'''MakeHDRFinal.py

'''

FOLDER = "Reduced-Still-Life"
HDRWIN = None      # Window for the HDR array
TOTALWEIGHT = None # Window for the weights array
TONEMAPPED = None  # Window for the preliminary tone-mapped image
OUTPUTWIN = None   # Window for the enhanced tone-mapped image
CONST = 200        # Used in the mappings to and from HDR values

# Map pixels from one input image into HDR values and weights:
def process(folder, filename, shutter_speed):
  global HDRWIN, TOTALWEIGHT, FOLDER, CONST
  print "Preparing to read in the image file: "+filename
  srcwin = pmOpenImage(0, folder+"/"+filename)
  width = pmGetImageWidth(srcwin)
  height = pmGetImageHeight(srcwin)
  if not HDRWIN:
    HDRWIN = pmNewImage(0, "HDR", width, height, 0, 0, 0)
    pmSetComplex(HDRWIN) # For extra pixel precision
    TOTALWEIGHT = pmNewImage(0,"Total Weight",width,height,0,0,0)
    pmSetComplex(TOTALWEIGHT) # Again, extra precision
  pmSetSource1(srcwin)
  pmSetDestination(TOTALWEIGHT)
  f="complex(dest(x,y)+200*\
       pow(2.718,-pow((S1(x,y)-127.5)/65,2)),0)"
  pmSetFormula(f)
  pmCompute()
  pmSetSource2(TOTALWEIGHT)
  pmSetDestination(HDRWIN)
  exposureFac = 1.0/shutter_speed
  f="complex(dest(x,y)+REAL2(x,y)*pow(S1(x,y), 2.2)*"+\
       str(exposureFac)+" * "+str(CONST)+",0.0)"
  pmSetFormula(f)
  pmCompute()

# To get correct weighted average HDR values, we
# divide HDR values by corresponding total weights.
def normalize_by_weights():
  global HDRWIN, TOTALWEIGHT
  pmSetSource1(TOTALWEIGHT)
  pmSetDestination(HDRWIN)
  pmSetFormula("complex(dest(x,y)/real1(x,y), 0.0)")
  pmCompute()

# The tone_map routine has the job of mapping back the values 
# from the HDR image to a normal image.  The contrast and 
# brightness can be adjusted by changing the arguments.

def tone_map(factor, power):
  global HDRWIN, TONEMAPPED
  width = pmGetImageWidth(HDRWIN)
  height = pmGetImageHeight(HDRWIN)
  if not TONEMAPPED:
    TONEMAPPED = pmNewImage(0,"Tone-mapped (preliminary)",width,height,0,128,0)
    # Initialize to green to show that the output is coming.
  pmSetSource1(HDRWIN)
  pmSetDestination(TONEMAPPED)
  f=str(factor)+"*pow(S1(x,y)/"+str(CONST)+", "+str(power)+")"
  pmSetFormula(f)
  pmCompute()

# Increase color saturation by factor, clipping at 1.0.
def saturate(factor):
  global TONEMAPPED, OUTPUTWIN
  if not OUTPUTWIN:
    OUTPUTWIN = pmCloneImage(TONEMAPPED)
    pmSetTitle(OUTPUTWIN, "Saturation-boosted, tone-mapped result")
  pmSetSource1(TONEMAPPED)
  pmSetDestination(OUTPUTWIN)
  f="HSV(hue1(x,y),min(1,sat1(x,y)*"+str(factor)+"),val1(x,y))"
  pmSetFormula(f)
  pmCompute()

def main():
  print "Starting to read in images"
  process(FOLDER, "REDUCED-still-life-1-1-60th.JPG", 
          1.0/30) # actual shutter speed = 1/60
  process(FOLDER, "REDUCED-still-life-6-1-half.JPG", 
          1.0/2)
  process(FOLDER, "REDUCED-still-life-11-15-secs.JPG", 
          8.0) # actual shutter speed = 15 sec. 
  normalize_by_weights()
  tone_map(5, 1.0/4)
  saturate(2.0)

main()