From fa8edce417aa3922f10900b52d5e2120a0251cd3 Mon Sep 17 00:00:00 2001
From: Jonathan Neuhauser <jonathan.neuhauser@outlook.com>
Date: Sun, 13 Mar 2022 08:26:42 +0100
Subject: [PATCH] fix #395

---
 raster_output_png.inx |  2 +-
 raster_output_png.py  | 22 +++++++++++++++++++---
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/raster_output_png.inx b/raster_output_png.inx
index 3cfb234d..26d053ef 100644
--- a/raster_output_png.inx
+++ b/raster_output_png.inx
@@ -7,7 +7,7 @@
     <label>Optimize PNG with 'optipng'</label>
     <param name="tab" type="notebook">
         <page name="lossless" gui-text="Lossless">
-            <param name="interlace" type="bool" gui-text="Interlaced">true</param>
+            <param name="interlace" type="bool" gui-text="Interlaced">false</param>
 
             <param name="level" type="optiongroup" appearance="combo" gui-text="Level:">
                 <option value="0">Minimal Effort</option>
diff --git a/raster_output_png.py b/raster_output_png.py
index b052bd21..b70baa0e 100755
--- a/raster_output_png.py
+++ b/raster_output_png.py
@@ -6,14 +6,14 @@ Optimise PNG file using optipng
 import os
 import inkex
 from inkex.extensions import TempDirMixin
-from inkex.command import call
+from inkex.command import ProgramRunError, call
 
 
 class PngOutput(TempDirMixin, inkex.RasterOutputExtension):
     def add_arguments(self, pars):
         pars.add_argument("--tab")
         # Lossless options
-        pars.add_argument("--interlace", type=inkex.Boolean, default=True)
+        pars.add_argument("--interlace", type=inkex.Boolean, default=False)
         pars.add_argument("--level", type=int, default=0)
         # Lossy options
         pars.add_argument("--bitdepth", type=inkex.Boolean, default=False)
@@ -35,7 +35,23 @@ class PngOutput(TempDirMixin, inkex.RasterOutputExtension):
             "nc": not self.options.color,
             "np": not self.options.palette,
         }
-        call("optipng", self.png_file, oldie=True, clobber=True, **options)
+        try:
+            call("optipng", self.png_file, oldie=True, clobber=True, **options)
+        except ProgramRunError as err:
+            if "IDAT recoding is necessary" in err.stderr.decode("utf-8"):
+                raise inkex.AbortExtension(
+                    _(
+                        "The optipng command failed, possibly due to a mismatch of the"
+                        "interlacing and compression level options. Please try to disable "
+                        '"Interlaced" or set "Level" to 1 or higher.'
+                    )
+                )
+            else:
+                raise inkex.AbortExtension(
+                    _("The optipng command failed with the following message:")
+                    + "\n"
+                    + err.stderr.decode("utf-8")
+                )
 
         if os.path.isfile(self.png_file):
             with open(self.png_file, "rb") as fhl:
-- 
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