Tuesday 20 March 2018

SNC Basics - Tracing a computer image into Canvas - jpeg/jpg, gif, png, bmp - bitmap files

DRAFT POST _ SUBJECT TO REVISION

Evening agan. So yesterday's blog was about the different file types and their characteristics and finding out why some files are traced using the Trace Icon function and some are just imported using the SVG Import icon in Canvas. You can read it HERE

I'm also just at the beginning of a personal project to make a hand embroidered sleeve cover for my smart phone. And I'm going to be using Canvas and the ScanNCut to do as much of it as I can. I have no idea how much that will be as I've not consciously taken this approach before. I blogged about how I was starting this from scratch, working out my design constraints and finding a suitable pattern online HERE
Pattern from Cliparts.co that I shall be using in this post to take into Canvas



And it seems natural to me, that as I go through each step from start to finish of the mobile phone cover, that I make sure I blog about how to do the things I am doing in Canvas and the SNC. This is the first of those, which is taking the PNG file I found online into Canvas. The added bonus to this is that because this file is a free online download, YOU TOO can join in! Hurrah!



You can download this file for yourself from this webaddress: http://cliparts.co/clipart/615650 or this link HERE  I should say that make sure you have proper anti-virus protection etc. Nothing nasty landed in my laptop when I downloaded it, and I have Norton antivirus. But it's not a website that has anything to do with me, so caution is always a good idea!

And hugely useful is that this file is so well designed by whoever did it, that it behaves EXACTLY as Brother Canvas designers expected a bitmap file to behave. Which means that when you get a file and you're trying to trace it and it doesn't behave, you can at least have a vague idea of what's going wrong because you know what it should do in the first place!

So.

Step 1 - Download your image file from the internet (or find it in your computer or wherever it's living) - for this particular example, go to the website in the above link, highlighted yellow. Click the download button. It will save into your Downloads folder. This is a temporary folder. Save it into the place on your computer where you keep your image computer files. I have a folder called 'SNC' that I save everything into relating to the SNC.

Step 2- Find out what type of file it is - the three letter file extension - go and look at the file in the folder you saved it in, without opening it. You may have to change the View to Details (windows) so that you can see the file extension. When it downloaded into my computer this is what it looked like, the file name is pToMXayTE.png. And what matters to us is, what are the 3 letters after the full stop/period - ie the file extension, we don't care about the actual file name itself, we only need to know that so we can find it again if we need to!

For this one, it is a PNG file, so we know from my blogpost of yesterday about file extensions that this is a bitmap file and therefore we need to use the TRACE Icon in Canvas and not the SVG Icon to get it into Canvas so that we can use it as a cut or draw file in the SNC machine.

filename is pToMXayTE.png. It's a PNG bitmap file that's 90kb in size.
Step 3 - Open Canvas Workspace - I'm assuming you have already set up a free login and know where to find it. The rest of this blogpost is all in Canvas Workspace.


Step 4 - Open a New Project by clicking the New Project mat space on the front page.



Step 5 - Click the Trace Icon - this is the shape of a leaf on top of a square and is the third icon from the left on the tool bar. When you select something on the tool bar it goes pink, and when you hover over it, a label appears that tells you what it does.

Step 6 - Tracing Screen 1 -  I have bought the small Pattern Collection, so my Canvas shows me the choice of Normal Tracing or Enhanced Tracing. The video is about Enhanced Tracing.



THIS BLOG POST IS ABOUT NORMAL TRACING.

NB: Enhanced Tracing is something you buy as part of a Pattern Collection and you get it from a Brother dealer/main distributor in the form of two Activation Cards, one for the Patterns and one for the Enhanced Tracing. I'll be doing a blog on Enhanced Tracing in due course.

Choose the Normal Tracing.

Step 7 - Tracing Screen 2 - this screen is where you bring in the existing computer file and also tell Canvas what sort of image it is/ what sort of trace you want.



So, the top section is Select Image. First box is Choose File (this is from your computer), the Second box is Choose a Scanned Image from your machine (wifi enabled machines only) and then the final part is where the filename shows once your image is selected.

The left section is a blank space, this is where your image will show up.

The right section is where you choose the TYPE of trace you want, whether you want the background there or not and how many colours the Trace is looking for. Plus a few notes about how it works.

At the bottom there is Preview, Ok and Cancel.

Step 8 - Click the Choose File in the select image box, this will open up another window showing you all the files in your computer, navigate your way to the folder you saved your PNG file in, and click on it once. This will bring the file name into the box at the bottom and then click ok or open (whatever your computer has).
I chose the paisley image, the filename is at the bottom then I click open


 The blank space at the left will fill with the picture of your chosen image file.
Filename shows at top right and picture of image shows in left Image File Section

TWO TYPES OF TRACE - OUTLINE AND COLOURThere's TWO types of trace
  • Outline - this literally traces the outline of the shapes in your image
  • Colour - this distinguishes shapes by colour region
The Canvas Manual at page 18 (find it via the Questionmark at the top right of the Canvas Workspace page, it is called Help.pdf) explains the two types of tracing like this

Outline - the outermost outline of the pattern is traced: where because there's white space between the stem and the apple, both the stem and the apple are traced as two different shapes.
Outline Trace
It's important to understand that with outline detection, that Canvas sees only (a) blank space or (b) space with image in it, and it traces a single line where one stops and the other begins. This can cause problems if your picture has no blank space, but is all image. I'll do a blogpost on troubleshooting awkward pictures in due course. This one is about the simple images that work as intended.

Colour Detection/ Region Detection - Canvas divides the image into regions of colour, and then creates outlines of each region and created a shape for each separate colour region.
It's important to understand the implications of this - because the software is creating an outline PER COLOUR what you get are nesting shapes, which fit together like a jigsaw in a single layer.

Therefore in the apple above,
  • with Colour Trace you get a shape that is tracing each side of the black line of the outline of the apple and the stem - this gives you a shape that's the outline of the apple itself. With Outline you get a single cut line that gives you a shape of an apple and a shape of the stem.
  • with Colour Trace you also get the red apple body but with the highlighting missing, you get the highlighting itself, you get the inside green of the stem - so in total you get 5 shapes - apple outline, apple body, apple highlight, and also stem outline and stem body. Whereas with Outline you get just the apple body and the stem body with the highlight ignored - 2 shapes.
  • What you don't get with the Colour Trace is the apple body without the highlight for layering one on top of the other. You can either do two traces, one Outline and one Colour and discard the bits you don't need, OR you can use process functions in Canvas once the trace has been finished, to remove the highlight from the Color Trace apple body to create an entire body that you can then stick the highlight on top of. Also, you can use the Offset function to create an outer border to stick all the parts onto if needed. Basically, what I'm saying is, just because something traces well, it doesn't mean that in that traced state, it's exactly what you need for your purposes.  You may be happy having jigsaw style pieces, if you are using vinyl for example and registration marks, or if you are making a greetings card you may want layers and need to do extra manipulation, or if you are making a standalone apple, you may want an offset to stick everything to.
Step 9 - Trace Using Outline

When you Trace using Outline, you can't choose whether or not to include the background. Why not? well because then all you'd be tracing is the outside edge of your image, which will produce a blank square.

You can however choose how many colours in the image. The lowest is 2, the highest is 20. With the image we're using here, the Paisley, it only has black and white. So the number of colours is irrelevant. However, if each paisley motif was a different colour, then that's when you use that option. (more on choosing colours in a later post). I chose 2 because I have black and white (but I also tried with 20 and it made no difference at all, as expected).


Ok so you have your image, and you are doing Outline and it's a black and white clear image with a nice crisp outline - click PREVIEW. It'll then do a fair bit of thinking with a little circle down at the bottom.

Step 10 - Preview is finished - and the trace shows as a BLUE LINE. It is this blue line that will show on the Mat once the trace is finished.
Preview Finished
As you can see, there's a blue line around every single element in my image. But ONLY the outline, not inside.

If I wanted to just have the outlines, then that's fine, and I could now click OK and it would take the blue lines and put them onto the New Project mat we started with.

But actually, for my purposes I want the inside elements as well. And to do that, we need to do the Colour/Region Option.

Step 11 - Colour Trace - to do this, click the Colour button which will turn pink and the Outline button will go white.

The tick box for Remove Background will no longer be greyed out.

My image has only 2 colours, so I set the colours at 2, and I left the Remove Background box alone.

I clicked Preview and this time, the software read the outer black and inner white elements as colour regions and gave me the outside and the inside shapes. Hurrah!
Colour Trace
However, the trace preview shows that the very points of the paisley shapes aren't traced - fine, they will either trace properly and it's just the preview screen being approximate, OR I can do node editing to make the points sharper once it's on the Mat and editable.
Preview shows points aren't very pointy. (with remove background ticked)

Step 12 - What difference does Remove Background tickbox make?
Well, that last preview was with the Remove Background ticked. Which means the software IGNORES what it considers to be background.

If I do another preview with the box unticked, the software will consider the background. This is what happened - I got a blue line around the outside of the image
Remove background is unticked, the software considers the background

So the choice for me is, do I want a box outlining this image or not? I don't in this instance, so I tick the box again, do one more preview to make sure it's tracing everything I want it to (I'll deal with when it doesn't trace everything I want it to in another blog post), and then, I shall click the OK button.

Step 13 - Click OK this makes the trace actually happen. And gives you a new screen asking if you really want to do this.
I do. So I click Yes.
I'M AN IDIOT - THIS SECTION WILL BE EDITED, I WORKED OUT WHAT IT MEANS. IT'S YES YOU WANT A SHADOW OF THE ORIGINAL IE THE BITMAP THAT CAN'T BE EDITED OR SAVED AS WELL AS THE VECTOR SHAPES, OR NO YOU JUST WANT THE VECTOR SHAPES. IN INKSCAPE WHEN YOU TRACE BITMAP (SORT OF LIKE CANVAS TRACE) YOU GET TWO IMAGES - THE ORIGINAL BITMAP AND THE NEW VECTOR SHAPES. IN INKSCAPE YOU HAVE TO DELETE THE BOTTOM ORIGINAL BITMAP ONE. ANYWAY, THE STUFF ABOUT THE BITMAP SHADOW BELOW IS NOT QUITE TRUE...
I'm not entirely sure what they mean by 'the image cannot be edited and saved' because actually it can be, but as you'll see as we carry on, not as a coloured image, only as cut/draw lines. This is because the Machine ignores colour, colour is something the user chooses with the media put on the mat for cutting etc. At the same time, the Canvas software allows you to use colour, but this is only to make it easier to differentiate various layers etc, and also to do more sophisticated actions in Node Editing etc. But I digress.

Step 14 - Your image is traced and now sitting on your mat as Project you can now work with
Ta da!!!! Oh but it looks a bit weird, what's that grey shading?
Traced image on the Mat screen

Well that puzzled me, I had a try at pulling shapes away and managed to get all the shapes away from the grey shading which I couldn't do anything with - it wouldn't let me select it or delete it etc.



Traced Lines selected and grouped and moved away leaves the grey shading behind
So I tried saving the file, and closing it, when I reopened the file, sure enough the grey shading was gone - and all I had was the cut lines. So from that, I think the sentance about not editing or saving refers to the grey shading, essentially the bitmap elements that are retained as part of the tracing, but only the vector elements are saved and can be manipulated (that will make more sense if you read the blogpost I referred to at the very beginning about the different file types there's a link to it at the top).

Step 15 - Save your image BEFORE you do any manipulation
Seriously. Save it. Name it and save it. Before you do anything especially if it was a bit of a faff getting it to trace well!
My saved 'raw' trace
The Canvas Manual tells you how to save files, but basically you type the filename into the box top right, and click the second icon, looks like a filing tray with a downward arrow. That's for a brand new project.  You can also do this from the Project tab.

If you've been working on a project and want to save a new version of it, go to the Project tab and pick the icon that is for a New Save which is a filing tray with a + sign next to the downward arrow.
Save as a different project
This whole process is exactly the same for any file that you can convert in Canvas from bitmap to vector - namely jpg/jpeg, gif, png and bmp.

Ok so the trace is done. Hurrah!!!! I can just use it right? well um no. Not quite.

Remember up in the section about the two types of tracing, how I said that Colour/Region tracing gave you a shape per colour, well, particularly with Colour tracing, but it's a good habit with ALL files you bring in that someone else created, you need to check how many cut lines there are (you only need one per shape) and also that the lines are where you want them to be.

So the second half of this post about Tracing an image, will be about how to check the 'raw' trace and make sure that it can be taken across to the SNC machine and do a single cut line exactly how you want it to.

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