--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/bitmap_plot.py Sat Nov 07 13:30:53 2015 +0100
@@ -0,0 +1,147 @@
+#!/usr/bin/env python
+
+ENGRAVE_SPEED = 20 * 60 # mm/min
+TRAVEL_SPEED = 130 * 60
+E_FACTOR = 0.1
+INVERT_PALETTE = True
+
+DPI = 300
+GREY_THRESHOLD = 0
+CHANGE_DIRECTION = True
+
+
+# DO NOT CHANGE WORLD's RULES!
+INCH = 25.4 # mm
+MM_PIXEL = round(INCH / DPI, 4)
+STEPS_PIXEL = MM_PIXEL * 80 # mine is 80 steps/mm on XY
+print "Resolution: %f mm per pixel" % MM_PIXEL
+print "Steps per pixel (needs to be > 5, otherwise marlin joins lines): %f" % STEPS_PIXEL
+
+from PIL import Image
+import sys
+
+def pixel_to_bit(pixel, threshold=128):
+ """Convert the pixel value to a bit."""
+ # some really weird stuff here ;-P
+
+ # RGB to greyscale
+ #print pixel
+ #print type(pixel)
+ if isinstance(pixel, tuple):
+ #rgb
+ pixel = pixel[0]*0.2989 + pixel[1]*0.5870 + pixel[2]*0.1140
+ threshold = 128
+ if pixel > threshold:
+ return 1
+ else:
+ return 0
+
+
+ # color palette
+ if (pixel > 0):
+ return 1
+ else:
+ return 0
+
+#
+# Open the image file and get the basic information about it.
+#
+try:
+ im = Image.open(sys.argv[1])
+except:
+ print "Unable to open %s" % sys.argv[1]
+ exit(-1)
+
+print "format: %s mode: %s palette: %s" % (im.format,im.mode,im.palette)
+width,height = im.size
+print "The image is %d x %d" % im.size
+
+pix = im.load()
+
+
+fo = open(sys.argv[1] + ".g", "w")
+#fo.write("G10 P1 X-30.0 Y1.5 Z0.0 R0 S0 ; Laser tool offset\n")
+#fo.write("M218 T1 X.30.0 Y1.5 ; Laser tool offset\")
+#fo.write("G28 X Y ; Home position\n")
+# G90 = absolute positioning, G91 = relative
+#fo.write("M83 ; Set extruder (laser) to relative mode\n")
+fo.write("""
+; Filename: %s
+; GCode generated by bitplotter one-night-quick-hack script (marlin code flavour)
+
+G21 ; Metric
+; We assume Z is in focus height and laser head is focus at bottom left of image!
+G92 X0 Y0 E0; set zero position - new origin
+G90 ; absolute positioning
+M82 ; Set extruder (laser) to absolute positioning
+M201 X1000 Y1000 E500 ; Set acceleration
+M203 X1000 Y1000 Z4 E10 ; Set max feedrate
+M209 S0 ; disable firmware retraction, we dont want to burn holes...
+M302 ; Allow cold extrudes - doesnt matter because we hack the extruder physically off with the M571 E mod
+M571 S1 E1 ; Activate Laser output on extrusion, but block real motor movement!
+G0 X0 Y0 F%d ; Set moving speed TRAVEL_SPEED
+G1 X0 Y0 F%d ; Set linear engraving speed ENGRAVE_SPEED
+
+""" % (sys.argv[1], TRAVEL_SPEED, ENGRAVE_SPEED) )
+
+fo.write(";Start engraving the raster image: %dx%d points @ %d DPI = %.0fx%.0f mm" % (
+ im.size[0], im.size[1], DPI, im.size[0]*MM_PIXEL, im.size[1]*MM_PIXEL) )
+
+INVERT_Y = MM_PIXEL * (im.size[1] -1) * (-1)
+
+DIR = 1
+for X in range(im.size[0]):
+ fo.write("; X=%d printing row: direction %i\n" % (X, DIR))
+ fo.write("G92 E0\n")
+ E = 0
+ last_bit = 1 # we engrave on black pixel = 0
+ START_Y = 0
+ if DIR > 0:
+ range_start = 0
+ range_stop = im.size[1]
+ else:
+ range_start = im.size[1] -1
+ range_stop = -1
+
+ for Y in range(range_start, range_stop, DIR):
+ YMM = abs((Y * MM_PIXEL) + INVERT_Y)
+ XMM = X * MM_PIXEL
+ #print "X %d Y %d" % (X, Y)
+ bit = pixel_to_bit(pix[X, Y], GREY_THRESHOLD)
+ if last_bit == bit:
+ if bit == 1:
+ # nothing to do,
+ continue
+ else:
+ # are we at the end of Y range?
+ #print Y
+ if (Y == (im.size[1] - 1)) or (Y == 0):
+ # draw line
+ if DIR > 0:
+ E = E + MM_PIXEL * (Y - START_Y)
+ else:
+ E = E + MM_PIXEL * (START_Y - Y)
+ fo.write("G1 X%.4f Y%.4f E%.4f F%d\n" % (XMM, YMM, E * E_FACTOR, ENGRAVE_SPEED))
+ else:
+ # bit value has changed!
+ if bit == 0:
+ # jump to start of line to write
+ START_Y = Y
+ fo.write("G0 X%.4f Y%.4f F%d\n" % (XMM, YMM, TRAVEL_SPEED))
+ else:
+ # end of line to write
+ if DIR > 0:
+ E = E + MM_PIXEL * (Y - START_Y)
+ else:
+ E = E + MM_PIXEL * (START_Y - Y)
+ fo.write("G1 X%.4f Y%.4f E%.4f F%d\n" % (XMM, YMM, E * E_FACTOR, ENGRAVE_SPEED))
+ last_bit = bit
+ if CHANGE_DIRECTION:
+ DIR = DIR * (-1) # change y direction on every X
+
+
+fo.write("M571 S0 E0\n")
+fo.write("M501 ; undo all settings made\n")
+#fo.write("G28 X0 Y0 ; Home position\n")
+
+fo.close()
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