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Class: Vips::Region

Inherits:
Object show all
Defined in:
lib/vips/region.rb

Overview

A region on an image. Create one, then use fetch to quickly get a region of pixels.

For example:

ruby region = Vips::Region.new(image) pixels = region.fetch(10, 10, 100, 100)

Defined Under Namespace

Modules: RegionLayout Classes: ManagedStruct , Struct

Instance Attribute Summary

Attributes inherited from GObject::GObject

#ptr , #references

Instance Method Summary collapse

Methods inherited from Object

#get , #get_pspec , #get_typeof , #get_typeof_error , print_all , #set , #signal_connect

Methods inherited from GObject::GObject

#ffi_managed_struct , ffi_managed_struct , #ffi_struct , ffi_struct

Constructor Details

#initialize(name) ⇒ Region

Returns a new instance of Region.

Raises:

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# File 'lib/vips/region.rb', line 46
def initialize(name)
 ptr = Vips .vips_region_new name
 raise Vips ::Error  if ptr.null?
 super ptr
end

Instance Method Details

#fetch(left, top, width, height) ⇒ Object

Fetch a region filled with pixel data.

Raises:

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# File 'lib/vips/region.rb', line 62
def fetch(left, top, width, height)
 len = Vips ::SizeStruct .new
 ptr = Vips .vips_region_fetch self, left, top, width, height, len
 raise Vips ::Error  if ptr.null?
 # wrap up as an autopointer
 ptr = FFI::AutoPointer.new(ptr, GLib ::G_FREE )
 ptr.get_bytes 0, len[:value]
end

#height ⇒ Object 

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# File 'lib/vips/region.rb', line 57
def height
 Vips .vips_region_height self
end

#width ⇒ Object 

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# File 'lib/vips/region.rb', line 53
def width
 Vips .vips_region_width self
end

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