It is possible to capture the whole screen or, as desired, only a part and save the result in an image file.
How to take a screenshot on IPhone
On iPhone just press the Power button and the main button simultaneously to make a capture.
How to take a screenshot on Android
How to make a screenshot under Android depends on the version used:
-for Android 4.0, 4.1 and 4.2, the "on / off" button and the "low volume" button must be pressed simultaneously until the image is saved in the gallery
-for Android 2.2 (froyo), it is necessary to press simultaneously the button "return" and "on / off".
-for Android 2.3 (gingerbread), press the "home" and "on / off" button simultaneously.
-for Android 3 (honeycomb), it is necessary to root the device.
In any case, it is also possible to install a third-party application (generally paying) to make screenshots. For example "No Root Screenshot It" or "Screenshot UX".
How to take a screenshot on PC
To capture the entire screen, simply press the "Print" or "Scrn" key or "Print Sys screen" (located next to the "F12" key).
Then, to insert it in a document, you must press the "Ctrl + V" keys or click, with the right mouse button, on "Paste".
How to take a screenshot on Mac
With Keyboard Shortcuts:
Knowing that numbers 3 and 4 are the keys on the top row of the keyboard, not the keys on the numeric keypad.
-capture of the whole screen: press simultaneously on these 3 keys: cmd Shift 3
-capture of a selection of the screen: press simultaneously on these 3 keys: cmd Shift 4, then at the appearance of the appropriate cursor, select the desired zone ... and release the click.
-capture of a window of your choice: press simultaneously on these 3 keys: cmd Shift 4 then press the space bar, then place the cursor in the form of camera in the desired window and click.
-Note: By default the screenshot will be in .png format, and will be on the desktop. It is possible to change these settings with a utility such as Onyx for Mac
NB: To stop the process, simply press the "esc"
With Preview:
It is also possible to make screenshots with the latest preview version provided with each Mac. In Preview, just go to the menu:- "File / Make a screenshot" ...
Here again, you will have the choice between taking a screen shot, a screen selection or a specific window.
With Capture:
Finally, another possibility, use the software Capture which is here:Applications / Utilities / Capture.
The interesting side of Capture, is that it allows to make a screenshot offline.
Capture produces images in .tiff format, heavier than PNG or jpeg, but sometimes useful to keep quality after retouching or editing. You can then export it in the format of your choice, simply with Preview.
Just drag and drop this software into the Dock, (left side), to have it always within mouse range.
(The right side of the Dock is reserved for your files or files, while the left side is intended for Applications).
Tip: Onyx freeware allows you to choose the captured file format. (Tiff, jpeg, pdf etc ...). Onyx can be downloaded here: http://www.titanium.free.fr
After launching Onyx, in the "Settings" button we decide the type of files, jpeg, pdf etc ...
And also very useful, we also decide where the files are stored in the Path: / "
A part of the screen
PC partial
To capture only a part of the screen, simply click on the desired part. Obviously, if no window is opened in the main screen, it does not work. So you have to click inside an open window. Press the (Alt / Print Scrn) button. To insert it in a document, you must press the keys (Ctrl / V) or click with the right mouse button on "Paste".
Once captured, it is possible to save it according to the selected document in the format that is best suited: JPEG, GIF, PNG, BMP, RTF, etc.
Partial Mac
To capture only a part of the screen, simply press the Cmd Shift 4 keys and select the desired area, or use the Capture software and choose to capture a Selection from the menu.
Note: If you press the Cmd Shift 4 keys simultaneously, and then press the spacebar, you can select a window to be captured using the cursor that has taken on the appearance of a camera. To insert the capture into a document, simply drag it into the desired document.
Linux partial
On some Linux systems, you need to use a tool such as XV (usually supplied with all distribs) to make a screenshot or a particular window.
For example, with XV (v3.10a), to make a copy of the full screen, you must:
-click on the "grab" button
-choose to hide window xv (hide XV windows), do OK
-click with the left button on a part of the screen other than a window
Nb: Some operating systems do not support the use of the Print Screen key, in which case you will be forced to use software that supports this function, waiting for a future compatible version. The Gimp, for example