how to define window stacking order? - x11

I'm trying to write my own window manager. One issue I faced is that I don't understand how to define in which order windows should be displayed. The only means I found is to use xcb_configure_window. But it looks very limited to me: it only allows either to rise the window on top of all, or put it to the very bottom (no notion of layers or something). What a limited functionality :(.
What I really would like to do is to define the window order and tell X about it. Or to define multiple layers of windows (e.g, normal, above all, below all). So I could rise (or lower) the window with respect to its layer. So windows from lower layers will not ever cover windows from upper layers.
So, is there any other library function to define the order of windows apart from xcb_configure_window? Or I need to live with it? That would mean I have to track the order of windows in my window manager.
Link to relevant XCB documentation: https://www.x.org/releases/X11R7.6/doc/libxcb/tutorial/index.html#winstack

X11 only gives you the absolute minimum. There are no layers or always-over or always-under windows. You implement all the fancy stuff yourself, typically in the window manager, which is what you are writing.
There is no raw protocol request to change the stacking order of windows at once. Xlib has a function XRestackWindows which does that, but it uses one configure request per window. The pseudocode is just
for each window in the list except the first
change the stacking order to be under the previous window
That's it. Nothing more fancy than that.
You do need to track the stacking order in your WM in order to implement layers, so that when a program tries to restack a top level window, you intercept the request and only restack it within its layer.
Another possible way to implement layers is to have several transparent full-screen windows and reparent users' top-level windows to those, instead of to the root window. I'm not totally sure it will always work though, and you need to deal with transparency in one way or another, which requires transparency supporting hardware or the composite extension or possibly both.

It is the responsibility of the window manager to order the windows. A window gives hints about which type it is (popup dialog, menu window, splashscreen, toolbox, etc), the window manager then decides how to display this on the screen. This includes keeping track of the order and deciding which gets priority.
There is a X11 call to change the order (XRestackWindows), but I don't know the Xcb equivalent.

Related

How to make a fixed position and size window in X11

So I wanna make my window not moveable and resizable, is there anyway to do it? Below is my current window creation code.
testbwidgetptr->basewin = XCreateWindow(BOTIFDisplay,
tmp->drawarea,
testbwidgetptr->bwidgetx,
testbwidgetptr->bwidgety,
testbwidgetptr->bwidgetwidth,
testbwidgetptr->bwidgetheight,
0, CopyFromParent, InputOutput,
CopyFromParent, valuemask, &winatt);
XSetWindowBackground(BOTIFDisplay, testbwidgetptr->basewin, WhiteDot);
I wanna make my window not moveable and resizable
In X11 window management, the client doesn't get to define what they want. They can ask the window manager to do this or that (or not to do that), but in the end it is always up to the window manager. In fact, the specifications state clearly that the client application must deal with any size the window manager assigns to it – so the answer is: no, you cannot do that if you want your window to be managed.
As pointed out in a comment, you can set override_redirect on your window. This tells the window manager not to manage your window, which means that the window manager will not interfere with it. However, in theory any client could still resize your window (though this is extremely unlikely to happen).
However, you should be careful about this. Bypassing the window manager also means that you lose a lot of things: window decorations, focus handling and the like will all be gone. In particular, focus handling must be done by you.
To summarize, you should really consider whether override_redirect is actually what you want to use. In most cases, you should instead just build a client that can deal with arbitrary window sizes and positions.

InvalidateRect called too frequently blocks other windows from redrawing

I develop audio plugins, which are run inside their hosts and work realtime. Each plugin has its own window with controls, which often contains some kind of analysis pane, a pretty big rectangle that gets repeatedly painted (e.g. 20-50x per second). This is all working well.
The trouble comes when the user adjusts a parameter - the plugin uses WM_MOUSEMOVE to track mouse movements and on each change calls ::InvalidateRect to make the relevant portion of the window be redrawn. If you move quickly enough, the window really gets quickly repainted, however there seems no time for the host and other windows to be redrawn and these usually perform some kind of analysis feedback too, so it is really not ideal.
No my questions:
1) Assuming the host and other window are using ::InvalidateRect too, why mine is prioritized?
2) How to make ::InvalidateRect not prioritized, meaning the window needs to be invalidated, but it may be later, the rest of the system must get time for their redrawing too.
Thanks in advance!

Keep part of a window always visible

It is possible to use the SetWindowPos API on Windows to keep a windows always on top of other windows, and there are many questions on StackOverflow dealing with this.
It is possible to keep only part of a Window always visible? I.e. specify a clipping region inside an existing window, and keep only that part visible?
A use case would be the following (on Windows):
User clicks on icon to run app.
User highlights a portion of the screen to focus on (similar to the Snipping Tool on Windows 7)
The highlighted part of the screen remains always visible, even when other windows/programs are moved over the selected region.
I know the issues that would spring up with having other applications that are also set to being topmost. Just curious if this is even possible?
Even if you change part of your window to be transparent to what's below (with a clipping region) it's still going to take all the mouse clicks, etc. that occur over the transparent part.
Your best bet is to create a new smaller window and make it top-most while hiding the main one.

How does a GUI Framework work?

I have been all over the web looking for an answer to this, and my question is this:
How does a GUI framework work? for instance how does Qt work, is there any books or wibsites on the topic of writing a GUI framework from scratch? and also does the framework have to call methods from the operating systems GUI framework?
-- Thank you to any one who takes the time to try to answer this question, and forgive me if i misspelled anything.
In the old days we did a lot of GUI programming from scratch. It is not as hard as it seems, but it requires a few weeks to come with results.
First you need a good drawing library. Minimal functionality for this library is drawing clipped rectangles (using patterns), lines, bitmaps, and fonts. You can cheat by creating fonts as bitmaps, and clipped rectangle is just a bunch of horizontal lines.
Now you need at least drivers for mouse, keyboard, and timer (if not already provided by the operating system). In general, you will need to detect keys, symbol keys (such as shift, etc.), mouse moves and mouse clicks. Basic timer functions will allow you to detect double clicks.
Then you need to create a window data structure. This data structure needs to have coordinates i.e. a rectangle, link to parent window (if not top window), and window function i.e. the function that will be called when this window should handle some events.
Once you can draw on screen you need some rectangle algebra functions. You need at least good function to calculate intersection of rectangles, and a quick resolution of relative to absolute coordinates. For example - if your child window has parent then its' x and y should recursively be added to parent x and y until you reach top window.
At this point you have your:
- primitive graphical functions,
- window structure,
- mouse driver, keyboard driver, and timer,
- rectangle arithmetic.
Now you can write your main event harvesting function. This function will run all the time. It's purpose will be to detect events and send messages to correct windows. What is an event? Well, when you start your program, store mouse x and y coordinates. Then in a loop check if they have changed. If they have changed, find the window at that position ... and send WM_MOUSEMOVE event to it. Your harvesting function should handle:
- mouse moves
- mouse clicks
- mouse double clicks (remember last click and position, measure time and decide if it is a double click or not)
- timer events
- keyboard buffer changes
...
Now you should be able to send events to windows. But you really need a mechanism for it. It is a combination of message queue, and window procedure. It usually works like this: each window has a window procedure which commonly accepts four arguments: message id (i.e. is it mouse move, is it paint message), window handle, parameter 1 and parameter 2. You can call this window procedure directly using something like a send_message functions. Or you can send this window a message via post_message function. This will put message to the queue and window will process messages one by one, eventually receiving this one. So why should you call one messages directly and put others to the queue? Because of priority. You see, a keyboard click can wait some time before being processed. But a window redraw must complete immediately to prevent flicker and wrong data on screen.
So your harvest_events function sends messages to windows using post_message, and send_message. And your window message pump gets them using typical message pump like this:
while (pmsg = get_message() != NULL) send_message(pmsg->id, pmsg->hwnd, pmsg->p1, pmsg->p2);
get_message simply obtains message from the queue, and calls send message. Simple, huh? Well, not quite so. This way you would only receive driver messages to windows, but you also need some functions to redraw windows, move them, etc.. When you create move_window function, resize_window, show_window, and hide_window function, your window coordinates will change. Parts of other windows will be uncovered (if top window is moved or closed).You need to calculate which windows are affected by coordinate changes and send paint message to those windows (to repaint only the parts that were uncovered - remember, you have clipping drawing functions so this will work).
These functions introduces messages msg_paint, msg_move, msg_resize, msg_hide...
Last, you need to maintain hierarchy of windows. Your top window should be the desktop. It should have child windows (application top windows). These windows may have further child windows (buttons, edit boxes, etc.) The obvious structure for holding these is the window tree. When you detect mouse click you have to traverse window tree and do it in a smart way (finding out who has focus, who is modal, etc.) to send message to the right window. And when you draw you also must traverse all children to see who is uncovered and who is not. Last but not least, you need to handle mouse rectangle as top window to prevent flickering the mouse as windows are re-drawn or (using timers and msg_paint events) animated.
That's roughly it.
A GUI framework like Qt generally works by taking the existing OS's primitive objects (windows, fonts, bitmaps, etc), wrapping them in more platform-neutral and less clunky classes/structures/handles, and giving you the functionality you'll need to manipulate them. Yes, that almost always involves using the OS's own functions, but it doesn't HAVE to -- if you're designing an API to draw an OpenGL UI, for example, most of the underlying OS's GUI stuff won't even work, and you'll be doing just about everything on your own.
Either way, it's not for the faint of heart. If you have to ask how a GUI framework works, you're not even close to ready to design one. You're better off sticking with an existing framework and extending it to do the spiffy stuff it doesn't do already.

Is there anything like Winsplit Revolution for Mac OS X?

Is there anything like Winsplit Revolution for Mac OS X?
Try these:
Zooom/2 ($15) has been my favorite since I installed it. Fast, flexible, and minimizes the number of key combinations I need to remember
Divvy ($15) might soon replace Zoom/2 for me. It's closer to Winsplit. You can arrange windows on a grid, define your own grid arrangements, and define your own shortcuts. It also minimizes the number of keystroke combinations you need to remember. BONUS: There are Mac and Windows versions, which means if you use both platforms you can use the same window management method across all your machines.
Breeze ($8) makes it easy to make windows fullscreen, split left, or split right. It also lets you save screen states (generic) and for specific apps.
Moom ($5) is a more recent entry. It supports both keyboard shortcuts and mouse shortcuts. For the mouse shortcuts, moving the cursor over the greeen zoom button displays a popup list of different layout options: full screen, left/right half, top/bottom half, or any of the corners.
SizeUp ($10) mimics various aspects of WinSplit functionality, but it relies on many keystroke combinations that take time to learn. The advantage is quickly moving windows. The drawback is that it uses up a lot of global keyboard shortcuts, and there are so many I couldn't remember them all.
Cinch ($7) is a mouse-driven app by the makers of SizeUp. Drag your window to various hot zones on the screen edges and the window will "cinch" to that edge and resize to fill half the screen. Similar to the built-in resizing feature in Windows 7.
MercuryMover ($20) is quite powerful and offers fine-grained control. However, there are a lot of different key combinations and, overall, I didn't find it as easy to learn or as elegant as WinSplit. I uninstalled it almost immediately. It struck me as powerful, but inefficient and unwieldy.
The DIY approach (free) mentioned in another post is to combine some applescripts and bind them to quicksilver triggers. I haven't tried this. But it is a free solution.
I found the weak window management one of the hardest things to cope with when I started using a Mac.
Why go beyond spaces and expose?
Winsplit significantly adds to what spaces and expose can do. I didn't understand the appeal until I actually used it. Before that, I thought virtual desktops (ie, like spaces) was enough. Now I consider it must-have functionality, especially on large monitors and multi-mon setups.
On my Windows machine running 3 monitors, I would rank the importance of these different apps in the following order:
Winsplit-like window rearranging
Spaces-like virtual desktops
Expose-like application switching
On my MacBook, I've learned to approach it the other way.
Expose-like application switching
Winsplit-like window rearranging
Spaces-like virtual desktops
From the Winsplit website I understand more or less the functionality; in the past I actually used to have my window manager (Waimea) configured to do exactly that in linux.
You may try using Quicksilver to trigger one of a custom set of applescripts; each applescript would resize and move the currently focused window to a predefined location.
See this macosxhints post for inspiration...
ShiftIt is a free option. Assignable hotkeys to resize to different portions of the screen (Left, Right, Top, Bottom, Top Left, Top Right, Bottom Left, Bottom Right, Full Screen and Center with current size)
Link to ShiftIt on github
Just click on the big download button towards the right of the screen.
Spectacle is a good option, its free and open source. And easy to use with keyboard shortcut :
Windows can be moved to a number of predefined regions of the screen:
Move to the left half ⌥⌘←
Move to the right half ⌥⌘→
Move to the top half ⌥⌘↑
Move to the bottom half ⌥⌘↓
Move to the upper left ⌃⌘←
Move to the lower left ⌃⇧⌘←
Move to the upper right ⌃⌘→
Move to the lower right — ⌃⇧⌘→
Another question on StackOverflow adresses the same issue
https://stackoverflow.com/questions/276760/tiling-window-manager-for-os-x
One answer provided links to an app called TwoUP. It's free, and does the job on OSX!
Thanks to Dong Hoon's answer, I have developed a hybrid solution. Using the AppleScript Editor, you can create scripts to resize the current window, like this:
tell application "System Events"
set _everyProcess to every process
repeat with n from 1 to count of _everyProcess
set _frontMost to frontmost of item n of _everyProcess
if _frontMost is true then set _frontMostApp to process n
end repeat
set _windowOne to window 1 of _frontMostApp
set position of _windowOne to {5, 0}
set size of _windowOne to {1150, 735}
end tell
such a script will work on a 13" MacBook. Using subtle variations of this script saved to /Users/[YourUserNameHere]/Library/Scripts, you can have configure the AppleScript Editor to show itself in the menu bar, where it will allow you to select a script to run.
Using several different scripts, I'm able to resize and reposition any window with only two clicks.
Hope this helps.
It looks like TwoUp is dead, but here are some other options:
Cinch ($7) is like Aero Snap for Mac.
Breeze ($8) allows you to save window states and restore them like a template to another window.
Divvy ($14) shows a grid on the screen where you can select boxes to indicate how you want the window to fill your screen.
I haven't used Winsplit, so I don't know how it compares, but an app I developed, Optimal Layout, offers very flexible window tiling, as well as moving and resizing from the keyboard:
http://most-advantageous.com/optimal-layout/
You can also try Arrange application which features resize and reposition with keyboard shortcuts, on screen menu and by dragging window.
You should also try out secondbar. gives you an extra menubar at the second display + re-arrange options. See this link.
You can even try SplitScreenapp.com. It allows you to resize Mac Windows in many ways including full split, half split, drag and snap, etc.
I doubt it. Between Spaces and Expose, there's not much need for a third-party app to help manage multiple windows.

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