Ruby Gem to detect a dark color based on luminance w3 standarts
- is a hex color dark
- is an Imagick pixel dark
- is an Imagick pixel from a blob dark
- is an area in a blob over a dark background (uses Imagick for it too). . An example practical aspect: it can be useful to understand will a black colored text be visible or not over an area.
Gemfile:
gem 'is_dark', '~> 0.0.3'
Install:
gem install is_dark
-
Declare a lib:
require 'is_dark' -
Is Hex color dark:
IsDark.color('#ffffff') => false -
is Imagick pixel dark:
IsDark.magick_pixel(pix) -
is Imagick pixel from a blob dark by coordinates:
IsDark.magick_pixel_from_blob(x, y, blob) -
is Imagick area from a blob dark (by coordinates of a dot + width and height from the dot):
IsDark.magick_area_from_blob(x, y, blob, height, width)#standart default settings
It also has kind of a development mode, when you can generate a debug outputs of all the generated dots based on provided coordinates. It can draw a test area over the file if you want, so you always can be sure, that you have valid coordinates on your tests.
-
IsDark.set_debug_data(true, false)#with debug info outputs in logs -
IsDark.set_debug_data(true, '/var/www/project/is_dark_debug_output.pdf')#with a generated debug pdf file (has displayed area of the analytics). You can use other file formats for the info (jpg, png, gif) -
IsDark.magick_area_from_blob(x, y, blob, height, width)#standart default settings -
IsDark.magick_area_from_blob(x, y, blob, cf_height, cf_width, 60, (1..10))#additional settings (percent of dark dots amount to mark an area as a dark, range of matrix to build dots 1..10 - means 10x10; 0..10 - will have 121 dots for the analytics)
Sometimes Imagick can't detect a pixel or it has no color, so it detects it as (RGB: 0,0,0), the gem has an option to consider pixels like this as "white", but if you need to disable this option add true or false at the end of the method:
IsDark.magick_area_from_blob(x, y, blob, cf_height, cf_width, 60, (1..10), false)#detection "as white" is disabled)