src/test/scripts/functions/builtin/image_brightness.R

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# to you under the Apache License, Version 2.0 (the
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args = commandArgs(TRUE)
options(digits=22)
library("Matrix")

adjustBrightness = function(M, val, chan_max)
{
  out = matrix(0, nrow(M), ncol(M));
  for( i in 1:ncol(M) ) 
  {
    col = as.vector(M[,i])
    #col = rev(col);
    col = pmax(0, pmin(col + val, chan_max))
    out[,i] = col;
  }
  return(out)
}

A = as.matrix(readMM(paste(args[1], "A.mtx", sep="")))
#print(paste("input dim:", toString(dim(X)),sep=" "))
#print(X)

#B = pmax(0, pmin(A + 123, 255))
B = adjustBrightness(A, 123, 255)

writeMM(as(B, "CsparseMatrix"), paste(args[2], "B", sep=""));
#print(paste("output Bx dim:", toString(dim(Bx)), sep=" "))
#print(Bx)