#Copyright ReportLab Europe Ltd. 2000-2012

#see license.txt for license details

__version__=''' $Id$ '''

__doc__='''Utility functions to position and resize boxes within boxes'''

def aspectRatioFix(preserve,anchor,x,y,width,height,imWidth,imHeight):

    """This function helps position an image within a box.

    It first normalizes for two cases:

    - if the width is None, it assumes imWidth

    - ditto for height

    - if width or height is negative, it adjusts x or y and makes them positive

    Given

    (a) the enclosing box (defined by x,y,width,height where x,y is the \

        lower left corner) which you wish to position the image in, and

    (b) the image size (imWidth, imHeight), and

    (c) the 'anchor point' as a point of the compass - n,s,e,w,ne,se etc \

        and c for centre,

    this should return the position at which the image should be drawn,

    as well as a scale factor indicating what scaling has happened.

    It returns the parameters which would be used to draw the image

    without any adjustments:

        x,y, width, height, scale

    used in canvas.drawImage and drawInlineImage

    """

    scale = 1.0

    if width is None:

        width = imWidth

    if height is None:

        height = imHeight

    if width<0:

        width = -width

        x -= width

    if height<0:

        height = -height

        y -= height

    if preserve:

        imWidth = abs(imWidth)

        imHeight = abs(imHeight)

        scale = min(width/float(imWidth),height/float(imHeight))

        owidth = width

        oheight = height

        width = scale*imWidth-1e-8

        height = scale*imHeight-1e-8

        if anchor not in ('nw','w','sw'):

            dx = owidth-width

            if anchor in ('n','c','s'):

                x += dx/2.

            else:

                x += dx

        if anchor not in ('sw','s','se'):

            dy = oheight-height

            if anchor in ('w','c','e'):

                y += dy/2.

            else:

                y += dy

    return x,y, width, height, scale