# NSBitmapImageRep.m

fedor@gnu.org
Generated at 2026-06-27 19:09:52 +0000

Bitmap image representation.

1996-2024 Free Software Foundation, Inc.
Class Description

NSBitmapImageRep is an image representation for handling images composed of pixels. The standard image format for NSBitmapImageRep is the TIFF format. However, through the use of image filters and other methods, many other standard image formats can be handled by NSBitmapImageRep. Images are typically handled through the NSImage class and there is often no need to use the NSBitmapImageRep class directly. However there may be cases where you want to manipulate the image bitmap data directly.

AppKit/NSBitmapImageRep.h
Description forthcoming.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
Warning the underscore at the start of the name of this instance variable indicates that, even though it is not technically private, it is intended for internal use within the package, and you should not use the variable in other code.
TIFFRepresentationOfImageRepsInArray:
anArray
Produces an NSData object containing a TIFF representation of all the images stored in anArray. BUGS: Currently this only works if the images are NSBitmapImageRep objects.
TIFFRepresentationOfImageRepsInArray:
anArray
usingCompression:
type
factor:
factor
Produces an NSData object containing a TIFF representation of all the images stored in anArray. The image is compressed according to the compression type and factor . BUGS: Currently this only works if the images are NSBitmapImageRep objects.
getTIFFCompressionTypes:
list
count:
numTypes
Returns a C-array of available TIFF compression types.
imageRepWithData:
imageData

Returns a newly allocated NSBitmapImageRep object representing the image stored in imageData. If the image data contains more than one image, the first one is choosen.

See Also: +imageRepsWithData:

imageRepsWithData:
imageData

Returns an array containing newly allocated NSBitmapImageRep objects representing the images stored in imageData.

See Also: +imageRepWithData:

localizedNameForTIFFCompressionType:
type
Returns a localized string describing a TIFF compression type.
representationOfImageRepsInArray:
imageReps
usingType:
storageType
properties:
properties

Returns a data object in the selected format with multiple images.

See Also: -setProperty:withValue: for the options supported in the properties.

FIXME: returns only the first image in the array, and only works for NSBitmapImageRep or subclasses thereof.

TIFFRepresentation
Returns an NSData object containing a TIFF representation of the receiver.
TIFFRepresentationUsingCompression:
type
factor:
factor
Returns an NSData object containing a TIFF representation of the receiver. The TIFF data is compressed using compresssion type and factor.
bitmapData
Returns the first plane of data representing the image.
bitmapFormat
Description forthcoming.
bitsPerPixel
Returns the number of bits need to contain one pixels worth of data. This is normally the number of samples per pixel times the number of bits in one sample.
bytesPerPlane
Returns the number of bytes in a plane. This is the number of bytes in a row times tne height of the image.
bytesPerRow
Returns the number of bytes in a row. This is typically based on the width of the image and the bits per sample and samples per pixel (if in medhed configuration). However it may differ from this if set explicitly in -initWithBitmapDataPlanes:pixelsWide:pixelsHigh:bitsPerSample:samplesPerPixel:hasAlpha:isPlanar:colorSpaceName:bytesPerRow:bitsPerPixel:.
canBeCompressedUsing:
compression
Returns `YES` if the receiver can be stored in a representation compressed using the compression type.
colorAtX:
x
y:
y
Returns an NSColor object representing the color of the pixel (x,y), where (0,0) is the top-left pixel in the image.
colorizeByMappingGray:
midPoint
toColor:
midPointColor
blackMapping:
shadowColor
whiteMapping:
lightColor
Description forthcoming.
getBitmapDataPlanes:
data
Files the array data with pointers to each of the data planes representing the image. The data array must be allocated to contain at least -samplesPerPixel pointers.
getCompression:
compression
factor:
factor
Returns the receivers compression and compression factor, which is set either when the image is read in or by -setCompression:factor: . Factor is ignored in many compression schemes. For JPEG compression, factor can be any value from 0 to 1, with 1 being the maximum quality.
getPixel:
pixelData
atX:
x
y:
y
Returns the values of the components of pixel ( x,y), where (0,0) is the top-left pixel in the image, by storing them in the array pixelData.
incrementalLoadFromData:
data
complete:
complete
Description forthcoming.
initForIncrementalLoad
Description forthcoming.
initWithBitmapDataPlanes:
planes
pixelsWide:
width
pixelsHigh:
height
bitsPerSample:
bps
samplesPerPixel:
spp
hasAlpha:
alpha
isPlanar:
isPlanar
colorSpaceName:
colorSpaceName
bitmapFormat:
bitmapFormat
bytesPerRow:
rowBytes
bitsPerPixel:
pixelBits
Description forthcoming.
initWithBitmapDataPlanes:
planes
pixelsWide:
width
pixelsHigh:
height
bitsPerSample:
bitsPerSample
samplesPerPixel:
samplesPerPixel
hasAlpha:
alpha
isPlanar:
isPlanar
colorSpaceName:
colorSpaceName
bytesPerRow:
rowBytes
bitsPerPixel:
pixelBits

Initializes a newly created NSBitmapImageRep object to hold image data specified in the planes buffer and organized according to the additional arguments passed into the method.

The planes argument is an array of char pointers where each array holds a single component or plane of data. Note that if data is passed into the method via planes, the data is NOT copied and not freed when the object is deallocated. It is assumed that the data will always be available. If planes is NULL, then a suitable amount of memory will be allocated to store the information needed. One can then obtain a pointer to the planes data using the -bitmapData or -getBitmapDataPlanes: method.

Each component of the data is in "standard" order, such as red, green, blue for RGB color images. The transparency component, if these is one, should always be last.

The other arguments to the method consist of:

width and height
The width and height of the image in pixels
bps
The bits per sample or the number of bits used to store a number in one component of one pixel of the image. Typically this is 8 (bits) but can be 2 or 4, although not all values are supported.
spp
Samples per pixel, or the number of components of color in the pixel. For instance this would be 4 for an RGB image with transparency.
alpha
Set to `YES` if the image has a transparency component.
isPlanar
Set to `YES` if the data is arranged in planes, i.e. one component per buffer as stored in the planes array. If `NO`, then the image data is mixed in one buffer. For instance, for RGB data, the first sample would contain red, then next green, then blue, followed by red for the next pixel.
colorSpaceName
This argument specifies how the data values are to be interpreted. Possible values include the typical colorspace names (although not all values are currently supported)
rowBytes
Specifies the number of bytes contained in a single scan line of the data. Normally this can be computed from the width of the image, the samples per pixel and the bits per sample. However, if the data is aligned along word boundaries, this value may differ from this. If rowBytes is 0, the method will calculate the value assuming there are no extra bytes at the end of the scan line.
pixelBits
This is normally bps for planar data and bps times spp for non-planar data, but sometimes images have extra bits. If pixelBits is 0 it will be calculated as described above.
initWithBitmapHandle:
bitmap
Description forthcoming.
initWithData:
imageData
Loads only the default (first) image from the image contained in data.
initWithFocusedViewRect:
rect
Initialize with bitmap data from a rect within the focused view
initWithIconHandle:
icon
Description forthcoming.
isPlanar
Returns `YES` if the image components are stored separately. Returns `NO` if the components are meshed (i.e. all the samples for one pixel come before the next pixel).
numberOfPlanes
Returns the number of planes in an image. Typically this is equal to the number of samples in a planar image or 1 for a non-planar image.
representationUsingType:
storageType
properties:
properties

Returns a data object in one of the supported bitmap graphics file types. A limited set of options may be passed via the properties. If the passed in properties is `nil`, it falls back to the options set with -setProperty:withValue: . File types not yet implemented return `nil` and log an error message.

See Also: -setProperty:withValue: for supported options in the properties.

samplesPerPixel
Returns the number of samples in a pixel. For instance, a normal RGB image with transparency would have a samplesPerPixel of 4.
setColor:
color
atX:
x
y:
y
Sets the color of pixel (x,y), where (0,0) is the top-left pixel in the image.
setCompression:
compression
factor:
factor
Description forthcoming.
setPixel:
pixelData
atX:
x
y:
y
Sets the components of pixel (x,y), where (0,0) is the top-left pixel in the image, to the given array of pixel components.
setProperty:
property
withValue:
value

Properties are key-value pairs associated with the representation. Arbitrary key-value pairs may be set. If the value is `nil`, the key is erased from properties. There are standard keys that are used to pass information and options related to the standard file types that may be read from or written to. Certain properties are automatically set when reading in image data. Certain properties may be set by the user prior to writing image data in order to set options for the data format.

NSImageCompressionMethod
NSNumber; automatically set when reading TIFF data; writing TIFF data
NSImageCompressionFactor
NSNumber 0.0 to 1.0; writing JPEG data (GNUstep extension: JPEG-compressed TIFFs too)
NSImageProgressive
NSNumber boolean; automatically set when reading JPEG data; writing JPEG data. Note: progressive display is not supported in GNUstep at this time.
NSImageInterlaced
NSNumber boolean; only for writing PNG data
NSImageGamma
NSNumber 0.0 to 1.0; only for reading or writing PNG data
NSImageRGBColorTable
NSData; automatically set when reading GIF data; writing GIF data
NSImageFrameCount
NSNumber integer; automatically set when reading animated GIF data. Not currently implemented.
NSImageCurrentFrame
NSNumber integer; only for animated GIF files. Not currently implemented.
NSImageCurrentFrameDuration
NSNumber float; automatically set when reading animated GIF data
NSImageLoopCount
NSNumber integer; automatically set when reading animated GIF data
NSImageDitherTranparency
NSNumber boolean; only for writing GIF data. Not currently supported.
valueForProperty:
property
Returns the value of a property
Software documentation for the NSBitmapImageRep(GNUstepExtension) category
AppKit/NSBitmapImageRep.h
Description forthcoming.
imageRepsWithFile:
filename
Description forthcoming.