Color IX in computer -- Summary: Fast conversion of RGB and HSV

Write a section about the colorArticle, Review the past several articles and make a staged summary. Based on the experiences of the previous articles, the formulas for fast conversion of RGB and HSV modes are derived.

RGB mode: The color is represented by the components of R, G, and B. The value range of the component is [0,255], and the integer type is

HSV mode: The color is represented by three components: H, S, and V.

Component H: The color of the color. The value ranges from 0,360 to an integer.

Component S: indicates the color purity. value range: [0, 1), floating point type.

Component V: The brightness of the color. value range: [0, 1), floating point

For more information, see the color III--HSV representation in the computer"

1. RGB to HSV

How to quickly convert colors (R, G, B) to (H, S, V)

See the article "Computer Color IV-solid color, color phase color", "Computer Color V-quick calculation of color phase value"

Make Max the maximum values of the three components R, G, and B; min the minimum values of the three components.

If max = min, then

H = 0

S = 0

V = max/255

If Max =min

When G is greater than or equal to B

H = (max-r '+ G'-min + B'-min)/(max-min) × 60

S = 1-min/MAX

V = max/255

When G <B

H = 360-(Max-R' + G'-min + B '-min)/(max-min) × 60

S = 1-min/MAX

V = max/255

2. HSV to RGB

How to quickly convert colors (H, S, v) to (R, G, B)

See article "color VIII in computer-quick calculation of color deflection"

Color (H, S, v) can be seen as color (0, S, v) clockwise deflection h to get the color, in fact, is to obtain the color Max and Min weight

Max = V x 255 = 255 v

If S = 0, it means max = min, which indicates the gray color.

R = max

G = max

B = max

If S> 0, P = MAX-MIN = 255sv, min = max-P

If H> 180, make H' = 360-h; otherwise, make H' = H

Set λ = H '/60 × P

R = 2 P-λ; if r <0, r = 0; if r> P, R = P;

G = λ; if G> P, G = P;

B = λ-2 p; if B <0; then B = 0;

If H> 180, the values of G and B are exchanged. Otherwise, the values are not exchanged. Last

R = R + min

G = G + min

B = B + min

In summary, the above are the mutual conversion formulas derived from HSV and RGB, which are simpler than the original formulas introduced on the Internet. See the color III--HSV Representation Method in the computer ".