Solution basement is desciption of linear-gradient in w3c site.
Preface: any changes in gradient function are mutable through CSS file, js script will process it in any mutadet format of gradient function inside CSS, from there it starts forward:
-
you can choose between linear or repeating-linear-gradient
-
you can add or NOT angle in first linear-gradient function argument in any format
-
you can add any numbers and any formats of colors into linear-gradient function
-
JS script program will recognize any linear-gradient function in any format
-
You can manipulate linear-gradient by multiple ColorPickers (All color pickers start values are taken from linear-gradient after style computing; All color pickers after manual color setttings changes their own linear-gradient function argument inside it; After manual mutabiling of particular LGradient color-inside element it will NOT recognize rgbA<-(A exectly) and "Color stop")
This is my simpliest way of solution of Linear-gradient problem
P.S.
There is another maniac solutions and considerations on it from Lea Verou, more difficult than my, maybe more professional, but not optimal and huge
Lea Verou blog professional solution
1 Manipulating by ANGLE argument and deconfusing directions of color pickers regardly to direction of angle argument
2 Manipulating by linear or repeating-linear-gradient function first name
3 Manipulating by "Color stops" === "... To create a linear gradient you must define at least two color stops. Color stops are the colors you want to render smooth transitions among. You can also set a starting point and a direction (or an angle) along with the gradient effect. ... === Syntax === background-image: linear-gradient(direction, color-stop1, color-stop2, ...); ..." © w3c