Added "Draw fractal dispatching work to a thread pool" example #176
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| [![threadpool-badge]][threadpool] [![num-badge]][num] [![num_cpus-badge]][num_cpus] [![image-badge]][image] [![cat-concurrency-badge]][cat-concurrency][![cat-science-badge]][cat-science][![cat-rendering-badge]][cat-rendering] | ||
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| Draws a fractal from [Julia set] to an image utilizing a thread pool for computation. |
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Add a thumbnail here with a link to the full sized image.
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| // Function converting intensity values to RGB | ||
| // Based on http://www.efg2.com/Lab/ScienceAndEngineering/Spectra.htm | ||
| fn wavelength_to_rgb(wavelength: u32) -> Rgb<u8> { |
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Hide this like we hide all the error handling code. This is not important to understanding threadpool.
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| } | ||
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| // Normalizes color intensity values within RGB range | ||
| fn normalize(color: f32, factor: f32) -> u8 { |
src/concurrency.md
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| } | ||
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| // Maps Julia set distance estimation to intensity values | ||
| fn julia(c: Complex<f32>, x: u32, y: u32, width: u32, height: u32, max_iter: u32) -> u32 { |
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| let iterations = 300; | ||
| // precomputed pixel colors from possible intensity range | ||
| let color_lut: Vec<_> = (0..iterations) |
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Remove this and inline the computation below. This seems like a performance optimization that has nothing to do with threadpool so it doesn't provide value to the example.
src/concurrency.md
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| let pixel = color_lut[i as usize]; | ||
| img.put_pixel(x, y, pixel); | ||
| } | ||
| let _ = img.save("output.png"); |
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| } | ||
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| fn run() -> Result<()> { | ||
| // resultant image size |
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Remove this comment. I think the names width and height and the next line are self-explanatory.
Also added thumbnail showing the final output. Added missing error handling for`ImageBuffer::save`
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Rebased and fixed :) Don't know how I've missed that Result on Also I did not know a better way to handle the thumbnail except for inline html pointing to github static content. |
fixes: https://github.com/brson/rust-cookbook/issues/102
Currently the example is marked as "no_run" as it leaves
output.pngin rust-cookbook cwd due to https://github.com/brson/rust-skeptic/issues/23 (there is a PR for it https://github.com/brson/rust-skeptic/pull/26)Also on weaker machines the example in debug build might take 1-2s and I would not like to make the test even slower.
Also maybe we could add additional thumbnail for the output.png?
