Add custom preamble/epilogue support.

Allows reading custom preamble and/or epilogue from file or command line.
Opens the road for metric support.

1 files changed, 49 insertions, 12 deletions

diff --git a/rastercarve/__main__.py b/rastercarve/__main__.py
index 8d38e31..b5149a8 100755
--- a/rastercarve/__main__.py
+++ b/rastercarve/__main__.py
@@ -20,6 +20,7 @@ from rastercarve import __version__
 
 import argparse
 import cv2 # image scaling
+import io # stringIO for parsing lines
 import json
 import numpy as np # a little vector stuff
 from tqdm import tqdm # progress bar
@@ -41,6 +42,10 @@ DEF_STEPOVER = 110
 DEF_LINE_ANGLE = 22.5 # angle of lines across image, [0-90) degrees
 DEF_LINEAR_RESOLUTION = .01 # spacing between image samples along a line (inches)
 
+#### G-code parameters
+DEF_PREAMBLE = "G00 G90 G80 G28 G17 G20 G40 G49\nM03"
+DEF_EPILOGUE = "M05"
+
 #### Image interpolation
 SUPERSAMPLE = 2 # scale heightmap by this factor before cutting
 
@@ -78,12 +83,17 @@ def debug(str):
         eprint(str)
     debug_msgs += 1
 
-line = 1
-gcodebuf = ""
+line_no = 1
 def gcode(s):
-    global line
-    print((s if hasattr(glob_args, 'suppress_linenos') else "N%d %s" % (line, s)) )
-    line += 1
+    global line_no
+    print((s if hasattr(glob_args, 'suppress_linenos') else "N%d %s" % (line_no, s)) )
+    line_no += 1
+
+def gcode_multiline(s):
+    f = io.StringIO(s)
+    for l in f:
+        gcode(l.rstrip())
+
 
 pathlen = 0 # in
 rapidlen = 0 # in
@@ -233,9 +243,9 @@ def dump_stats(orig_size, img_size, line_width, line_spacing,
     eprint("Output resolution: %.1f PPI" % (output_ppi))
     eprint("Scaled image by f=%.2f (%.1f PPI)" % (scale_factor, interp_ppi))
     eprint("Total toolpath length: %.1f in" % (pathlen))
-    eprint(" - Rapids:  %.1f in (%.1f s)" % (rapidlen, rapidlen / (glob_args.rapid_rate / 60)))
-    eprint(" - Plunges: %.1f in (%.1f s)" % (plungelen, plungelen / (glob_args.plunge_rate / 60)))
-    eprint(" - Moves:   %.1f in (%.1f s)" % (movelen, movelen / (glob_args.feed_rate / 60)))
+    eprint(" - Rapids:  %.1f in (%.1f sec)" % (rapidlen, rapidlen / (glob_args.rapid_rate / 60)))
+    eprint(" - Plunges: %.1f in (%.1f sec)" % (plungelen, plungelen / (glob_args.plunge_rate / 60)))
+    eprint(" - Moves:   %.1f in (%.1f sec)" % (movelen, movelen / (glob_args.feed_rate / 60)))
     eprint("Feed rate: %.1f in/min" % (glob_args.feed_rate))
     eprint("Plunge rate: %.1f in/min" % (glob_args.plunge_rate))
     eprint("Estimated machining time: %.1f sec" % (pathtime))
@@ -260,6 +270,23 @@ def dump_stats(orig_size, img_size, line_width, line_spacing,
 
             json.dump(stats, f)
 
+def getPreambleEpilogue():
+    global glob_args
+    pre, epi = DEF_PREAMBLE, DEF_EPILOGUE
+    if hasattr(glob_args, 'preamble'):
+        pre = glob_args.preamble
+    elif hasattr(glob_args, 'preamble_file'):
+        with open(glob_args.preamble_file) as f:
+            pre = f.read()
+
+    if hasattr(glob_args, 'epilogue'):
+        epi = glob_args.epilogue
+    elif hasattr(glob_args, 'epilogue_file'):
+        with open(glob_args.epilogue_file) as f:
+            epi = f.read()
+
+    return pre, epi
+
 def doEngrave():
     # check parameter sanity
     for c in CONSTRAINTS:
@@ -267,6 +294,8 @@ def doEngrave():
             eprint("Refusing to generate G-code.")
             return
 
+    preamble, epilogue = getPreambleEpilogue()
+
     # invert and convert to grayscale
     img = ~cv2.cvtColor(cv2.imread(glob_args.filename), cv2.COLOR_BGR2GRAY)
 
@@ -287,11 +316,10 @@ def doEngrave():
     img_interp = cv2.resize(img, None, fx = scale_factor, fy = scale_factor)
     interp_ppi = img_ppi * scale_factor
 
-    # preamble: https://www.instructables.com/id/How-to-write-G-code-basics/
     print("( Generated by rastercarve: github.com/built1n/rastercarve )")
     print("( Image name: %s )" % (glob_args.filename))
-    gcode("G00 G90 G80 G28 G17 G20 G40 G49\n")
-    gcode("M03") # start spindle
+
+    gcode_multiline(preamble)
 
     d = np.array([math.cos(glob_args.line_angle * DEG2RAD),
                   -math.sin(glob_args.line_angle * DEG2RAD)])
@@ -344,7 +372,7 @@ def doEngrave():
     moveSlow(end[0], end[1], glob_args.traverse_z)
     moveRapid(0, 0, glob_args.traverse_z)
 
-    gcode("M05") # stop spindle
+    gcode_multiline(epilogue)
 
     dump_stats(orig_size, img_size, line_width, line_spacing,
                nlines, img_ppi, output_ppi, scale_factor, interp_ppi, pathlen,
@@ -391,8 +419,17 @@ flag with caution on other machines.""")
 
 
     gcode_group = parser.add_argument_group('G-code parameters')
+
     gcode_group.add_argument('--no-line-numbers', help='suppress G-code line numbers (dangerous on ShopBot!)', action='store_true', dest='suppress_linenos', default=argparse.SUPPRESS)
 
+    preamble_group = gcode_group.add_mutually_exclusive_group(required=False)
+    preamble_group.add_argument('--preamble', help='override the default G-code preamble; to specify multiple lines on the command line, use $\'\' strings with \\n; each line of the preamble will be prepended with a line number, except when used with --no-line-numbers', action='store', dest='preamble', default=argparse.SUPPRESS)
+    preamble_group.add_argument('--preamble-file', help='like --preamble, but read from a file', action='store', dest='preamble_file', default=argparse.SUPPRESS)
+
+    epilogue_group = gcode_group.add_mutually_exclusive_group(required=False)
+    epilogue_group.add_argument('--epilogue', help='override the default G-code epilogue; see above notes for --preamble', action='store', dest='epilogue', default=argparse.SUPPRESS)
+    epilogue_group.add_argument('--epilogue-file', help='like --epilogue, but read from a file', action='store', dest='epilogue_file', default=argparse.SUPPRESS)
+
     parser.add_argument('--json', help='dump statistics in JSON format', action='store', dest='json_dest', default=argparse.SUPPRESS)
     parser.add_argument('--debug', help='print debug messages', action='store_true', dest='debug', default=argparse.SUPPRESS)
     parser.add_argument('-q', help='disable progress and statistics', action='store_true', dest='quiet', default=argparse.SUPPRESS)