Tk::Image - Create and manipulate images
$image =
$widget->type(?arg arg ...?)
$image->method(?arg arg
...?)
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
underlying 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 specifies the type
of the image, which must be one of the types currently defined (e.g.,
Bitmap). name specifies the name for the image; if it is
omitted then Tk picks a name of the form imagex, where
x is an integer. 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 widgets, 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.
- $image->inuse
- Returns a boolean value indicating whether or not the image is in use by
any widgets.
- $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 supplied for the type to create an
image).
- $image->width
- Returns a decimal string giving the width of image name in
pixels.
The following image types are defined by Tk so they will be available in any Tk
application. Individual applications 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 dithering to approximate
colors on displays with limited color capabilities. See Tk::Photo
documentation for more information.
It's necessary to use the "delete" method to delete an image object
and free memory associated with it. Just using a lexical variable for storing
the image object and letting the variable to go out of scope or setting to
"undef" is not sufficient.
Tk::Bitmap Tk::Pixmap Tk::Photo
height, image, types of images, width