refactor: simplify image format dtype validation (#1046)

* refactor: simplify image format dtype validation

* DOC: changes.md

---------

Co-authored-by: vincentsarago <[email protected]>

Author: pratapvardhan

CHANGES.md

@@ -4,14 +4,15 @@
 
 ### titiler.core
 
-* Add layer control to map viewer template (author @hrodmn, https://github.com/developmentseed/titiler/pull/1051)
+* add layer control to map viewer template (author @hrodmn, https://github.com/developmentseed/titiler/pull/1051)
 * improve query string handling in LowerCaseQueryStringMiddleware using urlencode (author @pratapvardhan, https://github.com/developmentseed/titiler/pull/1050)
+* add `titiler.core.utils.bounds_to_geometry` and reduce code duplication in factories (author @PratapVardhan, https://github.com/developmentseed/titiler/pull/1047)
+* simplify image format dtype validation in `render_image` (author @PratapVardhan, https://github.com/developmentseed/titiler/pull/1046)
 
 ### titiler.application
 
 * update `/healthz` endpoint to return dependencies versions (titiler, rasterio, gdal, ...) (author @scottyhq, https://github.com/developmentseed/titiler/pull/1056)
 * migrate `templates/index.html` to bootstrap5, remove unused css, reuse bs classes (author @PratapVardhan, https://github.com/developmentseed/titiler/pull/1048)
-* add `titiler.core.utils.bounds_to_geometry` and reduce code duplication in factories (author @PratapVardhan, https://github.com/developmentseed/titiler/pull/1047)
 
 ## 0.19.2 (2024-11-28)
 

src/titiler/core/titiler/core/utils.py

@@ -69,33 +69,20 @@ def render_image(
     if not output_format:
         output_format = ImageType.jpeg if mask.all() else ImageType.png
 
-    if output_format == ImageType.png and data.dtype not in ["uint8", "uint16"]:
+    # format-specific valid dtypes
+    format_dtypes = {
+        ImageType.png: ["uint8", "uint16"],
+        ImageType.jpeg: ["uint8"],
+        ImageType.jpg: ["uint8"],
+        ImageType.webp: ["uint8"],
+        ImageType.jp2: ["uint8", "int16", "uint16"],
+    }
+
+    valid_dtypes = format_dtypes.get(output_format, [])
+    if valid_dtypes and data.dtype not in valid_dtypes:
         warnings.warn(
-            f"Invalid type: `{data.dtype}` for the `{output_format}` driver. Data will be rescaled using min/max type bounds or dataset_statistics.",
-            InvalidDatatypeWarning,
-            stacklevel=1,
-        )
-        data = rescale_array(data, mask, in_range=datatype_range)
-
-    elif output_format in [
-        ImageType.jpeg,
-        ImageType.jpg,
-        ImageType.webp,
-    ] and data.dtype not in ["uint8"]:
-        warnings.warn(
-            f"Invalid type: `{data.dtype}` for the `{output_format}` driver. Data will be rescaled using min/max type bounds or dataset_statistics.",
-            InvalidDatatypeWarning,
-            stacklevel=1,
-        )
-        data = rescale_array(data, mask, in_range=datatype_range)
-
-    elif output_format == ImageType.jp2 and data.dtype not in [
-        "uint8",
-        "int16",
-        "uint16",
-    ]:
-        warnings.warn(
-            f"Invalid type: `{data.dtype}` for the `{output_format}` driver. Data will be rescaled using min/max type bounds or dataset_statistics.",
+            f"Invalid type: `{data.dtype}` for the `{output_format}` driver. "
+            "Data will be rescaled using min/max type bounds or dataset_statistics.",
             InvalidDatatypeWarning,
             stacklevel=1,
         )