image(3)
NAME
Tk::Image - Create and manipulate images
SYNOPSIS
$image = $widget->type(?arg arg ...?) $image->method(?arg arg ...?)
DESCRIPTION
The image constructors and methods are used to create,
delete, and query images. It can take several different
forms, depending on the type.
The constructors require a $widget to invoke them, this is
used to locate a MainWindow. (This is because the underly
ing Tk code registers the images in the data structure for
the MainWindow.)
The legal forms are:
- $widget->type?(?name?,?option=>value ...)?
- Creates a new image and returns an object. type spec
ifies the type of the image, which must be one of the
types currently defined (e.g., Bitmap). name speci fies the name for the image; if it is omitted then Tk
picks a name of the form imagex, where x is an inte
ger. There may be any number of option=>value pairs, which provide configuration options for the new image.
The legal set of options is defined separately for
each image type; see below for details on the options
for built-in image types. If an image already exists
by the given name then it is replaced with the new
image and any instances of that image will redisplay
with the new contents. - $image->delete
- Deletes the image $image and returns an empty string.
If there are instances of the image displayed in wid
gets, the image won't actually be deleted until all of
the instances are released. However, the association
between the instances and the image manager will be
dropped. Existing instances will retain their sizes
but redisplay as empty areas. If a deleted image is
recreated (with the same name) the existing instances
will use the new image. - $image->height
- Returns a decimal string giving the height of image
name in pixels. - $widget->imageNames
- Returns a list containing all existing images for
$widget's MainWindow. - $image->type
- Returns the type of $image (the value of the type method when the image was created).
- $widget->imageTypes
- Returns a list whose elements are all of the valid
image types (i.e., all of the values that may be sup
plied for the type to create an image). - $image->width
- Returns a decimal string giving the width of image
name in pixels.
BUILT-IN IMAGE TYPES
The following image types are defined by Tk so they will
be available in any Tk application. Individual applica
tions or extensions may define additional types.
- Bitmap
- Each pixel in the image displays a foreground color, a
background color, or nothing. See Tk::Bitmap for more
information. - Pixmap
- Pixmap is slightly more general than Bitmap, each
pixel can be any available color or "transparent"
(rendered as background color of the widget image is
displayed in). Pixmap is best used for icons and other simple graphics with only a few colors. - Pixmap is derived from Tix. See Tk::Pixmap for more
information. - Photo
- Displays a variety of full-color images, using dither
ing to approximate colors on displays with limited
color capabilities. See Tk::Photo documentation for
more information.
SEE ALSO
Tk::Bitmap Tk::Pixmap Tk::Photo
KEYWORDS
- height, image, types of images, width