Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Basically, the general method for smooth transition between two values is the following function:</p> <pre><code>function transition(value, maximum, start_point, end_point): return start_point + (end_point - start_point)*value/maximum </code></pre> <p>That given, you define a function that does the transition for triplets (RGB, HSV etc).</p> <pre><code>function transition3(value, maximum, (s1, s2, s3), (e1, e2, e3)): r1= transition(value, maximum, s1, e1) r2= transition(value, maximum, s2, e2) r3= transition(value, maximum, s3, e3) return (r1, r2, r3) </code></pre> <p>Assuming you have RGB colours for the <i>s</i> and <i>e</i> triplets, you can use the transition3 function as-is. However, going through the HSV colour space produces more "natural" transitions. So, given the conversion functions (stolen shamelessly from the Python colorsys module and converted to pseudocode :):</p> <pre><code>function rgb_to_hsv(r, g, b): maxc= max(r, g, b) minc= min(r, g, b) v= maxc if minc == maxc then return (0, 0, v) diff= maxc - minc s= diff / maxc rc= (maxc - r) / diff gc= (maxc - g) / diff bc= (maxc - b) / diff if r == maxc then h= bc - gc else if g == maxc then h= 2.0 + rc - bc else h = 4.0 + gc - rc h = (h / 6.0) % 1.0 //comment: this calculates only the fractional part of h/6 return (h, s, v) function hsv_to_rgb(h, s, v): if s == 0.0 then return (v, v, v) i= int(floor(h*6.0)) //comment: floor() should drop the fractional part f= (h*6.0) - i p= v*(1.0 - s) q= v*(1.0 - s*f) t= v*(1.0 - s*(1.0 - f)) if i mod 6 == 0 then return v, t, p if i == 1 then return q, v, p if i == 2 then return p, v, t if i == 3 then return p, q, v if i == 4 then return t, p, v if i == 5 then return v, p, q //comment: 0 &lt;= i &lt;= 6, so we never come here </code></pre> <p>, you can have code as following:</p> <pre><code>start_triplet= rgb_to_hsv(0, 255, 0) //comment: green converted to HSV end_triplet= rgb_to_hsv(255, 0, 0) //comment: accordingly for red maximum= 200 … //comment: value is defined somewhere here rgb_triplet_to_display= hsv_to_rgb(transition3(value, maximum, start_triplet, end_triplet)) </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POColor scaling function
      singulars
      1. PTQuestion
    1. PTAnswer
    1. UStzot
    1. UStzot
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POColor scaling function
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CO+1; I was going to ask a new question about how to improve a color algorithm i have for coloring a bar chart in HTML/PHP... SO suggested this question as similar and your answer helped me fix the issue without having to ask the question! Thanks!
      singulars
      1. PO
      1. USbeggs
    2. CO+1, and a better name for your `transition` function would be `lerp` as that's mathematically what you're doing: http://en.wikipedia.org/wiki/Lerp_(computing)
      singulars
      1. PO
      1. USKeith
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload