Consistent DPI rounding

python-pillow · Mar 11, 2019 · 5f8ff40 · 5f8ff40
1 parent 578dec9
commit 5f8ff40
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Showing 4 changed files with 8 additions and 10 deletions.
diff --git a/src/PIL/BmpImagePlugin.py b/src/PIL/BmpImagePlugin.py
@@ -27,7 +27,6 @@
 from . import Image, ImageFile, ImagePalette
 from ._binary import i8, i16le as i16, i32le as i32, \
                      o8, o16le as o16, o32le as o32
-import math
 
 # __version__ is deprecated and will be removed in a future version. Use
 # PIL.__version__ instead.
@@ -122,8 +121,7 @@ def _bitmap(self, header=0, offset=0):
                 file_info['colors'] = i32(header_data[28:32])
                 file_info['palette_padding'] = 4
                 self.info["dpi"] = tuple(
-                    map(lambda x: int(math.ceil(x / 39.3701)),
-                        file_info['pixels_per_meter']))
+                    int(x / 39.3701 + 0.5) for x in file_info['pixels_per_meter'])
                 if file_info['compression'] == self.BITFIELDS:
                     if len(header_data) >= 52:
                         for idx, mask in enumerate(['r_mask',
@@ -310,7 +308,7 @@ def _save(im, fp, filename, bitmap_header=True):
     dpi = info.get("dpi", (96, 96))
 
     # 1 meter == 39.3701 inches
-    ppm = tuple(map(lambda x: int(x * 39.3701), dpi))
+    ppm = tuple(map(lambda x: int(x * 39.3701 + 0.5), dpi))
 
     stride = ((im.size[0]*bits+7)//8+3) & (~3)
     header = 40  # or 64 for OS/2 version 2

diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
@@ -133,7 +133,7 @@ def APP(self, marker):
             if resolution_unit == 3:  # cm
                 # 1 dpcm = 2.54 dpi
                 dpi *= 2.54
-            self.info["dpi"] = dpi, dpi
+            self.info["dpi"] = int(dpi + 0.5), int(dpi + 0.5)
         except (KeyError, SyntaxError, ZeroDivisionError):
             # SyntaxError for invalid/unreadable exif
             # KeyError for dpi not included

diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
@@ -1259,7 +1259,7 @@ def _setup(self):
             if resunit == 2:  # dots per inch
                 self.info["dpi"] = xres, yres
             elif resunit == 3:  # dots per centimeter. convert to dpi
-                self.info["dpi"] = xres * 2.54, yres * 2.54
+                self.info["dpi"] = int(xres * 2.54 + 0.5), int(yres * 2.54 + 0.5)
             elif resunit is None:  # used to default to 1, but now 2)
                 self.info["dpi"] = xres, yres
                 # For backward compatibility,
@@ -1472,8 +1472,8 @@ def _save(im, fp, filename):
     dpi = im.encoderinfo.get("dpi")
     if dpi:
         ifd[RESOLUTION_UNIT] = 2
-        ifd[X_RESOLUTION] = dpi[0]
-        ifd[Y_RESOLUTION] = dpi[1]
+        ifd[X_RESOLUTION] = int(dpi[0] + 0.5)
+        ifd[Y_RESOLUTION] = int(dpi[1] + 0.5)
 
     if bits != (1,):
         ifd[BITSPERSAMPLE] = bits

diff --git a/src/PIL/WmfImagePlugin.py b/src/PIL/WmfImagePlugin.py
@@ -131,8 +131,8 @@ def _open(self):
             size = x1 - x0, y1 - y0
 
             # calculate dots per inch from bbox and frame
-            xdpi = 2540 * (x1 - y0) // (frame[2] - frame[0])
-            ydpi = 2540 * (y1 - y0) // (frame[3] - frame[1])
+            xdpi = int(2540 * (x1 - y0) / (frame[2] - frame[0]) + 0.5)
+            ydpi = int(2540 * (y1 - y0) / (frame[3] - frame[1]) + 0.5)
 
             self.info["wmf_bbox"] = x0, y0, x1, y1