Merge pull request #412 from MentalPower/master

Added a way to specify the render size for EPS files.

.travis.yml

@@ -6,7 +6,7 @@ python:
   - 3.2
   - 3.3
 
-install: "sudo apt-get -qq install libfreetype6-dev liblcms2-dev libwebp-dev"
+install: "sudo apt-get -qq install libfreetype6-dev liblcms2-dev libwebp-dev ghostscript"
 
 script:
   - python setup.py clean

PIL/EpsImagePlugin.py

@@ -50,14 +50,22 @@ if sys.platform.startswith('win'):
     else:
         gs_windows_binary = False
 
-def Ghostscript(tile, size, fp):
+def Ghostscript(tile, size, fp, scale=1):
     """Render an image using Ghostscript"""
 
     # Unpack decoder tile
     decoder, tile, offset, data = tile[0]
     length, bbox = data
 
-    import tempfile, os
+    #Hack to support hi-res rendering
+    scale = int(scale) or 1
+    orig_size = size
+    orig_bbox = bbox
+    size = (size[0] * scale, size[1] * scale)
+    bbox = [bbox[0], bbox[1], bbox[2] * scale, bbox[3] * scale]
+    #print("Ghostscript", scale, size, orig_size, bbox, orig_bbox)
+
+    import tempfile, os, subprocess
 
     file = tempfile.mktemp()
 
@@ -65,33 +73,32 @@ def Ghostscript(tile, size, fp):
     command = ["gs",
                "-q",                    # quite mode
                "-g%dx%d" % size,        # set output geometry (pixels)
+               "-r%d" % (72*scale),     # set input DPI (dots per inch)
                "-dNOPAUSE -dSAFER",     # don't pause between pages, safe mode
                "-sDEVICE=ppmraw",       # ppm driver
                "-sOutputFile=%s" % file,# output file
-               "- >/dev/null 2>/dev/null"]
+            ]
 
     if gs_windows_binary is not None:
         if gs_windows_binary is False:
             raise WindowsError('Unable to locate Ghostscript on paths')
         command[0] = gs_windows_binary
-        command[-1] = '- >nul 2>nul'
-
-    command = " ".join(command)
 
     # push data through ghostscript
     try:
-        gs = os.popen(command, "w")
+        gs = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
         # adjust for image origin
         if bbox[0] != 0 or bbox[1] != 0:
-            gs.write("%d %d translate\n" % (-bbox[0], -bbox[1]))
+            gs.stdin.write(("%d %d translate\n" % (-bbox[0], -bbox[1])).encode('ascii'))
         fp.seek(offset)
         while length > 0:
             s = fp.read(8192)
             if not s:
                 break
             length = length - len(s)
-            gs.write(s)
+            gs.stdin.write(s)
-        status = gs.close()
+        gs.stdin.close()
+        status = gs.wait()
         if status:
             raise IOError("gs failed (status %d)" % status)
         im = Image.core.open_ppm(file)
@@ -304,11 +311,11 @@ class EpsImageFile(ImageFile.ImageFile):
         if not box:
             raise IOError("cannot determine EPS bounding box")
 
-    def load(self):
+    def load(self, scale=1):
         # Load EPS via Ghostscript
         if not self.tile:
             return
-        self.im = Ghostscript(self.tile, self.size, self.fp)
+        self.im = Ghostscript(self.tile, self.size, self.fp, scale)
         self.mode = self.im.mode
         self.size = self.im.size
         self.tile = []

Tests/images/create_eps.gnuplot

@@ -0,0 +1,30 @@
+#!/usr/bin/gnuplot
+
+#This is the script that was used to create our sample EPS files
+#We used the following version of the gnuplot program
+#G N U P L O T
+#Version 4.6 patchlevel 3    last modified 2013-04-12
+#Build System: Darwin x86_64
+
+#This file will generate the non_zero_bb.eps variant, in order to get the
+#zero_bb.eps variant you will need to edit line6 in the result file to
+#be "%%BoundingBox: 0 0 460 352" instead of "%%BoundingBox: 50 50 410 302"
+
+set t postscript eps color
+set o "sample.eps"
+set dummy u,v
+set key bmargin center horizontal Right noreverse enhanced autotitles nobox
+set parametric
+set view 50, 30, 1, 1
+set isosamples 10, 10
+set hidden3d back offset 1 trianglepattern 3 undefined 1 altdiagonal bentover
+set ticslevel 0
+set title "Interlocking Tori"
+
+set style line 1 lt 1 lw 1 pt 3 lc rgb "red"
+set style line 2 lt 1 lw 1 pt 3 lc rgb "blue"
+
+set urange [ -3.14159 : 3.14159 ] noreverse nowriteback
+set vrange [ -3.14159 : 3.14159 ] noreverse nowriteback
+splot cos(u)+.5*cos(u)*cos(v),sin(u)+.5*sin(u)*cos(v),.5*sin(v) ls 1,\
+      1+cos(u)+.5*cos(u)*cos(v),.5*sin(v),sin(u)+.5*sin(u)*cos(v) ls 2

Tests/test_file_eps.py

@@ -0,0 +1,82 @@
+from tester import *
+
+from PIL import Image
+
+#Our two EPS test files (they are identical except for their bounding boxes)
+file1 = "Tests/images/zero_bb.eps"
+file2 = "Tests/images/non_zero_bb.eps"
+
+#Due to palletization, we'll need to convert these to RGB after load
+file1_compare = "Tests/images/zero_bb.png"
+file1_compare_scale2 = "Tests/images/zero_bb_scale2.png"
+
+file2_compare = "Tests/images/non_zero_bb.png"
+file2_compare_scale2 = "Tests/images/non_zero_bb_scale2.png"
+
+def test_sanity():
+    #Regular scale
+    image1 = Image.open(file1)
+    image1.load()
+    assert_equal(image1.mode, "RGB")
+    assert_equal(image1.size, (460, 352))
+    assert_equal(image1.format, "EPS")
+
+    image2 = Image.open(file2)
+    image2.load()
+    assert_equal(image2.mode, "RGB")
+    assert_equal(image2.size, (360, 252))
+    assert_equal(image2.format, "EPS")
+
+    #Double scale
+    image1_scale2 = Image.open(file1)
+    image1_scale2.load(scale=2)
+    assert_equal(image1_scale2.mode, "RGB")
+    assert_equal(image1_scale2.size, (920, 704))
+    assert_equal(image1_scale2.format, "EPS")
+
+    image2_scale2 = Image.open(file2)
+    image2_scale2.load(scale=2)
+    assert_equal(image2_scale2.mode, "RGB")
+    assert_equal(image2_scale2.size, (720, 504))
+    assert_equal(image2_scale2.format, "EPS")
+
+def test_render_scale1():
+    #We need png support for these render test
+    codecs = dir(Image.core)
+    if "zip_encoder" not in codecs or "zip_decoder" not in codecs:
+        skip("zip/deflate support not available")
+
+    #Zero bounding box
+    image1_scale1 = Image.open(file1)
+    image1_scale1.load()
+    image1_scale1_compare = Image.open(file1_compare).convert("RGB")
+    image1_scale1_compare.load()
+    assert_image_similar(image1_scale1, image1_scale1_compare, 5)
+
+    #Non-Zero bounding box
+    image2_scale1 = Image.open(file2)
+    image2_scale1.load()
+    image2_scale1_compare = Image.open(file2_compare).convert("RGB")
+    image2_scale1_compare.load()
+    assert_image_similar(image2_scale1, image2_scale1_compare, 10)
+
+def test_render_scale2():
+    #We need png support for these render test
+    codecs = dir(Image.core)
+    if "zip_encoder" not in codecs or "zip_decoder" not in codecs:
+        skip("zip/deflate support not available")
+
+    #Zero bounding box
+    image1_scale2 = Image.open(file1)
+    image1_scale2.load(scale=2)
+    image1_scale2_compare = Image.open(file1_compare_scale2).convert("RGB")
+    image1_scale2_compare.load()
+    assert_image_similar(image1_scale2, image1_scale2_compare, 5)
+
+    #Non-Zero bounding box
+    image2_scale2 = Image.open(file2)
+    image2_scale2.load(scale=2)
+    image2_scale2_compare = Image.open(file2_compare_scale2).convert("RGB")
+    image2_scale2_compare.load()
+    assert_image_similar(image2_scale2, image2_scale2_compare, 10)
+

docs/handbook/image-file-formats.rst

@@ -36,6 +36,20 @@ PIL identifies EPS files containing image data, and can read files that contain
 embedded raster images (ImageData descriptors). If Ghostscript is available,
 other EPS files can be read as well. The EPS driver can also write EPS images.
 
+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
+
+**scale**
+    Affects the scale of the resultant rasterized image. If the EPS suggests
+    that the image be rendered at 100px x 100px, setting this parameter to
+    2 will make the Ghostscript render a 200px x 200px image instead. The
+    relative position of the bounding box is maintained::
+
+        im = Image.open(...)
+        im.size #(100,100)
+        im.load(scale=2)
+        im.size #(200,200)
+
 GIF
 ^^^