class Vips::SourceCustom

Overview

A source you can attach action signal handlers to to implement custom input types.

For example:

file = File.open("some/file/name", "rb")
source = Vips::SourceCustom.new
source.on_read { |slice| file.read(slice) }
image = Vips::Image.new_from_source(source)

(just an example -- of course in practice you'd use Source#new_from_file to read from a named file)

Direct Known Subclasses

Defined in:

vips/source.cr

Constructors

Instance Method Summary

Instance methods inherited from class Vips::Source

finalize finalize

Class methods inherited from class Vips::Source

new_from_descriptor(descriptor : Int) new_from_descriptor, new_from_file(filename : String) new_from_file, new_from_memory(data : String | Bytes | IO) new_from_memory

Instance methods inherited from class Vips::Connection

filename : String | Nil filename, nick : String | Nil nick

Instance methods inherited from class Vips::VipsObject

get(name : String) get, get_blurb(name : String) get_blurb, get_description get_description, get_pspec(name : String) : LibVips::GParamSpec | Nil get_pspec, get_typeof(name : String) get_typeof, post_close(&block : -> ) post_close, print_all print_all, set(gtype, name, value)
set(options : String) set

Instance methods inherited from class Vips::GObject

finalize finalize, get(name : String, gval : GValue) get, object_ref object_ref, ref_count ref_count, release_handle release_handle, set(name : String, gval : GValue) set, signal_connect(signal : String, callback : Proc, data : Pointer(Void) = Pointer(Void).null) : LibVips::Gulong signal_connect, signal_disconnect(handler_id : LibVips::Gulong)
signal_disconnect(func : Proc, data : Pointer(Void) = Pointer(Void).null)
signal_disconnect(data : LibVips::Gpointer) signal_disconnect

Constructor Detail

def self.new #

[View source]

Instance Method Detail

def finalize #

[View source]
def on_read(&block : Bytes -> Int32) #

The block is executed to read data from the source. The interface is exactly as IO::read, ie. it takes a slice and reads atmost slice.size and returns a number of bytes read from the source, or 0 if the source is already at end of file.


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def on_seek(&block : Int64, IO::Seek -> Int64) #

The block is executed to seek the source. The interface is exactly as IO::seek, ie. it should take an offset and whence, and return the new read position.

This handler is optional -- if you do not attach a seek handler, Source will treat your source like an unseekable pipe object and do extra caching.


[View source]