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Article contents:== stb-image-write CHICKEN bindings to [[https://github.com/nothings/stb/blob/master/stb_image_write.h|stb_image_write]] [[toc:]] === Requirements None, {{stb_image_write.h}} v1.09 is embedded in the egg. === Repository [[https://github.com/kristianlm/chicken-stb-image-write|https://github.com/kristianlm/chicken-stb-image-write]] === API <procedure> (write-png pixels width height components #!key flip compression stride filter)</procedure> <procedure> (write-jpg pixels width height components #!key flip quality)</procedure> <procedure> (write-tga pixels width height components #!key flip rle)</procedure> <procedure> (write-bmp pixels width height components #!key flip)</procedure> Writes the u8vector {{pixels}} to {{(current-output-port)}} using the image format of the procedure name. The pixel format depends on {{components}}, which represents the number of bytes per pixel: 1: y8 (gray) 2: ya16 (gray + alpha) 3: rgb24 4: rgba32 Extra parameters are: * {{flip}} specifies whether to flip the image vertically before outputting * png {{compression}} sets the {{zlib}} compression quality. defaults to 8, try higher values for more compression * png {{stride}} is the distance in bytes from the first byte of a row of pixels to the first byte of the next row of pixels. * png {{filter}} forces a particular [[https://en.wikipedia.org/wiki/Portable_Network_Graphics#Filtering|filter type]] for all scanlines. defaults to trying all and picking the most efficient ({{#f}}), other valid values are 0-4. * jpg {{quality}} specifies lossy compression amount as a percentage (defaults to 80) * tga {{rle}} enables or disable run-length-encoding compression. it is on by default, set to {{#f}} to disable rle compression Note that on 32-bit systems, blobs cannot be larger than 16M. This also limits image sizes as pixel data is stored in a blob. === Example <enscript highlight="scheme"> (with-output-to-file "red.png" (lambda () (write-png (let ((r '(255 0 0 255)) (b '( 0 0 255 128)) (_ '( 0 0 0 0))) (list->u8vector (flatten (list b b b b b b b b b b b b b b b b b _ _ _ _ _ _ _ _ _ _ _ _ _ _ b b _ _ r r r _ r r r _ r r _ _ b b _ _ r _ r _ r _ _ _ r _ r _ b b _ _ r r r _ r r r _ r _ r _ b b _ _ r r _ _ r _ _ _ r _ r _ b b _ _ r _ r _ r r r _ r r _ _ b b _ _ _ _ _ _ _ _ _ _ _ _ _ _ b b b b b b b b b b b b b b b b b)))) 16 9 4))) </enscript> === TODO * test png stride * see if it's possible to write data to port without copying memory === Source The source is located [[https://github.com/kristianlm/chicken-stb-image-write|here]]. Description of your changes:

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