Make backup file logic smarter

Automatically re-use an existing target layer backup file in subsequent
runs instead of using a previous run's output. I.e., if the target
extension is set to ".GTO" and both "foo.GTO" and "foo.GTO.bak" exist,
automatically use "foo.GTO.bak" and write to "foo.GTO". This behavior
can be overridden by stating an explicit filename.

1 files changed, 12 insertions, 6 deletions

diff --git a/gerbimg.py b/gerbimg.py
index 4bfdac4..d3ed7f9 100755
--- a/gerbimg.py
+++ b/gerbimg.py
@@ -58,7 +58,7 @@ def paste_image(
         status_print('  * target layer')
         ctx.render_layer(target, settings=fg, bgsettings=bg)
         for fn, sub in subtract_gerber:
-            status_print('  * extra layer', fn)
+            status_print('  * extra layer', os.path.basename(fn))
             layer = gerber.loads(sub)
             ctx.render_layer(layer, settings=fg, bgsettings=bg)
         status_print('Rendering keepout composite')
@@ -210,14 +210,20 @@ def replace_file_in_zip(zip_path, filename, contents):
 def paste_image_file(zip_or_dir, target, outline, source_img, subtract=[], status_print=lambda *args:None, debugdir=None):
     if path.isdir(zip_or_dir):
         tname, target = find_gerber_in_dir(zip_or_dir, target)
-        _fn, outline  = find_gerber_in_dir(zip_or_dir, outline)
+        status_print('Target layer file {}'.format(os.path.basename(tname)))
+        oname, outline  = find_gerber_in_dir(zip_or_dir, outline)
+        status_print('Outline layer file {}'.format(os.path.basename(oname)))
         subtract = [ (fn, layer) for fn, layer in (find_gerber_in_dir(zip_or_dir, elem) for elem in subtract) ]
         
         out = paste_image(target, outline, source_img, subtract, debugdir=debugdir, status_print=status_print)
 
-        shutil.copy(tname, tname+'.bak')
-        with open(tname, 'w') as f:
-            f.write(out)
+        if not tname.endswith('.bak'):
+            shutil.copy(tname, tname+'.bak')
+            with open(tname, 'w') as f:
+                f.write(out)
+        else:
+            with open(tname[:-4], 'w') as f:
+                f.write(out)
     elif zipfile.is_zipfile(zip_or_dir):
         _fn, outline  = find_gerber_in_zip(zip_or_dir, outline)
         subtract = [ (fn, layer) for fn, layer in (find_gerber_in_zip(zip_or_dir, elem) for elem in subtract) ]
@@ -243,7 +249,7 @@ if __name__ == '__main__':
     args = parser.parse_args()
 
     if not args.target:
-        args.target   = '.GBO' if args.bottom else '.GTO'
+        args.target   = '.GBO.bak,.GBO' if args.bottom else '.GTO.bak,.GTO'
     if not args.subtract:
         args.subtract = ['.GBS', '.TXT'] if args.bottom else ['.GTS', '.TXT']