Editing Producing a stippled image with Gimp
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To produce TSP art of an image, you will first want to generate a stippled rendition of the image. That is, you need to stipple the image. The stipples themselves will then be the cities in the Travelling Salesman Problem to be solved. The traveller will move from stipple to stipple on your canvas and their path will be your TSP art. | To produce TSP art of an image, you will first want to generate a stippled rendition of the image. That is, you need to stipple the image. The stipples themselves will then be the cities in the Travelling Salesman Problem to be solved. The traveller will move from stipple to stipple on your canvas and their path will be your TSP art. | ||
− | The easiest way to stipple your image is with a stippling extension to your image editor. If your image editor lacks a stippling extension, you will need another means to generate stipplings. This document explains how to do so with Gimp, the GNU Image Manipulation Program | + | The easiest way to stipple your image is with a stippling extension to your image editor. If your image editor lacks a stippling extension, you will need another means to generate stipplings. This document explains how to do so with Gimp, the GNU Image Manipulation Program. |
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+ | Gimp may be downloaded from | ||
:[http://www.gimp.org/ www.gimp.org] | :[http://www.gimp.org/ www.gimp.org] | ||
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Now for the detailed steps. [Note that on a Mac, Gimp's menu does not appear along the top of your screen but rather along the tops of the individual GImp windows.] | Now for the detailed steps. [Note that on a Mac, Gimp's menu does not appear along the top of your screen but rather along the tops of the individual GImp windows.] | ||
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'''1. Open your image file in Gimp'''<br/> | '''1. Open your image file in Gimp'''<br/> | ||
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step01.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step01.png | ||
− | A file selection dialog will appear. Navigate to the file containing your image and click the "Open" button. | + | A file selection dialog will appear. Navigate to the file containing your image and click the "Open" button. Gimp will likely toss up a question like the one shown below. You can click "Cancel" or "Assign". For our purposes, either choice is okay. |
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step02.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step02.png | ||
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step03.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step03.png | ||
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'''2. Convert your image to grayscale'''<br/> | '''2. Convert your image to grayscale'''<br/> | ||
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[http://wiki.evilmadscience.com/s3/eggbot/tspart/step05.png | [http://wiki.evilmadscience.com/s3/eggbot/tspart/step05.png | ||
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'''3. Wash out the image'''<br/> | '''3. Wash out the image'''<br/> | ||
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step08.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step08.png | ||
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'''4. Stipple the image'''<br/> | '''4. Stipple the image'''<br/> | ||
− | To produce the stipples we will convert the image to black and white, dithering it in the process. In graphics, "dithering" is the process of intermixing colored pixels from the allowed palette of colors to produce what our human eyes will interpret as an intermediate color not found in the palette. When the palette only contains black and white pixels, dithering attempts to mix differing amounts of black and white | + | To produce the stipples we will convert the image to black and white, dithering it in the process. In graphics, "dithering" is the process of intermixing colored pixels from the allowed palette of colors to produce what our human eyes will interpret as an intermediate color not found in the palette. When the palette only contains black and white pixels, dithering attempts to mix differing amounts of black and white so as to produce shades of gray. |
To convert the image to black and white, use the "Mode..." item in the "Image" drop down menu. Select the "Indexed..." mode, | To convert the image to black and white, use the "Mode..." item in the "Image" drop down menu. Select the "Indexed..." mode, | ||
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step09.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step09.png | ||
− | The "Convert Image to Indexed Colors" window will then appear. In this window, select "Use black and white (1-bit) palette" for the colormap. Also, for dithering select "Floyd-Steinberg (normal)". | + | The "Convert Image to Indexed Colors" window will then appear. In this window, select "Use black and white (1-bit) palette" for the colormap [sic]. Also, for dithering select "Floyd-Steinberg (normal)". |
http://wiki.evilmadscience.com/s3/eggbot/tspart/step10.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step10.png | ||
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http://wiki.evilmadscience.com/s3/eggbot/tspart/step11.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step11.png | ||
− | If you do not see individual stipples, or there are too many, or some regions just look like a gray cloud, then you probably have too many stipples. Go back to Step 2 and reduce the size of the image to 50 or 25% of its original size. | + | If you do not see individual stipples, or there are too many, or some regions just look like a gray cloud, then you probably have too many stipples. Go back to Step 2 and reduce the size of the image to 50 or 25% of its original size. Or, alternatively, wash the image out even more in Step 3. Or, try both. The image size may be reduced with the "Scale Image..." item of the "Image" drop down menu. |
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'''5. Save the stippled image as a PBM file'''<br/> | '''5. Save the stippled image as a PBM file'''<br/> | ||
− | Once you are satisfied with your stippling effort, save your result in a new file. For use with the Python scripts described at | + | Once you are satisfied with your stippling effort, save your result in a new file. For use with the Python scripts described at (to be determined), you must save the stippled image using the PBM format (Portable Bit Map). This is easily achieved with Gimp. First, from the "File" menu select the "Save As..." item, |
http://wiki.evilmadscience.com/s3/eggbot/tspart/step12.png | http://wiki.evilmadscience.com/s3/eggbot/tspart/step12.png | ||
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Now, go ahead and click the "Save" button. You may be presented with a window with the title "Save as PNM". That's misleading but don't worry: a PBM file will be produced. You can select either "Raw" or "ASCII" as the data formatting: the TSP art scripts accept either. The raw format takes up much less space and is faster for the TSP art tools to load, so you might as well pick "Raw". | Now, go ahead and click the "Save" button. You may be presented with a window with the title "Save as PNM". That's misleading but don't worry: a PBM file will be produced. You can select either "Raw" or "ASCII" as the data formatting: the TSP art scripts accept either. The raw format takes up much less space and is faster for the TSP art tools to load, so you might as well pick "Raw". | ||
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'''6. Generate TSP art'''<br/> | '''6. Generate TSP art'''<br/> |