

2008-06-16T12:23:00.001-07:00

Did i say my exams are nearing and i'll stop working for now on GSoC ?
Argg... GraphicsView is so addictive!

Fortunately i could pull out a couple of hours on umbrello, and guess what - I got resizing of the widgets working !!

All the eight resize handles which appear on selecting a widget are functional :-)
And the resize handles respect the minimum size and maximum size constraints of widget, neat (aseigo's TM ;) )

The current trunk and its predecessors have a size-grip which is the only way a widget can be resized. OTOH, I removed this size-grip. I am not really sure whether this move is sane or not.

And I am happy because I could achieve this in a clean generic way - including the changing cursor on hovering :-) I digged a bit of Qt-designer code which helped me a bit.

Here is a screen shot.

One good thing i have learnt so far is to document the code first before writing the actual code. This maximizes the focus on the exact functionality of a method/class before it is actually coded.

Update: Btw i also tweaked the enum widget painting code to use the extra space generated due to resizing. Here is screen shot of that.

Ok ok, no more gsoc until July 5th!
Study Study Study :)
Cheers.

Umbrello gets gradient support!

2008-06-14T14:09:00.000-07:00

Groovy!

I just committed the new version of base widget classes (not QWidget but QGraphicsItem) into my soc branch which enables gradients to be used with umbrello widgets like EnumWidget and it already works :) I tested this change by creating a NewEnumWidget class, and it already makes the old enum widget feel as second class citizen :)

Here is a screenshot.

To be technically honest, i just had to make QPen and QBrush as widget members rather than QColors.
But designing the base classes is not that easy as I need to keep in my mind about all possible usages by the subclasses. I have spent lot of time on the design. I was in a dilemma whether to inherit QGraphicsItem or QGraphicsWidget, but later settled onto the former as it is not heavy. So i had to duplicate a bit of functionality of QGraphicsWidget like sizeHint.
/me is happy with the design so far :)

Also i did a dired-do-query-replace-regexp (yeah i am emacsean ;) ) on the source directory to convert all widget::draw methods to its equivalent widget::paint method, which means almost all widgets are now shown on diagram as and when dropped. The widgets can be moved around. Also the AssociationWidgets show up, but are static i.e they don't update when any connected widget moves.

I should now better study for my exam. I'll get back to work after July 5th.
Until then bbye!!

Hello planet (late hello ;) )

2008-06-09T14:45:00.000-07:00

Hello planet

I noticed it late, that my blog got syndicated to planet. Thanks a lot Chris for adding me :-)

So here is just a small introduction of me and my gsoc project,
I am Gopala Krishna, doing engineering in Information Science at Bangalore.

My gsoc project is to do the GraphicsView port of Umbrello and add a couple of usability/cool features like inplace editing of diagram texts, gradient editor..

My mentor is Jonathan Riddell - a kool kubentero :)

I have done some progress with my gsoc work and i have blogged it here.

My gsoc project helps me in my exam!

2008-06-09T11:00:00.000-07:00

Yeah, thats true.. Today my gsoc project - Umbrello helped me do well in my viva during my practical exam for the subject OOPS.

The actual program i got in my exam was to demo Quick Sort which was fairly easy. After that there was a brief session of viva. The first few were good ground up c++ questions which i could answer.
The last two questions were surprisingly based on uml class diagrams (which we have in next semester) Good news, is i could answer them easily as that is what my project is based on :P
Honestly though the answers might not directly map to marks it surely has helped to earn some *impression* about me :)

Now, that one practical is over, I have Microprocessor programming practical exam on 11th. The problem with that exam is, we are most of the times not confident of getting output in the hardware part(elevator, keypad..)

I have actually understood the assembly language constructs well, as i also double as teacher sometimes to my friends ;)
Good thing is i found an 8086 emulator designed by my seniors which works fairly well. I was just thinking why they didn't make it open source.

Anyways I got to still practice some programs.
GSoC needs to wait for my exams to get over now :(

First progress!

2008-06-06T11:38:00.000-07:00

Yay!!
I could complete my first round of the GraphicsView port of umbrello after ~15 days of hard work. My morale was low until now because, i was not able to commit anything.
The quote "no commit means no work" which i read somewhere in GSoC docs was banging my head. I made my mind strong and worked for about 16hrs a day for the last two days which beared fruits in the end. Usually the port kind of work takes longer time than expected as it involves lots of files.

The good news is I got umbrello compiling and also some bits of the diagram tools working. Umbrello is now free from QCanvas based code ! There are tons of int-qreal, QRect-QRectF and QPoint-QPointF changes. Screenshot at this stage is useless!

I have to attribute part of my success to emacs, which helped me simplify repetitive work by using simple keyboard macros. That feature is so simple yet extremely powerful!

Of course i still have lots to do. There is simply no direct mapping for QCanvas to QGraphicsView technology. Infact all the book keeping and manual mouseEvent mapping code has to be scrapped as GraphicsView does it in best way.

I had two options to continue with my project

1) Get all the diagram widgets working by least modification, that is forcefully fit the code to GV framework.

2) Redesign the base-foundation classes like UMLWidget(not a QWidget), UMLScene.. and then port the remaining widgets to use this robust base classes later.

I being brave, chose the option 2 :-)
I am designing new classes like NewUMLWidget which will become UMLWidget soon. This way i don't have to port other widget subclasses now (smart right ? ;-) )

On the other side of development, I also did my first ever bug fix within umbrello.
The bug was nasty, resulting in displaced partial fonts throughout the umbrello gui(menu/toolbars..). The strange thing was, the bug showed up only when not using default font that comes with kde4. Rafael challenged me to fix it on #umbrello for a chocolate box ;)

Here is a snapshot of the buggy display

I by looking at screenshot immediately knew that it was because of creation of QFont object before creation of QApplication object. I knew it because, i had faced exactly same situation in the qucs-port. Indeed there was a global object of a state structure which had QFont objects in it.
The first fix to my branch was to create my own singleton class, but then later Rafael mention K_CONFIG_STATIC. Using that code was way simple and I committed the fix to trunk as well :)

I am happy for seeing so many positives , that too on a single day. :-) I hope it continues :)
My next objective is to perform well in my exams.
Practical exams are due on 9th and 11th of this month and
Theory subjects are between 24th june to 5th july.

Summer of code

2008-04-22T07:06:00.000-07:00

Hurray!!!
I am really elated and jumping around. I got into Google summer of Code this time. I am doing GraphicsView port of widget system of Umbrello, a KDE based UML modeling tool.
A big thanks to Pradeepto for his encouragement and planting the initial sprout of soc in me.

What does that mean ?
It means I have finally got a great opportunity to contribute to the KDE, the set of tools and environment i have been using since a few years.

Here is a link.

I will keep you people updated about the developments.

Svg support in qucs-qt4

2007-11-21T11:01:00.000-08:00

Well actually i haven't blogged for quite a long time as i am hardly used to blogging but let me change it ;)

Today was a fresh day, the day after my class internal tests. After my daily morning routine, i started thinking about what i can code in qucs-qt4 today. Ideas started sprouting up in my mind.
I had written a few classes to render svg before which somehow seemed to have flaws in them. Well i had neglected the fact that QSvgRenderer::repaintNeeded() signal is indeed needed to update svg when the style of svg changes. I could imagine bug where changing stylesheet of an item, didn't change all the svg items sharing the renderer.

Hmm i thought and i started sketching up my thoughts for the new design and SvgItem, SvgPainter and SvgItemData classes were born.
SvgItemData simply wraps the shared data in a class and SvgPainter renders the svg. SvgItem uses SvgPainter internally. I used the repaintNeeded() signal this time.
The design seems neat atleast for now ;) It was tiring in the end with more that 550 lines of code and modifications here and there in other files.

Here are sample screen shots

Back to cycling

2007-08-01T12:28:00.000-07:00

Finally the day, which I had been delaying since 6 months arrived. I had to clean up my cycle which was in a total state of mess. I had parked my cycle next to my house in first floor for 6 long months :o (due to my laziness and busy college schedule)

Its vacation time. So I cleaned up my cycle today, then took it to a cycle shop. I had to walk to the shop which was a km away. Unfortunately the shop owner wasn't there. Luckily the shop was open. I waited for 15 minutes and the owner arrived. I happily left my cycle for service there and took it back in the evening.

I cycled while returning and that was really an amazing feeling. I was joyful. I relished my sweet memories of my cycle back to the good old school days. Especially I remember the days where i used to return from school with my friends on cycle. We used to chat about various topics while coming. And yes I also remember the occasion where our Sanskrit teacher used to send me and my friend to Mutt to get Prathama/Dwithiya books during school hours !! I really miss those days :(

Anyway one thing is for sure. I've decided not to sell my cycle. I'll try to keep it in running condition(as warned by cycle shop owner ;) ) That way i'll also be contributing something good to the environment :)

qucs and what i am doing in it

2007-07-17T12:02:00.000-07:00

QUCS is a universal circuit simulator written in c++. It is cross platform due to fact that it is written using the awesome qt tookit. Here you can simulate many electrical and electronic circuits. The GUI is quite intuitive.
You can have a look at the screen shot of it which shows the simulation of simple adder circuit.

There are lots of cool circuits you can simulate. You can do digital simulation too. Take a look at the examples here. They are awesome!

I got hooked up with this project somewhere in aug-2006 with small gui improvements. The vertical tabs in the sidebar was added by me which was horizontal before and which used more real estaste on screen. The adoption of my patch excited me and i slowly became the project member. Initially i did very minute improvements.
One fine day i decided to take up a big responsibilty in the project. Qucs was/is using qt3 framework for the GUI. A major updated version of qt was available(qt4). The important advantage of qt4 is that it is free even for windows unlike qt3. Also there were tons of improvement in qt4 particularly the GraphicsView framework which made application development easier and faster. I took up the responsibility of transforming the qt3 code of qucs to qt4.

Initially i started by porting small tools in qucs to qt4. Then i started with the main part sometime in december-2006. Due to exams i couldn't do much. Also i lacked the basic knowledge of qt4 and i had to learn them. Now the project is half complete. I am taking this opportunity to redesign some part of qucs for better scalability and efficiency. You can have a look at the screen shot of the progress i have made below

I am yet to do the simulator integration and plotting tool. I have also planned to introduce plugin system and other goodies. I will be achieving my targets soon. So wish me some luck!

Solid edge tips and tricks

2007-06-18T11:39:00.000-07:00

Solid edge(v18/v19) is a nice cad software. VTU has made it the official cad software to be used by first year engineering students. I've collected a few tricks(related to basic 2d drawings) from my friends and also by my experience and thought it would be nice to share it with you people.
The intended audience is first year VTU engg students but others also might find it useful.

Use Ctrl + Left Click + Drag to copy and Release Mouse to paste any element. This is very useful to copy text(labels).

Use the move command to move complex elements rather than just dragging them. The advantage of using move is you can select the required point of selected complex figure and use IntelliSketch to determine the destination instead of relying totally on your sight which is also error prone. Also you can copy instead of moving by toggling Move- copy button on top left corner of the toolbar that appears.

You can place common elements like xy-line on background sheet rather than repeating the same for all sheets.

To get special characters like ß , φ, º you can use any one of the following approach

Use the character map and select "Symbol" font. You can select the required symbol, copy and paste it.
Use Symbol font for text box itself where you get ß for B..
Discover the required character in the font of your choice in Character Map. In the bottom of that dialog you can see the code of that character in the form U+0186. This is unicode of that character in hexadecimal. Convert it to decimal using calculator. (You might have to go to View menu and select Scientific in the calculator.) Once you get to know this code you can type it by doing Alt + Decimal code. Eg try Alt + 0186 to get degree symbol.

Did you know you could do all drawing in normal scale and reduce it isometric in one shot ? This is awesome which will save lot of time spent on keystrokes. Do the drawing in normal scale i.e without any .8165*no for dimension. Now select the drawing , click scale (available in toolbuttons listbox where move,rotate is present). Enter 0.8165 and press "Enter". Boom! You got the isometric! This is faster , elegant and less error prone (imagine you forget .8165*no for any one of elements :o)
You can get a cocentroidal plane inside itself(for eg 30mm pentagon inside 60mm pentagon) using offset command. It might be useful for isometric projections.
The last one is very handy when doing prisms, cylinders, frustum of cones.. Consider an example of frustum of cone whose base diameter is 60mm and top face diameter 30 mm of some height. When you are done with base, select the base - go to scale and give 0.5. Wait! Before you type 0.5, toggle scale -copy button on top left of toolbar that appears after selecting scale option so that you get a copy instead of changing the original. Now type 0.5 and you get the top face without any work! Place it appropriately using move command.

Well I tried to sum up the tips to my best. I really thank my friends for sharing their tricks with me. If you find any mistakes here you can correct me. You can also share your tips & tricks by commenting.

Disclaimer: The above, though works for me and my friends, might not work for you. I am not responsible in any way if it doesn't work appropriately for you or if it causes any undesirable side-effects.

Introduction

2007-06-18T11:10:00.000-07:00

Hey folks,

I am doing engineering at PESIT in Information Science. My main interest lies in computer progamming. I've learnt c, c++, bit of python and lisp. I am a great GNU/Linux fan and my system dual boots with windows xp and kubuntu. Recently i've been involved with an opensource project called qucs (Quite Universal Circuit Simulator).
Other than this i am a movie buff, sports crazy(football and cricket).. I'm very lazy when it comes to studies since i hardly do that regularly :p

Thats it! Thanks for reading :)