def list_tiles_for_bounds(image, s2p, paper_width_pt, paper_height_pt, north,
west, south, east):
""" Return a list of coordinates and scan-to-coord functions for a full set of zoom levels.
Internal work is done by list_tiles_for_bounds_zoom().
"""
osm = OpenStreetMapProvider()
coords = []
for zoom in range(19):
#
# Coordinates of three print corners
#
ul = osm.locationCoordinate(Location(north, west)).zoomTo(zoom)
ur = osm.locationCoordinate(Location(north, east)).zoomTo(zoom)
lr = osm.locationCoordinate(Location(south, east)).zoomTo(zoom)
#
# Matching points in print and coordinate spaces
#
ul_pt = Point(1 * ptpin - paper_width_pt,
1.5 * ptpin - paper_height_pt)
ul_co = Point(ul.column, ul.row)
ur_pt = Point(0, 1.5 * ptpin - paper_height_pt)
ur_co = Point(ur.column, ur.row)
lr_pt = Point(0, 0)
lr_co = Point(lr.column, lr.row)
scan_dim = hypot(image.size[0], image.size[1])
zoom_dim = hypot((lr_co.x - ul_co.x) * 256, (lr_co.y - ul_co.y) * 256)
if zoom_dim / scan_dim < .05:
# too zoomed-out
continue
if zoom_dim / scan_dim > 3.:
# too zoomed-in
break
#
# scan2coord by way of scan2print and print2coord
#
p2c = triangle2triangle(ul_pt, ul_co, ur_pt, ur_co, lr_pt, lr_co)
s2c = s2p.multiply(p2c)
coords += list_tiles_for_bounds_zoom(image, s2c, zoom)
return coords
def list_tiles_for_bounds(image, s2p, paper_width_pt, paper_height_pt, north, west, south, east):
""" Return a list of coordinates and scan-to-coord functions for a full set of zoom levels.
Internal work is done by list_tiles_for_bounds_zoom().
"""
osm = OpenStreetMapProvider()
coords = []
for zoom in range(19):
#
# Coordinates of three print corners
#
ul = osm.locationCoordinate(Location(north, west)).zoomTo(zoom)
ur = osm.locationCoordinate(Location(north, east)).zoomTo(zoom)
lr = osm.locationCoordinate(Location(south, east)).zoomTo(zoom)
#
# Matching points in print and coordinate spaces
#
ul_pt = Point(1 * ptpin - paper_width_pt, 1.5 * ptpin - paper_height_pt)
ul_co = Point(ul.column, ul.row)
ur_pt = Point(0, 1.5 * ptpin - paper_height_pt)
ur_co = Point(ur.column, ur.row)
lr_pt = Point(0, 0)
lr_co = Point(lr.column, lr.row)
scan_dim = hypot(image.size[0], image.size[1])
zoom_dim = hypot((lr_co.x - ul_co.x) * 256, (lr_co.y - ul_co.y) * 256)
if zoom_dim/scan_dim < .05:
# too zoomed-out
continue
if zoom_dim/scan_dim > 3.:
# too zoomed-in
break
#
# scan2coord by way of scan2print and print2coord
#
p2c = triangle2triangle(ul_pt, ul_co, ur_pt, ur_co, lr_pt, lr_co)
s2c = s2p.multiply(p2c)
coords += list_tiles_for_bounds_zoom(image, s2c, zoom)
return coords
def extract_image(scan2print, print_bbox, scan_img, dest_dim, step=50):
""" Extract a portion of a scan image by print coordinates.
scan2print - transformation from scan pixels to original print.
"""
dest_img = Image.new('RGB', dest_dim)
#
# Compute transformation from print image bbox to destination image.
#
print2dest = triangle2triangle(Point(print_bbox[0], print_bbox[1]),
Point(0, 0),
Point(print_bbox[0], print_bbox[3]),
Point(0, dest_dim[1]),
Point(print_bbox[2], print_bbox[1]),
Point(dest_dim[0], 0))
#
# Compute transformation from source image to destination image.
#
scan2dest = scan2print.multiply(print2dest)
dest_w, dest_h = dest_dim
for y in range(0, dest_h, step):
for x in range(0, dest_w, step):
# dimensions of current destination cell
w = min(step, dest_w - x)
h = min(step, dest_h - y)
# transformation from scan pixels to destination cell
m = scan2dest
m = m.multiply(Transform(1, 0, -x, 0, 1, -y))
m = m.inverse()
a = m.affine(0, 0, w, h)
p = scan_img.transform((w, h), AFFINE, a, BICUBIC)
dest_img.paste(p, (x, y))
return dest_img
def extract_image(scan2print, print_bbox, scan_img, dest_dim, step=50):
""" Extract a portion of a scan image by print coordinates.
scan2print - transformation from scan pixels to original print.
"""
dest_img = Image.new('RGB', dest_dim)
#
# Compute transformation from print image bbox to destination image.
#
print2dest = triangle2triangle(Point(print_bbox[0], print_bbox[1]), Point(0, 0),
Point(print_bbox[0], print_bbox[3]), Point(0, dest_dim[1]),
Point(print_bbox[2], print_bbox[1]), Point(dest_dim[0], 0))
#
# Compute transformation from source image to destination image.
#
scan2dest = scan2print.multiply(print2dest)
dest_w, dest_h = dest_dim
for y in range(0, dest_h, step):
for x in range(0, dest_w, step):
# dimensions of current destination cell
w = min(step, dest_w - x)
h = min(step, dest_h - y)
# transformation from scan pixels to destination cell
m = scan2dest
m = m.multiply(Transform(1, 0, -x, 0, 1, -y))
m = m.inverse()
a = m.affine(0, 0, w, h)
p = scan_img.transform((w, h), AFFINE, a, BICUBIC)
dest_img.paste(p, (x, y))
return dest_img
