PDF layout: Allow to show photos from questions (#1919)

src/pretix/helpers/reportlab.py

@@ -0,0 +1,22 @@
+from PIL.Image import BICUBIC
+from reportlab.lib.utils import ImageReader
+
+
+class ThumbnailingImageReader(ImageReader):
+    def resize(self, width, height, dpi):
+        if width is None:
+            width = height * self._image.size[0] / self._image.size[1]
+        if height is None:
+            height = width * self._image.size[1] / self._image.size[0]
+        self._image.thumbnail(
+            size=(int(width * dpi / 72), int(height * dpi / 72)),
+            resample=BICUBIC
+        )
+        self._data = None
+        return width, height
+
+    def _jpeg_fh(self):
+        # Bypass a reportlab-internal optimization that falls back to the original
+        # file handle if the file is a JPEG, and therefore does not respect the
+        # (smaller) size of the modified image.
+        return None