Difference between revisions of "Post process trace bitmap"

Revision as of 19:57, 9 October 2010

Introduction

The "Post process trace bitmap" extension is an experimental extension. Presently, it is only available as a separate install. See the Notes section at the end of this document for directions on obtaining and installing this extension.

The "Post process trace bitmap" extension moves to distinct Inkscape layers each collection of regions of the same color or gray tone which were traced by Inkscape's "Trace Bitmap" tool. This extension can optionally remove the color fill applied by that tool, add outlines of the regions, or remove from the drawing the original bitmap image which was traced.

In the presentation which follows, Inkscape's Trace Bitmap tool is discussed. However, this is not a tutorial on the use of that tool. For tutorials on tracing bitmaps, please see the links cited on the Tracing images page.

Step-by-step usage

As this extension assumes a specific usage of Inkscape's Trace Bitmap tool, the basic procedure of using that tool is demonstrated. This demonstration does not concern itself with the tool's "single scan" options nor the options on tabs other than the tool's "Mode" tab. Consequently, all the nuances of getting nice results from the Trace Bitmap tool are ignored in that which follows: those nuances are not relevant to the discussion at hand.

1. First, begin with a new Inkscape drawing. Do not attempt to operate on an existing drawing with other material in it. When you are done with this extension, you can cut and paste your result to another drawing.

From the "File" menu, use the "New" item to begin a new document. Into that document, import your bitmap graphic using the "Import..." item under the "File" menu,

2. After you select the bitmap image file, you will be asked whether to embed the image in the new document or link to it. Select "embed" and click "OK",

3. Once the image is imported, position it somewhere on the drawing page,

4. With the image selected, choose the "Trace Bitmap..." option from the "Path" menu,

5. In the Trace Bitmap tool, use either the "Colors" or "Grays" mode of the "Multiple scans: create a group of paths" section. Uncheck the "Stack scans" box. The "Smooth" and "Remove background" boxes can be checked.

6. Set the number of scans to the desired number. Then, click the "Update" button. Adjust other settings as you see fit, but be sure to use either "Colors" or "Grays". And be sure to leave "Stack scans" unchecked.

7. Once you are satisfied with your results, click the "OK" button. Then dismiss the Trace Bitmap window. The result will then appear in your drawing. The drawing may not look too different than from before as the image is still embedded in it as well.

8. Now, from the EggBot category of the "Extensions" menu, select the "Post process trace bitmap" item,

9. When the extension is launched, you will be given several options. Check the box to remove the original image from your drawing. Check or uncheck the other two items according to your needs. Then click the "Apply" button.

10. After the extension runs, you will be presented with a window indicating how many layers were created. Click the "OK" button. Then, to dismiss the extension window, click its "Close" button. Within your drawing window, you can examine the various layers with the "Layers..." item under the "Layer" menu. In the following figure, several layers have been turned off,

Notes

Currently this extension is experimental. It is not included with the Eggbot software package. You will need to download it from the Eggbot code site as the zip file eggbot_pptb_x_y.zip,

http://code.google.com/p/eggbotcode/downloads/list

Unzip that file and place the eggbot_pptb.py and eggbot_pptb.inx files in your Inkscape extensions directory. Putting it in your account's private extension directory is not recommended: there may be future conflicts if this extension is included with the Eggbot software package.