image2svg_位图矢量图_位图转矢量图_

#------------------------------------------------------------------------ # Name: image2svg.py # # Description: # Convert an image file to a 6-shades svg "line art" file to # be printed on an XY Plotter # # An aliased & upscaled bitmap (~1600x1000) is preferable # for optimal results. # # To be drawn on a XY plotter with no optimization, vectors # coords start from left to right, then right to left # every other line. # # Version 3 - Use PIL Image instead of the now depreciated # scipy imread + major cleanup # Todo: investigate why PIL antialias/degrade jpg (open? convert?) # automate upscaling #------------------------------------------------------------------------- from PIL import Image import numpy as np import codecs, sys # Set visible to True to display the vector lines on screen (for testing) # False to prevent G-Code generator from double-stroking each line (but produce invisible output on SVG viewers) visible = True # Shades thresholds. May require tweaking for better results on darker/lighter images # Pixels values are reduced (darkened) to the nearest # C64 palette vals: 0, 87, 96, 111, 114, 132, 158, 164, 173, 174, 212, 213, 230, 238, 255 shade1 = 0 # Black shade2 = 50 shade3 = 100 shade4 = 158 shade5 = 212 shade6 = 240 #------ Functions definition ------# def needLineX(val, rowIndex): # Determine if a segment must be drawn depending on its shade & row number if rowIndex % 2 == 0 and val <= shade1: return True elif rowIndex % 4 == 0 and val <= shade3: return True elif rowIndex % 8 == 0 and val <= shade5: return True else: return False def needLineY(val, rowIndex): if rowIndex % 2 == 0 and val <= shade1: return False # Only draw horizontal lines elif rowIndex % 4 == 0 and val <= shade2: return True elif rowIndex % 4 == 0 and val <= shade3: return False # Only draw horizontal lines elif rowIndex % 8 == 0 and val <= shade4: return True else: return False def svgPrint(start, stop, rowNum, invert, axes, axisDimension): svgFile.write('<line '+ axes[0] + '1="' + str(axisDimension-start if invert == True else start) + '" ' + axes[1] + '1="' + str(rowNum) + '" ' + axes[0] + '2="' + str(axisDimension-stop if invert == True else stop) + '" ' + axes[1] + '2="' + str(rowNum) + '"/>\n') def generateVectors(img, needLine, axes, axisDimension): invert = False for rowIndex, row in enumerate(img): # Go through each row rowDrawn = False firstEndpoint = 0 if invert == True: # Invert every other line where something is drawn on a row row = np.flipud(row) for index, pixel in enumerate(row): # Go through each column if index > 0 and pixel != row[index-1]: # If the pixel color is different from the last if needLine(row[index-1], rowIndex): # Check if this last segment must be "printed" svgPrint(firstEndpoint, index, rowIndex, invert, axes, axisDimension) rowDrawn = True firstEndpoint = index # Store the first endpoint of the next line segment if needLine(row[index], rowIndex): # Test/Print last segment at the end of each line svgPrint(firstEndpoint, index, rowIndex, invert, axes, axisDimension) rowDrawn = True if rowDrawn == True: invert = not invert def main(inputFile): image = Image.open(inputFile).convert('L', dither=False) width, height = image.size # Reduce color to 6 shades image = Image.eval(image, lambda px: shade1 if px < shade2 else (shade2 if px < shade3 else (shade3 if px < shade4 else (shade4 if px < shade5 else (shade5 if px < shade6 else 255))))) # Convert image to array image = np.asarray(image) # Create SVG file + header global svgFile svgFile = codecs.open("output.svg", "w+") svgFile.write('<?xml version="1.0" encoding="UTF-8" ?>\n') svgFile.write('<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n') svgFile.write('<svg width="'+ str(width)+ 'pt" height="'+str(height)+'pt" viewBox="0 0 ' + str(width)+ " " +str(height)+'" version="1.1" xmlns="http://www.w3.org/2000/svg">\n') # Stroke lines if option is set if visible == True: svgFile.write('<g stroke="black" stroke-width="1">\n') # Create X axis segments generateVectors(image, needLineX, ['x', 'y'], width) # Create Y axis segments image = np.swapaxes(image, 0, 1) generateVectors(image, needLineY, ['y', 'x'], height) # Close SVG file if visible == True: svgFile.write('</g>') svgFile.write('</svg>') svgFile.close() # End Main if __name__ == "__main__": try: main(sys.argv[1]) except IndexError: print("No input file specified.") wait = input("Press enter to continue...") sys.exit(1) except FileNotFoundError: print("Input file not found.") wait = input("Press enter to continue...") sys.exit(1) except OSError: print("Image file not recognized.") wait = input("Press enter to continue...") sys.exit(1)