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Tracing control for dirty images

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Not all the images you have to vectorize are clean and neat. Far from it! Besides, line crossing at sharp angle creates ambiguity for a tracing tool even in the best ones.

Not all the images you have to vectorize are clean and neat. Far from it! Besides, line crossing at sharp angle creates ambiguity for a tracing tool even in the best ones. The knack for quick overtaking of troublesome and "dirty" areas without UNDOs accelerates your work about half as much again.

Stop of the tracer and selection of further route

The tracer in Easy Trace stops if:

  • the raster line has ended (at a breakthrough or at the image border);
  • the vector line has come to its initial point and closed;
  • the vector line has joined to another vector line with node or common vertex forming;
  • you have clicked the RIGHT button of the mouse.
Besides, the tracer makes a pause at a complicated fork. If you do nothing, it will select the direction and continue moving. Shift the mouse during the delay to select a tracing direction differing from one suggested by the program, and click the LEFT button to resume vectorizing.

If none of the suggested line continuations is correct, act as following:

  • click the mouse RIGHT button to stop the tracer and start the "elastic thread" mode;
  • specify the desirable continuation with the LEFT button, and the tracer will "run" again.
By the way, it may be reasonable to stop the tracer in advance - RIGHT click before the tracer comes to a "dirty" part of the line.

If the tracer stops at gaps of a dashed line, tracing strategy needs additional adjustment. Click twice in the Parameters bar on the name of the current tracing strategy, then the Properties button in the appeared dialog box, and increase the "Permissible line gap" and maybe also "Continuation search cone".

How to avoid wrong tracing

"Dirty" part of the line is often rather long and curved, whereas the "elastic thread" is always straight. You may certainly edit this part of vector line after digitizing but it's much easier to use keyboard commands at tracing:

  • RIGHT click before the "dirty" line part to break tracing and start the "elastic thread" mode;
  • press the ? key to start the manual tracing mode;
  • specify desirable positions of vertices along the "dirty" part of the line with the mouse LEFT button;
  • press the ? key to start the automatic tracing mode;
  • specify next vertex with the mouse LEFT button.
There are three ways of automatic tracing mode change for manual one and vice versa:
  • hot key (? by default);
  • the button in the Parameters bar;
  • command of the submenu that will appear at RIGHT click (button ).
And what should I do if the tracer "raced thorough" the fork and continued vectorizing in a wrong direction? When this is the case, act as following:
  • RIGHT click to break tracing and start the "elastic thread" mode;
  • press the W key (or in submenu of the Editor) to start the "cut off" mode;
  • cut off the "polyline tail" with the "scissors";
  • specify correct line continuation or start the manual mode to pass the "dirty" zone.
It may be reasonable to use stepwise UNDO instead of the "scissors" if the tracer has not "run away" too far. To do it, press the Z key for several times.

Sometimes the tracer passes the line well but snaps to an existing vector object awry. If it happens, stop the tracer just before snapping with the mouse RIGHT button and specify correct snapping point.

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