Struct lodepng::ffi::CompressSettings
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[src]
pub struct CompressSettings { pub btype: c_uint, pub use_lz77: c_uint, pub windowsize: c_uint, pub minmatch: c_uint, pub nicematch: c_uint, pub lazymatching: c_uint, pub custom_zlib: Option<extern fn(arg1: *mut *mut c_uchar, arg2: *mut size_t, arg3: *const c_uchar, arg4: size_t, arg5: *const CompressSettings) -> c_uint>, pub custom_deflate: Option<extern fn(arg1: *mut *mut c_uchar, arg2: *mut size_t, arg3: *const c_uchar, arg4: size_t, arg5: *const CompressSettings) -> c_uint>, pub custom_context: *const c_void, }
Settings for zlib compression. Tweaking these settings tweaks the balance between speed and compression ratio.
Fields
btype: c_uint
the block type for LZ (0, 1, 2 or 3, see zlib standard). Should be 2 for proper compression.
use_lz77: c_uint
whether or not to use LZ77. Should be 1 for proper compression.
windowsize: c_uint
must be a power of two <= 32768. higher compresses more but is slower. Typical value: 2048.
minmatch: c_uint
mininum lz77 length. 3 is normally best, 6 can be better for some PNGs. Default: 0
nicematch: c_uint
stop searching if >= this length found. Set to 258 for best compression. Default: 128
lazymatching: c_uint
use lazy matching: better compression but a bit slower. Default: true
custom_zlib: Option<extern fn(arg1: *mut *mut c_uchar, arg2: *mut size_t, arg3: *const c_uchar, arg4: size_t, arg5: *const CompressSettings) -> c_uint>
use custom zlib encoder instead of built in one (default: None)
custom_deflate: Option<extern fn(arg1: *mut *mut c_uchar, arg2: *mut size_t, arg3: *const c_uchar, arg4: size_t, arg5: *const CompressSettings) -> c_uint>
use custom deflate encoder instead of built in one (default: null) if custom_zlib is used, custom_deflate is ignored since only the built in zlib function will call custom_deflate
custom_context: *const c_void
optional custom settings for custom functions
Methods
impl CompressSettings
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fn new() -> CompressSettings
Default compression settings