From 84cf7c8d86b11ca0faf566a067c25723a96abd20 Mon Sep 17 00:00:00 2001
From: David Manthey <david.manthey@kitware.com>
Date: Thu, 5 Dec 2024 12:33:57 -0500
Subject: [PATCH] Adjusting the expected full alpha value on some float tiles

This adjust how compositing is done on styled images.

Also, improve documentation of multi-source schema
---
 CHANGELOG.md                                       | 6 ++++++
 large_image/tilesource/utilities.py                | 6 ++++++
 sources/multi/large_image_source_multi/__init__.py | 8 +++++---
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 792abbdca..6ec3cc4d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Change Log
 
+## 1.30.5
+
+### Changes
+
+- Adjust how compositing is done on styled images by adjusting the expected full alpha value ([#1735](../../pull/1735))
+
 ## 1.30.4
 
 ### Bug Fixes
diff --git a/large_image/tilesource/utilities.py b/large_image/tilesource/utilities.py
index 5f31ba738..eceb55a2a 100644
--- a/large_image/tilesource/utilities.py
+++ b/large_image/tilesource/utilities.py
@@ -758,6 +758,12 @@ def fullAlphaValue(arr: Union[np.ndarray, npt.DTypeLike]) -> int:
         dtype = np.dtype(dtype)
     if cast(np.dtype, dtype).kind == 'u':
         return np.iinfo(dtype).max
+    if isinstance(arr, np.ndarray) and cast(np.dtype, dtype).kind == 'f':
+        amax = np.amax(arr)
+        if amax > 1 and amax < 256:
+            return 255
+        if amax > 1 and amax < 65536:
+            return 65535
     return 1
 
 
diff --git a/sources/multi/large_image_source_multi/__init__.py b/sources/multi/large_image_source_multi/__init__.py
index 6ca7ac781..458a2b8ae 100644
--- a/sources/multi/large_image_source_multi/__init__.py
+++ b/sources/multi/large_image_source_multi/__init__.py
@@ -300,10 +300,12 @@ def _lazyImport():
                 'sampleScale is applied',
             'type': 'number',
         },
-        'style': {'type': 'object'},
+        'style': {
+            'description': 'A style specification to pass to the base tile source',
+            'type': 'object',
+        },
         'params': {
-            'description':
-                'Additional parameters to pass to the base tile source',
+            'description': 'Additional parameters to pass to the base tile source',
             'type': 'object',
         },
     },