Python util.in2gerb函数代码示例

def writeBoundingBox(fid, OriginX, OriginY, MaxXExtent, MaxYExtent):
    x = util.in2gerb(OriginX)
    y = util.in2gerb(OriginY)
    X = util.in2gerb(MaxXExtent)
    Y = util.in2gerb(MaxYExtent)

    makestroke.drawPolyline(fid, [(x, y), (X, y), (X, Y), (x, Y), (x, y)], 0, 0)

def writeScoring(fid, Place, OriginX, OriginY, MaxXExtent, MaxYExtent, xspacing, yspacing):
    # For each job, write out 4 score lines, above, to the right, below, and
    # to the left. After we collect all potential scoring lines, we worry
    # about merging, etc.
    dx = xspacing / 2.0
    dy = yspacing / 2.0
    extents = (OriginX, OriginY, MaxXExtent, MaxYExtent)

    Lines = []
    for layout in Place.jobs:
        x = layout.x - dx
        y = layout.y - dy
        X = layout.x + layout.width_in() + dx
        Y = layout.y + layout.height_in() + dy

        # Just so we don't get 3.75000000004 and 3.75000000009, we round to
        # 2.5 limits.
        x, y, X, Y = [round(val, 5) for val in [x, y, X, Y]]

        addHorizontalLine(Lines, OriginX, MaxXExtent, Y, extents)   # above job
        addVerticalLine(Lines, X, OriginY, MaxYExtent, extents)     # to the right of job
        addHorizontalLine(Lines, OriginX, MaxXExtent, y, extents)   # below job
        addVerticalLine(Lines, x, OriginY, MaxYExtent, extents)     # to the left of job

    # Combine disparate lines into single lines
    Lines = mergeLines(Lines)

    # Write 'em out
    for line in Lines:
        makestroke.drawPolyline(fid, [(util.in2gerb(line[0]), util.in2gerb(line[1])),
                                      (util.in2gerb(line[2]), util.in2gerb(line[3]))], 0, 0)

def writeDimensionArrow(fid, OriginX, OriginY, MaxXExtent, MaxYExtent):
    x = util.in2gerb(OriginX)
    y = util.in2gerb(OriginY)
    X = util.in2gerb(MaxXExtent)
    Y = util.in2gerb(MaxYExtent)

    # This constant is how far away from the board the centerline of the dimension
    # arrows should be, in inches.
    dimspace = 0.2

    # Convert it to Gerber (0.00001" or 2.5) units
    dimspace = util.in2gerb(dimspace)

    # Draw an arrow above the board, on the left side and right side
    makestroke.drawDimensionArrow(fid, x, Y + dimspace, makestroke.FACING_LEFT)
    makestroke.drawDimensionArrow(fid, X, Y + dimspace, makestroke.FACING_RIGHT)

    # Draw arrows to the right of the board, at top and bottom
    makestroke.drawDimensionArrow(fid, X + dimspace, Y, makestroke.FACING_UP)
    makestroke.drawDimensionArrow(fid, X + dimspace, y, makestroke.FACING_DOWN)

    # Now draw the text. First, horizontal text above the board.
    s = "{:.3f}\"".format(MaxXExtent - OriginX)
    ll, ur = makestroke.boundingBox(s, 0, 0)
    s_width = ur[0] - ll[0]   # Width in 2.5 units
    s_height = ur[1] - ll[1]  # Height in 2.5 units

    # Compute the position in 2.5 units where we should draw this. It should be
    # centered horizontally and also vertically about the dimension arrow centerline.
    posX = x + (x + X) / 2
    posX -= s_width / 2
    posY = Y + dimspace - s_height / 2
    makestroke.writeString(fid, s, posX, posY, 0)

    # Finally, draw the extending lines from the text to the arrows.
    posY = Y + dimspace
    posX1 = posX - util.in2gerb(0.1)  # 1000
    posX2 = posX + s_width + util.in2gerb(0.1)  # 1000
    makestroke.drawLine(fid, x, posY, posX1, posY)
    makestroke.drawLine(fid, posX2, posY, X, posY)

    # Now do the vertical text
    s = "{:.3f}\"".format(MaxYExtent - OriginY)
    ll, ur = makestroke.boundingBox(s, 0, 0)
    s_width = ur[0] - ll[0]
    s_height = ur[1] - ll[1]

    # As above, figure out where to draw this. Rotation will be -90 degrees
    # so new origin will be top-left of bounding box after rotation.
    posX = X + dimspace - s_height / 2
    posY = y + (y + Y) / 2
    posY += s_width / 2
    makestroke.writeString(fid, s, posX, posY, -90)

    # Draw extending lines
    posX = X + dimspace
    posY1 = posY + util.in2gerb(0.1)  # 1000
    posY2 = posY - s_width - util.in2gerb(0.1)  # 1000
    makestroke.drawLine(fid, posX, Y, posX, posY1)
    makestroke.drawLine(fid, posX, posY2, posX, y)

def writeOutline(fid, OriginX, OriginY, MaxXExtent, MaxYExtent):
  # Write width-1 aperture to file
  AP = aptable.Aperture(aptable.Circle, 'D10', 0.001)
  AP.writeDef(fid)

  # Choose drawing aperture D10
  fid.write('D10*\n')

  # Draw the rectangle
  fid.write('X%07dY%07dD02*\n' % (util.in2gerb(OriginX), util.in2gerb(OriginY)))        # Bottom-left
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(OriginX), util.in2gerb(MaxYExtent)))     # Top-left
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(MaxXExtent), util.in2gerb(MaxYExtent)))  # Top-right
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(MaxXExtent), util.in2gerb(OriginY)))     # Bottom-right
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(OriginX), util.in2gerb(OriginY)))        # Bottom-left

def writeDrillLegend(fid, Tools, OriginY, MaxXExtent):
    # This is the spacing from the right edge of the board to where the
    # drill legend is to be drawn, in inches. Remember we have to allow
    # for dimension arrows, too.
    dimspace = 0.5  # inches

    # This is the spacing from the drill hit glyph to the drill size
    # in inches.
    glyphspace = 0.1  # inches

    # Convert to Gerber 2.5 units
    dimspace = util.in2gerb(dimspace)
    glyphspace = util.in2gerb(glyphspace)

    # Construct a list of tuples (toolSize, toolNumber) where toolNumber
    # is the position of the tool in Tools and toolSize is in inches.
    L = []
    toolNumber = -1
    for tool in Tools:
        toolNumber += 1
        L.append((config.GlobalToolMap[tool], toolNumber))

    # Now sort the list from smallest to largest
    L.sort()

    # And reverse to go from largest to smallest, so we can write the legend
    # from the bottom up
    L.reverse()

    # For each tool, draw a drill hit marker then the size of the tool
    # in inches.
    posY = util.in2gerb(OriginY)
    posX = util.in2gerb(MaxXExtent) + dimspace
    maxX = 0
    for size, toolNum in L:
        # Determine string to write and midpoint of string
        s = "{:.3f}\"".format(size)
        ll, ur = makestroke.boundingBox(s, posX + glyphspace, posY)  # Returns lower-left point, upper-right point
        midpoint = (ur[1] + ll[1]) / 2

        # Keep track of maximum extent of legend
        maxX = max(maxX, ur[0])

        makestroke.drawDrillHit(fid, posX, midpoint, toolNum)
        makestroke.writeString(fid, s, posX + glyphspace, posY, 0)

        posY += int(round((ur[1] - ll[1]) * 1.5))

    # Return value is lower-left of user text area, without any padding.
    return maxX, util.in2gerb(OriginY)

def writeUserText(fid, X, Y):
    fname = config.Config['fabricationdrawingtext']
    if not fname:
        return

    try:
        tfile = open(fname, 'rt')
    except Exception as detail:
        raise RuntimeError("Could not open fabrication drawing text file '{:s}':\n  {:s}".format(fname, detail))

    lines = tfile.readlines()
    tfile.close()
    lines.reverse()  # We're going to print from bottom up

    # Offset X position to give some clearance from drill legend
    X += util.in2gerb(0.2)  # 2000

    for line in lines:
        # Get rid of CR
        line = line.replace('\x0D', '')

        # Strip off trailing whitespace
        line = line.rstrip()

        # Blank lines still need height, so must have at least one character
        if not line:
            line = ' '

        ll, ur = makestroke.boundingBox(line, X, Y)
        makestroke.writeString(fid, line, X, Y, 0)

        Y += int(round((ur[1] - ll[1]) * 1.5))

  def rectangleAsRect(self, X, Y):
    """Return a 4-tuple (minx,miny,maxx,maxy) describing the area covered by
    this Rectangle aperture when flashed at center co-ordinates (X,Y)"""
    dx = util.in2gerb(self.dimx)
    dy = util.in2gerb(self.dimy)

    if dx & 1:    # Odd-sized: X extents are (dx+1)/2 on the left and (dx-1)/2 on the right
      xm = (dx+1)/2
      xp = xm-1
    else:         # Even-sized: X extents are X-dx/2 and X+dx/2
      xm = xp = dx/2

    if dy & 1:    # Odd-sized: Y extents are (dy+1)/2 below and (dy-1)/2 above
      ym = (dy+1)/2
      yp = ym-1
    else:         # Even-sized: Y extents are Y-dy/2 and Y+dy/2
      ym = yp = dy/2

    return (X-xm, Y-ym, X+xp, Y+yp)

def writeFiducials(fid, drawcode, OriginX, OriginY, MaxXExtent, MaxYExtent):
  """Place fiducials at arbitrary points. The FiducialPoints list in the config specifies
  sets of X,Y co-ordinates. Positive values of X/Y represent offsets from the lower left
  of the panel. Negative values of X/Y represent offsets from the top right. So:
         FiducialPoints = 0.125,0.125,-0.125,-0.125
  means to put a fiducial 0.125,0.125 from the lower left and 0.125,0.125 from the top right"""
  fid.write('%s*\n' % drawcode)    # Choose drawing aperture

  fList = config.Config['fiducialpoints'].split(',')
  for i in range(0, len(fList), 2):
    x,y = float(fList[i]), float(fList[i+1])
    if x>=0:
      x += OriginX
    else:
      x = MaxXExtent + x
    if y>=0:
      y += OriginX
    else:
      y = MaxYExtent + y
    fid.write('X%07dY%07dD03*\n' % (util.in2gerb(x), util.in2gerb(y)))

def writeOutline(fid, OriginX, OriginY, MaxXExtent, MaxYExtent):
    # Write width-1 aperture to file
    AP = aptable.Aperture(aptable.Circle, 'D10', 0.001)
    AP.writeDef(fid)

    # Choose drawing aperture D10
    writeCurrentAperture(fid, 10)

    # Draw the rectangle starting at the bottom left and going clockwise.
    fid.write("X{:07d}Y{:07d}D02*\n".format(util.in2gerb(OriginX), util.in2gerb(OriginY)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(MaxYExtent)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(MaxXExtent)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(OriginY)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(OriginX)))

#.........这里部分代码省略.........
        writeFiducials(fid, drawing_code_fiducial_soldermask, OriginX, OriginY, MaxXExtent, MaxYExtent)
      
# KHK Patch Begin: added for Seeed Studio to generate an outline for all panelized gerber files

    if config.Config['outlinelayers'] and (layername in config.Config['outlinelayers']):
      writeOutline(fid, OriginX, OriginY, MaxXExtent, MaxYExtent)

# KHK Patch End: added for Seeed Studio to generate an outline for all panelized gerber files

      
    writeGerberFooter(fid)
    fid.close()

  # Write board outline layer if selected
  fullname = config.Config['outlinelayerfile']
  if fullname and fullname.lower() != "none":
    OutputFiles.append(fullname)
    #print 'Writing %s ...' % fullname
    fid = file(fullname, 'wt')
    writeGerberHeader(fid)

    # Write width-1 aperture to file
    # add metric support
    if config.Config['measurementunits'] == 'inch':
      AP = aptable.Aperture(aptable.Circle, 'D10', 0.001)
    else:
      AP = aptable.Aperture(aptable.Circle, 'D10', 0.25) # we'll use 0.25 mm - same as Diptrace
    AP.writeDef(fid)

    # Choose drawing aperture D10
    fid.write('D10*\n')

    # Draw the rectangle
    fid.write('X%07dY%07dD02*\n' % (util.in2gerb(OriginX), util.in2gerb(OriginY)))        # Bottom-left
    fid.write('X%07dY%07dD01*\n' % (util.in2gerb(OriginX), util.in2gerb(MaxYExtent)))     # Top-left
    fid.write('X%07dY%07dD01*\n' % (util.in2gerb(MaxXExtent), util.in2gerb(MaxYExtent)))  # Top-right
    fid.write('X%07dY%07dD01*\n' % (util.in2gerb(MaxXExtent), util.in2gerb(OriginY)))     # Bottom-right
    fid.write('X%07dY%07dD01*\n' % (util.in2gerb(OriginX), util.in2gerb(OriginY)))        # Bottom-left

    writeGerberFooter(fid)
    fid.close()

  # Write scoring layer if selected
  fullname = config.Config['scoringfile']
  if fullname and fullname.lower() != "none":
    OutputFiles.append(fullname)
    #print 'Writing %s ...' % fullname
    fid = file(fullname, 'wt')
    writeGerberHeader(fid)

    # Write width-1 aperture to file
    AP = aptable.Aperture(aptable.Circle, 'D10', 0.001)
    AP.writeDef(fid)

    # Choose drawing aperture D10
    fid.write('D10*\n')

    # Draw the scoring lines
    scoring.writeScoring(fid, Place, OriginX, OriginY, MaxXExtent, MaxYExtent)

    writeGerberFooter(fid)
    fid.close()

  # Get a list of all tools used by merging keys from each job's dictionary
  # of tools.
  if 0:

def writeCropMarks(fid, drawing_code, OriginX, OriginY, MaxXExtent, MaxYExtent):
  """Add corner crop marks on the given layer"""

  # Draw 125mil lines at each corner, with line edge right up against
  # panel border. This means the center of the line is D/2 offset
  # from the panel border, where D is the drawing line diameter.

  # use 3mm lines for metric

  fid.write('%s*\n' % drawing_code)    # Choose drawing aperture

  offset = config.GAT[drawing_code].dimx/2.0

  # should we be using 'cropmarkwidth' from config.py?
  if config.Config['measurementunits'] == 'inch':
    cropW = 0.125 #inch
  else:
    cropW = 3 #mm

  
  # Lower-left
  x = OriginX + offset
  y = OriginY + offset
  fid.write('X%07dY%07dD02*\n' % (util.in2gerb(x+cropW), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+cropW)))

  # Lower-right
  x = MaxXExtent - offset
  y = OriginY + offset
  fid.write('X%07dY%07dD02*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+cropW)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x-cropW), util.in2gerb(y+0.000)))

  # Upper-right
  x = MaxXExtent - offset
  y = MaxYExtent - offset
  fid.write('X%07dY%07dD02*\n' % (util.in2gerb(x-cropW), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y-cropW)))

  # Upper-left
  x = OriginX + offset
  y = MaxYExtent - offset
  fid.write('X%07dY%07dD02*\n' % (util.in2gerb(x+0.000), util.in2gerb(y-cropW)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+0.000), util.in2gerb(y+0.000)))
  fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+cropW), util.in2gerb(y+0.000)))

def writeCropMarks(fid, drawing_code, OriginX, OriginY, MaxXExtent, MaxYExtent):
    """Add corner crop marks on the given layer"""

    # Draw 125mil lines at each corner, with line edge right up against
    # panel border. This means the center of the line is D/2 offset
    # from the panel border, where D is the drawing line diameter.
    fid.write("{:s}*\n".format(drawing_code))    # Choose drawing aperture

    offset = config.GAT[drawing_code].dimx / 2.0

    # Lower-left
    x = OriginX + offset
    y = OriginY + offset
    fid.write("X{:07d}Y{:07d}D02*\n".format(util.in2gerb(x + 0.125), util.in2gerb(y + 0.000)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(x + 0.000)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(y + 0.125)))

    # Lower-right
    x = MaxXExtent - offset
    y = OriginY + offset
    fid.write("X{:07d}Y{:07d}D02*\n".format(util.in2gerb(x + 0.000), util.in2gerb(y + 0.125)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(y + 0.000)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(x - 0.125)))

    # Upper-right
    x = MaxXExtent - offset
    y = MaxYExtent - offset
    fid.write("X{:07d}Y{:07d}D02*\n".format(util.in2gerb(x - 0.125), util.in2gerb(y + 0.000)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(x + 0.000)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(y - 0.125)))

    # Upper-left
    x = OriginX + offset
    y = MaxYExtent - offset
    fid.write("X{:07d}Y{:07d}D02*\n".format(util.in2gerb(x + 0.000), util.in2gerb(y - 0.125)))
    fid.write("Y{:07d}D01*\n".format(util.in2gerb(y + 0.000)))
    fid.write("X{:07d}D01*\n".format(util.in2gerb(x + 0.125)))

def writeUserText(fid, X, Y):
  fname = config.Config['fabricationdrawingtext']
  if not fname: return

  try:
    tfile = file(fname, 'rt')
  except Exception, detail:
    raise RuntimeError, "Could not open fabrication drawing text file '%s':\n  %s" % (fname,str(detail))

  lines = tfile.readlines()
  tfile.close()
  lines.reverse()  # We're going to print from bottom up

  # Offset X position to give some clearance from drill legend
  X += util.in2gerb(0.2) # 2000

  for line in lines:
    # Get rid of CR
    line = string.replace(line, '\x0D', '')

    # Chop off \n
    #if line[-1] in string.whitespace:
    #  line = line[:-1]

    # Strip off trailing whitespace
    line = string.rstrip(line)

    # Blank lines still need height, so must have at least one character
    if not line:
      line = ' '

def writeDimensionArrow(fid, OriginX, OriginY, MaxXExtent, MaxYExtent):
  x = util.in2gerb(OriginX)
  y = util.in2gerb(OriginY)
  X = util.in2gerb(MaxXExtent)
  Y = util.in2gerb(MaxYExtent)

  # This constant is how far away from the board the centerline of the dimension
  # arrows should be, in inches.
  # dimspace = 0.2          # KHK was the original line
  if config.Config['measurementunits'] == 'inch':  
     dimspace = 0.2 # inches
  else:
     dimspace = 10 # mm     - Distance of dimension line to board outline line

  # Convert it to Gerber (0.00001" or 2.5) units
  dimspace = util.in2gerb(dimspace)

  # Draw an arrow above the board, on the left side and right side
  makestroke.drawDimensionArrow(fid, x, Y+dimspace, makestroke.FacingLeft)
  makestroke.drawDimensionArrow(fid, X, Y+dimspace, makestroke.FacingRight)

  # Draw arrows to the right of the board, at top and bottom
  makestroke.drawDimensionArrow(fid, X+dimspace, Y, makestroke.FacingUp)
  makestroke.drawDimensionArrow(fid, X+dimspace, y, makestroke.FacingDown)

  # Now draw the text. First, horizontal text above the board.
  # s = '%.3f"' % (MaxXExtent - OriginX) # KHK orig line
  if config.Config['measurementunits'] == 'inch':  
      s = '%.3f"' % (MaxXExtent - OriginX) # inche
  else:
      s = '%.3fmm' % (MaxXExtent - OriginX) # mm 
  ll, ur = makestroke.boundingBox(s, 0, 0)
  s_width = ur[0]-ll[0]   # Width in 2.5 units
  s_height = ur[1]-ll[1]  # Height in 2.5 units

  # Compute the position in 2.5 units where we should draw this. It should be
  # centered horizontally and also vertically about the dimension arrow centerline.
  posX = x + (x+X)/2
  posX -= s_width/2
  posY = Y + dimspace - s_height/2
  makestroke.writeString(fid, s, posX, posY, 0)

  # Finally, draw the extending lines from the text to the arrows.
  posY = Y + dimspace
  #posX1 = posX - util.in2gerb(0.1*24.5) # 1000  # KHK orig. line
  if config.Config['measurementunits'] == 'inch':  
     posX1 = posX - util.in2gerb(0.1 ) # 1000
  else:
     posX1 = posX - util.in2gerb(0.1*24.5) # 1000
  # posX2 = posX + s_width + util.in2gerb(0.1*25.4) # 1000  # KHK orig. line
  if config.Config['measurementunits'] == 'inch':  
     posX2 = posX + s_width + util.in2gerb(0.1) # 1000
  else:
     posX2 = posX + s_width + util.in2gerb(0.1*25.4) # 1000
  makestroke.drawLine(fid, x, posY, posX1, posY)
  makestroke.drawLine(fid, posX2, posY, X, posY)

  # Now do the vertical text
  # s = '%.3f"' % (MaxYExtent - OriginY) # KHK orig line
  if config.Config['measurementunits'] == 'inch':  
     s = '%.3f"' % (MaxYExtent - OriginY) 
  else:
     s = '%.3fmm' % (MaxYExtent - OriginY) 
  ll, ur = makestroke.boundingBox(s, 0, 0)
  s_width = ur[0]-ll[0]
  s_height = ur[1]-ll[1]

  # As above, figure out where to draw this. Rotation will be -90 degrees
  # so new origin will be top-left of bounding box after rotation.
  posX = X + dimspace - s_height/2
  posY = y + (y+Y)/2
  posY += s_width/2
  makestroke.writeString(fid, s, posX, posY, -90)

  # Draw extending lines
  posX = X + dimspace
  # posY1 = posY + util.in2gerb(0.1) # 1000  # KHK orig. line
  if config.Config['measurementunits'] == 'inch':  
     posY1 = posY + util.in2gerb(0.1) # 1000  # KHK orig. line
  else:
     posY1 = posY + util.in2gerb(0.1*25.4) # 1000  # KHK orig. line
  # posY2 = posY - s_width - util.in2gerb(0.1) # 1000  # KHK orig. line
  if config.Config['measurementunits'] == 'inch':  
     posY2 = posY - s_width - util.in2gerb(0.1) # 1000  # KHK orig. line
  else:
     posY2 = posY - s_width - util.in2gerb(0.1*25.4) # 1000
  makestroke.drawLine(fid, posX, Y, posX, posY1)
  makestroke.drawLine(fid, posX, posY2, posX, y)

  fname = config.Config['fabricationdrawingtext']
  if not fname: return

  try:
    tfile = file(fname, 'rt')
  except Exception, detail:
    raise RuntimeError, "Could not open fabrication drawing text file '%s':\n  %s" % (fname,str(detail))

  lines = tfile.readlines()
  tfile.close()
  lines.reverse()  # We're going to print from bottom up

  # Offset X position to give some clearance from drill legend
  # X += util.in2gerb(0.2*25.4) # 2000  # KHK orig. line
  if config.Config['measurementunits'] == 'inch':  
     X += util.in2gerb(0.2) # 2000
  else:
     X += util.in2gerb(10) # 2000  # additional text is placed right of drill legend 

  for line in lines:
    # Get rid of CR
    line = string.replace(line, '\x0D', '')

    # Chop off \n
    #if line[-1] in string.whitespace:
    #  line = line[:-1]

    # Strip off trailing whitespace
    line = string.rstrip(line)

    # Blank lines still need height, so must have at least one character