I want to code sth. that basically works like TiVo. Switch it on, you only see the menu or an output, so no underlying OS or anything else is directly visible to the user.
So I want to use Linux as base. Can you suggest a good base distribution?
Can I code a frontend without having a window-manager up and running?
If yes, is that possible with java-gnome or what language/gui-framework combination would you suggest?
If no, what's the minimal window manager that can handle fancy menus, etc?
What does it take to create video-overlays over a HD-stream? Are there some libraries I should take a look at?
Thanks
Yes. If you only have one window you don't need a window manager. Using X you can start some application and set it's position and size from the commandline (making it fullscreen). You might want to take a look at xinit if this is what you want. This is likely the easiest why to get something working. But another option is skip X and use DirectFB. If you want to display several windows, on the other hand, you need some sort of window manager to manage them.
As long as you run X there is no problem using java-gnome as framework if that's what you are confortable with. I guess you didn't mean to run the stock gnome applications, but code everything visible to the user yourself.
This very much depends on what you mean with fancy menus. If you mean transparancy and such you need a composite manager (if you don't just render everything yourself inside your application window). I'm not sure about this but I think you can run a composite manager independent from a window manager if you find that suitable. Again, this is if you run X. Using DirectFB transparency and such are done in a more simple way.
If you intend to write your own media player you should take a look at GStreamer. It can stream, decode and display video and also add video-overlays (among other things) and is extremly easy to use.
Minimalistic tiling window manages like Awesome, Ratpoison or XMonad may be useful as a base, otherwise you'll have to manage focus and window sizing yourself. It is normally fairly easy to make these invisible to the user.
Absolutely.
I wouldn't count on Gnome itself working without a window manager. Other than that... language doesn't matter.
Window managers only do window management. Menus and the like are the job of the widget toolkit. Anyways, Metacity.
... This one I have no clue about.
Related
The More General Question
I am wondering if there is a standard way that operating systems / desktop managers use to expose the user's preference regarding the placement of the window frame controls (Close, Maximize/Miniaturize, Minimize).
For platforms like Windows and MacOS, it's "pretty" safe to assume that the users wants their window controls on the right and left respectively to match the rest of the windows in the GUI. But the key word here is "assume'. I hate to assume things when I code.
Furthermore, what about all the different Linux distributions and flavors?
I think this information could be useful to application developers in the same way that it's useful to know the user's preferences regarding dark or light themes.
My More Specific Question
Now, what I'm building currently is an Electron application that could really benefit from a custom title bar (a.k.a. a frameless window). And I do understand that my problem is caused by the fact that I want to bypass the window frame abstraction that is normally offered by the operating systems, but I'd really like to be able to position my custom controls in my title bar without having to guess.
But anyway, since I use Electron, I do have access to native features using NodeJS, but I'd also be curious to know if browsers have or are planning to implement a way for the CSS or JavaScript running in the browser to determine the intended placement of the window controls, again, similarly to prefers-color-scheme?
I'm developing a small j2me game and i want to create a menu for this application. I imagine the menu as a vertical list of items with a cursor on the left or right side that i can move from item to item, something like this menu example but as a main menu.
What elements should i use to obtains such effects? I need only advices or links, i will develope it myself.
Thanks in advance!
import java.util.Vector;
import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Font;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
What you plan looks doable. Can't give much links because don't recall any that could help on stuff like you're doing. Actually, most useful link for you will probably be MIDP (JSR 118) API reference - your part is going to be mostly lcdui package, and especially Graphics API.
As for advice, no problem. First thing to note is that there will be more coding and more (much more) testing/debugging than it was in your prior experiment with implicit list. If you can think of some possible deadline / timing requirements that may become a problem - just keep in mind that prior design with implicit list as a fallback. It won't look as fancy but it'll work work safe and correct.
Another important thing is to decide what kind devices you are going to target. For menu like one you are going to develop, it may be rather difficult to get consistent look and feel both at 160x200 basic phone with ITU-T keypad and on 400x600 touchscreen smartphone. Below I am going to assume you'll try to target as wide variety of devices as possible - note the narrower you can get it, the easier it will be to code and test.
When targeting lots of different devices it is helpful to use an emulator that can be configured to simulate various display sizes and resolution, presense or absence of touchscreen input etc. Keep in mind though that emulator alone won't fully simulate real device. To keep your feets on the ground, consider also some regular smoke testing of your application with real device, preferable using over-the-air (OTA) installation.
Here are some particular API tips that I can think of now.
Use Canvas.getGameAction to handle pressed key code - that is likely the most reliable/portable way to figure up/down and select actions for menu.
Use Canvas.hasPointerEvents to figure if there's touch screen support. Users with touch screen devices may get disappointed if it turns out that your fancy menu can't react when they tap on screen.
Use Font.getHeight and Font.stringWidth to figure how much space is occupied by menu item text.
Use Image.getGraphics if you want to draw something over the image object.
As I mentioned, you most likely will do a lot of stuff using lcdui.Graphics API. It's mostly rather simple, but you will probably need to understand somewhat tricky stuff about clipping. Good luck.
I am working on a project where I need to run Google chromium over Linux FrameBuffer, I need to run it without any windowing system dependency ( It should draw on the buffer we provide it to draw, this will make its porting to any embedded system very easy) , I do not need its multi-tab GUI, I just need its renderer window in the buffer, has any body ever tried this? Any help on what approach should I use for this?
If you need to have some direct control of the window functions, or want to poke around in the DOM data, then the right way to solve this problem is to probably look at embedding webkit directly. This will be much faster and cleaner than what I am about to suggest.
Now, let's suppose you don't need all that fancy control and that you are really lazy. An ancient, low tech solution to your problem could be to create a virtual frame buffer and then read its contents directly. To do this, you can set up xvfb on your server:
http://www.x.org/releases/X11R7.6/doc/man/man1/Xvfb.1.xhtml
xvfb is an old unix tool that lets you create a virtual x-server with whatever type of configuration you want. More importantly, it can be configured to write the contents of its X server's screen directly to a memory mapped file! You can also set it up to use shared memory, which is a bit faster though also more complicated.
I guess you will have better luck with uzbl and GTK/DirectFB. Same engine, and works with javascripts. For the facebook chat issue, I think you just have to change the user-agent string.
There is the Origyn Web Browser, which is supposed to be an embedded WebKit-based browser that looks portable and does not depend on "heavy" libraries (like GTK). Their web page is http://www.sand-labs.org/owb but it looks like their database crashed, which is a little worrying maybe.
try to port webkit engine to the netsurf framebuffer-based code.
HTH
You could buy one of the remaining 10 (or so) OGD1 boards.
http://en.wikipedia.org/wiki/Open_Graphics_Project
Then you can talk directly to hardware using libpci.
However you will still need code that draws a picture into a memory buffer.
I realize this answer is more a shameless plug.
But people who are interested in your question might want such a board.
I already have a board like this and it would help a lot if it got more exposure.
This project:
http://code.google.com/p/wkhtmltopdf/
Achieves that. It runs Webkit on a virtual display and captures the rendered output in form of PDF. You can customize that do do something else.
OR you can create a display with tigthvnc, and set DISPLAY variable so that Chrome renders in that display.
I suggest using the webkit2pdf package (which is available for many different Linux distributions). Then use fbgs which is a wrapper for the fbi frame buffer program, that displays PDF files right on the frame buffer.
I need to write a small application in C/C++ to implement a panel task bar like thing to display information along the top of a desktop window (specifically an xorg desktop on a Linux system). I need to avoid bloat and steep learning curves for the GUI programming.
My research is pointing me at GTK+/GTKmm or FLTK. It looks like FLTK is probably the simpler to get to grips with and the most likely to provide a small clean package with minimal dependencies. So I've based my research on FLTK so far.
I've been doing some reading and am struggling to find out how to write a basic program that will create a narrow undecorated window that covers the width of a monitor in such a way that maximising other applications would not obscure it. The FLTK tutorials I have found so far (including the FLTK documentation) only implement standard windows with borders that can be moved around the screen.
I'd like to start by writing a simple program in FLTK (or GTK+/GTKmm) that creates a 20 pixel deep bar across the with of the screen containing a "hello world" message. The bar's area would be reserved outside the area that other programs can access so that maximising another application would not hide the "hello world" message. I think this has something to do with a WM_STRUT_PARTIAL property but I can't find information about this in FLTK.
Doing this is partially to understand how to write a simple GUI program and partially to solve a specific need that I have.
I'm looking for any help/guidance to put me in the right direction to get started. Many thanks.
starfry, it is not a trivial task I believe. The problem is that your desktop (say GNOME2/Metacity) reserved that space, and paints its panel in the area where you want your bar. -
If you really want your tray-bar applet to be based on FLTK, the you would have to "embed" it in a (GNOME) applet. It was long ago when I did similar thing with SDL application, but I am afraid I forgot how to do it. The first thing that comes to my mind is to use somehow get the XID from the GNOME applet and somehow pass it to the FLTK part of it, and then let FLTK do the rest...
Sure, you may use another desktop, like KDE, or i3 or IceWM, they ALL have their own ways of dealing with the tray bar (there is no standard for it!) so, pardon my "French" - it is going to be a PITA to support all environments...
If I was on GNOME, i would write the applet entirely using GNOME/GTK. Forget FLTK in that case. That is my recommendation. If you target KDE, then do it using KDE/QT libraries (Plasma widget would be what to look for).
However, if you still want to use FLTK, start with the fltk::draw_into() function (it is probably called fl_draw_into() in FLTK 1.x), fltk::xid() and related functions.
PyQt experts: I developed the GUI in Windows and used setGeometry to position the widgets. When I tried to run the same code in Linux it looks cluttered.
And added to that in Windows the font size of 8 seems good. But in Linux, especially in Ubuntu, it doesn't appear well since the font size is 10 by default. Some among the differences are the border of the group box doesn't appear in Linux while it is visible in Windows..
Is there a way that I can make the same code to get the same look and feel in Windows and Linux irrespective of the font and size changes and other differences?
In future if I port my application to Mac will the same code work there too? Or should I have to maintain the separate code for each by checking with platform.system() equal to "windows" or "linux"?
The answer is simple: don't use setGeometry directly (to position your widgets).
Consider the following: what if the user wants to resize your application window?
Compose the user interface (you could do this from Designer or from code) within QSplitters (if you want a resize handle between two components) and/or within QVBoxLayouts / QHBoxLayouts (note that these can be nested).
This will make your UI components behave consistently.
I agree with #ChristopheD. Using setGeometry is bad. It's like designing a webpage with fixed pixel geometry and then wondering why it looks bad on another device.
Qt has a lot of wonderful layout code. Let it do it's job.
Qt by default will paint a widget according to instructions contained in the QStyle. You can test how badly you break your layout in different styles easily enough... run your program with different style options. Like so:
program.py -style motif
Also try -style platinum or -style windows. Even different versions of Windows will probably break your layout.
If you really want to see how bad pixel-based layouts are, try running your program with the -reverse parameter... that's how your program will look to someone running it who speaks a Right-To-Left language, like Hebrew or Farsi.
The problem that you have with widgets not drawing where you want them to can be solved by creating custom painting code for your widget. See the PyQt QPainter docs or better yet, the original Qt QPainter docs..
While I hope my answer is useful, it probably means your program needs to be partially rewritten. In the long term, however, it means that you'll have code that is portable between styles and operating systems, and will even work translated (assuming you care about that).