Windows PowerShell command on Get-command photo

Manual Pages for UNIX Operating System command usage for man photo

Tk Built-In Commands photo(1T)

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NAME

photo - Full-color images

SYNOPSIS

image create photo ?name? ?options?

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DESCRIPTION

A photo is an image whose pixels can display any color or be

transparent. A photo image is stored internally in full

color (32 bits per pixel), and is displayed using dithering

if necessary. Image data for a photo image can be obtained

from a file or a string, or it can be supplied from C code through a procedural interface. At present, only GIF and

PPM/PGM formats are supported, but an interface exists to allow additional image file formats to be added easily. A

photo image is transparent in regions where no image data

has been supplied or where it has been set transparent by | the transparency set subcommand. CREATING PHOTOS

Like all images, photos are created using the image create

command. Photos support the following options:

-data string

Specifies the contents of the image as a string. The string should contain binary data or, for some formats,

base64-encoded data (this is currently guaranteed to be

supported for GIF images). The format of the string must be one of those for which there is an image file format handler that will accept string data. If both

the -data and -file options are specified, the -file

option takes precedence.

-format format-name

Specifies the name of the file format for the data

specified with the -data or -file option.

-file name

name gives the name of a file that is to be read to

supply data for the photo image. The file format must

be one of those for which there is an image file format handler that can read data.

-gamma value

Specifies that the colors allocated for displaying this

image in a window should be corrected for a non-linear

display with the specified gamma exponent value. (The intensity produced by most CRT displays is a power Tk Last change: 4.0 1

Tk Built-In Commands photo(1T)

function of the input value, to a good approximation; gamma is the exponent and is typically around 2). The value specified must be greater than zero. The default value is one (no correction). In general, values greater than one will make the image lighter, and values less than one will make it darker.

-height number

Specifies the height of the image, in pixels. This option is useful primarily in situations where the user wishes to build up the contents of the image piece by piece. A value of zero (the default) allows the image to expand or shrink vertically to fit the data stored in it.

-palette palette-spec

Specifies the resolution of the color cube to be allo-

cated for displaying this image, and thus the number of colors used from the colormaps of the windows where it

is displayed. The palette-spec string may be either a

single decimal number, specifying the number of shades of gray to use, or three decimal numbers separated by slashes (/), specifying the number of shades of red, green and blue to use, respectively. If the first form (a single number) is used, the image will be displayed in monochrome (i.e., grayscale).

-width number

Specifies the width of the image, in pixels. This option is useful primarily in situations where the user wishes to build up the contents of the image piece by piece. A value of zero (the default) allows the image to expand or shrink horizontally to fit the data stored in it. IMAGE COMMAND

When a photo image is created, Tk also creates a new command

whose name is the same as the image. This command may be used to invoke various operations on the image. It has the following general form: imageName option ?arg arg ...?

Option and the args determine the exact behavior of the com-

mand. Those options that write data to the image generally expand the size of the image, if necessary, to accommodate the data

written to the image, unless the user has specified non-zero

values for the -width and/or -height configuration options,

in which case the width and/or height, respectively, of the image will not be changed. Tk Last change: 4.0 2

Tk Built-In Commands photo(1T)

The following commands are possible for photo images:

imageName blank Blank the image; that is, set the entire image to have no data, so it will be displayed as transparent, and the background of whatever window it is displayed in will show through. imageName cget option Returns the current value of the configuration option given by option. Option may have any of the values

accepted by the image create photo command.

imageName configure ?option? ?value option value ...? Query or modify the configuration options for the image. If no option is specified, returns a list describing all of the available options for imageName

(see Tk_ConfigureInfo for information on the format of

this list). If option is specified with no value, then the command returns a list describing the one named

option (this list will be identical to the correspond-

ing sublist of the value returned if no option is

specified). If one or more option-value pairs are

specified, then the command modifies the given option(s) to have the given value(s); in this case the command returns an empty string. Option may have any

of the values accepted by the image create photo com-

mand. imageName copy sourceImage ?option value(s) ...? Copies a region from the image called sourceImage

(which must be a photo image) to the image called

imageName, possibly with pixel zooming and/or subsam-

pling. If no options are specified, this command

copies the whole of sourceImage into imageName, start-

ing at coordinates (0,0) in imageName. The following options may be specified:

-from x1 y1 x2 y2

Specifies a rectangular sub-region of the source

image to be copied. (x1,y1) and (x2,y2) specify diagonally opposite corners of the rectangle. If x2 and y2 are not specified, the default value is

the bottom-right corner of the source image. The

pixels copied will include the left and top edges of the specified rectangle but not the bottom or

right edges. If the -from option is not given,

the default is the whole source image.

-to x1 y1 x2 y2

Specifies a rectangular sub-region of the destina-

tion image to be affected. (x1,y1) and (x2,y2) Tk Last change: 4.0 3

Tk Built-In Commands photo(1T)

specify diagonally opposite corners of the rectan-

gle. If x2 and y2 are not specified, the default value is (x1,y1) plus the size of the source

region (after subsampling and zooming, if speci-

fied). If x2 and y2 are specified, the source region will be replicated if necessary to fill the destination region in a tiled fashion.

-shrink

Specifies that the size of the destination image should be reduced, if necessary, so that the

region being copied into is at the bottom-right

corner of the image. This option will not affect the width or height of the image if the user has

specified a non-zero value for the -width or

-height configuration option, respectively.

-zoom x y

Specifies that the source region should be magni-

fied by a factor of x in the X direction and y in the Y direction. If y is not given, the default value is the same as x. With this option, each pixel in the source image will be expanded into a block of x x y pixels in the destination image, all the same color. x and y must be greater than 0.

-subsample x y

Specifies that the source image should be reduced in size by using only every xth pixel in the X

direction and yth pixel in the Y direction. Nega-

tive values will cause the image to be flipped about the Y or X axes, respectively. If y is not given, the default value is the same as x.

-compositingrule rule

Specifies how transparent pixels in the source | image are combined with the destination image. | When a compositing rule of overlay is set, the old | contents of the destination image are visible, as | if the source image were printed on a piece of | transparent film and placed over the top of the | destination. When a compositing rule of set is | set, the old contents of the destination image are |

discarded and the source image is used as-is. The |

default compositing rule is overlay. imageName data ?option value(s) ...?

Returns image data in the form of a string. The follow-

ing options may be specified:

-background color

Tk Last change: 4.0 4

Tk Built-In Commands photo(1T)

If the color is specified, the data will not con-

tain any transparency information. In all tran-

sparent pixels the color will be replaced by the specified color.

-format format-name

Specifies the name of the image file format handler to be used. Specifically, this subcommand searches for the first handler whose name matches

an initial substring of format-name and which has

the capability to read this image data. If this option is not given, this subcommand uses the first handler that has the capability to read the image data.

-from x1 y1 x2 y2

Specifies a rectangular region of imageName to be returned. If only x1 and y1 are specified, the

region extends from (x1,y1) to the bottom-right

corner of imageName. If all four coordinates are given, they specify diagonally opposite corners of the rectangular region, including x1,y1 and excluding x2,y2. The default, if this option is not given, is the whole image.

-grayscale

If this options is specified, the data will not contain color information. All pixel data will be transformed into grayscale. imageName get x y Returns the color of the pixel at coordinates (x,y) in the image as a list of three integers between 0 and 255, representing the red, green and blue components respectively. imageName put data ?option value(s) ...? Sets pixels in imageName to the data specified in data. This command first searches the list of image file format handlers for a handler that can interpret the data in data, and then reads the image encoded within into imageName (the destination image). If data

does not match any known format, an attempt to inter-

pret it as a (top-to-bottom) list of scan-lines is

made, with each scan-line being a (left-to-right) list

of pixel colors (see Tk_GetColor for a description of

valid colors.) Every scan-line must be of the same

length. Note that when data is a single color name, you are instructing Tk to fill a rectangular region

with that color. The following options may be speci-

fied: Tk Last change: 4.0 5

Tk Built-In Commands photo(1T)

-format format-name

Specifies the format of the image data in data. Specifically, only image file format handlers

whose names begin with format-name will be used

while searching for an image data format handler to read the data.

-to x1 y1 ?x2 y2?

Specifies the coordinates of the top-left corner

(x1,y1) of the region of imageName into which data from filename are to be read. The default is (0,0). If x2,y2 is given and data is not large enough to cover the rectangle specified by this option, the image data extracted will be tiled so it covers the entire destination rectangle. Note that if data specifies a single color value, then

a region extending to the bottom-right corner

represented by (x2,y2) will be filled with that color. imageName read filename ?option value(s) ...? Reads image data from the file named filename into the image. This command first searches the list of image file format handlers for a handler that can interpret the data in filename, and then reads the image in filename into imageName (the destination image). The following options may be specified:

-format format-name

Specifies the format of the image data in filename. Specifically, only image file format

handlers whose names begin with format-name will

be used while searching for an image data format handler to read the data.

-from x1 y1 x2 y2

Specifies a rectangular sub-region of the image

file data to be copied to the destination image. If only x1 and y1 are specified, the region

extends from (x1,y1) to the bottom-right corner of

the image in the image file. If all four coordi-

nates are specified, they specify diagonally oppo-

site corners or the region. The default, if this option is not specified, is the whole of the image in the image file.

-shrink

If this option, the size of imageName will be reduced, if necessary, so that the region into which the image file data are read is at the

bottom-right corner of the imageName. This option

will not affect the width or height of the image Tk Last change: 4.0 6

Tk Built-In Commands photo(1T)

if the user has specified a non-zero value for the

-width or -height configuration option, respec-

tively.

-to x y

Specifies the coordinates of the top-left corner

of the region of imageName into which data from filename are to be read. The default is (0,0). imageName redither

The dithering algorithm used in displaying photo images

propagates quantization errors from one pixel to its neighbors. If the image data for imageName is supplied in pieces, the dithered image may not be exactly correct. Normally the difference is not noticeable, but if it is a problem, this command can be used to recalculate the dithered image in each window where the image is displayed. imageName transparency subcommand ?arg arg ...? Allows examination and manipulation of the transparency |

information in the photo image. Several subcommands |

are available: | imageName transparency get x y || Returns a boolean indicating if the pixel at (x,y) | is transparent. | imageName transparency set x y boolean || Makes the pixel at (x,y) transparent if boolean is | true, and makes that pixel opaque otherwise. | imageName write filename ?option value(s) ...? Writes image data from imageName to a file named filename. The following options may be specified:

-background color

If the color is specified, the data will not con-

tain any transparency information. In all tran-

sparent pixels the color will be replaced by the specified color.

-format format-name

Specifies the name of the image file format handler to be used to write the data to the file. Specifically, this subcommand searches for the

first handler whose name matches an initial sub-

string of format-name and which has the capability

to write an image file. If this option is not given, this subcommand uses the first handler that has the capability to write an image file. Tk Last change: 4.0 7

Tk Built-In Commands photo(1T)

-from x1 y1 x2 y2

Specifies a rectangular region of imageName to be written to the image file. If only x1 and y1 are specified, the region extends from (x1,y1) to the

bottom-right corner of imageName. If all four

coordinates are given, they specify diagonally opposite corners of the rectangular region. The default, if this option is not given, is the whole image.

-grayscale

If this options is specified, the data will not contain color information. All pixel data will be transformed into grayscale. IMAGE FORMATS

The photo image code is structured to allow handlers for

additional image file formats to be added easily. The photo

image code maintains a list of these handlers. Handlers are added to the list by registering them with a call to

Tk_CreatePhotoImageFormat. The standard Tk distribution

comes with handlers for PPM/PGM and GIF formats, which are automatically registered on initialization.

When reading an image file or processing string data speci-

fied with the -data configuration option, the photo image

code invokes each handler in turn until one is found that claims to be able to read the data in the file or string. Usually this will find the correct handler, but if it

doesn't, the user may give a format name with the -format

option to specify which handler to use. In fact the photo

image code will try those handlers whose names begin with

the string specified for the -format option (the comparison

is case-insensitive). For example, if the user specifies

-format gif, then a handler named GIF87 or GIF89 may be

invoked, but a handler named JPEG may not (assuming that such handlers had been registered). When writing image data to a file, the processing of the

-format option is slightly different: the string value given

for the -format option must begin with the complete name of

the requested handler, and may contain additional informa-

tion following that, which the handler can use, for example, to specify which variant to use of the formats supported by the handler. Note that not all image handlers may support | writing transparency data to a file, even where the target | image format does. COLOR ALLOCATION

When a photo image is displayed in a window, the photo image

code allocates colors to use to display the image and dith-

ers the image, if necessary, to display a reasonable Tk Last change: 4.0 8

Tk Built-In Commands photo(1T)

approximation to the image using the colors that are avail-

able. The colors are allocated as a color cube, that is, the number of colors allocated is the product of the number of shades of red, green and blue. Normally, the number of colors allocated is chosen based on

the depth of the window. For example, in an 8-bit Pseu-

doColor window, the photo image code will attempt to allo-

cate seven shades of red, seven shades of green and four

shades of blue, for a total of 198 colors. In a 1-bit Sta-

ticGray (monochrome) window, it will allocate two colors,

black and white. In a 24-bit DirectColor or TrueColor win-

dow, it will allocate 256 shades each of red, green and blue. Fortunately, because of the way that pixel values can be combined in DirectColor and TrueColor windows, this only requires 256 colors to be allocated. If not all of the

colors can be allocated, the photo image code reduces the

number of shades of each primary color and tries again. The user can exercise some control over the number of colors

that a photo image uses with the -palette configuration

option. If this option is used, it specifies the maximum number of shades of each primary color to try to allocate. It can also be used to force the image to be displayed in shades of gray, even on a color display, by giving a single number rather than three numbers separated by slashes. CREDITS

The photo image type was designed and implemented by Paul

Mackerras, based on his earlier photo widget and some

suggestions from John Ousterhout.

EXAMPLE

Load an image from a file and tile it to the size of a win-

dow, which is useful for producing a tiled background:

# These lines should be called once

image create photo untiled -file "theFile.ppm"

image create photo tiled

# These lines should be called whenever .someWidget changes

# size; a binding is useful here

set width [winfo width .someWidget] set height [winfo height .someWidget]

tiled copy untiled -to 0 0 $width $height -shrink

photo, image, color

Tk Last change: 4.0 9

Tk Built-In Commands photo(1T)

ATTRIBUTES

See attributes(5) for descriptions of the following attri-

butes:

_______________________________________

| ATTRIBUTE TYPE | ATTRIBUTE VALUE|

|____________________|__________________|_

| Availability | runtime/tk-8 |

|____________________|__________________|_

| Interface Stability| Uncommitted |

|____________________|_________________|

NOTES Source for Tk is available on http://opensolaris.org. Tk Last change: 4.0 10

Manual Pages for UNIX Operating System command usage for man photo

Tk Built-In Commands photo(1T)

NAME

photo - Full-color images

SYNOPSIS

image create photo ?name? ?options?

DESCRIPTION

A photo is an image whose pixels can display any color or be

transparent. A photo image is stored internally in full

if necessary. Image data for a photo image can be obtained

photo image is transparent in regions where no image data

Like all images, photos are created using the image create

supply data for the photo image. The file format must

Tk Built-In Commands photo(1T)

When a photo image is created, Tk also creates a new command

Tk Built-In Commands photo(1T)

The following commands are possible for photo images:

accepted by the image create photo command.

of the values accepted by the image create photo com-

(which must be a photo image) to the image called

Tk Built-In Commands photo(1T)

Tk Built-In Commands photo(1T)

Tk Built-In Commands photo(1T)

Tk Built-In Commands photo(1T)

The dithering algorithm used in displaying photo images

information in the photo image. Several subcommands |

Tk Built-In Commands photo(1T)

The photo image code is structured to allow handlers for

additional image file formats to be added easily. The photo

fied with the -data configuration option, the photo image

option to specify which handler to use. In fact the photo

When a photo image is displayed in a window, the photo image

Tk Built-In Commands photo(1T)

doColor window, the photo image code will attempt to allo-

colors can be allocated, the photo image code reduces the

that a photo image uses with the -palette configuration

The photo image type was designed and implemented by Paul

Mackerras, based on his earlier photo widget and some

EXAMPLE

image create photo untiled -file "theFile.ppm"

image create photo tiled

SEE ALSO

photo, image, color

Tk Built-In Commands photo(1T)

ATTRIBUTES

| ATTRIBUTE TYPE | ATTRIBUTE VALUE|