Can we improve screenshot DPI

On Aug 23, 2017, David B. wrote
(in article ):

On 23/08/2017 14:57, Savageduck wrote:
On Aug 23, 2017, Mayayana wrote
(in article ):

wrote

So I will ask once again; what is your purpose for these
higher resolution screenshots, why do you need the higher resolution?

He wants better screenshots. Isn't that
enough reason? The problem seems to be
that he doesn't understand that he's not
taking a picture of something, but is rather
just copying the pixels displayed onscreen.

Obviously the starting point is to have a higher resolution display, and the
something he is trying to capture should not be postage stamp size.

Can I change this format?

https://youtu.be/uRucAkHZIp4

Your question should be; When will I remember to have my iPhone correctly
oriented when shooting video?

--

Regards,
Savageduck

In article , Bram van den Heuvel
wrote:

The question is just one of what determines resolution of any given
screenshot.

the screen

Specifically, how do I increase the number of pixels copied off the screen?

by getting a bigger screen (or screenshotting a larger area).

Someone asked "what" I'm taking a screenshot of, where I can't imagine that
his question has any technical merit since it shouldn't matter what you're
taking a screenshot of since the screen is displaying it - so you can't do
better than the screen, right?

it does, because some content is rendered rather than blitted.

Someone else also mentioned printing, which again has no bearing on the
question since the question is only about how to increase the resolution of
the captured screenshot.

printing does matter, because dpi/ppi, which is what you originally
asked, only exists when printing. otherwise, it's just pixels.

Let's say I have a current screenshot resolution of X.
And let's say I want to double that resolution to 2X.

How can a person do that?

They're not going to double their resolution by what they're looking at.
They're not going to double their resolution by printing it.

How can you double the resolution of a screenshot?

you're incredibly confused.

Do you change a software driver?
Do you double your screen size?
Do you double your memory?

What determines the resolution of any given screenshot on your own screen?

why do you repeat yourself?

On Aug 23, 2017, Bram van den Heuvel wrote
(in article ):

Givennews wrote:

He wants better screenshots. Isn't that
enough reason? The problem seems to be
that he doesn't understand that he's not
taking a picture of something, but is rather
just copying the pixels displayed onscreen.

I appreciate that you're helpful since some of the others don't even seem
to understand the question where they think printing is involved or where
they think it matters what you're screenshotting.

The question is just one of what determines resolution of any given
screenshot.

Specifically, how do I increase the number of pixels copied off the screen?

You can’t create data that doesn’t exist, not even with some odd
extrapolation.

Someone asked "what" I'm taking a screenshot of, where I can't imagine that
his question has any technical merit since it shouldn't matter what you're
taking a screenshot of since the screen is displaying it - so you can't do
better than the screen, right?

Yup. The screen resolution is the determining factor when it comes to screen
captures.

Someone else also mentioned printing, which again has no bearing on the
question since the question is only about how to increase the resolution of
the captured screenshot.

You started that part of the debate when you briught up DPI.

Let's say I have a current screenshot resolution of X.
And let's say I want to double that resolution to 2X.

How can a person do that?
Do you want to double the resolution, or the physical dimensions?
A useful tool is *Resize* from On1, but at $80 that might be overkill for
you.
https://www.on1.com/products/resize10/

They're not going to double their resolution by what they're looking at.

No, but we can get some idea of what you are trying to do.

They're not going to double their resolution by printing it.

No.
However, from what you said in your OP you seemed to believe that a change of
DPI would improve the resolution of your screen capture, when DPI only
relates to printing.

How can you double the resolution of a screenshot?

You cannot add data which never existed. You can take a screen capture image
into editing software and adjust the dimensions, but you are not going to
change the resolution of the original without degradation of the screenshot.

Do you change a software driver?

What software?

Do you double your screen size?

You are still limited by screen resolution.

Do you double your memory?

Nope!

What determines the resolution of any given screenshot on your own screen?

The screen resolution and the quality of the item being viewed on that
screen. The max resolution of any of your screen captures is always going to
be limited by the resolution of your screen.

--

Regards,
Savageduck

On Wed, 23 Aug 2017 14:12:49 +0000 (UTC), Bram van den Heuvel
wrote:


The question is just one of what determines resolution of any given
screenshot.

I'll give it a try. Most of the answers you have received are
correct, but I think you are missing the point.

Specifically, how do I increase the number of pixels copied off the screen?

You can't. ALL the pixels are copied off the screen (assuming your
screenshot is full screen). In some cases, you can screenshot just
one window. In that case, increasing the size of that window to its
max size will get you the most pixels.

Someone asked "what" I'm taking a screenshot of, where I can't imagine that
his question has any technical merit
He isn't asking what your subject is. He is asking if the material is
from a website vs some app on your machine vs a picture in an email,
etc. If, for example, you answered website, he would have told you to
make your browser window as big as possible or to save the image on
disk and then use that.

since it shouldn't matter what you're
taking a screenshot of since the screen is displaying it - so you can't do
better than the screen, right?
Not with screenshot.

Someone else also mentioned printing, which again has no bearing on the
question since the question is only about how to increase the resolution of
the captured screenshot.

You started the printer discussion without intending to do so by using
DPI.

Let's say I have a current screenshot resolution of X.
And let's say I want to double that resolution to 2X.

How can a person do that?
Assuming a full screen screenshot, the only way is to buy a screen and
associated video board with a higher resolution.

They're not going to double their resolution by what they're looking at.
They're not going to double their resolution by printing it.

How can you double the resolution of a screenshot?

Do you change a software driver?
Not unless your driver is using lower resolution that your display
supports.
Do you double your screen size?
Yes. Double in resolution, not double in physical size.
Do you double your memory?
Only if needed for a higher resolution display.

What determines the resolution of any given screenshot on your own screen?
The resolution of your screen. Screenshots copy pixels from your
video adapter. They can't have more pixels than your screen.

Some basic about pictures: The quality of the images in any picture is
determined by the lens of the device used to capture a picture. The
ability of the lens to focus the image on the file/sensor determines the
absolute quality of the picture. This is fixed an there is no way to
improve it!

Originally the resolution of the resulting picture was determine by the
grain size in the film that was being used. With a digital image it is
the pixel in the camera sensor that records the image. ie my 2MP tablet
with poor optics takes pictures of documents that are not readable,
while my cheap cellphone with better optics and a 1MP sensor can.

This is the native picture that is put on the web.

Usually video picture are of lower pixel resolution than a still camera.
So if you are looking at a video verse a still picture the image will be
more blurry and when you zoom, it will pixelate before the still image.

Specifically, how do I increase the number of pixels copied off the screen?

You can not. In some programs like Irfanview, you can change the pixel.
But, it does not change the native resolutions as it only adds/subtracts
pixel between the native pixel to get the different resolution.


Someone asked "what" I'm taking a screenshot of, where I can't imagine that
his question has any technical merit since it shouldn't matter what you're
taking a screenshot of since the screen is displaying it - so you can't do
better than the screen, right?

As said it depends on the resolution of the original picture, when shown
on a screen, pixels are added or subtracted to get the original picture
to the resolution of the screen so you can see it.

Someone else also mentioned printing, which again has no bearing on the
question since the question is only about how to increase the resolution of
the captured screenshot.

I believe you started the thread by mentioning DPI, which has nothing to
do with the digital image on a screen. DPI is only relative to how many
dots of ink per inch (DPI) that the printer can put on a piece of paper.
(This is directly related to the grains in the emulsion placed the
paper that is used to print chemical pictures Remember Kodak )


Let's say I have a current screenshot resolution of X.
And let's say I want to double that resolution to 2X.

How can a person do that?

You can, but by doing that you will not increase the clarity of the
picture. What happens is the an additional pixel is added to the image.
This additional pixel is interpolated from the pixels on each side of of
the native pixels.

ie. For a 2X resizing: pixel A = 100 Pixel B = 140; the pixel added to
the image to increase the size would be (100 + 140)/2 or 120.

The effect is that the resolution is soften/blurred in the larger
resized picture. ie a one pixel line becomes a two pixel line.


They're not going to double their resolution by what they're looking at.
They're not going to double their resolution by printing it.

How can you double the resolution of a screenshot?
Do you change a software driver?

You can change the resolution of most screen, it is in the settings for
your monitor. But you don't improve the resolution of the original
picture, as the pixels in the original picture are interpolated to the
resolution of the monitor.

Do you double your screen size?
Do you double your memory?

What determines the resolution of any given screenshot on your own screen?

First you can not change the resolution of the image shown on the
screen. It is determined by the person who places the image on the web.

Bottom line if you are trying to get a picture with better resolutions
of the subjects in the picture on the screen so you can see more detail
in the picture, it is fixed by the original picture placed on the web.

I always loved the crime movie where they would take a picture at a half
mile, and blow up the license plate on the car and read the license
number. It is not going to happen in real life. Even my 26MP camera has
limits to what can be blown up and still be readable.


If you are interested I would recommend you get a good book from the
library on photography. While the mechanics for preserving the picture
are different in Chemical and Digital pictures, the basic principals are
the same




--
2017: The year we lean to play the great game of Euchre

"Bram van den Heuvel" wrote

| They're not going to double their resolution by what they're looking at.
| They're not going to double their resolution by printing it.
|
| How can you double the resolution of a screenshot?
|
| Do you change a software driver?
| Do you double your screen size?
| Do you double your memory?
|
| What determines the resolution of any given screenshot on your own screen?

It gets confusing because there are several aspects.
First, DPI should be thought of as printing terminology.
PPI is screen terminology. But those terms describe how a
given image displays in a given medium. They have nothing
to do with the image itself.

Any digital image (without confusing the issue with
vector graphics) is just a grid of color values that
represent pixels. That's why the most basic image is
called a bitmap. It's a map of color dots as numeric
byte data. The display reads those color values -
numbers - and shows colors onscreen acccordingly.
You can make that grid bigger by resizing your
screen, but that doesn't change the bitmap. Thus
it doesn't change the resolution.

I'm assuming by higher resolution you mean more
pixels, thus more detail, for a given image.

You can get a bigger monitor and with a good graphics
card you can get a high pixel count. You can also adjust
the DPI for the monitor. But all of that is merely resizing
the screenshot bitmap. (Which is what it is. Windows
literally paints pixels onscreen whenever things change,
in order to create the feel of interaction. A screenshot is
just a copy of that bitmap.)

Two examples: You have a 32x32px icon. It's displayed
onscreen. When you capture that you get the 32 x 32 grid
of pixel values. If you display that on a giant screen with
high pixel count you'll just get a tiny icon. When you give
that image to someone else they may see it large on
their screen. On an old TV it will be very big. On a cellphone
it wll be tiny. But all of those images are the same 32x32
pixels. None of that changes the resolution of the image.
Only the resolution of the display.

So, what about an image that starts out as high
resolution? Maybe a 4000x4000px photo. Say you
open that in IrfanView and size it to fit the screen
comfortably. Maybe you want to take a screenshot
of working on a photo in a graphic editor. Say it's
displaying at 600x600. When you do a screenshot of
that you don't get the 4000x4000 pixels of data. You
just get the 600x600 pixels onscreen. No matter how
good that photo is, you're only getting the reduced
version in your screenshot, so you can't somehow
retrieve the lost data. Since the screenshot contains
the pixel data for that 600x600 grid, that's all the data
you have to work with.

You might then ask how to improve the resolution
of the 600x600 image. You can't. You can enlarge it,
adding more pixels, but resizing that way just fills
in the image with similar color pixels and you lose
details. And again, if you get a bigger monitor you're
just displaying the exact same pixels over a bigger area.
Each pixel is larger. Resolution is not increased.

The quality will vary with OSs to some extent,
and with display. In Win95 with 16-color icons and
solid colors, the display was blocky. With 24-bit color
icons can be more interesting and Windows can make
more interesting window display. Thus, the Aero look,
with transparency and skins and 24-bit color, is more
fine than the "classic" look, where 3D appearance is
achieved merely by putting a 1 or 2-pixel white line along
the top and left of objects, while putting a 1 or 2-pixel
black line along the right and bottom. So if you enlarge
a screenshot of an Aero window it will probably look
better than a screenshot of a classic window. But
that's in the detail of the image. Again, it's not resolution.

Is this making sense? I'm afraid it just gets more
confusing the more it gets explained. I think it helps
if you focus on what a digital image is -- a grid of
color dot values. The rest is just in how those dots get
displayed. To improve the picture, to the extent it's
possible, can only be done with graphic tools like
sharpening, brightness, saturation, etc. But those
are all just math formulae applied to the pixel data.
Nothing can magically retrieve more detail that's not
there.

In article , Pat
wrote:

What determines the resolution of any given screenshot on your own screen?
The resolution of your screen. Screenshots copy pixels from your
video adapter. They can't have more pixels than your screen.

yes they can.

several aftermarket screen shot utilities save directly from the window
manager, not the screen buffer, which allows for capturing whatever is
offscreen and/or keeping each ui element as a separate object.

In article , Keith Nuttle
wrote:

Some basic about pictures: The quality of the images in any picture is
determined by the lens of the device used to capture a picture. The
ability of the lens to focus the image on the file/sensor determines the
absolute quality of the picture. This is fixed an there is no way to
improve it!

not true.

Bram van den Heuvel wrote:
Given news wrote:

He wants better screenshots. Isn't that
enough reason? The problem seems to be
that he doesn't understand that he's not
taking a picture of something, but is rather
just copying the pixels displayed onscreen.

I appreciate that you're helpful since some of the others don't even seem
to understand the question where they think printing is involved or where
they think it matters what you're screenshotting.

The question is just one of what determines resolution of any given
screenshot.

Specifically, how do I increase the number of pixels copied off the screen?

Someone asked "what" I'm taking a screenshot of, where I can't imagine that
his question has any technical merit since it shouldn't matter what you're
taking a screenshot of since the screen is displaying it - so you can't do
better than the screen, right?

Someone else also mentioned printing, which again has no bearing on the
question since the question is only about how to increase the resolution of
the captured screenshot.

Let's say I have a current screenshot resolution of X.
And let's say I want to double that resolution to 2X.

How can a person do that?

They're not going to double their resolution by what they're looking at.
They're not going to double their resolution by printing it.

How can you double the resolution of a screenshot?

Do you change a software driver?
Do you double your screen size?
Do you double your memory?

What determines the resolution of any given screenshot on your own screen?

You can make a virtual screen (a pan and scan screen),
where the size of the desktop the OS uses, is larger than the screen.

When you move the mouse around, where it hits the edge of the screen,
the viewport moves so you can see a different part of the screen.

This is an example of taking a screenshot of a 16000 pixel high
(160") Firefox window. The original picture is 1440x15900 pixels.
Since this site will not accept pictures that big, it is scaled
by a factor of 14 (that's why it is fuzzy). The intention is not
to show a clear picture, merely to show how much info can be
captured in one screenshot.

https://s17.postimg.org/r2ixgy3lb/linux.gif

The one in Windows was done with a printer driver. I can get
108" high pages with that. It's possible that 108" times 300DPI
is the coordinate space limit at some step in the process.

https://s18.postimg.org/kyjya0gex/sample3.gif

To make a pan and scan setup in Windows, at one time you
needed to "enable unavailable resolutions" in a control panel.
And when you selected one of those, you could get a larger
virtual surface. But it would be subject to the video card
coordinate limits. Early cards were 2048 or so. Later cards
might have supported slightly larger values (the value doesn't
have to correspond to an output crossbar value, like 4K Displayport
or something).

When the Linux setup supported 16000, I was surprised. It implies
the addressing inside the video card goes that high. And the Linux
setup didn't "like" what I was doing. I ran a vanilla Xorg with no
DE, and it still didn't behave properly. I had to take my screenshot
with GIMP, as XWD wouldn't work right. And that's a bad sign.

*******

The software has an idea of "what an inch is". If you're using
Photoshop, you might see a scale around the edges. The scale
can be in pixels. Or it can be in inches.

Your monitor, in the EDID, might declare it is 96x96 DPI. And
when the software is doing the math, it uses that scale factor.

You would need a means to interfere with that declaration, to
improve the resolution on screen objects. If you told the OS
(whatever OS you're using), that the monitor is 192 DPI (a Hi-DPI
display), then the Firefox display would end up twice as wide
on a virtual display. In my example above, I can capture
160" @ 96DPI, or I could capture 80" @ 192DPI. Firefox would think
it was displaying 80" of content, and would be driving sufficient
pixels to (what it thinks) is an inch of screen.

There is the possibility of improved resolution by doing that.

But these ideas are not general purpose, and not a "daily driver"
configuration. They're suitable for a bar bet, and that's about it.

I did something like this 20 years ago, in Unix, using XMX or something
and a second X server. I couldn't see the screen. I launched programs
with an XYWH on the command line, to control their position. And I
took pictures of the screen I could not see, with XWD. Try driving
a screen some time, which you cannot see :-) At least in the experiment
this year, I could see the 16000 pixel high screen, 900 pixels at a time.
But the Xorg server really didn't like that, and I could tell sooner
or later, I would pay a price for using that as a 24/7 solution.

*******

In Linux xorg.conf, this has to be added. Of course, a vanilla system
install has no xorg.conf, and I used aticonfig to snag one. (It will
dump one for you.) Then, you edit, and add this to make the display
larger. I don't know if Xorg would start if this was larger,
so you have to experiment.

SubSection "Display"
Virtual 2048 2048
EndSubSection

Then, this is done while the screen is running, to make a huge desktop.
I didn't make any attempt to make a "square surface" here. Just wide
enough for the Firefox window, and as long as it would tolerate.

# Panning on a 1440x16000 desktop while displaying
# 1440x900 mode on an output called CRT1:

xrandr --fb 1440x16000 --output CRT1 --mode 1440x900 --panning 0x16000

*******

And there are people doing this sort of thing on Windows.

https://web.archive.org/web/20151220...ic.php?t=21972

DALNonStandardModesBCD1

Paul

In article ,
Whisky-dave wrote:


Obviously the starting point is to have a higher resolution display, and
the something he is trying to capture should not be postage stamp size.


But what should he do if he wants to capture screen shots of postage stamps.

lick them and stick them to the screen