Draw polygon using pyvips example

[aravind3134]

Hey, I want to draw a polygon / polyline on to a big image.

So, I am migrating from PIL/opencv to pyvips. Recently, I came across loadsvg_buffer method that can actually do it without the use of draw_mask and draw_image methods.

Can someone give me one fill example using loadsvg_buffer or draw_mask or draw_image. The documentation wasn't much helpful.

Also, what if I have to draw multiple polylines?

Any other insights are welcome!

Please help. Thanks in advance!

[jcupitt]

Hello @aravind3134,

You can draw anything with SVG, for example:

import pyvips

x = pyvips.Image.svgload_buffer(b"""
<svg viewBox="0 0 100 100">
  <circle r="15" cx="50" cy="18" fill="#900"/>
</svg>
""")

x.write_to_file("x.png")

It can draw any size image and it's pretty quick. Use the boolean operators, or perhaps composite, to layer or mask another image.

[aravind3134]

Hey John, Thanks for the quick response.

I tried to run the code snippet that you sent me. I am facing issues with it. Looks like it cannot find the function.

I get the following error. I am using version 2.1.8

pyvips.error.Error: no such operation svgload_buffer VipsOperation: class "svgload_buffer" not found

[jcupitt]

Your libvips has been built without librsvg. You'll need to install librsvg-dev and rebuild it.

[aravind3134]

I couldn't install this in conda or pip.

However, I tried installing conda install librsvg and it worked fine with installation but says segmentation fault (core dumped) when trying to run the same code.

import pyvips
print(pyvips.__version__)
x = pyvips.Image.svgload_buffer(b"""
  <svg viewBox="0 0 100 100">
  <circle r="15" cx="50" cy="18" fill="#900"/>
</svg>
""")
x.write_to_file("x.png")

Is this fine? If not, should I be removing pyvips and libvips completely. Please guide me as I am new to this library.

Thank you.

[jcupitt]

It won't work in conda.

Anaconda is a different world and nothing works properly unless there's an official conda package. You need to switch to standard Python, or wait for conda to support libvips.

[aravind3134]

So, if I have used conda to create the environment and if I use "pip install librsvg-dev". Will it work?

I tried but it didn't work. Can you please explain me the requirements to install it, including the command to be entered on the linux terminal?

Thanks.

[jcupitt]

Is this Ubuntu? Just sudo apt install libvips-dev, then pip3 install pyvips. Don't use conda! Uninstall it, and everything related to it.

Alternatively, I'm trying to make a libvips package for conda. It should be ready in a week or two, and then pyvips might work there too.

The issue is being tracked here:

https://github.com/conda-forge/staged-recipes/pull/8912