I have an image on screen, and I want to measure its width. Of course I can use a ruler, but that's whimsical and slow. Is there something where I can click a shortcut key, drag out an area, and it will tell me the height and width of that area?
Something similar to Page Ruler for Google Chrome.
Currently, I am using Shift + PrtScn and dragging out the area, save the image, and then go into Properties to find out its height and width.
The script below measures the size of an area, between two locations of the mouse pointer.
It works as followes:
Place the mouse pointer in the first position (without clicking)
Press the key combination of your choice (see further below)
Place the mouse in the second position (again without clicking)
Press your key combination again. A notification will tell you the exact size (px) of the area.
You can choose (by uncommenting one of the lines) how you'd like to be notified; either by a notification:
Or a Zenity info window:
(The examples are from different areas)
The script uses xdotool:
sudo apt-get install xdotool
Copy the script below into an empty file, uncomment either one of the lines:
command = ['notify-send', 'Area size', str(w)+' x '+str(h)]
(to be notified by the notify-send option)
or:
command = ['zenity', '--info', '--title', 'Area Size', '--text', str(w) + ' x ' + str(h)]
for the Zenity option.
Save the script in ~/bin (you will probably have to create the directory) as measure_area (no extension) and make it executable.
Add a key combination of your choice to run the script: Choose: System Settings > "Keyboard" > "Shortcuts" > "Custom Shortcuts". Click the "+" and add the command:
measure_area
#!/usr/bin/env python3
import subprocess
import os
import math
home = os.environ["HOME"]
area = home+"/"+".measure_area.txt"
def get_pos():
pos_data = subprocess.check_output(["xdotool", "getmouselocation"]).decode("utf-8")
return [m[2:] for m in pos_data.split()[:2]]
def confirm():
get = subprocess.check_output(["xrandr", "--verbose"]).decode("utf-8").split()
for s in [get[i-1] for i in range(len(get)) if get[i] == "connected"]:
br_data = float(get[get.index("Brightness:")+1])
brightness = lambda br: ["xrandr", "--output", s, "--brightness", br]
flash = ["sleep", "0.1"]
for cmd in [brightness(str(br_data-0.1)), flash, brightness(str(br_data))]:
subprocess.call(cmd)
if not os.path.exists(area):
with open(area, "wt") as measure:
measure.write(str(get_pos()))
confirm()
else:
second = get_pos()
with open(area) as first_m:
try:
first = eval(first_m.read())
w = int(math.fabs(int(second[0]) - int(first[0])))
h = int(math.fabs(int(second[1]) - int(first[1])))
#--- uncomment either one of the lines below:
# command = ['notify-send', 'Area size', str(w)+' x '+str(h)]
command = ['zenity', '--info', '--title', 'Area Size', '--text', str(w) + ' x ' + str(h)]
#---
confirm()
except SyntaxError:
text = "Please try again, there was an error in the data"
command = ['zenity', '--info', '--title', 'Please try again', '--text', text]
subprocess.Popen(command)
os.remove(area)
When the script is called the first time, it gets the current mouse position with the xdotool command:
xdotool getmouselocation
It then saves the position into an (invisible) file .measure_area.txt, waiting for the second call.
On the second call, it reads the file, removes it and compares the stored x/y coordinates to the latest ones, and calculates the size of the area between them.
Updated the script with a number of improvements:
subprocess.Popen()/subprocess.check_output() commands (thanks to @muru, @Trengot)xdotool installed)
First install Shutter if you don't have it installed.
sudo apt-get install shutter
Open up preferences under Edit -> Preferences and select the behaviour tab.
Check 'Start shutter at login' and 'Hide window on first launch'.
See screenshot below:
Using slop
Another simple way of determining the area of a selection is by using slop (Select Operation), a command-line utility "that queries for a selection from the user and prints the region to stdout."
slop is a comparitively new tool and has not been packaged for Debian/Ubuntu, yet. As it stands you will have to compile it from source:
sudo apt-get install build-essential cmake libxext-dev
git clone https://github.com/naelstrof/slop.git
cd slop
cmake ./
make && sudo make install
The installation is the most difficult part. slop itself is actually very easy to work with. For instance, the following one-liner will prompt you to select a screen area and will both display the result as a notification and write it to the clipboard:
eval $(slop -t 0 -b 1) && notify-send "Selection info" "Area: ${W} x ${Y}px \n Position: X = ${X}px, Y = ${Y}px" && echo ${W}x${H} | xsel -bi
Screenshot:
A quick breakdown of the commands used:
slop -t 0 -b 1 - prompt the user to select a screen area; do not select full windows (-t 0), set selection border to 1px (-b 1)eval $(...) - read output of slop into variablesnotify-send ... - send GUI notification with information on selected areaecho ${W}x${H} | xsel -bi - copy dimensions to clipboard (requires xsel → sudo apt-get install xsel)
Popen(['/bin/bash',...instead ofPopen(['zenity', '--info', ...? – muru Feb 10 '15 at 10:59command = ['zenity', '--info', '--title', 'Area Size', '--text', str(w) + ' x ' + str(h)]; subprocess.Popen(command)requires a lot less messing around with'and", I think. – muru Feb 10 '15 at 11:21xdotools? Something likecheck_output(['xdotools', 'getmouseposition'])? – Holloway Feb 10 '15 at 13:55