Implement scaling manipulation support

kodak/manipulations.py

@@ -7,7 +7,36 @@ from kodak import constants
 
 
 def scale(image: Image.Image, config: configuration.ManipConfig) -> Image.Image:
-    pass
+    """Scale an image to new dimensions"""
+
+    if config.scale.strategy == constants.ScaleStrategy.ABSOLUTE:
+        width = config.scale.horizontal or image.width
+        height = config.scale.vertical or image.height
+    elif config.scale.strategy == constants.ScaleStrategy.RELATIVE:
+        width = (
+            (config.scale.horizontal * image.width)
+            if config.scale.vertical
+            else image.width
+        )
+        height = (
+            (config.scale.horizontal * image.height)
+            if config.scale.vertical
+            else image.height
+        )
+    else:
+        raise ValueError("Here there be dragons")
+
+    logging.getLogger(__name__).debug(
+        f"Scaling image: old {image.width}x{image.height}; new {width}x{height})"
+    )
+
+    if config.scale.horizontal is None or config.scale.vertical is None:
+        image = image.copy()
+        image.thumbnail((width, height), Image.ANTIALIAS)
+    else:
+        image.resize((width, height))
+
+    return image
 
 
 def crop(image: Image.Image, config: configuration.ManipConfig) -> Image.Image:
@@ -18,56 +47,51 @@ def crop(image: Image.Image, config: configuration.ManipConfig) -> Image.Image:
     width = config.crop.horizontal or image.width
     height = config.crop.vertical or image.height
 
-    top = 0
-    left = 0
-    bottom = image.height
-    right = image.width
-
     if config.crop.anchor == constants.CropAnchor.TL:
-        x_1 = left
-        y_1 = top
+        x_1 = 0
+        y_1 = 0
         x_2 = width
         y_2 = height
     elif config.crop.anchor == constants.CropAnchor.TC:
-        x_1 = (right / 2) - (width / 2)
-        y_1 = top
-        x_2 = (right / 2) + (width / 2)
+        x_1 = (image.width / 2) - (width / 2)
+        y_1 = 0
+        x_2 = (image.width / 2) + (width / 2)
         y_2 = height
     elif config.crop.anchor == constants.CropAnchor.TR:
-        x_1 = right - width
-        y_1 = top
-        x_2 = right
+        x_1 = image.width - width
+        y_1 = 0
+        x_2 = image.width
         y_2 = height
     elif config.crop.anchor == constants.CropAnchor.CL:
-        x_1 = left
-        y_1 = (bottom / 2) - (height / 2)
+        x_1 = 0
+        y_1 = (image.height / 2) - (height / 2)
         x_2 = width
-        y_2 = (bottom / 2) + (height / 2)
+        y_2 = (image.height / 2) + (height / 2)
     elif config.crop.anchor == constants.CropAnchor.C:
-        x_1 = (right / 2) - (width / 2)
-        y_1 = (bottom / 2) - (height / 2)
-        x_2 = (right / 2) + (width / 2)
-        y_2 = (bottom / 2) + (height / 2)
+        x_1 = (image.width / 2) - (width / 2)
+        y_1 = (image.height / 2) - (height / 2)
+        x_2 = (image.width / 2) + (width / 2)
+        y_2 = (image.height / 2) + (height / 2)
     elif config.crop.anchor == constants.CropAnchor.BL:
-        x_1 = left
-        y_1 = bottom - height
+        x_1 = 0
+        y_1 = image.height - height
         x_2 = width
-        y_2 = bottom
+        y_2 = image.height
     elif config.crop.anchor == constants.CropAnchor.BC:
-        x_1 = (right / 2) - (width / 2)
-        y_1 = bottom - height
-        x_2 = (right / 2) + (width / 2)
-        y_2 = bottom
+        x_1 = (image.width / 2) - (width / 2)
+        y_1 = image.height - height
+        x_2 = (image.width / 2) + (width / 2)
+        y_2 = image.height
     elif config.crop.anchor == constants.CropAnchor.BR:
-        x_1 = right - width
-        y_1 = bottom - height
-        x_2 = right
-        y_2 = bottom
+        x_1 = image.width - width
+        y_1 = image.height - height
+        x_2 = image.width
+        y_2 = image.height
     else:
         raise ValueError("Ye gadds! This codepath is impossible!")
 
     logging.getLogger(__name__).debug(
-        f"Cropping image {image.filename}: old {right}x{bottom}; new {width}x{height}; upper-left anchor ({x_1}, {y_1}); lower-right anchor ({x_2}, {y_2})"
+        f"Cropping image: old {image.width}x{image.height}; new {width}x{height}; upper-0 anchor ({x_1}, {y_1}); lower-image.width anchor ({x_2}, {y_2})"
     )
 
     return image.crop((x_1, y_1, x_2, y_2))
@@ -78,5 +102,5 @@ def black_and_white(
 ) -> Image.Image:
     """Convert an image to full-depth black and white"""
     logger = logging.getLogger(__name__)
-    logger.debug(f"Converting image {image.filename} to black and white")
+    logger.debug("Converting image to black and white")
     return image.convert("L")