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update readme.md

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jangko 2015-12-09 11:51:30 +07:00
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@ -58,26 +58,33 @@ let png = loadPNG32("image.png")
#png.data -> pixels data in RGBA format
```
if you already have the whole file in memory
if you already have the whole file in memory:
```nimrod
let png = decodePNG32(raw_bytes)
will do the same as above
#will do the same as above
```
other variants:
loadPNG24 -> will produce pixels in RGB format 8 bpp
decodePNG24 -> load png from memory instead of file
* loadPNG24 -> will produce pixels in RGB format 8 bpp
* decodePNG24 -> load png from memory instead of file
to create PNG:
savePNG32("output.png", rgba_pixels, width, height)
or savePNG24
encodePNG32(rgba_pixels, width, height)
or encodePNG24
use **loadPNG** or **savePNG** if you need specific input/output format by supplying supported **colorType** and **bitDepth** information. Use **encodePNG** or **decodePNG** to do in memory encoding/decoding by supplying desired colorType and bitDepth information
* savePNG32("output.png", rgba_pixels, width, height) or savePNG24
* encodePNG32(rgba_pixels, width, height) or encodePNG24
pixels are stored as raw bytes using Nim's string as container.
r1,g1,b1,a1,r2,g2,b2,a1,...,rn,gn,bn,an -> RGBA format 8 bit
r1,g1,b1,r2,g2,b2,...,rn,gn,bn -> RGB format 8 bit
grey1,grey2,grey3, ..., greyn -> GREY format 8 bit
grey1,alpha1,grey2,alpha2,...,greyn,alphan -> GREY ALPHA format 8 bit
special notes:
* Use **loadPNG** or **savePNG** if you need specific input/output format by supplying supported **colorType** and **bitDepth** information.
* Use **encodePNG** or **decodePNG** to do *in-memory* encoding/decoding by supplying desired colorType and bitDepth information
pixels are stored as raw bytes using Nim's string as container:
| Byte Order | Format |
|:------------------------------:|:----------------:|
| r1,g1,b1,a1,...,rn,gn,bn,an | RGBA 8 bit |
| r1,g1,b1,r2,g2,b2,...,rn,gn,bn | RGB 8 bit |
| grey1,grey2,grey3, ..., greyn | GREY 8 bit |
| grey1,a1,grey2,a2,...,greyn,an | GREY ALPHA 8 bit |