How to get real screen size?

For a MacBook retina display with get(0,'ScreenSize') I get [1 1 1280 800]; Why?

[Geoff Hayes]

What are you expecting instead? For my MacBook Pro (Retina, 15-inch), the resolution according to the About this Mac->Displays states 2880x1800, but if I call

 >> get(0,'ScreenSize')
 ans =
           1           1        1920        1200

which is the scaled resolution of my display as shown at System Preferences->Displays.

[Christopher Wong]

yeah just use get(0, 'ScreenSize') or get(0, 'MonitorPositions)

Answer 1

[Ulrik]

You can get the real values by the following code:

ScreenPixelsPerInch = java.awt.Toolkit.getDefaultToolkit().getScreenResolution()
ScreenDevices = java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getScreenDevices();
MainScreen = java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getScreen()+1;
MainBounds = ScreenDevices(MainScreen).getDefaultConfiguration().getBounds();
MonitorPositions = zeros(numel(ScreenDevices),4);
for n = 1:numel(ScreenDevices)
    Bounds = ScreenDevices(n).getDefaultConfiguration().getBounds();
    MonitorPositions(n,:) = [Bounds.getLocation().getX() + 1,-Bounds.getLocation().getY() + 1 - Bounds.getHeight() + MainBounds.getHeight(),Bounds.getWidth(),Bounds.getHeight()];
end
MonitorPositions

Answer 2

[Guillaume]

See last week's post on undocumentedmatlab

Saying that, you should use the resolution returned by matlab, not the actual screen resolution. Using real screen resolution is why so many programs fail to scale properly on high DPI displays.

[Mr M.]

properly? resolution is resolution, and pixel is pixel, I expect the real pixel resolution

[Guillaume]

On any modern OS, there is a physical resolution and a virtual resolution which may or may not be equal. You should be using the latter so that whatever you're displaying does not become microscopic and unreadable on high DPI displays.

See this for more details. resolution is not resolution.

[adams13]

Mathworks was stupid enough to name "Pixel" something else and not provide anything like "pixelphysical" or so. We all know what "pixel on the screen" is. Why to misuse the known property without warning? I do have a high DPI display and an information from Matlab is crap.

This is what I have accidently found deep in the help ("figure", under "Units" for "pixels"):

Description

Pixels.

Starting in R2015b, distances in pixels are independent of your system resolution on Windows and Macintosh systems:

On Windows systems, a pixel is 1/96th of an inch.

On Macintosh systems, a pixel is 1/72nd of an inch.

On Linux® systems, the size of a pixel is determined by your system resolution.