DZI syntax to IIIF

dzi_to_iiif.py

# Take params from the DZI syntax and turn them into an IIIF request 

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import math

# would-be params from dzi syntax, i.e. `/level/x_y.jpg`
level = 9
x = 0
y = 0

# would-be values from iiif info service
img_tile_width = 256
img_tile_height = 256
img_width = 2717
img_height = 3600

# constants
IIIF_ROTATION = '0'
IIIF_QUALITY = 'native.jpg'

## get the scale (level as a decimal)
max_img_dimension = max(img_width, img_height)
max_level = int(math.ceil(math.log(max_img_dimension, 2)))
scale = math.pow(0.5, max_level - level)


## get iiif size
iiif_pct_size = scale * 100
iiif_size = str('pct:' + str(iiif_pct_size))

## iiif region
iiif_region = ''
iiif_tile_size_width = int(math.ceil(img_tile_width / scale))
iiif_tile_size_height = int(math.ceil(img_tile_height / scale))

# image dimensions at this level
level_width = int(math.ceil(img_width * scale))
level_height = int(math.ceil(img_height * scale))

if level_width < img_tile_width or level_height < img_tile_height:
	iiif_region = 'full'
else:
	iiif_tile_x = x * iiif_tile_size_width + x
	iiif_tile_y = y * iiif_tile_size_height + y
	iiif_tile_w = min(iiif_tile_size_width, img_width - iiif_tile_x)
	iiif_tile_h = min(iiif_tile_size_height, img_height - iiif_tile_y)
	
	bounds = (iiif_tile_x, iiif_tile_y, iiif_tile_w, iiif_tile_h)
	iiif_region = ','.join(map(str, bounds))


print '/'.join((iiif_region, iiif_size, IIIF_ROTATION, IIIF_QUALITY))

dzi_to_iiif_2.py

import math

# DZI to IIIF 2.0

# constants
IIIF_ROTATION = '0'
IIIF_QUALITY = 'default.jpg'

def dzi_to_iiif(level, x_idx, y_idx, img_w, img_h, img_tile_w, image_tile_h):
    ## get the scale (level as a decimal)
    long_dimension = max(img_w, img_h)
    max_level = int(math.ceil(math.log(long_dimension, 2)))
    print max_level
    scale = math.pow(0.5, max_level - level)

    ## get iiif size
    iiif_size = '%d,' % int(math.ceil(img_w * scale))

    ## iiif region
    iiif_region = ''
    iiif_tile_size_width = int(math.ceil(img_tile_w / scale))
    iiif_tile_size_height = int(math.ceil(img_tile_h / scale))

    # image dimensions at this level
    level_width = int(math.ceil(img_w * scale))
    level_height = int(math.ceil(img_h * scale))

    if level_width < img_tile_w or level_height < img_tile_h:
        iiif_region = 'full'
    else:
        iiif_tile_x = x_idx * iiif_tile_size_width + x_idx
        iiif_tile_y = y_idx * iiif_tile_size_height + y_idx
        iiif_tile_w = min(iiif_tile_size_width, img_w - iiif_tile_x)
        iiif_tile_h = min(iiif_tile_size_height, img_h - iiif_tile_y)
        
        bounds = (iiif_tile_x, iiif_tile_y, iiif_tile_w, iiif_tile_h)
        iiif_region = ','.join(map(str, bounds))

    return '/'.join((iiif_region, iiif_size, IIIF_ROTATION, IIIF_QUALITY))

# would-be params from dzi syntax, i.e. `/level/x_y.jpg`
level = 10
x = 0
y = 0
    
# would-be values from iiif info service
img_tile_w = 1024
img_tile_h = 1024
img_w = 5434
img_h = 7200

print dzi_to_iiif(level, x, y, img_w, img_h, img_tile_w, img_tile_h)

@bgilbert, @iangilman: no problem, I've changed it up top. I'm not sure that the CodePlex line needs to be in there...but just used the text verbatim. Let me know if I should take it out.

Looks good. Thanks again.

Note: while this served as the basis for the initial OpenSeadragon/IIIF Image API implementation, both OSd and the Image API have changed. Leaving this around for the sake of history, but that's all it is...history.