Add image conversion backends

camelot/backends/__init__.py

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+# -*- coding: utf-8 -*-
+
+from .image_conversion import ImageConversionBackend

camelot/backends/ghostscript_backend.py

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+# -*- coding: utf-8 -*-
+
+import ghostscript
+
+
+class GhostscriptBackend(object):
+    def convert(self, pdf_path, png_path, resolution=300):
+        gs_args = [
+            "gs",
+            "-q",
+            "-sDEVICE=png16m",
+            "-o",
+            png_path,
+            f"-r{resolution}",
+            pdf_path,
+        ]
+        ghostscript.Ghostscript(*gs_args)

camelot/backends/image_conversion.py

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+# -*- coding: utf-8 -*-
+
+from .poppler_backend import PopplerBackend
+from .ghostscript_backend import GhostscriptBackend
+
+backends = {"poppler": PopplerBackend, "ghostscript": GhostscriptBackend}
+
+
+class ImageConversionBackend(object):
+    def __init__(self, backend="poppler"):
+        self.backend = backend
+
+    def convert(self, pdf_path, png_path):
+        converter = backends[self.backend]()
+        converter.convert(pdf_path, png_path)

camelot/backends/poppler_backend.py

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+# -*- coding: utf-8 -*-
+
+from pdftopng import pdftopng
+
+
+class PopplerBackend(object):
+    def convert(self, pdf_path, png_path):
+        pdftopng.convert(pdf_path, png_path)