Merge pull request #5620 from radarhere/eps

Added "transparency" argument to EpsImagePlugin load()

Tests/test_file_eps.py

@@ -96,6 +96,17 @@ def test_showpage():
             assert_image_similar(plot_image, target, 6)
 
 
+@pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
+def test_transparency():
+    with Image.open("Tests/images/reqd_showpage.eps") as plot_image:
+        plot_image.load(transparency=True)
+        assert plot_image.mode == "RGBA"
+
+        with Image.open("Tests/images/reqd_showpage_transparency.png") as target:
+            #  fonts could be slightly different
+            assert_image_similar(plot_image, target, 6)
+
+
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
 def test_file_object(tmp_path):
     # issue 479

docs/handbook/image-file-formats.rst

@@ -66,7 +66,7 @@ than leaving them in the original color space. The EPS driver can write images
 in ``L``, ``RGB`` and ``CMYK`` modes.
 
 If Ghostscript is available, you can call the :py:meth:`~PIL.Image.Image.load`
-method with the following parameter to affect how Ghostscript renders the EPS
+method with the following parameters to affect how Ghostscript renders the EPS
 
 **scale**
     Affects the scale of the resultant rasterized image. If the EPS suggests
@@ -79,6 +79,11 @@ method with the following parameter to affect how Ghostscript renders the EPS
         im.load(scale=2)
         im.size #(200,200)
 
+**transparency**
+    If true, generates an RGBA image with a transparent background, instead of
+    the default behaviour of an RGB image with a white background.
+
+
 GIF
 ^^^
 

docs/releasenotes/8.4.0.rst

@@ -19,6 +19,18 @@ the default required length, also removing the need for the size parameter.
 API Additions
 =============
 
+Added "transparency" argument for loading EPS images
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This new argument switches the Ghostscript device from "ppmraw" to "pngalpha",
+generating an RGBA image with a transparent background instead of an RGB image with a
+white background.
+
+.. code-block:: python
+
+    with Image.open("sample.eps") as im:
+        im.load(transparency=True)
+
 Added WalImageFile class
 ^^^^^^^^^^^^^^^^^^^^^^^^
 

src/PIL/EpsImagePlugin.py

@@ -61,7 +61,7 @@ def has_ghostscript():
     return False
 
 
-def Ghostscript(tile, size, fp, scale=1):
+def Ghostscript(tile, size, fp, scale=1, transparency=False):
     """Render an image using Ghostscript"""
 
     # Unpack decoder tile
@@ -108,6 +108,8 @@ def Ghostscript(tile, size, fp, scale=1):
                 lengthfile -= len(s)
                 f.write(s)
 
+    device = "pngalpha" if transparency else "ppmraw"
+
     # Build Ghostscript command
     command = [
         "gs",
@@ -117,7 +119,7 @@ def Ghostscript(tile, size, fp, scale=1):
         "-dBATCH",  # exit after processing
         "-dNOPAUSE",  # don't pause between pages
         "-dSAFER",  # safe mode
-        "-sDEVICE=ppmraw",  # ppm driver
+        f"-sDEVICE={device}",
         f"-sOutputFile={outfile}",  # output file
         # adjust for image origin
         "-c",
@@ -325,11 +327,11 @@ def _find_offset(self, fp):
 
         return (length, offset)
 
-    def load(self, scale=1):
+    def load(self, scale=1, transparency=False):
         # Load EPS via Ghostscript
         if not self.tile:
             return
-        self.im = Ghostscript(self.tile, self.size, self.fp, scale)
+        self.im = Ghostscript(self.tile, self.size, self.fp, scale, transparency)
         self.mode = self.im.mode
         self._size = self.im.size
         self.tile = []