img.alpha = type
Set a flag to indicate whether or not to use alpha channel data. Set-only.
One of the following values of the AlphaChannelType enumeration:
img.matte =
true.img.matte = false.img.background_color ->
string
img.background_color = string or pixel
The image's background color. By default the background color is "white".
A color name.
img.base_columns -> integer
The number of columns in the image before any transformations. Get-only.
img.base_filename -> string
The image's original filename before any transformations. Get-only.
img.base_rows -> integer
The number of rows in the image before any transformations. Get-only.
img.bias -> float
img.bias = float
img.bias = string
Add bias when convolving an image
Either a number between 0.0 and 1.0 or a string in the form "NN%".
img.black_point_compensation ->
true or false
img.black_point_compensation =
true or false -> self
Use black point compensation. Typically used in CMYK-to-RGB
conversion along with image.rendering_intent=Magick::RelativeIntent
img.blur -> float
img.blur = float
> 1.0 is blurry, < 1.0 is sharp.
img.border_color ->
string
img.border_color = string or pixel
Either a color name or a Pixel object.
A color name.
img.bounding_box -> rectangle
The image's bounding box. The bounding box is the rectangle that encloses all the pixels not in the border color. Uses the current fuzz value. Get-only.
In this example, the bounding box is the gray square enclosing the blue circle. (The coordinates and red circles were added after the bounding box was computed.)
img.chromaticity ->
chromaticity
img.chromaticity = chromaticity
The red, green, blue, and white-point chromaticity values..
img.class_type ->
storage_class
img.class_type = storage_class
The image's storage class. If DirectClass then the pixels contain valid RGB or CMYK colors. If PseudoClass then the image has a colormap referenced by the pixel's index member.
A ClassType constant.
A ClassType constant.
img.color_profile ->
string
img.color_profile = string
The ICC color profile.
A color profile is represented as a string. If the argument
is nil instead of string
then any ICC color profile present in the image is deleted.
The setter form of this attribute deletes any existing ICC color profile(s) before adding the new one. If you need to add both source and destination profiles use add_profile or profile!.
The current color profile, or nil if there is
no profile.
img.colors -> integer
The number of colors in the colormap. Only meaningful for PseudoClass images. Get-only.
img.colorspace ->
colorspace
img.colorspace = colorspace
Image pixel interpretation. If the colorspace is RGBColorspace the pixels are red, green, blue. If matte is true, then red, green, blue, and opacity. If it is CMYKColorspace, the pixels are cyan, yellow, magenta, black. Otherwise the colorspace is ignored.
A ColorspaceType constant.
A ColorspaceType constant.
img.columns -> integer
The width of the image in pixels. Get-only.
img.compose ->
operator
img.compose = operator
The image composite operator. The default is OverCompositeOp. See montage.
A composite operator constant.
A composite operator constant.
img.compression ->
type
img.compression = type
A CompressionType constant.
A CompressionType constant.
img.delay ->
integer
img.delay = integer
Number of ticks which must expire before displaying the next image in an animated sequence. The default number of ticks is 0. By default there are 100 ticks per second but this number can be changed via the ticks_per_second attribute.
The current delay value.
img.density ->
string
img.density = string or geometry
The vertical and horizontal resolution in pixels of the image. The default is "72x72".
The density may be expressed either as a string or a
Geometry object. If a
string, it is in the form "XxY", or simply "X". If "Y" is
omitted it is set to "X". To specify the density with a
Geometry object, set the width attribute to the x
resolution and the height argument to the y
resolution. If height is nil, width
will be used as the y resolution as well.
The image density represented as a string.
Also see x_resolution and y_resolution.
img.depth -> integer
The image depth (8, 16, or 32). Get-only.
img.directory -> string
Tile names from within an image montage. Only valid after calling montage or reading a MIFF file which contains a directory. Get-only.
A newline ("\n")-delimited list of the images in the montage.
img.dispose ->
method
img.dispose = method
GIF disposal method. This attribute is used to control how successive images are rendered (how the preceding image is disposed of) when creating a GIF animation.
An integer corresponding to the disposal method.
img.endian ->
type
img.endian = type
Get or set the endian attribute. (As best I can tell, only the TIFF format supports this attribute.)
An EndianType value.
An EndianType value.
img.extract_info ->
rectangle
img.extract_info = rectangle
Specify a rectangle within an image, or retrieve the rectangle specified when the image was constituted. See extract=.
A Rectangle object.
A Rectangle object.
img.filename -> string
The image filename. Get-only.
img.filesize -> integer
The image filesize in bytes. Get-only.
img.filter ->
type
img.filter = type
Filter to use when resizing image. The reduction filter employed has a significant effect on the time required to resize an image and the resulting quality. The default filter is Lanczos which has been shown to produce high quality results when reducing most images.
A FilterTypes constant.
img.format ->
string
img.format = string
The image encoding format. For example, "GIF" or "PNG". See formats.
The format name.
The format name.
img.fuzz -> float
img.fuzz = integer or string
Colors within this distance are considered equal. A number of algorithms search for a target color. By default the color must be exact. Use this [attribute] to match colors that are close to the target color in RGB space.
See opaque, texture_floodfill, and transparent.
The argument may be a floating-point numeric value or a
string in the form "NN%". In the second case, the argument is
computed as a percentage of QuantumRange. For
example, a value of '5%' sets fuzz to
0.05*QuantumRange.
A Float
img.gamma ->
float
image.gamma = float
Gamma level of the image. The same color image displayed on two different workstations may look different due to differences in the display monitor. Use gamma correction to adjust for this color difference.
img.geometry ->
string
img.geometry = string or geometry
Preferred size of the image when encoding.
A geometry string or a Geometry object.
image.gravity ->
gravity
image.gravity = gravity
Used with the ImageList#composite_layers method. The direction that the image gravitates within the composite.
A GravityType value.
img.image_type -> type
The image type classification. For example, GrayscaleType. Don't confuse this attribute with the format, that is "GIF" or "JPG". Get-only.
An ImageType value.
img.interlace ->
type
img.interlace = type
The type of interlacing scheme (default NoInterlace). This option is used to specify the type of interlacing scheme for raw image formats such as RGB or YUV. NoInterlace means do not interlace, LineInterlace uses scanline interlacing, and PlaneInterlace uses plane interlacing. PartitionInterlace is like PlaneInterlace except the different planes are saved to individual files (e.g. image.R, image.G, and image.B). Use LineInterlace or PlaneInterlace to create an interlaced GIF or progressive JPEG image.
An InterlaceType constant.
An InterlaceType constant.
img.iptc_profile ->
string
img.iptc_profile = string
The International Press Telecommunications Council profile.
A IPTC profile is represented as a string. If the argument
is nil instead of string
then any IPTC profile present in the image is deleted.
The current IPTC profile, or nil if there is no
profile.
img.mask -> image or
nil
img.mask = image or
imagelist or nil
The mask= attribute writer sets an image clip
mask created from the specified mask image. The mask image must have the same dimensions as the
image being masked. If not, the mask image is resized to
match. If the mask image has an alpha
channel the opacity of each pixel is used to define the mask.
Otherwise, the intensity (gray level) of each pixel is
used.
In general, if the mask image does not have an alpha channel, a white pixel in the mask prevents changes to the corresponding pixel in the image being masked, while a black pixel allows changes. A pixel that is neither black nor white will allow partial changes depending on its intensity.
Use matte= to specify whether or not the mask image has an alpha channel.
The mask attribute reader returns a copy of the
clip mask. This is not a copy of the mask image that
was used to create the clip mask, nor is it the clip mask image
itself. Therefore, modifying the image returned by
mask does not change the clip mask itself. To
change the clip mask you must assign a new image to the
mask= attribute writer.
If the value is an imagelist, uses the current image as the
mask image. Assign nil to remove the clip
mask.
img.matte -> true
or false
img.matte = true or
false
If true, honor the opacity values in the image
pixels. See Pixel.
This attribute is deprecated in ImageMagick 6.3.5 and later. Use alpha instead.
img.mean_error_per_pixel -> float
The mean error per pixel computed when
a image is color reduced. This attribute is only valid
if the measure_error argument to
quantize[ImageList][Image] is set to true.
Get-only.
img.mime_type -> string
Returns the officially registered (or de facto) MIME media-type. If there is no registered media-type, returns "image/x-magick". Get-only.
img.monitor = proc
Establish a progress monitor. Most Image and
ImageList methods will periodically call the
monitor with arguments indicating the progress of the method.
The argument is a Proc object that accepts the three arguments
listed here:
If the monitor proc returns nil or
false the operation will be immediately
terminated. To stop monitoring, set monitor to
nil. Set-only.
Any object that can respond to
obj.call(method_name, quantum, span)
With very large images it is possible, though not very
likely, for the quantum and
span arguments to be
Bignum objects.
img.monitor = Proc.new do |method, offset, span|
printf("%s is %3.0f%% complete.\n", method, (offset.to_f/span)*100)
true
end
img.blur_image(0,20)
produces:
blur_image is 0% complete. blur_image is 0% complete. blur_image is 0% complete. blur_image is 1% complete. blur_image is 2% complete. blur_image is 4% complete. blur_image is 7% complete. blur_image is 14% complete. blur_image is 28% complete. blur_image is 56% complete. blur_image is 56% complete. blur_image is 56% complete. blur_image is 56% complete. blur_image is 57% complete. blur_image is 59% complete. blur_image is 63% complete. blur_image is 70% complete. blur_image is 84% complete. blur_image is 100% complete.
img.montage ->
string
Tile size and offset within an image montage. Only valid for [images produced by montage.] The string is in the form of a geometry string. Get-only.
img.normalized_mean_error -> float
The normalized mean error computed
when an image is color reduced. This attribute is only
valid if the measure_error argument to
quantize[ImageList][Image] is set to true.
Get-only.
img.normalized_maximum_error -> float
The normalized mean error per pixel
computed when an image is color reduced. This attribute
is only valid if the measure_error argument to
quantize[ImageList][Image] is set to true.
Get-only.
img.number_colors -> integer
Number of unique colors in the image. Get-only.
img.offset ->
integer
img.offset = integer
Number of initial bytes to skip over when reading raw image.
img.opacity = integer
Attenuates the opacity channel of an image. If the image pixels are opaque, they are set to the specified opacity level. Otherwise, the pixel opacity values are blended with the supplied transparency value. Set-only.
img.orientation ->
type
img.orientation = type
The value of the Exif Orientation Tag.
An OrientationType value.
img.page ->
rectangle
img.page = rectangle
When compositing, this attribute describes the position of this image with respect to the underlying image. See coalesce, flatten_images, and mosaic.
A Rectangle object.
A Rectangle object.
img.pixel_interpolation_method
-> method
img.pixel_interpolation_method =
method
Get/set the pixel color interpolation method. Some methods (such as wave, swirl, implode, and composite) use the pixel color interpolation method to determine how to blend adjacent pixels.
An InterpolatePixelMethod enum value.
An InterpolatePixelMethod enum value.
img.quality -> integer
For JPEG images, returns the Independent JPEG Group quality value. This number is a measurement of the amount of compression used when the image was saved. Lower numbers mean higher compression.
A number between 0-100.
For more information, see The JPEG image compression FAQ.
img.quantum_depth -> integer
The image depth to the nearest Quantum (8, 16, or 32). Get-only.
img.rendering_intent ->
type
img.rendering_intent = type
The type of rendering intent. See http://www.cambridgeincolour.com/tutorials/color-space-conversion.htm
A RenderingIntent constant.
img.rows -> integer
The height of the image in pixels. Get-only.
img.scene -> integer
The scene number assigned to the image the last time the
image was written to a multi-image image file. Don't confuse
this attribute with ImageList's scene attribute, which denotes the image
to which Image methods will be sent.
img.start_loop ->
true or false
img.start_loop = true or
false
Indicates the first image in an animation.
img.ticks_per_second ->
integer
iamge.ticks_per_second = integer
Gets/sets the number of ticks per second. This attribute is used in conjunction with the delay attribute to establish the amount of time that must elapse between frames in an animation.The default is 100.
The current number of ticks per second
img.total_colors -> integer
The number of colors in the image after quantization. Set by
quantize [ImageList][Image] if the
measure_error argument is true.
Get-only.
img.units -> type
img.units = type
Units of image resolution.
A ResolutionType constant.
A ResolutionType constant.
img.virtual_pixel_method ->
method
img.virtual_pixel_method =
method
Specify how "virtual pixels" behave. Virtual pixels are pixels that are outside the boundaries of the image. Methods such as blur_image, sharpen, and wave use virtual pixels.
The virtual pixel method can be any one of the following
VirtualPixelMethod constants:
Some of these values are not supported by older versions of ImageMagick. To see what values are available, enter the following code in irb:
Magick::VirtualPixelMethod.values {|v| puts v}
A VirtualPixelMethod constant.
img.virtual_pixel_method = Magick::TransparentVirtualPixelMethod
img.x_resolution ->
float
img.x_resolution = float
img.y_resolution ->
float
img.y_resolution = float