因 9VA-pi 選單

 

之灰階對比令人疑惑︰

想要理解什麼是『灰色』其實並不容易！？

Grey

Grey (British English) or gray (American English;^{[citation needed]} see spelling differences) is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is a color “without color.”^[2] This means that there are equal components of red, green, and blue. The variations in intensity of these colors uniformly produce different shades of grey. It is the color of a cloud-covered sky, of ash and of lead.^[3]

The first recorded use of grey as a color name in the English language was in AD 700.^[4] Grey is the dominant spelling in European and Commonwealth English, although gray remained in common usage in the UK until the second half of the 20th century.^[5] Gray has been the preferred American spelling since approximately 1825,^[6] although grey is an accepted variant.^[7][8]

In Europe and the United States, surveys show that grey is the color most commonly associated with neutrality, conformity, boredom, uncertainty, old age, indifference, and modesty. Only one percent of respondents chose it as their favorite color.^[9]

 

因為『純灰』指稱沒有『色相』 HUE 之『顏色』也◎

─ 摘自《GoPiGo 小汽車︰格點圖像算術《色彩空間》灰階‧乙》

 

知其恐非以 sRGB 為預設︰

edidparser edid.dat

Enabling fuzzy format match…
Parsing edid.dat…
HDMI:EDID version 1.3, 1 extensions, screen size 70×39 cm
HDMI:EDID features – videodef 0x80 standby suspend active off; colour encoding:RGB444|YCbCr422; sRGB is not default colourspace; preferred format is native; does not support GTF

 

故想安裝

Mark Kness 先生寫作『顏色派』

ColorPy

Physical color calculations in Python.

More documentation is currently at http://markkness.net/colorpy/ColorPy.html.

A taste of the plots that ColorPy can create: RGB values for the pure spectral lines.

Version 0.1.1. Changes from 0.1.0: Various things I did on my local machine. A better shark fin plot, for example. Now on GitHub!

Version 0.1.0. I had this hosted at http://markkness.net (and still do) but GitHub is a better place for it now.

這時仍喜派生二 Python2 。簡單準備環境後︰

sudo pip install scipy
sudo pip3 install scipy

sudo pip install numpy
sudo pip3 install numpy

sudo apt-get install python-matplotlib python3-matplotlib
sudo apt-get install python-zmq python3-zmq

sudo apt-get install ipython ipython3

─── 摘自《GoPiGo 小汽車︰格點圖像算術《彩色世界》【顏色ABC】二》

 

驗證與查核後，看如何在 Raspbian Stretch 裡產合宜的

ICC profile

In color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium (ICC). Profiles describe the color attributes of a particular device or viewing requirement by defining a mapping between the device source or target color space and a profile connection space (PCS). This PCS is either CIELAB (L*a*b*) or CIEXYZ. Mappings may be specified using tables, to which interpolation is applied, or through a series of parameters for transformations.

Every device that captures or displays color can be profiled. Some manufacturers provide profiles for their products, and there are several products that allow an end-user to generate his or her own color profiles, typically through the use of a tristimulus colorimeter or preferably a spectrophotometer.

The ICC defines the format precisely but does not define algorithms or processing details. This means there is room for variation between different applications and systems that work with ICC profiles. Since late 2010, the current version of the specification is 4.3.^[1]

ICC has also published a preliminary specification for iccMAX, a next-generation color management architecture with significantly expanded functionality and a choice of colorimetric, spectral or material connection space. Details are at http://www.color.org/iccmax/

 

呦？莫非萬聖奔騰之夜剛過，所以遭遇

pip fails with “TypeError: unsupported operand type(s) for -=: ‘Retry’ and ‘int'” #4779

• Pip version: python-pip (9.0.1-2+rpt1)
• Python version: 2.7
• Operating system: Linux

Description:

pip is trying to install rsa<=3.5.0,>=3.1.2 (from awscli), and randomly fails with this error:
TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'. By random, I mean it works about 80% of the time, fails about 20%, and I don’t why it fails.

I don’t speak python, so I think it’s pip that’s failing, and not something in the rsa module as it’s being installed.

 

事件耶？？谷歌後發現當時半信半疑的舊聞

Python PIP Install throws TypeError: unsupported operand type(s) for -=: ‘Retry’ and ‘int’

TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

 

。且先用備份系統確認，竟然 OK 哩！！不得已一時岔路乎？？