the OUTPUT_WIDTH and OUTPUT_HEIGHT params

I am trying to use the map script and need to know the the Image size as I need the ratio of width to height. I expected this to be the OUTPUT_WIDTH and OUTPUT_HEIGHT params. The problem I have is that my image is 1229 x 706 pixels but these params return 96 and 96. Anybody any idea how to get the correct image sizes please?

My script is only one line long:

function get_sample(x, y)
error(OUTPUT_WIDTH .. ", " .. OUTPUT_HEIGHT)
end;

so I don't think the trouble is with the script. The variables simply return the incorrect values.

If I change the thumbnails to "large" then the value changes to 128. However, the spec says:

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"OUTPUT_WIDTH and OUTPUT_HEIGHT – width and height of the image currently loaded into Filter Forge".

So I expect these 2 values to reflect the loaded image size. The preview window (upper left) has the correct dimensions. The code does not.

Thank you for your code idea - but I don't understand how your code helps. You have the alpha set to 0. If I change that to 1 then I get a pure yellow output. What I don't get to see - either in preview mode or in the final render are the correct values. It seems to be a bug in the implementation. I have not found how to get it to work as documented.

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Sphinx. wrote: before your input image is processed, FF "borrows" your script for rendering the thumbnail.

Sphinx is right, except that thumbnail rendering is performed simultaneously to the input image processing. The Lua subsystem seems to monitor the thumbnail thread first. I'm afraid there's little you can do to change that, just keep this in mind.

Thanks Sphinx for your help.

Knowing that there is a pre-pass where the values are set to the thumbnail size rather than the actual image size helps a lot. It means that error() was not appropriate in my case as it applied to the pre-pass not the final pass.

Also your idea of using the image to store results was something I had not considered and was helpful in finding out some details which would have been almost impossible using the error() function.

The end result of all this was that I completely rewrote my lua script and it is all the better for it! Whilst I have submitted it to the snippets it has not been accepted yet but will hopefully be available soon. It will be called "Hello World" where you can define a message and it will be converted to graphics using a 10x12 dot matrix display format. I am just trying to do the regular first coding challenge of "Hello World" which was rather more of a challenge than anticipated! I also have a much higher resolution version which I have not submitted of 14x24 dot matrix grid. If someone wants the higher definition grid I can upload it.

It was the need to get these dot matrices to have the right aspect ratio irrespective of the original image size which caused me so many problems with the OUTPUT_WIDTH and OUTPUT_HEIGHT values.