Added a regression test and an image mangling python script

- Added docimages_regression_tests.py
-- It's a test for Bug1844, concerning envelope points.
- Added decorate_images.py
-- It's a script to crop and drop shadow.

scripts/piped-work/docimages_regression_tests.py

@@ -0,0 +1,30 @@
+# docimages_regression_tests.py
+# Sends commands to get images for the manual.
+# Tests against bug numbers to confirm that they are still fixed.
+
+# Make sure Audacity is running first and that mod-script-pipe is enabled
+# before running this script.
+
+#load and run the common core.
+exec( open("docimages_core.py" ).read() )
+
+
+def bug_test_1844():
+    makeWayForTracks()
+    do( 'Select: Start=0 End=30' )
+    do( 'Silence' )
+    do( 'Select: Start=0 End=40' )
+    do( 'ZoomSel' )
+    do( 'Select: Start=0 End=30' )
+    do( 'Tone' )
+    do( 'EnvelopeTool' )
+    do( 'SetEnvelope: Time=10 Value=1.0' )
+    do( 'SetEnvelope: Time=12 Value=0.5' )
+    do( 'Select: Start=0 End=4' )
+    do( 'AdjustableFade: curve="0" gain0="0" gain1="100" preset="None Selected" type="Fade Up" units="% of Original" ' )
+    capture( "Bug1844.png", "All_Tracks" )
+    do( 'SelectTool' )
+        
+# Should have envelop points at 0s, 2x4s, 10s and 12s and no others.
+bug_test_1844()
+