General and Desktop

Perspective in 2d? No such thing! ;) You can easily use 3 points as well, but it is overkill and unnecessary - you still can create a triangle and follow its transformations and apply those to the scene but it just adds to the complexity without adding any actual value. You can do it for the sake of doing it thou, you can use the area or perimeter/circumference of the triangle for scale and its orientation for rotation, but the latter you will still have to reduce to a line, i.e. follow the rotation of the triangle's height.

I am not familiar with MVC, it seems comprehensive study necessary for learn it. So i found temporary solution for this project. Thanks for your answer.

Hi, ~Leon! Qt doesn't have this widget in defaults, but it's very simple to implement it on your own! I will do it in this way. In switcher - create horizontal layout. Create QLabel and set it's style via QSS. Move it in layout.

Wilk, this is what I mentioned above. But it depends on the application someone wants to deploy. However, I don't think that it makes sense using multithreaded insertion into a database in general. Since nearly everything is possible in coder's world ('beam me up' not yet) it should be clear what the user wants to enter and how - not inverse - looking at what Qt does and then decide what the user has to do. Besides, the example DB does only have one integer key.

Hi, ~jnewing! Problem not in you - problem is in OS'es. They are not allowing to catch PrintScreen key press event. But there are a few solutions specified for systems' API's

See http://www.qtcentre.org/threads/49840-Awful-flickering-with-QGridLayout-on-Mac-OS-X?p=223935#post223935 for the 'solution'...

Phil, It appears that there is a bug with query.next() using ODBC in Mac OS X. The bug report for 4.8.0 with a temporary work around is here: https://bugreports.qt-project.org/browse/QTBUG-25260 I know that this bug still exists in 4.8.1, but I've not looked at 4.8.2's source so I can't verify. Hopefully this bug is fixed in Qt 5.0. I had to recompile the ODBC sql driver plugin from source making the modifications suggested in the work around in qsql_odbc.cpp in the QODBCResult::fetchNext() function on line 1043. The class file, qsql_odbc.cpp, can be found at /Users/[you]/QtSources/4.8.[x]/src/sql/drivers/odbc/qsql_odbc.cpp. Note: If you downloaded the source outside of Qt Creator, you'll need to browse to where you extracted the source. This applies to all paths supplied in this post. I commented out the conditional part, beginning on line 1033, where SQLFetchScroll is called so that it looks like this: @// if (d->hasSQLFetchScroll) // r = SQLFetchScroll(d->hStmt, // SQL_FETCH_NEXT, // 0); // else r = SQLFetch(d->hStmt);@ Then I opened up /Users/you/QtSources/4.8.x/src/plugins/sqldrivers/odbc/odbc.pro within Qt Creator and built the source. The outputted dylibs are put in the sqldrivers directory in their respective release and debug folders. When building the plugin, it's very important that you use the correct version of Qt to build. For instance, if you're targeting Qt 4.8.2, make sure you have Qt 4.8.2 configured in your Qt versions from Qt Creator. After you build the ODBC plugin, you're ready to replace your Qt installation's dylibs with the newly built dylibs. First, make a back up of libqsqlodbc.dylib and libqsqlodbc_debug.dylib from your Qt installation. This is typically in /Users/you/QtSDK/Desktop/Qt/4.8.x/gcc/plugins/sqldrivers. Then you can overwrite your Qt installation's dylibs. Now you should be able to get results from query.next() within your application.

My five cents: I, too, come from a similar background (Quantum physics), so I'm not a software developer by profession. My way of getting a grip of those things was to go to the computer science area of our university library and read books that seemed useful for such purposes, including the big design pattern book by the "Gang of four" ("Design Patterns: Elements of Reusable Object-Oriented Software"). They don't explain large scale application development itself, but teach you certain non-adhoc ways of solving recurring problems (what's called a "pattern"). Some of those patterns are essential because they form a well-known basis for your approaches to certain problems. This way other Programmers also familiar with the patterns will have an easier time understanding your code – equally you will need some of the patterns to understand their code. This is something small applications don't necessarily need, because the code is small enough to not fall apart in spite of adhoc-solutions. Although I've read many other advanced software development books here and there, because I, too am fascinated by how large software projects can possibly work, I'm afraid I know none of them from the top of my head (the content is always more interesting than the title you know ;). Getting into this topic was a rather inefficient process for me, so I never sat down with a serious curriculum and worked through the material. I just got it bit by bit. (Oh yeah, don't get me wrong, I'd never consider myself a professional large scale software developer. For that you'll need to do it as a job and think about this stuff for eight hours a day for ten years.) Further, some very useful information can be distilled from coding guides of large projects. See google's coding rules or the ones of Qt and KDE. And nothing's worth more than failing. Start writing your geophysics application. Maybe it works out great, then you're happy. Maybe it falls apart or becomes inflexible. Then you start over, know your design mistake, do it better. Then you're happy, too. :)

Thanks for creating the feature request. I've voted for it.

Yep, I found a solution: @QPixmap pix=QIcon::fromTheme("dialog-error").pixmap(22);@ Yet, thanks for being kind with the newbies :)

@ #ifndef MAINWINDOW_H #define MAINWINDOW_H #include <QtGui> namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); QFileSystemModel *dirModel; QFileSystemModel *fileModel; private slots: void on_treeView_clicked(const QModelIndex &index); private: Ui::MainWindow *ui; }; #endif // MAINWINDOW_H @ and @ #include "mainwindow.h" #include "ui_mainwindow.h" MainWindow::~MainWindow() { delete ui; } MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); dirModel = new QFileSystemModel( this ); dirModel->setFilter( QDir::NoDotAndDotDot | QDir::AllDirs ); dirModel->setRootPath( "" ); ui->treeView->setModel( dirModel ); fileModel = new QFileSystemModel( this ); fileModel->setFilter( QDir::NoDotAndDotDot | QDir::Files ); ui->listView->setModel( fileModel ); } void MainWindow::on_treeView_clicked(const QModelIndex &index) { QString str = dirModel->fileInfo( index ).absoluteFilePath(); ui->listView->setRootIndex( fileModel->setRootPath( str ) ); } @ in treeView shown directory and other side of treeView, listView that shown files in dir on selected in treeView ! there is one bug when you active like go to directory ‘a’ . in this directory exist some file and other dirctory you click on one directory in subdirectory of ‘a’ and then again click on ‘a’ directory ! you will see subdirectory break filter and display in listView !!

[quote author="mafiozzi" date="1341661720"]What libraries do you have? I mean it is 4.8.1 or 4.8.2. Some times ago I had the same problem. When I compile my app in Windows it looks fine, but when I compile app in Linux (Debian) it looks awful. So I asked here about that problem and they recommended me to update my libraries http://qt-project.org/forums/viewthread/16819/#84760[/quote] Thanks for the reply. In Linux I use the latest libraries, in Windows and OS X I use 4.8.1. Since in Windows and OS X I use the SDK, I will have to wait for an upgrade, although I doubt this will solve it:-)

[quote author="goocreations" date="1341655010"]Ok, I've use Valgrind. Seems like there are no "real" leaks. Valgrind reports leaks way beyond Qt, somewhere in the GNU linux libraries.[/quote] Well, this doesn't mean much! After all, the call stack for every memory allocation (including those that are "leaks") will end up in C/C++ or OS library functions. It doesn't mean the cause of the problem is there tough. The problem usually is somewhere "above" in the call hierarchy. So only if the call stack for a memory leak's allocation neither originates from a Qt function nor passes through a Qt function, you can be sure that it's not Qt's fault. In the other case, if you see some Qt-related function somewhere on the call stack, it might be Qt's fault. But it might be as well your application code using the Qt library in the wrong way (e.g. constructing some Qt object but never destroying it). Further investigation will be needed along all the functions on the stack...

Holly s... what a shame ;) yeah I had QT -=gui But... I compiled it earlier on Linux without any errors. Strange. :o Thanks a lot.

No raaghuu, I am trying to making something more or less like cyber software.

I think my mousemoveevent is already lightweight because the if condtions are rarely satisfied: @void MatrixW::mouseMoveEvent(QMouseEvent *e) { if(thismove!=none) { int xnew=e->x()/larghcell; int ynew =e->y()/altcell; if((xnew!=xN||ynew!=yN)&&(xnew<size_x && ynew<size_y)) { if (isarelease) { isarelease=false; if (thismove==del) setcell(xN,yN,0); else if (thismove==add) setcell(xN,yN,1); } xN=xnew; yN=ynew; if (thismove==del) setcell(xN,yN,0); else if (thismove==add) setcell(xN,yN,1); update(); } } }@ (thismove!=none) only if the mouse is clicked ((xnew!=xN||ynew!=yN)&&(xnew<size_x && ynew<size_y)) is rarely true each 50-100 ms The good way to do this I think is to start a timer when the mouse was clicked, the timer call each 50-100ms a function like MatrixW::mouseMoveEvent(QMouseEvent *e) where the program can read the muose position. The mouse release event stop the timer. But I don't know how to read the mouse position in the function called by the timer continually read the mouse position would be the same as what I do now (about the slowdowns)

:) perfect, thank you so much!!

Cool but wouldn't all my Item inside the View been flipped as well ? as if I apply a scale(1,-1) to flip the y direction axis and then the transform to reset the origin . the "space" woulld be upside down ? would I have then to also scale(-1,1) all my childs item so they are the right way around ? I will do some test, I want to try to do it the correct way rather than "a way" that kinda works :) Thanks for your reply Damien