PureBasic Forums - English

Hi All,

Some time ago, AAT and I collaborated on an OpenCV example for my project, PureBasic Interface to OpenCV. Years later, another forum member developed a RAD SVG tool, which reminded me of the example AAT and I had worked on. With only a few minor modifications, literally just a dozen new lines of code, a promising new SVG tool began to take shape.

When I initially shared my results as an animated GIF, the response appeared limited, so I decided to set the example aside.

I don’t necessarily expect significant interest this time either, but revisiting OpenCV was enjoyable. It was great to see that, even though the version is somewhat dated, the algorithms remain highly relevant today.

Back when I first posted this in 2020, my thought was that it could serve as an add-on to any future SVG tools, essentially adding the Rapid to RAD.
• Useful for mapping complex shapes, animating sprite-sheet images, and more.

Watch the video here: Vector Drawing
1. Two JPG images are displayed for the demonstration.
2. The original 2020 example is copied into the main OpenCV folder.
3. The code executes, deriving x/y points from the image contours.
4. These points are drawn onto a copy of the selected image.
5. The SVG library uses the x/y points to render the results onto a CanvasGadget.
6. Various other SVG rendering options are also demonstrated.

Excellent work as always!

That's cool, good job.

Did I understand correctly? :
Does this code define the points around a shape?
In OpenGL, the instruction that creates polygons only creates convex polygons. Is there a way to "slice" any shape into convex polygons? (If so, that would be great for me.)
Thanks

Hi Caronte3D, miso,

Thank you for your positive comments.

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Hi SPH,

SPH wrote:Does this code define the points around a shape?

Yes, it has been part of the PureBasic Interface to OpenCV for over ten years, and it’s just one of many examples that can map points to objects.
• The two examples shown in the videos were quick modifications of an existing example.

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As I mentioned in my previous post, animations are a no-brainer...

Watch the video here: Vector Animation
1. The generated sprite sheet is displayed for the demonstration.
2. In a loop the sprite sheet is broken-down into regions of interest.
3. X/Y points are derived from the image contours.
4. These points are drawn onto a copy of the selected image.
5. The x/y points are used to render the results onto a CanvasGadget at 2x the scale.

JHPJHP wrote: Sat Oct 18, 2025 7:20 pmWhen I initially shared my results as an animated GIF, the response appeared limited, so I decided to set the example aside.

I read almost every post on this forum but don't always respond to them. Like this topic: I have no idea what SVG is and have no need for it, but I read it anyway without any plan to respond to it. But your quote made me write this reply to remind you that your work is actually seen and appreciated, even if I don't use it personally. Thumbs up!

Hi BarryG,

BarryG wrote:I have no idea what SVG is and have no need for it

That’s a bit of a paradox: How can you be sure you don’t need it if you don’t know what it is
• For reference, SVG stands for Scalable Vector Graphics; see PureBasic - VectorDrawing.

BarryG wrote:your quote made me write this reply to remind you that your work is actually seen and appreciated

That was kind of you but really not necessary. I was just having a bit of fun. The code has been available for over ten years, so anyone who works with SVG and still finds themselves manually mapping coordinates around objects, my point should be fairly obvious

There are countless uses; one example is my Old-Skool Fire Effect.

Hi JHP²
I'd like to get the gist of what I'm looking for. All I need for what I need is minimal.
I'd like to use your code to create an algorithm that allows me to find the points surrounding a shape.
Could you provide me with a simple code that does this?
I know my request is rather... bold, but if you have it up your sleeve, I'm all ears...
Thanks

Hi SPH,

Your curiosity and interest are appreciated, but before I invest time in developing a standalone package, let’s first confirm whether the current implementation aligns with your requirements.

The script operates using Contours and Polygon Approximations as follows:
• It first identifies the contours of an object for the purpose of shape analysis.
• It then approximates those contours, returning a sequence of X/Y coordinate points.

If a standalone package is created, it would include a minimum of three DLLs along with their corresponding LIB files.
• PureBasic Interface to OpenCV is a much larger framework that already includes over 250 examples.

While the framework supports Windows (32-bit / 64-bit), Linux (64-bit), and macOS (64-bit), this particular package would include only the script and binaries for Windows 64-bit.

The algorithm can identify points for multiple objects. Object filtering by area size and point granularity are both user-configurable.
• If you remain interested, provide a link to a test image so I can verify that the script will perform as intended.

There are advantages and disadvantages.
There are a lot of files (>1) for the little I've been looking for. Additionally, we should see if your algorithm can create polygons that trace an entire area.
I'm skeptical.

Hi SPH,

You mentioned that there are advantages and disadvantages, which ultimately depend on user requirements rather than the framework itself. OpenCV is used by millions, and for good reason: About OpenCV

As for the number of files, I don’t see why that should be an issue, especially if this is intended as a personal tool. Even in cases of broader distribution, dependencies are commonplace. In fact, I can’t recall downloading any useful software in recent years that didn’t include some form of dependency or supporting files.

Regarding your point about creating polygons that trace an entire area, the skepticism is misplaced. It’s not my algorithm, and in this case, skepticism isn’t relevant. The script performs exactly as designed.

If it doesn’t meet your expectations, it’s likely due to a misunderstanding of its intended function. Alternatively, if it works but not to the desired level of precision, it can certainly be adjusted. Moreover, given the vast range of algorithms available, one or more of the many alternatives could achieve better results for your specific objective.

Anyway, this wasn’t intended as a sales pitch. As I get older, I’ve come to appreciate the value of my time. Good luck.

SPH wrote: Tue Oct 21, 2025 7:31 pm Additionally, we should see if your algorithm can create polygons that trace an entire area.

An example image will be great to see what you mean. Thanks.

Well, for example: a drawing of the letter "P"
The trick would be to avoid creating a polygon that would cover the "hole" of the letter.
Furthermore, the OpenGL instruction I'm using only creates convex polygons.
All this taken into account, we end up with a rather demanding algorithm...

JHPJHP wrote: Sun Oct 19, 2025 11:43 pmHow can you be sure you don’t need it if you don’t know what it is

Ignorance is bliss.

Hi BarryG,

BarryG wrote:Ignorance is bliss.

I can’t say I disagree but if curiosity ever gets the better of you, I’ve added a standalone version to my website.

Important Update Regarding Project Releases:
With the latest version of PureBasic, I have implemented hundreds of updates and enhancements across my various projects. However, since PureBasic is still in beta, most of the updated projects will not be published on my website until the final release becomes available.