GraphicsMagick

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# Enumerations

# 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 | RGB Red channel
CyanChannel | CMYK Cyan channel
GreenChannel | RGB Green channel
MagentaChannel | CMYK Magenta channel
BlueChannel | RGB Blue channel
YellowChannel | CMYK Yellow channel
OpacityChannel | Opacity channel (inverse of transparency)
BlackChannel | CMYK Black (K) channel
MatteChannel | Same as Opacity channel (deprecated)
AllChannels | All color channels
GrayChannel | Color channels represent an intensity

# 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, GRAYColorspace, or YCbCrColorspace 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 | Kodak PhotoCD sRGB

# 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 | Not defined.
OverCompositeOp | Union of the two image shapes, with opaque areas of change-image obscuring base-image in the region of overlap.
InCompositeOp | Change-image cut by the shape of base-image. None of the image data of base-image will be in the result.
OutCompositeOp | Change-image with the shape of base-image cut out.
AtopCompositeOp | Same shape as base-image, with change-image obscuring base-image where the image shapes overlap. Note this differs from over because the portion of change-image outside base-image's shape does not appear in the result.
XorCompositeOp | Image data from both change-image and base-image that is outside the overlap region. The overlap region will be blank
PlusCompositeOp | Sum of the image data. Output values are cropped to MaxRGB (no overflow). This operation is independent of the matte channels.
MinusCompositeOp | Change-image - base-image, with underflow cropped to zero. The matte channel is ignored (set to opaque, full coverage)
AddCompositeOp | Change-image + base-image, with overflow wrapping around (mod MaxRGB+1)
SubtractCompositeOp | Change-image - base-image, with underflow wrapping around (mod MaxRGB+1). The add and subtract operators can be used to perform reversible transformations
DifferenceCompositeOp | Absolute value of change-image minus base-image.
MultiplyCompositeOp | Change-image * base-image. This is useful for the creation of drop-shadows.
BumpmapCompositeOp | Base-image shaded by change-image
CopyCompositeOp | Base-image replaced with change-image. Here the matte information is ignored
CopyRedCompositeOp | Red channel in base-image replaced with the red channel in change-image. The other channels are copied untouched
CopyGreenCompositeOp | Green channel in base-image replaced with the green channel in change-image. The other channels are copied untouched.
CopyBlueCompositeOp | Blue channel in base-image replaced with the blue channel in change-image. The other channels are copied untouched.
CopyOpacityCompositeOp | Opacity channel in base-image replaced with the opacity channel in change-image. The other channels are copied untouched.
ClearCompositeOp | Pixels are set to transparent.
DissolveCompositeOp |
DisplaceCompositeOp |
ModulateCompositeOp |
ThresholdCompositeOp |
NoCompositeOp |
DarkenCompositeOp |
LightenCompositeOp |
HueCompositeOp |
SaturateCompositeOp |
ColorizeCompositeOp |
LuminizeCompositeOp |
ScreenCompositeOp | Not yet implemented (Photoshop & PDF)
OverlayCompositeOp | Not yet implemented (Photoshop & PDF)
CopyCyanCompositeOp |
CopyMagentaCompositeOp |
CopyYellowCompositeOp |
CopyBlackCompositeOp | Copy CMYK Black (K) channel.
DivideCompositeOp | Change-image / base-image. This is useful for improving the readability of text on unevenly illuminated photos. (by using a gaussian blurred copy of change-image as base-image)

# 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 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
RLECompression | Run-Length encoded (RLE) compression
ZipCompression | Lempel-Ziv compression (LZ77) as used in GNU gzip.
LZMACompression | Lempel-Ziv-Markov chain algorithm
JPEG2000Compression | ISO/IEC std 15444-1
JBIG1Compression | ISO/IEC std 11544 / ITU-T rec T.82
JBIG2Compression | ISO/IEC std 14492 / ITU-T rec T.88

# 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)
NativeEndian | Use native endian of this CPU

# 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
Enumeration | Description
--- | ---
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 bi-level 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
OptimizeType | Optimize type based on image characteristics

# InterlaceType

InterlaceType specifies the ordering of the red, green, and blue pixel information in the image. Interlacing is often 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.

LineJoin
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
--- | ---
UndefinedNoise | Unset value.
UniformNoise | Uniform noise
GaussianNoise | Gaussian noise
MultiplicativeGaussianNoise | Multiplicative Gaussian noise
ImpulseNoise | Impulse noise
LaplacianNoise | Laplacian noise
PoissonNoise | Poisson noise
RandomNoise | Random 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 (typically 8, 16, or 32 bits, but any value from 1-64 bits integer or float is supported).

RGB(A) Image Quantums
Enumeration | Description
--- | ---
IndexQuantum | PseudoColor colormap indices
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 (1 to 64 bits)
RGBAQuantum | RGBA pixel (1 to 64 bits)
CMYKQuantum | CMYK pixel (1 to 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

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