[chronojump] Encoder Force/Speed graph crosses axis and plots crossing values

[Xavier de Blas <xaviblas src gnome org>]

commit 92e127c223cc40726a7f697fabac669bdb4d96a2
Author: Xavier de Blas <xaviblas gmail com>
Date:   Mon Oct 17 19:23:29 2016 +0200

    Encoder Force/Speed graph crosses axis and plots crossing values

 encoder/graph.R |   47 ++++++++++++++++++++++++++++++++++++++---------
 1 files changed, 38 insertions(+), 9 deletions(-)
---
diff --git a/encoder/graph.R b/encoder/graph.R
index 1a618d5..d8b96c7 100644
--- a/encoder/graph.R
+++ b/encoder/graph.R
@@ -1566,6 +1566,7 @@ paintCrossVariables <- function (paf, varX, varY, option,
 
        colBalls = NULL
        bgBalls = NULL
+       doBox = TRUE
 
        isPowerLoad = FALSE
        if( (varX == "Load" || varX == "Inertia") && varY == "Power" )
@@ -1737,7 +1738,32 @@ paintCrossVariables <- function (paf, varX, varY, option,
                                        }
                                }
                                else {
-                                       plot(x,y, xlab=varXut, ylab="", pch=pchVector, 
col=colBalls,bg=bgBalls,cex=cexBalls,axes=F)
+                                       if(varX == "Speed" && varY == "Force")
+                                       {
+                                               fit = lm(y ~ x)
+                                               x.intercept = -coef(fit)[[1]] / coef(fit)[[2]]
+                                               y.intercept = coef(fit)[[1]]
+
+                                               plot(x,y,
+                                                    xlim=c(0, max(x,x.intercept)), ylim=c(0, 
max(y,y.intercept)),
+                                                    xlab=varXut, ylab="", pch=pchVector, 
col=colBalls,bg=bgBalls,cex=cexBalls,axes=F)
+
+                                               #force x and y axis to start at 0
+                                               axis(1,pos=0)
+                                               axis(2,pos=0)
+                                               #draw ablines to arrive to the fitLine values
+                                               abline(h=0)
+                                               abline(v=0)
+                                               #draw points and mtext
+                                               points(x.intercept,0,col="red")
+                                               points(0,y.intercept,col="red")
+                                               text(x=x.intercept, y=0, paste(round(x.intercept,2), 
"\n\n\n", sep=""), col="red", cex=.8, adj=0.5)
+                                               text(x=0, y=y.intercept, paste("   ", round(y.intercept,2), 
sep=""), col="red", cex=.8, adj=0)
+                                               #don't plot box because it's not nice with 0,0 axis
+                                               doBox = FALSE
+                                       } else {
+                                               plot(x,y, xlab=varXut, ylab="", pch=pchVector, 
col=colBalls,bg=bgBalls,cex=cexBalls,axes=F)
+                                       }
                                        
                                        paintCrossVariablesLaterality(x, y, laterality, colBalls)
                                        
@@ -1869,24 +1895,27 @@ paintCrossVariables <- function (paf, varX, varY, option,
        }
                
        if(isAlone == "ALONE") {
-               if(dateAsX)
-                       axis.Date(1,as.Date(x))
-               else
-                       axis(1)
+               if(doBox) {
+                       if(dateAsX)
+                               axis.Date(1,as.Date(x))
+                       else
+                               axis(1)
 
-               axis(2)
+                       axis(2)
+               }
                mtext(varYut, side=2, line=3)
-               #box()
        } else if(isAlone == "LEFT") {
                axis(1)
                axis(2,col=colBalls)
                mtext(varYut, side=2, line=3, col=colBalls)
-               #box()
        } else { #"RIGHT"
                axis(4,col=colBalls)
                mtext(varYut, side=4, line=3, col=colBalls)
        }
-       box()
+
+       if(doBox) {
+               box()
+       }
 
 }