growCanvasToBbox

growCanvasToBbox.py

############################################
# growCanvasToBbox 0.1
# 2016.04.29
# Brian Willard
# info@brianwillard.org
#
# analyze bbox over a sequence and create a reformat scaled to the optimal size to contain the bbox.
# create a 2nd reformat expression linked to shrink the canvas back to the original size.

############################################

def growCanvasToBbox():
        selNode=nuke.selectedNode()
        r = nuke.root().frameRange()
        range, views = nuke.getFramesAndViews('Calculate Bbox', '%s-%s' %(r.first(), r.last()) )
        curFirst, curLast = range.split('-')

        # shuffle black into rgba
        shuffle = nuke.nodes.Shuffle()
        shuffle['red'].setValue('black')
        shuffle['green'].setValue('black')
        shuffle['blue'].setValue('black')
        shuffle['alpha'].setValue('black')
        shuffle.setInput(0, selNode)

        # sum the bbox across frames by using a FrameBlend node
        fb = nuke.nodes.FrameBlend()
        fb.setInput(0, shuffle)
        fb['userange'].setValue(True)
        fb['startframe'].setValue(int(curFirst))
        fb['endframe'].setValue(int(curLast))

        # grow the format by checking if the bbox fits inside the reformat node
        reformat = nuke.nodes.Reformat(label="GrowCanvas", type='scale', resize='none', pbb=True)
        reformat.setInput(0, fb)
        scale=1.0
        while reformat.bbox().x() < 0:
                print "reformat.bbox().x(): ", reformat.bbox().x()
                scale = scale + 0.1
                reformat['scale'].setValue(scale) 

        while reformat.bbox().y() < 0:
                print "reformat.bbox().y(): ", reformat.bbox().y()
                scale = scale + 0.1
                reformat['scale'].setValue(scale)  

        while reformat.bbox().w()+ reformat.bbox().x() > reformat.format().width():
                print 'reformat.bbox().w()+ reformat.bbox().x() ', reformat.bbox().w()+ reformat.bbox().x()        
                scale = scale + 0.1
                reformat['scale'].setValue(scale)  
        while reformat.bbox().h()+ reformat.bbox().y() > reformat.format().height():
                print 'reformat.bbox().h()+ reformat.bbox().y() ', reformat.bbox().h()+ reformat.bbox().y()        
                scale = scale + 0.1
                reformat['scale'].setValue(scale)  

        nuke.delete(shuffle)
        nuke.delete(fb)

        unFormat = nuke.nodes.Reformat(label="ShrinkCanvas", type='scale', resize='none', pbb=True)
        unFormat.setInput(0, reformat)
        unFormat['scale'].setExpression("1/parent.%s.scale" % reformat['name'].value())