Inkscape

Problem following Quick Start Northern Pacific Railway tutorial

Asked by Kara A. Rowe

Hello:

I am so sorry to bother you again so soon.

I have been trying and trying to follow the lesson/tutorial for the Northern Pacific Railway Logo which is located under the "Quick Start Guide".

Everything goes well until I get to the "Trace Bitmap" tool. < I "check the Gray Option" & "Set the Scans to 3".

"... will give three regions ..." < this doesn't happen. I made certain to also check the "Stack Scans" I moved the image & underneath there's only one other image not two as described above.

Next ... "Brightness Cut Off" < I adjust & set the "Threshold to 0.15".

"... after finding a good value, click 'OK' to generate a path" < Nothing happens to either image on top or bottom.

I've tried several times, starting over from the beginning but only twice have the steps i followed generated the images that appear in the tutorial. In other words only twice did the image of just the Ying Yang & circles with the "Blobs" and in just black & white were ever generated.

Also, the instructions mention ... "after finding a good value" < At this point I wouldn't know a good value if it bit me in the leg. : )

Even though I don't have the image that should have been generated at this point I went on to the next steps.

Back to the "Trace Bitmap" I click the "Options" tab & select the "Suppress Speckles" and I set it to "50", check "Smooth Corners" & "Optimize Paths".

It then says: "Rescan" < Does this mean to click "OK" ? When I do click "OK" nothing appears to happen.

But, I move on to the "Transform" tool nonetheless.

After following the steps to "Transform" the image it generates a clearer (but undefined) image of the original image and it's placed to the left.

Next the steps say: "Repeat trace with a new 'Threshold' of 0.65. Execute the trace" < Does this mean to click "OK" ?
Again nothing seems to happen.

Both images at this point still contain all of the original components. E.G. the Ying Yang, two circles & text. NOT one with just the Ying Yang & two circles and one with just the two circles and text as are shown in the steps/tutorial.

Well, this is as far as I have gone with this lesson.

Can you help me at all with the information I have given?

I have a Dell Laptop 64 bit and have Windows & Home Edition. When I was using GIMP I learned about Python-Fu. I have been unable to download and install Python to GIMP thus far. I recall that there is an issue with the 64 bit version. Or something to that affect. I think it said in order to install it properly I had to choose a particular download for 64 bit.

Do you think there could be a similar issue with Inkscape & the 64 bit system? Or do you think I am doing something wrong and/or just not understanding the directions clearly enough?

Is the "Quick Start"not meant for beginners?

I am sorry to write so much in this message but I am determined to learn this AWESOME software you've kindly developed for people like myself. I understand bugs & kinks can occur and so I also thought that maybe my writing to you may help to pinpoint an actual issue. : ) Not to assume there is one.

I do think the directions could use a bit more information or better descriptions of what steps to take as well as a few more screen shots to help learn visually. I am not griping as I appreciate how much time and effort goes in to making tutorials and I do greatly appreciate the help.

Again, thank you so much for your time and efforts.

Sincerely,
Kara A.Rowe

Question information

Language:
English Edit question
Status:
Solved
For:
Inkscape Edit question
Assignee:
No assignee Edit question
Solved by:
su_v
Solved:
Last query:
Last reply:
Revision history for this message
Best su_v (suv-lp) said : 		#1

Some general notes:

A - Current selection must be the imported bitmap image
Even if you follow the tutorial word by word, you might have done some clicks in-between which are not described there. The most important thing to know about using the 'Trace bitmap' dialog: you need to make sure that you actually have the imported bitmap image selected - the message in the status bar will help (it always informs you about the current selection and its type): with the bitmap recommended to download and import for the tutorial, you see this message:
"Image 350x350 file:// (…)"
If the message in the status bar says "No objects selected. …", you have to click on the bitmap image again to select it. If message says " Path (…) …" or "Group of …", you have selected a tracing resulting from an earlier attempt. Delete the path or group, and select the bitmap image (check again the message in the status bar).

B - Maybe the basic misunderstanding is about the two aspects of the 'Trace Bitmap…' dialog:
1) the button 'Update' will rescan the selected bitmap image and update the preview image in the dialog, using the current options
2) the button 'OK' will actually trace the bitmap, generate the paths and insert them into the drawing, right on top of the traced bitmap.

C - The two groups of settings / trace modes ('Single Scan' and 'Multiple Scans') will insert different objects types:
- A single scan will generate a single path which can be later edited with the node tool
- The 'multiple scans' option will create a 'group' object, inside that group are several paths - each one representing one level of the chosen option (brightness,color, grayscale). If you click on such a group withe the select tool, it acts as a single object (keep an eye on the message in the status bar which tells you the object type of the current selection). Such a group can be ungrouped to be able to select and edit each path individually

Specific questions:
1) «Everything goes well until I get to the "Trace Bitmap" tool. < I "check the Gray Option" & "Set the Scans to 3".»
Keep in mind that this step is mentioned to illustrate the possibilities of tracing a bitmap, it is not relevant to the remaining part of the tutorial: "The paths generated with the Grays option are usable as a starting point for the NP logo. However, we might be able to do better if we use the Single scan, Brightness cutoff method, optimizing the threshold for each scan. "
You might as well skip that step if it confuses you. The author doesn't explicitly tell to delete the result (but implies so).

2) «Next ... "Brightness Cut Off"
The first set of instructions are: "Select the Brightness cutoff option in the Trace Bitmap dialog. Adjust the Threshold to create a well-defined Yin and Yang path. Pressing the Update button will create a preview. A threshold of 0.15 seems to work well. After finding a good value, click on the OK button to generate the path. "

Reading on one can assume that the settings for this first tracing are not sufficiently optimized -> the tracing can be discarded (deleted) or the step skipped as well.

The next precise instructions are: "Select the Options tab in the Trace Bitmap dialog. The Suppress speckles option allows the automatic suppression of paths smaller than the specified size. Make sure the Suppress speckles box is checked and set the Size to 50. While you're at it, make sure the Smooth corners and Optimize paths boxes are checked. This will result in a smooth scan with fewer nodes. Rescan and the “blobs” should be gone. "

'Rescan' in this context refers to clicking on 'Update' for the preview image and subsequently on 'OK' to actually trace with these options and insert the generated path into the drawing, right on top of the traced bitmap. Note: before clicking on 'Update' or 'OK', do not forget to verify that you still have the bitmap image selected (and not the group of paths generated with the 'Multiple Scans > Grays' option mentioned earlier).

Questions:
-> Does it fail to update the preview image? Then you are hitting a known bug in the Windows port of Inkscape [1]
-> Note: if you click on 'OK' (whether the preview is shown or not), a single path with a black fill is generated and inserted right on top of the bitmap image. You might not detect it visually, but the message in the status line gives you the hint: if it changed from "Image 350x350 … " to "Path (166 nodes) …" (or a similar number of nodes), the tracing was successfully inserted into the drawing.

3) «But, I move on to the "Transform" tool nonetheless.»
If tracing actually failed ("Nothing happens to either image on top or bottom.") or you still have the group of paths with the grayscale levels on top of the bitmap image, there's no point in moving on yet.

Could you try again based on the information I just provided and report back whether you get the result with the options

[1] see
Bug #922177 “Manual: The Northern Pacific Railway Logo / Brightness cutoff method not working”
<https://bugs.launchpad.net/inkscape/+bug/922177>
which is a duplicate of <https://bugs.launchpad.net/inkscape/+bug/631444>
Note: while the preview image is broken (normally updated when clicking on 'Update'), the command to actually trace the bitmap image and insert the resulting path(s) into the drawing (by clicking on the 'OK' button) is still functional.

Revision history for this message
su_v (suv-lp) said : 		#2

> I have a Dell Laptop 64 bit and have Windows& Home Edition. When I
> was using GIMP I learned about Python-Fu. I have been unable to
> download and install Python to GIMP thus far. I recall that there is
> an issue with the 64 bit version. Or something to that affect. I
> think it said in order to install it properly I had to choose a
> particular download for 64 bit.
>
> Do you think there could be a similar issue with Inkscape& the 64
> bit system? Or do you think I am doing something wrong and/or just
> not understanding the directions clearly enough?

The official package of Inkscape 0.48 works fine on Windows - be it a 32bit or 64bit system.

Any issues with GIMP and getting Python-Fu installed should not affect Inkscape (Inkscape includes its own version of Python which is called for most of the extensions (see menu 'Extensions')). For the tutorial in question, nothing related to Python is used in Inkscape (all is based on internal routines).
A known issue affecting the Windows ports of Inkscape is that with certain settings, the preview image in the 'Trace bitmap…' dialog is not properly updating - but as mentioned before - this does not affect the actual tracing and the insertion of the generated paths into the drawing (the 'OK' button in the dialog).

Revision history for this message
Kara A. Rowe (kararowe) said : 		#3

Thank you!!

Revision history for this message
Kara A. Rowe (kararowe) said : 		#4

Thanks ~suv, that solved my question.

Revision history for this message
Mark Grieveson (dg135) said : 		#5

Hello. I am having problems too, specifically with the ""Select the Options tab in the Trace Bitmap dialog. The Suppress speckles option allows the automatic suppression of paths smaller than the specified size. Make sure the Suppress speckles box is checked and set the Size to 50." It doesn't work. I still have the blobs. I made sure that the image was selected, and verified this by viewing different Updates when selecting different options on the first tab (Mode), but when I tried selecting the Options tab and the Suppress Speckles option (set at 50), it made no difference. In fact, I tried again with it higher (set at 1000), which should have made a difference, but none was made.

Revision history for this message
Bob Wolfe (blu.wolf) said : 		#6

This has been the most confusing tutorial lesson. I get up to suppress speckles and nothing happens. I don't get the Update (rescan?) button unless I unclick Live Preview and then it still doesn't work. I didn't realize anything was even happening at all until I read where someone said to click and drag the the image to see any thing at all.
Maybe if you redid the tutorial with clear step by step instructions. No "you can also do it this way" - save that for later or put it in parenthesis.

Revision history for this message
Bob Wolfe (blu.wolf) said : 		#7

OK I went on with the tutorial. I had to remove the blobs by hand.

When I got to scale the letters I had to use 103% not 3% to get the desired result.

 I think these tutorials should be rewritten by a beginner or using a beginner doing the exercise in person while writing the tutorial. It would help to say where things are again, like Transform dialog. We are new to this and a lot is being thrown at us. We can't yet remember where everything is located yet especially if we've only been there once or twice before.