multiple monitor support in application - visual-studio

What does it mean by multiple monitor support for an application?

In the old days computers only ever had a single screen attached. Now they often have more than one attached and a desktop that spans those screens.
You need to make sure that your app:
Maximises to the monitor that it is most closely associated. A badly written app might always maximise a window to the primary monitor.
Remember which monitor it was displayed on when last run, and restore to that monitor when it starts up again.
Avoid displaying on a monitor that is no longer available. For example, consider a laptop with an attached screen. If you show the window at coordinates for a screen that has been disconnected (e.g. laptop user on the move) then they won't be able to see it.

It all depends on the application.
For some applications it just means that that you could open a very big window.
For others it might mean that you could open two windows, one for each monitor. For example, Lightroom, lets you view a collection of thumbnails on one window and a full-sized image on the other.

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discontinuous BitBlt capture

I am using BitBlt heavily in my project. I create a number of threads and in each thread I capture the screen by BitBlt. It works great and as expected for now except the following problem.
The problem happens when the user clicks on a running program or for example already opened explorer on the taskbar. You know when you click on the running program on the taskbar, it either minimizes or appears on the screen. The issue that I am talking about happens just in this transition. At that moment, something like an interrupt, all threads stop capturing the screen for a fraction of a second and then they continue capturing. The same thing happen when you move down or up the thing on the volume control window. Could you please shed some light why this is happening and how I can prevent this happening?
Thanks.
Jay
It could be a scheduling issue. When you activate an app, it gets a small, momentary boost in its priority (so that it can seem responsive in the UI). This boost might last about as long as the animation and momentarily pre-empt your screen capture threads.
It's also possible that the desktop manager is serializing stuff, and your bitblts are simply stalled until the animation is over. Even if you've turned Aero off, I believe the desktop window manager may still be in compositing mode, which has the effect Hans Passant was describing in the comments.
If you're trying to make a video from the screen, I think it's going to be impossible to rely on GDI. I strongly suggest reading about the Desktop Window Manager. For example, this caveat directly applies to what you're trying to do:
Avoid reading from or writing to a display DC. Although supported by DWM, we do not recommend it because of decreased performance.
When you use GDI to try to read the screen, DWM has to stop what it's doing, possibly render a fresh copy of the desktop to video memory, and to copy data from video memory back to system memory. It's possible that the DWM treats these as lower-priority requests than an animation in progress, so by the time it responds to the BitBlt, the animation is over.
This question suggests that DirectShow with a screen capture filter might be the way to go.

XMonad - How to make a window appear on more than one physical screens?

As the title said, I need to show a window on two or more screens.
I tried XMonad.Actions.CopyWindow. But it seems although the window is copied to a correct workspace, it shows on only on one physical screen.
As far as I understand the problem, you simply cannot. One window is only visible once. By copying the window, you make it available to multiple workspaces, but it will only be displayed once. If you have only one monitor, e.g. the laptop screen, this will create the illusion that the window is everywhere. Even more so, if you float it and thereby keep the position fixed.
However, one window is displayed only once at a time.
You could mirror the whole desktop to all displays. If you have a laptop attached to a beamer, this might make sense. Then both physical displays will show the same windows.

X11 unable to maximize applications when no window manager is used

We have a Linux based system that does not use a Window manager. When we start certain applications (for instance Firefox) from a terminal window (e.g. Firefox &) we find that no matter what we do, we can't get the application to display full screen.
If we run xrandr, it shows the default resolution is 1280x1024, but when we try to maximize Firefox (by pressing F11) the application is only sized to 1203x650.
Another application that seems to have the same problem is the evince PDF reader.
Our application is not configured to run a window manager (and we don't want to add one), so I'm wondering if there is something else that we can do to get these applications to render full screen.
Thanks...
Although you don't want to use a window manager, you might need to use a window manager.
I haven't dug into the X server sources around this, so I can't definitively say X requires a window manager to run properly. But as somebody who writes X client code, and hacks the X server, on minimalist embedded devices with small screens, low CPU power and no GPU... let's just say, all the major players in that space use one, and have good reasons for it.
If you want to avoid chewing up a lot of disk space, RAM or CPU power doing window management, you should check out matchbox. It's a low-footprint window manager designed to meet those criteria, and it's what many folks in that minimalist embedded space are using. My employer uses it on cell phones, configured so that only one app at a time is visible to the user, and the foreground app takes up the whole screen with no window borders. But you can use it other ways, too - Nokia uses it for their Maemo-based network tablets.
You could use xwit(1) to forcibly resize and place the windows. But as as far as I know, X11 in itself does not have the concept of a "maximized" window; the very idea is only added by most window managers and/or applications (like Firefox).
Does passing the "-geometry=1280x1024+0+0" option to Firefox help?
Oh, also... if you don't explicitly set a window manager, you might be unexpectedly falling back to the default X11 window manager. If you're not absolutely positive there's no window manager, you should check into this possibility.

Defaulting to full screen or allowing users to choose default at first startup?

In a fairly graphics intsensive application the requirements state that it should default to full screen mode even though the application is running under Windows. I know many games do this but I find it annoying. The default IMO should be to open in a window rather than full screen mode. I am proposing the first time the user runs the application they should select the default behavior. Am I wrong?
I think the annoyance-factor depends a lot on what the application tries to do.
If it is some utility that I might start while working in 5 different applications and it forces its fullscreen-ness on my, then I'd get highly annoyed.
If it is a specialized application that helps me with the entire workflow of a given task (so that I never or rarely need any other apps open at the same time), then fullscreen might actually be a valid default.
Whatever you do, just make sure that toggling the startup behaviour is very discoverable. Because no matter which way you'll go, some of your users will disagree with your decision. And for them it should be very easy to change to their prefered way.
I would follow the requirement the first time the application is launched. I would also provide a simple way to switch from full screen to windowed, for instance by pressing ESC (and another way to go back to full screen). Then I would store the mode when quitting the application and restore this mode at next launch.
Before doing the opposite of what your requirements say, I'd have the requirements changed.
However, what about giving the user the choice at install time?
The window at first-start-up should default to the optimal size for the largest proportion of users. For a graphics-intensive full-featured app, that may very well be full screen.
As for individual user preferences for window size, it seems to me most users won’t know if they want full screen or not until after they’ve started to use the app and see how much screen space they need and how much they use the window in conjunction with other windows. Asking them which size they want at install or first-start-up could thus be annoying and even confusing. It’s better to put such a setting under Options/Preferences.
Perhaps the best thing to do is save the window status on exit. Users who like it non-maximized thus only have to non-maximize it (and size it) once and then forget about it. The only consideration is to have some way to reset the window to the default (e.g., Window > Standard Size menu item) for novice users who accidentally resize or reposition the window to something bizarre and don’t know how to get it back. Alternatively, you could have a Window > Keep Sizes and Positions menu item for users to explicitly save the window status across sessions.
Go back to the requirements writers and ask them if they have considered non-traditional monitor setups, such as:
30" or larger monitor. Do you really want your app hogging up all the screen real-estate?
Multiple monitors. Which monitor will you run on? Can the user move your app from one monitor to another? Can your app span more than one monitor?
Virtual desktops. Can the user move your app from one desktop to another? Can they switch desktops while your app is running? Can your app span more than one desktop?
Such setups are increasingly common, especially large monitors. IMO, full-screen mode (the default for many older Windows apps) is becoming less and less useful.
The problem with presenting the user with the option of initially selecting fullscreen / vs windows is that they haven't used the software yet. How can they make a decision on which is better for them, without experience?
I would run the app in whichever mode provided the best user experience and then offer an option to change it both in the Preferences and though a hint while starting up the application for the 2nd time.

Is there still a place for MDI? [closed]

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Even though MDI is considered harmful, several applications (even MS Office, Adobe apps) still use it either in its pure form or some as a hybrid with a tabbed/IDE-like interface.
Is an MDI interface still appropriate for some applications?
I'm thinking of an application where one typically works with several documents at one time, and often wants to have multiple documents side to view or copy/paste between them.
An example would be Origin, where one has multiple worksheet and graph windows in a project; a tabbed or IDE-like interface would be much more inconvenient with a lot of switching back and forth.
On the mac, it's natural and convenient for an application to have multiple top-level windows to solve this, what is the preferred way in Windows if one doesn't use MDI?
The disadvantages of MDI are the following:
It generally requires the user to learn and understand a more complicate set of window relations.
Many simple actions can require a two-step process. For example, bringing a desired window to the foreground can require that the user first brings the container window forward then bring the right primary window in the container window forward. Resizing or maximizing a window can mean first adjusting the container window then the primary window within.
If multiple container windows are open, the user can forget which one has the desired primary window, requiring a tedious search.
Users are easily confused by the dual ways to maximize, iconify, layer, and close a window. For example they may close the entire app rather than a window within the container window. Or they may “lose” a window because they iconified it within the container window without realizing it.
The user is limited in the sizes and positions his or her windows can assume. Suppose I want to look simultaneously at 3 windows of one app and 1 from another app. With SDI, I can have each window take a quadrant of the screen, but I can’t do that with MDI. What if I want one window in the MDI to be large and the other small? I have to make the container window large to accommodate the large window (where it occludes the windows of other apps), but that wastes space when looking at the child.
Note that all of these disadvantages apply to tabbed document interfaces (TDI) too, with tabbed interfaces having the additional disadvantage that the user can’t look at two documents in the same container window side by side. Tabs also add clutter and consume real estate in your windows. However, overall TDI tend to be less problematic than MDI, so they might be preferred for special cases (read on)
In summary, it hard to think of any situation to use MDI. It’s no better than an SDI while adding more complexity and navigation overhead, and working poorly with the windows of other apps.
There’s no reason an app can’t have multiple top-level SDI windows. Even with an app like Origin, I don’t see a problem with a project being spread across multiple SDI windows as long as the project is well identified in each window. SDI also allows different kinds of windows (e.g., graph vs worksheet) to have different menus and toolbars, rather than hiding or disabling items depending on the active window (the former is confusing, and the latter wastes space).
SDI gives your users the more flexibility over either MDI or TDI. Users can overlap or maximize the windows, and use the taskbar/dock as a de facto tab interface. Users can alternatively resize and reposition the windows so they can look at multiple at once. Each window can be sized independently to optimize screen space. Whatever advantages an MDI or TDI may have, you may be able augment SDI to have those advantages too (e.g., provide a thumbnailed menu that makes switching among windows faster than using the taskbar and comparable to selecting tabs, or provide a control that iconifies all windows of an app with one click).
Unless you have compelling reasons to use a TDI, go SDI to allow this flexibility. Compelling reasons include some subset of the following:
Each tab is used for unrelated high-order tasks and user will not be switching among tabs frequently or comparing information across tabs.
You’re working with very low-end users who are ignorant of or confused by the taskbar/dock and multiple windows, and don’t know how to resize windows (it seems compelling tab imagery works better than the taskbar for such users).
You anticipate there’re typically be a large set of tabs (e.g., 4 or more) and you can control their display in a manner more effectively for the task than the OS can if they were SDI windows on the taskbar/dock (e.g., with regard to order and labeling).
With SDI, you’re having problems with users confusing the toolbars or palettes of inactive windows with active windows.
Tabs are fixed in number and permanently open (e.g., when each tab is a different component of the same data object). The user is not saddled with trying to distinguish between closing a tab and closing the entire window; figuring out the window to navigate to is not an issue because all windows have the same tabs.
There is really only one way to properly arrange the data for task, with no variation among users or what they actually use the app for. You might as well set it up for the user with a combination of tabs and master-detail panes and rather than relying on the user to arrange and size SDI windows right.
In summary, given your users’ abilities, app complexity, and task structure, if your app can manage the content display better than the user/OS, use TDI, otherwise use SDI.
Note that the examples you used (MS Office and Adobe applications) are big programs and have lots of features. Users will be dealing with that program, and only that program for much of the program's lifetime.
Newer versions of MS Office (2007) and Adobe Photoshop (CS4) use multiple windows and tabs, respectively.
Note that with Windows 7, MDI's will probably lose popularity even more because of the extra power of tabs given by Microsoft's API's (although you needn't strictly use tabs -- MDI windows could work, but would be more confusing for the user than usual).
The old-style MDI (where to switch between documents, you had to go through the Windows menu) was annoying. The newer MDI (like tabs in Opera and Mozilla) make switching between documents very easy and seem to have been accepted well. They also don't clutter your taskbar as happens if you had more than one document open in something without MDI.
The main advantage of MDI is when you want to keep track of two or more windows at the same time, and those windows need to be grouped together. For example, there's a running process in one window, but you need to work on another window, MDI would be the most ideal.
I agree with slavy13 (old-MDI = bad, new-MDI = much better). But don't use programs like Microsoft Excel as your model. Ick! You get one window on your desktop, regardless of how many spreadsheets you have open (which may or may not be your preference.) But you get one taskbar icon for each and every document you have open. And your Alt+Tab window similarly has one icon for each document you have open. Plus, there is an additional icon in there just for "Excel" which takes you to whichever document happens to be "current". So yeah, do your MDI like Mozilla. Or at least give your users the option of switching to the cleaner style.
To more succinctly answer your question, I feel the answer is yes, MDI is still appropriate in some instances. But, in all things, moderation is the key.
It appears that multiple top-level windows is the way to go. As for whether there should be one global app instance or one per document is up to you I think. It's not visible to the user.
Only one benefit for MDI:
Programs that use large amounts of resources, such as Adobe Photoshop, often have an MDI due to the prohibitive cost of running more than one instance at a time.
But you shouldn't develop programs that drain huge amounts of resources to start with.
One advantage I can see for MDI occurs if a lot of screen real estate is going to be used for stuff that's shared among many windows. It may be more logical to have such material at the top or side of the enclosing window than to have it repeated in each SDI window, or have it appear in a window entirely separate from the SDI windows. For example, a chat program might have a status pane and a control pane. Having those be somewhat tied visually tied to the chat windows might be better than having them as standalone windows.

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