I’m talking about wallpaper for a computer screen? Is it possible to create a wallpaper that acts as a mirror?
Possible but unlikely. You would need a PC cam that took a picture from the within-the-monitor perspective (i.e., perched on top of your monitor), saved it to disk, and set it as the background image at least five to ten times a second.
CPU performance would be seriously impacted and hard drive space would go away in the long run.
Instead of a conventional screen saver, set the computer up to, after X minutes idle, run software that simply shows the video from your monitor-positioned camera, fullscreen and reversed so it looks like a mirror. This can’t be technically difficult.
There is nothing stopping you from writing an application that feeds webcam straight to the desktop without saving anything to disk. Most modern operating systems let you do pretty much anything on the desktop.
However, I think the OP is asking if there is a pixel color that is mirror “reflective”, and no there is not and cannot be using current monitor technologies. A completely black LCD is about as close to a mirror as you can get with current tech.
Why? It’s certainly possible to have your screensaver app directly display the cam image without needing to write it to disk. I can’t think of any reason this couldn’t be done simply and effectively, without draining resources.
Uh, not quite. A cam above the monitor can’t see all the things a cam perched at an imaginary location inside (or just behind) the monitor could see. It sees more of the top of the head and less of the bottom of the chin, for one thing. You could have two cams, one above the monitor and one below, and integrate the views into a single fictional image by throwing enough CPU power at the problem.
The vast majority of operating systems in use are not made by Microsoft, even if you consider Windows ‘modern’. Most modern operating systems keep a tight reign on what gets access to RAM and hardware.
What does this mean? Modern operating systems don’t let you write prgrams that display stuff to the screen? Man no wonder microsoft is cleaning up in the market place I can really see how displaying stuff to the screen would be useful.
The vast majority of operating systems run on machines that don’t even have screens at all. But I don’t see how those are relevant to the question.
All I do is set my background to black with no wallpaper. In a brightly lit room it acts like kind of a mirror. It allows me to see who is coming up behind me.
Yes, however, I am not aware of any modern operating system (barring weird non-accessible embedded software) that is fundamentally incapable of running software that a) Generates a desktop on a local or remote terminal b) Accesses a peripherally attached camera c) Feeds the image from the camera to the desktop.
Theoretically this is possible on any major operating system for all you need is a) ability to run external software (or built in software that already accomplishes what we want) b) ability to run external drivers (or built in camera drivers) c) ability to connect peripherals d) and either a graphical output device or networking. This covers most mainframes, clusters, blades and desktop operating systems. Hell it might even be possible on an avionics computer of an F22 for all I know.
Now, theoretical does not mean the proper software has been written/hardware made, nor that it’s worth the effort. The reason I am replying like this is because I am sick of people replying with snarky mainframe/server/embedded references anytime anybody mentions ‘most computers’ or ‘most operating systems’. Possibility in computing is a question of available man-hours and is limited by technological abilities.
If hard pressed I could come up with the links but I’m lazy. There might even be a program/utility that does this directly, but you can at the very least do it indirectly on a mac. There is a screensaver that just shows your cam footage live. And there is at least two utilities that lets you use any screensaver as an animated desktop wallpaper. Combine the two and wallah!
groman: I think I misread you. I thought you said that modern OSes allow userland applications direct access to graphics devices, as opposed to forcing them to go through an OS-controlled API. My statement was directed at that remark, something that nobody seems to have caught. Thus, none of the statements commenting on my post are at all relevant to my point, which is that the hallmark of a modern OS is that the OS alone has direct access to hardware, including RAM.
I’m assuming that the OP doesn’t mean literally like a mirror: i.e. a desktop that’s reflective of incoming light by setting the background to some silver color.
That won’t work because monitors emit light at a much higher level than they reflect it – in fact many monitor screens are coated specifically to be antireflective.
Old Palm computers had a program called “Mirror” which made the screen entirely black – since these weren’t anti-reflective coated, this basically just made the glass covering the uniform black screen act as a mirror. The same trick (making the screen entirely black) would produce the minimum amount of emitted light, and give the greatest amount of contrast between whatever reflection is available and the monitor background. You could get the same effect by turning the monitor off.
On my three LCDs, one produces effectively no reflection at all when off, and the other two produce sort of highly-diffused “ghosted” images. A CRT without an anti-glare screen would probably make an acceptable mirror – look at your TV set when it’s off.
My understanding of the question was that the OP wanted to have the background image be a live image underneath all the icons on the desktop, while he was busy pointing and clicking and typing. He hasn’t returned to the post to clarify this, so we may never know.
If your goal is to have your screen look like a mirror when you’re away, my suggestion is to have your screen go completely black, and to cover your monitor with a partially reflecting mirror. When it’s off, with no light coming through, it’ll look like a perfect mirror. When it’s on, the colors underneath will bleed through. Of course, you’ll have to deal with the reflecgted light, and maybe experiment with different reflectivities.
What you’d be doing is juast the opposite of what those reflection-damping screens were made for. Those were uniform density screens that wer intended to minimize reflections from the monitor screen. Light that passed through the density screen got attenuated in passing through both that first tyime and when reflected, whereas light from the monitor only saw the density screen once. Looks like a giant step backwards, to me, in the name of having a cool-looking monitor (if I’m interpreting this correctly). But , whatever turns you on…
Well, even that isn’t something that’s impossible even under modern OSes, as far as I know. But, it would be pretty impractical to implement. You’d be constantly writing to the hard drive to update the file every x seconds or whatever. You’d probably get sick of everything lagging so badly that you’d shut it off after a short time.
Sorry, Ethilrist, I was confusing you with Derleth. In other words, I agree with you, although I don’t think disk space needs to be a limiting factor, since you’d be simply writing and rewriting the same file over and over. Access time would certainly limit things, though.
At least on Windows the desktop is capable of displaying active content and no rewriting should be required. You could just set an HTML page to be your desktop that feeds from a webcam (since it’s local, anything goes). There also should be API hooks for installing active content as well, but I’m not sure about that.
You could be right, it’s been a lot of years since I’ve done any Windows programing.