Bitmap -> GIF/PNG/JPG

[Michael Mahemoff]

Hi,

Can anyone please recommend a package for generating images from a
bitmap vector. e.g. If I have an list of integers, each representing a
colour on the bitmap, and I want to build a GIF from it (along with some
other meta-info like dimensions).

The main options seem to be RMagick and RCairo, but neither seems to
take a bitmap input. I'd have to create a blank canvas and draw each
pixel. Do-able but inefficient.

Thanks,
Michael

 

[Tim Hunter]

Hi,

Can anyone please recommend a package for generating images from a
bitmap vector. e.g. If I have an list of integers, each representing a
colour on the bitmap, and I want to build a GIF from it (along with some
other meta-info like dimensions).

The main options seem to be RMagick and RCairo, but neither seems to
take a bitmap input. I'd have to create a blank canvas and draw each
pixel. Do-able but inefficient.

Check out Magick::Image#import_pixels:
http://www.simplesystems.org/RMagick/doc/image2.html#import_pixels. If
the input pixels are in a string buffer this is an extremely fast
method. If the pixel data are in an array it's still faster than drawing
each pixel separately.

If your pixel data are in a file you may be able to simply describe it
as being in "RGB" or "RGBA" format, in which case RMagick can convert it
for you. See http://www.imagemagick.org/script/formats.php.