# Enumerations

Contents

- ChannelType

- ClassType

- ColorspaceType

- CompositeOperator

- CompressionType

- DecorationType

- FillRule

- FilterTypes

- GravityType

- ImageType

- InterlaceType

- ChannelType

- LineCap

- LineJoin

- NoiseType

- OrientationType

- PaintMethod

- QuantumTypes

- RenderingIntent

- ResolutionType

- StorageType

- StretchType

- StyleType

ChannelType

ChannelType is used as an argument when doing color separations. Use ChannelType when extracting a layer from an image. MatteChannel is useful for extracting the opacity values from an image. Note that an image may be represented in RGB, RGBA, CMYK, or CMYKA, pixel formats and a channel may only be extracted if it is valid for the current pixel format.

ChannelType

Enumeration | Description
UndefinedChannel | Unset value.
RedChannel | Extract red channel (RGB images only)
CyanChannel | Extract cyan channel (CMYK images only)
GreenChannel | Extract green channel (RGB images only)
MagentaChannel | Extract magenta channel (CMYK images only)
BlueChannel | Extract blue channel (RGB images only)
YellowChannel | Extract yellow channel (CMYK images only)
OpacityChannel | Extract matte (opacity values) channel (CMYKA images only)
BlackChannel | Extract black channel (CMYK images only)
MatteChannel | Extract matte (opacity values) channel (RGB images only)

ClassType

ClassType specifies the image storage class.

ClassType

Enumeration | Description
UndefinedClass | Unset value.
DirectClass | Image is composed of pixels which represent literal color values.
PseudoClass | Image is composed of pixels which specify an index in a color palette.

ColorspaceType

The ColorspaceType enumeration is used to specify the colorspace that quantization (color reduction and mapping) is done under or to specify the colorspace when encoding an output image. Colorspaces are ways of describing colors to fit the requirements of a particular application (e.g. Television, offset printing, color monitors). Color reduction, by default, takes place in the RGBColorspace. Empirical evidence suggests that distances in color spaces such as YUVColorspace or YIQColorspace correspond to perceptual color differences more closely han do distances in RGB space. These color spaces may give better results when color reducing an image. Refer to quantize for more details.

When encoding an output image, the colorspaces RGBColorspace, CMYKColorspace, and GRAYColorspace may be specified. The CMYKColorspace option is only applicable when writing TIFF, JPEG, and Adobe Photoshop bitmap (PSD) files.

ColorspaceType

Enumeration | Description
UndefinedColorspace | Unset value.
RGBColorspace | Red-Green-Blue colorspace.
GRAYColorspace | Grayscale colorspace
TransparentColorspace | The Transparent color space behaves uniquely in that it preserves the matte channel of the image if it exists.
OHTAColorspace |
XYZColorspace |
YCbCrColorspace |
YCCColorspace |
YIQColorspace |
YPbPrColorspace |
YUVColorspace | Y-signal, U-signal, and V-signal colorspace. YUV is most widely used to encode color for use in television transmission.
CMYKColorspace | Cyan-Magenta-Yellow-Black colorspace. CYMK is a subtractive color system used by printers and photographers for the rendering of colors with ink or emulsion, normally on a white surface.
sRGBColorspace |

CompositeOperator

CompositeOperator is used to select the image composition algorithm used to compose a composite image with an image. By default, each of the composite image pixels are replaced by the corresponding image tile pixel. Specify CompositeOperator to select a different algorithm.

CompositeOperator

Enumeration | Description
UndefinedCompositeOp | Unset value.
OverCompositeOp | The result is the union of the the two image shapes with the composite image obscuring image in the region of overlap.
InCompositeOp | The result is a simply composite image cut by the shape of image. None of the image data of image is included in the result.
OutCompositeOp | The resulting image is composite image with the shape of image cut out.
AtopCompositeOp | The result is the same shape as image image, with composite image obscuring image there the image shapes overlap. Note that this differs from OverCompositeOp because the portion of composite image outside of image's shape does not appear in the result.
XorCompositeOp | The result is the image data from both composite image and image that is outside the overlap region. The overlap region will be blank.
PlusCompositeOp | The result is just the sum of the image data. Output values are cropped to 255 (no overflow). This operation is independent of the matte channels.
MinusCompositeOp | The result of composite image - image, with overflow cropped to zero. The matte chanel is ignored (set to 255, full coverage).
AddCompositeOp | The result of composite image + image, with overflow wrapping around (mod 256).
SubtractCompositeOp | The result of composite image - image, with underflow wrapping around (mod 256). The add and subtract operators can be used to perform reverible transformations.
DifferenceCompositeOp | The result of abs(composite image - image). This is useful for comparing two very similar images.
MultiplyCompositeOp |
BumpmapCompositeOp | The result image shaded by composite image.
CopyCompositeOp | The resulting image is image replaced with composite image. Here the matte information is ignored.
CopyRedCompositeOp | The resulting image is the red layer in image replaced with the red layer in composite image. The other layers are copied untouched.
CopyGreenCompositeOp | The resulting image is the green layer in image replaced with the green layer in composite image. The other layers are copied untouched.
CopyBlueCompositeOp | The resulting image is the blue layer in image replaced with the blue layer in composite image. The other layers are copied untouched.

CopyOpacityCompositeOp

The resulting image is the matte layer in image replaced with the matte layer in composite image. The other layers are copied untouched.

The image compositor requires a matte, or alpha channel in the image for some operations. This extra channel usually defines a mask which represents a sort of a cookie-cutter for the image. This is the case when matte is 255 (full coverage) for pixels inside the shape, zero outside, and between zero and 255 on the boundary. For certain operations, if image does not have a matte channel, it is initialized with 0 for any pixel matching in color to pixel location (0,0), otherwise 255 (to work properly borderWidth must be 0).

ClearCompositeOp |
DissolveCompositeOp |
DisplaceCompositeOp |
ModulateCompositeOp |
ThresholdCompositeOp |

CompressionType

CompressionType is used to express the desired compression type when encoding an image. Be aware that most image types only support a sub-set of the available compression types. If the compression type specified is incompatable with the image, GraphicsMagick selects a compression type compatable with the image type.

CompressionType

Enumeration | Description
UndefinedCompression | Unset value.
NoCompression | No compression
BZipCompression | BZip (Burrows-Wheeler block-sorting text compression algorithm and Huffman coding) as used by bzip2 utilities
FaxCompression | CCITT Group 3 FAX compression
Group4Compression | CCITT Group 4 FAX compression (used only for TIFF)
JPEGCompression | JPEG compression
LZWCompression | Lempel-Ziv-Welch (LZW) compression (caution, patented by Unisys)
RunlengthEncodedCompression | Run-Length encoded (RLE) compression
ZipCompression | Lempel-Ziv compression (LZ77) as used in PKZIP and GNU gzip.

DecorationType

The DecorationType enumerations are used to specify line decorations of rendered text.

DecorationType

Enumeration | Description
NoDecoration | No decoration
UnderlineDecoration | Underlined text
OverlineDecoration | Overlined text
LineThroughDecoration | Strike-through text

EndianType

The EndianType enumerations are used to specify the endian option for formats which support it (e.g. TIFF).

EndianType

Enumeration | Description
UndefinedEndian | Not defined (default)
LSBEndian | Little endian (like Intel X86 and DEC Alpha)
MSBEndian | Big endian (like Motorola 68K, Mac PowerPC, & SPARC)

FillRule

FillRule specifies the algorithm which is to be used to determine what parts of the canvas are included inside the shape. See the documentation on SVG's fill-rule property for usage details.

FillRule

UndefinedRule | Fill rule not specified
EvenOddRule | See SVG fill-rule evenodd rule.
NonZeroRule | See SVG fill-rule nonzero rule.

FilterTypes

FilterTypes is used to adjust the filter algorithm used when resizing images. Different filters experience varying degrees of success with various images and can take sipngicantly different amounts of processing time. GraphicsMagick uses the LanczosFilter by default since this filter has been shown to provide the best results for most images in a reasonable amount of time. Other filter types (e.g. TriangleFilter) may execute much faster but may show artifacts when the image is re-sized or around diagonal lines. The only way to be sure is to test the filter with sample images.

FilterTypes

Enumeration | Description
UndefinedFilter | Unset value.
PointFilter | Point Filter
BoxFilter | Box Filter
TriangleFilter | Triangle Filter
HermiteFilter | Hermite Filter
HanningFilter | Hanning Filter
HammingFilter | Hamming Filter
BlackmanFilter | Blackman Filter
GaussianFilter | Gaussian Filter
QuadraticFilter | Quadratic Filter
CubicFilter | Cubic Filter
CatromFilter | Catrom Filter
MitchellFilter | Mitchell Filter
LanczosFilter | Lanczos Filter
BesselFilter | Bessel Filter
SincFilter | Sinc Filter

GravityType

GravityType specifies positioning of an object (e.g. text, image) within a bounding region (e.g. an image). Gravity provides a convenient way to locate objects irrespective of the size of the bounding region, in other words, you don't need to provide absolute coordinates in order to position an object. A common default for gravity is NorthWestGravity.

GravityType

Enumeration | Description
ForgetGravity | Don't use gravity.
NorthWestGravity | Position object at top-left of region.
NorthGravity | Postiion object at top-center of region
NorthEastGravity | Position object at top-right of region
WestGravity | Position object at left-center of region
CenterGravity | Position object at center of region
EastGravity | Position object at right-center of region
SouthWestGravity | Position object at left-bottom of region
SouthGravity | Position object at bottom-center of region
SouthEastGravity | Position object at bottom-right of region

ImageType

ImageType indicates the type classification of the image.

ImageType

Enumeration | Description
UndefinedType | Unset value.
BilevelType | Monochrome image
GrayscaleType | Grayscale image
GrayscaleMatteType | Grayscale image with opacity
PaletteType | Indexed color (palette) image
PaletteMatteType | Indexed color (palette) image with opacity
TrueColorType | Truecolor image
TrueColorMatteType | Truecolor image with opacity
ColorSeparationType | Cyan/Yellow/Magenta/Black (CYMK) image

InterlaceType

InterlaceType specifies the ordering of the red, green, and blue pixel information in the image. Interlacing is usually used to make image information available to the user faster by taking advantage of the space vs time tradeoff. For example, interlacing allows images on the Web to be recognizable sooner and satellite images to accumulate/render with image resolution increasing over time.

Use LineInterlace or PlaneInterlace to create an interlaced GIF or progressive JPEG image.

InterlaceType

Enumeration | Description
UndefinedInterlace | Unset value.
NoInterlace | Don't interlace image (RGBRGBRGBRGBRGBRGB...)
LineInterlace | Use scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...)
PlaneInterlace | Use plane interlacing (RRRRRR...GGGGGG...BBBBBB...)
PartitionInterlace | Similar to plane interlaing except that the different planes are saved to individual files (e.g. image.R, image.G, and image.B)

ChannelType

ChannelType is used as an argument when doing color separations. Use ChannelType when extracting a layer from an image. MatteLayer is useful for extracting the opacity values from an image.

ChannelType

Enumeration | Description
UndefinedLayer | Unset value.
RedLayer | Select red layer
GreenLayer | Select green layer
BlueLayer | Select blue layer
MatteLayer | Select matte (opacity values) layer

LineCap

The LineCap enumerations specify shape to be used at the end of open subpaths when they are stroked. See SVG's 'stroke-linecap' for examples.

LineCap

Enumeration | Description
UndefinedCap | Unset value.
ButtCap | Square ending.
RoundCap | Rounded ending (half-circle end with radius of 1/2 stroke width).
SquareCap | Square ending, extended by 1/2 the stroke width at end.

LineJoin

The LineJoin enumerations specify the shape to be used at the corners of paths or basic shapes when they are stroked. See SVG's 'stroke-linejoin' for examples.

ChannelType

Enumeration | Description
UndefinedJoin | Unset value.
MiterJoin | Sharp-edged join
RoundJoin | Rounded-edged join
BevelJoin | Beveled-edged join

NoiseType

NoiseType is used as an argument to select the type of noise to be added to the image.

NoiseType

Enumeration | Description
UniformNoise | Uniform noise
GaussianNoise | Gaussian noise
MultiplicativeGaussianNoise | Multiplicative Gaussian noise
ImpulseNoise | Impulse noise
LaplacianNoise | Laplacian noise
PoissonNoise | Poisson noise

OrientationType

OrientationType specifies the orientation of the image. Useful for when the image is produced via a different ordinate system, the camera was turned on its side, or the page was scanned sideways.

OrientationType

Enumeration | Scanline Direction | Frame Direction
UndefinedOrientation | Unknown | Unknown
TopLeftOrientation | Left to right | Top to bottom
TopRightOrientation | Right to left | Top to bottom
BottomRightOrientation | Right to left | Bottom to top
BottomLeftOrientation | Left to right | Bottom to top
LeftTopOrientation | Top to bottom | Left to right
RightTopOrientation | Top to bottom | Right to left
RightBottomOrientation | Bottom to top | Right to left
LeftBottomOrientation | Bottom to top | Left to right

PaintMethod

PaintMethod specifies how pixel colors are to be replaced in the image. It is used to select the pixel-filling algorithm employed.

PaintMethod

Enumeration | Description
PointMethod | Replace pixel color at point.
ReplaceMethod | Replace color for all image pixels matching color at point.
FloodfillMethod | Replace color for pixels surrounding point until encountering pixel that fails to match color at point.
FillToBorderMethod | Replace color for pixels surrounding point until encountering pixels matching border color.
ResetMethod | Replace colors for all pixels in image with pen color.

QuantumTypes

QuantumTypes is used to indicate the source or destination format of entire pixels, or components of pixels ("Quantums") while they are being read, or written to, a pixel cache. The validity of these format specifications depends on whether the Image pixels are in RGB format, RGBA format, or CMYK format. The pixel Quantum size is determined by the Image depth (eight or sixteen bits).

RGB(A) Image Quantums

Enumeration | Description
IndexQuantum | PseudoColor colormap indices (valid only for image with colormap)
RedQuantum | Red pixel Quantum
GreenQuantum | Green pixel Quantum
BlueQuantum | Blue pixel Quantum
OpacityQuantum | Opacity (Alpha) Quantum

CMY(K) Image Quantum

Enumeration | Description
CyanQuantum | Cyan pixel Quantum
MagentaQuantum | Magenta pixel Quantum
YellowQuantum | Yellow pixel Quantum
BlackQuantum | Black pixel Quantum

Grayscale Image Quantums

Enumeration | Description
GrayQuantum | Gray pixel
GrayOpacityQuantum | Pixel opacity

Entire Pixels (Expressed in Byte Order)

Enumeration | Description
RGBQuantum | RGB pixel (24 or 48 bits)
RGBAQuantum | RGBA pixel (32 or 64 bits)
CMYKQuantum | CMYK pixel (32 or 64 bits)

RenderingIntent

Rendering intent is a concept defined by ICC Spec ICC.1:1998-09, "File Format for Color Profiles". GraphicsMagick uses RenderingIntent in order to support ICC Color Profiles.

From the specification: "Rendering intent specifies the style of reproduction to be used during the evaluation of this profile in a sequence of profiles. It applies specifically to that profile in the sequence and not to the entire sequence. Typically, the user or application will set the rendering intent dynamically at runtime or embedding time."

RenderingIntent

Enumeration | Description
UndefinedIntent | Unset value.
SaturationIntent | A rendering intent that specifies the saturation of the pixels in the image is preserved perhaps at the expense of accuracy in hue and lightness.
PerceptualIntent | A rendering intent that specifies the full gamut of the image is compressed or expanded to fill the gamut of the destination device. Gray balance is preserved but colorimetric accuracy might not be preserved.
AbsoluteIntent | Absolute colorimetric
RelativeIntent | Relative colorimetric

ResolutionType

By default, GraphicsMagick defines resolutions in pixels per inch. ResolutionType provides a means to adjust this.

ResolutionType

Enumeration | Description
UndefinedResolution | Unset value.
PixelsPerInchResolution | Density specifications are specified in units of pixels per inch (english units).
PixelsPerCentimeterResolution | Density specifications are specified in units of pixels per centimeter (metric units).

StorageType

The StorageType enumerations are used to specify the storage format of pixels in the source or destination pixel array.

StorageType

Enumeration | Description
CharPixel | Character type
ShortPixel | Short type
IntegerPixel | Integer type
FloatPixel | Float type
DoublePixel | Double type

StretchType

The StretchType enumerations are used to specify the relative width of a font to the regular width for the font family. If the width is not important, the AnyStretch enumeration may be specified for a wildcard match.

StretchType

Enumeration | Description
AnyStretch | Wildcard match for font stretch
NormalStretch | Normal width font
UltraCondensedStretch | Ultra-condensed (narrowest) font
ExtraCondensedStretch | Extra-condensed font
CondensedStretch | Condensed font
SemiCondensedStretch | Semi-Condensed font
SemiExpandedStretch | Semi-Expanded font
ExpandedStretch | Expanded font
ExtraExpandedStretch | Extra-Expanded font
UltraExpandedStretch | Ultra-expanded (widest) font

StyleType

The StyleType enumerations are used to specify the style (e.g. Italic) of a font. If the style is not important, the AnyStyle enumeration may be specified for a wildcard match.

StyleType

Enumeration | Description
AnyStyle | Wildcard match for font style
NormalStyle | Normal font style
ItalicStyle | Italic font style
ObliqueStyle | Oblique font style