| 1 | ;------------------------------------------------------------ |
|---|
| 2 | ;------------------------------------------------------------ |
|---|
| 3 | ;------------------------------------------------------------ |
|---|
| 4 | ;+ |
|---|
| 5 | ; |
|---|
| 6 | ; @file_comments |
|---|
| 7 | ; project linearly a segment, a vector whose boundaries are [a,b] on |
|---|
| 8 | ; a vector whose boundaries are [c,d] |
|---|
| 9 | ; |
|---|
| 10 | ; @categories |
|---|
| 11 | ; calculation |
|---|
| 12 | ; |
|---|
| 13 | ; @param VECTEUR |
|---|
| 14 | ; A vector whose the first element must be the smallest one and the last must be the biggest one. |
|---|
| 15 | ; |
|---|
| 16 | ; @param BORNES |
|---|
| 17 | ; New boundaries of the vector. |
|---|
| 18 | ; |
|---|
| 19 | ; @keyword MP |
|---|
| 20 | ; Activate this keyword to the function send back this a vector of 2 |
|---|
| 21 | ; elements which are the m and p of the linear projection y=mx+p used |
|---|
| 22 | ; to pass from the [a,b] segment to the [c,d] segment. |
|---|
| 23 | ; |
|---|
| 24 | ; @returns |
|---|
| 25 | ; A vector whose new boudaries are specified by BORNES. |
|---|
| 26 | ; |
|---|
| 27 | ; @examples |
|---|
| 28 | ; |
|---|
| 29 | ; IDL> a=indgen(9) |
|---|
| 30 | ; IDL> print, a |
|---|
| 31 | ; 0 1 2 3 4 5 6 7 8 |
|---|
| 32 | ; IDL> print, projsegment(a,[0,80]) |
|---|
| 33 | ; 0 10 20 30 40 50 60 70 80 |
|---|
| 34 | ; IDL> print, projsegment(a,[0,-80]) |
|---|
| 35 | ; 0 -10 -20 -30 -40 -50 -60 -70 -80 |
|---|
| 36 | ; IDL> print, projsegment(a,[-80,0]) |
|---|
| 37 | ; -80 -70 -60 -50 -40 -30 -20 -10 0 |
|---|
| 38 | ; |
|---|
| 39 | ; @history |
|---|
| 40 | ; Sebastien Masson (smasson@lodyc.jussieu.fr) |
|---|
| 41 | ; 24/6/1999 |
|---|
| 42 | ; |
|---|
| 43 | ; @version |
|---|
| 44 | ; $Id$ |
|---|
| 45 | ; |
|---|
| 46 | ;- |
|---|
| 47 | ;------------------------------------------------------------ |
|---|
| 48 | ;------------------------------------------------------------ |
|---|
| 49 | ;------------------------------------------------------------ |
|---|
| 50 | FUNCTION projsegment, vecteur, bornes, MP = mp |
|---|
| 51 | ;-------------------------------------------------------------- |
|---|
| 52 | ; |
|---|
| 53 | compile_opt idl2, strictarrsubs |
|---|
| 54 | ; |
|---|
| 55 | a1 = float(vecteur[0]) |
|---|
| 56 | b1 = float(vecteur[n_elements(vecteur)-1]) |
|---|
| 57 | a2 = float(bornes[0]) |
|---|
| 58 | b2 =float( bornes[1]) |
|---|
| 59 | if a1 EQ b1 then return, -1 |
|---|
| 60 | m = (b2-a2)/(b1-a1) |
|---|
| 61 | p = a2-m*a1 |
|---|
| 62 | ;-------------------------------------------------------------- |
|---|
| 63 | if keyword_set(mp) then return, [m, p] ELSE return, m*vecteur+p |
|---|
| 64 | ;-------------------------------------------------------------- |
|---|
| 65 | end |
|---|
