Add Python script to slice into numbered variants (I-am-Erk#1618)

* add a script to slice into numbered variants, minor fixes

* add slice_variants.py to the docs

doc/how-to/autotiles.md

@@ -184,3 +184,17 @@ when you want to adjust all sprites as one image:
 cd mud_tiles
 $ tools/unslice_multitile.py mud
 ```
+
+### Slicing variants
+
+Randomly selected sprite variants can be used based on weights.
+For easier creation of these variants, multitile-like images can be sliced into numbered variant sprites using `slice_variants.py`.
+
+Usage is the same as with `slice_multitile.py`. E.g.:
+
+```sh
+$ tools/slice_variants.py t_floor_multitile.png 32 32
+```
+
+The script can handle any multitile size, not only 4x4.
+For iso multitiles, use switch `--iso`.

tools/slice_multitile.py

@@ -190,12 +190,12 @@ def main(args):
     if rearrange is not None:
         template_size = 5 if len(slices) == 25 else 4
         order = OUTPUT_ORDER[template_size]
-        
+
         img_out = pyvips.Image.new_from_array(
             np.full(shape=(rearrange * template_size, args.width * template_size, 4),
                     fill_value=1, dtype=np.uint8),
             interpretation="rgb")
-        
+
         for col in range(template_size):
             for row in range(template_size):
                 sprite = slices[slicing_map[order[col + template_size * row]]]
@@ -211,7 +211,7 @@ def main(args):
 
         if args.no_json:
             return
-        
+
         if len(slices) != 25:
             json_content = {  # double quotes here to make copying easier
                 "id": args.tile,
@@ -326,6 +326,14 @@ def iso_mask(width, height):
 
 
 def extract_slices(img, width, height, iso):
+    try:
+        if not img.hasalpha():
+            img = img.addalpha()
+        if img.get_typeof('icc-profile-data') != 0:
+            img = img.icc_transform('srgb')
+    except Vips.Error as vips_error:
+        raise Exception(vips_error)
+
     slices = []
 
     if iso:
@@ -335,7 +343,7 @@ def extract_slices(img, width, height, iso):
         if width != 2 * height:
             raise Exception(
                 'Only tiles with a width:height ration 2:1 are supported in ISO mode.')
-        
+
         template_size = 0
         if img.width == 4 * width and img.height == 4 * height:
             template_size = 4
@@ -359,7 +367,7 @@ def extract_slices(img, width, height, iso):
             for col in range(per_row):
                 s = img.crop(x_offset + col * width, y_offset, width, height)
                 masked = s.numpy() * mask
-                slices.append(pyvips.Image.new_from_array(masked, interpretation="rgb"))
+                slices.append(pyvips.Image.new_from_array(masked, interpretation="srgb"))
 
     else:
         for y in range(0, img.height, height):

tools/slice_variants.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+'''
+Slice multitiles of arbitrary size into numbered variants.
+'''
+
+import argparse
+import os
+import pathlib
+
+from slice_multitile import iso_mask
+
+try:
+    vips_path = os.getenv("LIBVIPS_PATH")
+    if vips_path is not None and vips_path != "":
+        os.environ["PATH"] += ";"+os.path.join(vips_path, "bin")
+    import pyvips
+    Vips = pyvips
+except ImportError:
+    import gi
+    gi.require_version('Vips', '8.0')  # NoQA
+    from gi.repository import Vips
+
+
+def main(args):
+    args.height = args.height or args.width
+
+    if args.tile is None:
+        args.tile = pathlib.Path(args.image).stem \
+            .replace('autotile_', '').replace('multitile_', '') \
+            .replace('_autotile', '').replace('_multitile', '')  # TODO: regex
+
+    output_dir = args.out or os.path.join(
+        os.path.dirname(args.image), args.tile)
+
+    img = pyvips.Image.new_from_file(args.image)
+
+    slices = extract_slices(img, args.width, args.height, args.iso)
+
+    pathlib.Path(output_dir).mkdir(parents=True, exist_ok=True)
+
+    for i, sl in enumerate(slices):
+        out_idx = i
+        while args.append and os.path.isfile(os.path.join(output_dir, f'{args.tile}_{out_idx:02d}.png')):
+            out_idx += 1
+        sl.pngsave(
+            os.path.join(output_dir, f'{args.tile}_{out_idx:02d}.png'))
+
+
+def extract_slices(img, width, height, iso):
+    try:
+        if not img.hasalpha():
+            img = img.addalpha()
+        if img.get_typeof('icc-profile-data') != 0:
+            img = img.icc_transform('srgb')
+    except Vips.Error as vips_error:
+        raise Exception('%s', vips_error)
+
+    slices = []
+
+    template_size_x = img.width // width
+    template_size_y = img.height // height
+    if img.width != template_size_x * width or img.height != template_size_y * height:
+        raise Exception(
+            f"Unexpected image size. Expecting integer multiple of tile size."
+        )
+
+    if iso:
+        if width % 2 != 0 or height % 2 != 0:
+            raise Exception(
+                'Only even width and height values are supported in ISO mode.')
+        if width != 2 * height:
+            raise Exception(
+                'Only tiles with a width:height ration 2:1 are supported in ISO mode.')
+
+        mask = iso_mask(width, height)
+
+        dx = width / 2
+        dy = height / 2
+        double_size = 2 * template_size_x
+        for row in range(double_size - 1):
+            per_row = min(row, double_size - 2 - row) + 1
+            half_offsets = (double_size - 2 * per_row) / 2
+            x_offset = half_offsets * dx
+            y_offset = row * dy
+            for col in range(per_row):
+                s = img.crop(x_offset + col * width, y_offset, width, height)
+                masked = s.numpy() * mask
+                slices.append(pyvips.Image.new_from_array(masked, interpretation="srgb"))
+
+    else:
+        for y in range(0, img.height, height):
+            for x in range(0, img.width, width):
+                slices.append(img.crop(x, y, width, height))
+
+    return slices
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description="Slice a multitile image")
+    parser.add_argument(
+        "image",
+        help="path to the multitile image that will be sliced")
+    parser.add_argument(
+        "width", type=int,
+        help="tile width in pixels")
+    parser.add_argument(
+        "height", type=int,
+        nargs='?',
+        help="tile height in pixels, defaults to tile width")
+    parser.add_argument(
+        "--tile", dest="tile",
+        help="base name of the tile, defaults to the image name"
+             " without .png, autotile_ and/or multitile_ parts")
+    parser.add_argument(
+        "--out", dest="out",
+        help="output directory path, "
+             "defaults to the tile name in the directory of the image")
+    parser.add_argument(
+        "--iso", action='store_true',
+        help="slice iso multitile")
+    parser.add_argument(
+        "--append", action='store_true',
+        help="do not overwrite numbered sprites, write with increased IDs")
+
+    main(parser.parse_args())

tools/unslice_multitile.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 '''
-Combine a set of multitile sprites into 4x4 grid
+Combine a set of multitile sprites into 4x4 or 5x5 grid grid
 '''
 
 import argparse
@@ -29,7 +29,7 @@ def main(args):
     height = None
     num_sprites = 25 if os.path.isfile(os.path.join(args.path, f'{args.tile}_unconnected_faceN.png')) else 16
     template_size = math.isqrt(num_sprites)
-    
+
     id_map = MAPS_ISO[num_sprites] if args.iso else MAPS[num_sprites]
     for suffix, position in id_map.items():
         sprite = pyvips.Image.new_from_file(os.path.join(args.path, f'{args.tile}_{suffix}.png'))