You are looking at historical revision 35575 of this page. It may differ significantly from its current revision.
CHICKEN bindings to stbimagewrite
Requirements
None, stb_image_write.h v1.09 is embedded in the egg.
API
[procedure] (write-png pixels width height components #!key flip compression stride filter)[procedure] (write-jpg pixels width height components #!key flip quality)
[procedure] (write-tga pixels width height components #!key flip rle)
[procedure] (write-bmp pixels width height components #!key flip)
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 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
Example
(with-output-to-file "red.png"
(lambda ()
(write-png 16 9 4
(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)))))))