fix: use inference config (#456)

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> Aligns PDF rendering DPI with centralized config and bumps version.
> 
> - Add `PDF_RENDER_DPI` to `InferenceConfig` (default `350`)
> - `convert_pdf_to_image` now uses `inference_config.PDF_RENDER_DPI`
when `dpi` is unset (replacing env var lookup)
> - Bump version to `1.1.6` and update `CHANGELOG.md`
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
8bf6d27. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: qued

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.1.6
+
+- Use inference_config to set default rendering DPI
+
 ## 1.1.5
 
 - Render PDF to image using PyPDFium instead of pdf2image, due to much improved performance for certain docs

unstructured_inference/__version__.py

@@ -1 +1 @@
-__version__ = "1.1.5"  # pragma: no cover
+__version__ = "1.1.6"  # pragma: no cover

unstructured_inference/config.py

@@ -116,5 +116,10 @@ def IMG_PROCESSOR_SHORTEST_EDGE(self) -> int:
         """configuration for DetrImageProcessor to scale images"""
         return self._get_int("IMG_PROCESSOR_SHORTEST_EDGE", 800)
 
+    @property
+    def PDF_RENDER_DPI(self) -> int:
+        """DPI to render PDF pages to images"""
+        return self._get_int("PDF_RENDER_DPI", 350)
+
 
 inference_config = InferenceConfig()

unstructured_inference/inference/layout.py

@@ -10,6 +10,7 @@
 import pypdfium2 as pdfium
 from PIL import Image, ImageSequence
 
+from unstructured_inference.config import inference_config
 from unstructured_inference.inference.elements import (
     TextRegion,
 )
@@ -422,7 +423,7 @@ def convert_pdf_to_image(
     try:
         images: dict[int, Image.Image] = {}
         if dpi is None:
-            dpi = int(os.environ.get("PDF_RENDER_DPI", 400))
+            dpi = inference_config.PDF_RENDER_DPI
         scale = dpi / 72.0
         for i, page in enumerate(pdf, start=1):
             try: