Class

Summary

The class simple-pane is the superclass for any elements that actually appear as a native window, and is itself an empty window.

Package

capi

Superclasses

element

Subclasses

display-pane
interface
title-pane
button-panel
list-panel
option-pane
output-pane
progress-bar
slider
text-input-pane
tree-view
toolbar
layout
button

Initargs

:enabled

A boolean controlling whether the pane is enabled.

:background

The background color of the pane.

:foreground

The foreground color of the pane.

:font

The default font for the pane.

:horizontal-scroll

t, :without-bar, or nil. If true the pane can scroll horizontally.

:vertical-scroll

t, :without-bar, or nil. If true the pane can scroll vertically.

:visible-border

A boolean or a keyword controlling whether the pane has a border, for some pane classes.

:internal-border

A non-negative integer, or nil. Controls the width of the internal border.

:cursor

A keyword naming a built-in cursor, or a cursor object, or nil.

:pane-menu

Specifies a menu to be raised by the :post-menu gesture.

:drop-callback

Specifies a drop callback for output-pane, interface, list-panel or tree-view.

Note that this is now supported for list-panel and tree-view on Cocoa and GTK+.

:drag-callback

Specifies a drag callback for list-panel or tree-view.

:automatic-resize

A plist.

:scroll-if-not-visible-p

Defines whether, when the focus is given to the pane and the pane is not fully visible, the pane's parent is automatically scrolled to show it.

:toolbar-title

A string.

The following initargs specify scroll parameters. These are actually useful only for output-pane and subclasses and for layouts. See entry for set-horizontal-scroll-parameters:

:scroll-horizontal-slug-size

:scroll-vertical-slug-size

:scroll-start-x

:scroll-start-y

:scroll-width

:scroll-height

:scroll-initial-x

:scroll-initial-y

:scroll-horizontal-step-size

:scroll-vertical-step-size

:scroll-horizontal-page-size

:scroll-vertical-page-size

Accessors

simple-pane-enabled
simple-pane-background
simple-pane-foreground
simple-pane-font
simple-pane-cursor
simple-pane-scroll-callback
simple-pane-drop-callback
simple-pane-drag-callback

Readers

simple-pane-horizontal-scroll
simple-pane-vertical-scroll
simple-pane-visible-border

Description

enabled determines whether the pane is enabled. The default value is t. Note that changing the enabled state of a visible pane by (setf simple-pane-enabled) changes its appearance.

background and foreground are colors specified using the Graphics Ports color system. Additionally on Cocoa, the special value :transparent is supported, which makes the pane's background match that of its parent.

font should be a font, a font-description, a font alias, or nil. If it is not a font, it is converted to a font when the pane is created. nil is converted to the default font, and a font-description is converted as if by calling find-best-font.

pane-menu can be used to specify or create a menu to be displayed when the :post-menu gesture is received by the pane. It has the default value :default which means that make-pane-popup-menu is called to create the menu. For a full description of pane-menu , see Popup menus for panes.

Notes

1. foreground is ignored for buttons on Windows and Cocoa.
2. On Microsoft Windows pane-menu is not supported for title-pane. See title-pane for alternative approaches.

Description: Cursor

cursor specifies a cursor for the pane. On Cocoa and GTK+, the cursor initarg has an effect only in output-pane and its subclasses. On other platforms it changes the cursor for other CAPI pane classes, although this may contravene style guidelines.

nil means use the default cursor, and this is the default value. cursor can also be a cursor object as returned by load-cursor. The other allowed values are keywords naming built-in cursors which are supported on each platform as shown in the table below.

 

cursor	Cocoa	Windows	Motif
:busy	No	Yes	Yes
:i-beam	Yes	Yes	Yes
:top-left-arrow	Yes	Yes	Yes
:h-double-arrow	Yes	Yes	Yes
:v-double-arrow	Yes	Yes	Yes
:left-side	Yes	Yes	Yes
:right-side	Yes	Yes	Yes
:top-side	Yes	Yes	Yes
:bottom-side	Yes	Yes	Yes
:wait	No	Yes	Yes
:crosshair	Yes	Yes	Yes
:gc-notification	No	Yes	Yes
:top-left-corner	No	Yes	Yes
:top-right-corner	No	Yes	Yes
:bottom-left-corner	No	Yes	Yes
:bottom-right-corner	No	Yes	Yes
:hand	Yes	Yes	Yes
:fleur	Yes	Yes	Yes
:move	Yes	Yes	Yes
:closed-hand	Yes	No	No
:open-hand	Yes	No	No
:disappearing-item	Yes	No	No

 

Description: Drag and drop

drop-callback can be specified for a pane that is an instance of output-pane, interface, list-panel, tree-view or a subclass of one of these. When the user drags an object over a window, the CAPI first tries to call the drop-callback of any pane under the mouse and otherwise calls the drop-callback of the top-level interface. The default value of drop-callback is nil, which means that there is no support for dropping into the pane.

For editor-pane, drop-callback can be :default, which provides support for dropping a string into the pane and inserting the string into the pane's editor buffer.

If drop-callback is any other non-nil value, it should be either a list (for simple cases) or function designator (to use all options). When it is a function designator, it needs to have this signature:

drop-callback pane drop-object stage

The function drop-callback is called by the CAPI at various times such as when the pane is displayed and when the user attempts to drop data into the pane. pane is the pane itself, drop-object is an object used to communicate information about the current dropping operation (see below) and stage is a keyword. drop-callback should handle these values of stage :

:formats

This might occur when the pane is being displayed or might occur each time the user drags or drops an object over the pane. It should call set-drop-object-supported-formats with the drop-object and a list of formats that the pane wants to receive. Each format is a keyword. The list of the formats must be the same each time it is called.

:enter

This occurs when the user drags an object into a pane which is an output-pane or interface (but not for a pane which is a list-panel or tree-view). It can query the drop-object using drop-object-provides-format and drop-object-allows-drop-effect-p to discover what the user is dragging. It can also use drop-object-pane-x and drop-object-pane-y to query the mouse position relative to the pane. It should call (setf drop-object-drop-effect) with an effect if it wants to allow the object to be dropped. If this is not called, then the object cannot be dropped into the pane.

:leave

This occurs when the user drags an object out of a pane which is an output-pane or interface (but not for a pane which is a list-panel or tree-view).

:drag

This occurs while the user is dragging an object over the pane. It can query the drop-object using drop-object-provides-format and drop-object-allows-drop-effect-p to discover what the user is dragging. For output-pane, it can use drop-object-pane-x and drop-object-pane-y to query the mouse position relative to the pane. For list-panel and tree-view, it can use drop-object-collection-index or drop-object-collection-item to query where the user is attempting to drop the object and can call their setf functions to adjust this position. It should call (setf drop-object-drop-effect) with an effect if it wants to allow the object to be dropped. If this is not called, then the object cannot be dropped into the pane. For output-pane and interface, it might also want to update the pane to indicate where the object will be dropped.

:drop

This occurs when the user drops an object over the pane. It can query the drop-object as for the :drag stage, but can also obtain the object itself using drop-object-get-object for one of the formats in the list returned by drop-object-provides-format. Once the object is received, it should call (setf drop-object-drop-effect) with the effect that has been used by the callback. It should also update the pane to incorporate the object in whatever way the application requires.

When drop-callback is a list, it specifies a simple response. The list should be of the form:

( effects formats drop-stage-callback &optional checker )

Both effects and formats can be either a list of effects or formats, or an atom which is interpreted as a list of one element. effects and formats specify which effects and formats are allowed.

For the stages except :formats, the first effect of the given effects that the drop-object allows is set (by calling (setf drop-object-drop-effect)), except when checker is supplied. In the latter case, before setting an effect it loops through the formats and calls the checker with three arguments:

funcall checker pane effect format

If checker returns non-nil it sets the effect. If checker returns nil for the formats, it goes to the next effect.

In the :drop stage, after setting the effect, it gets the object with first format that is provided by the drop-object , and then calls the drop-stage-callback with four arguments:

funcall drop-stage-callback pane object x-or-index y-or-placement

If the pane is a tree-view or list-panel, the last two arguments are the item index (for get-collection-item) and placement (:above, :item, :below), which are the results of drop-object-collection-index. Otherwise, the last two arguments are the x and y (results of drop-object-pane-x and drop-object-pane-y). It is the responsibility of the drop-stage-callback to perform whatever dropping should mean.

drag-callback can be specified for a pane that is an instance of list-panel or tree-view. The default value of drag-callback is nil, which means that there is no support for dragging from the pane. Otherwise, it should be a function designator with this signature:

drag-callback pane info => result

When the user drags items in the pane, the CAPI calls the drag-callback . pane is the pane itself and info is a list of item indices that are being dragged (compare with choice-selection).

The drag-callback should normally return a plist result whose keys are the data formats to be dragged, with a value associated with each format. Formats are arbitrary keywords that must be interpreted by the pane where you intend to drop the values (see the drop-callback ). The format :string is understood by some other panes that expect text.

The plist result returned by drag-callback can contain the key :image-function with a function image-function as value.

This function is used to generate the image that is used in the dragging itself, exactly as the image-function in drag-pane-object is used. On Cocoa, tree-view and list-panel ignore this key in result .

drag-callback can also be used in top-level interfaces. In this case the second argument info is a flag describing the gesture that caused the call. Currently the only value is :drag-image, which means it was invoked by dragging the drag-image (see interface).

drag-callback is allowed to return the result :default rather than a plist. :default tells the system to do default dragging if there is any. At the time of writing the only place where there is default dragging is on Cocoa for an interface with an :interface-pathname. drag-callback is allowed to return the result nil, meaning do not do dragging.

On output-pane you add dragging by adding an entry to the input-model and which initiates the dragging by calling drag-pane-object.

Notes: Drag and drop

If :image is supplied in the plist returned by drag-callback , the dragging mechanism automatically frees the image object as if by free-image when it no longer needs it.

Description: Scroll

Any simple pane can be made scrollable by specifying t to :horizontal-scroll or :vertical-scroll. By default these values are nil, but some subclasses of simple-pane default them to t where appropriate (for instance editor-pane s always default to having a vertical scroll-bar).

For a pane which is scrollable but does not display a scroll bar, pass the value :without-bar for :horizontal-scroll or :vertical-scroll. See the example in output-panes/scrolling-without-bar.lisp.

The height and width of a scrollable simple pane can be specified by the initargs :scroll-height and :scroll-width, which have the same meaning as :internal-min-height and :internal-min-width. See Constraint Formats for more information about height and width initargs.

scroll-if-not-visible-p controls scrolling behavior of the parent when the pane is given the input focus. scroll-if-not-visible-p can be t, nil, or :non-mouse. See scroll-if-not-visible-p for details. When this initarg is supplied, the generic function (setf scroll-if-not-visible-p) is called with it.

Description: Border

The value for visible-border can be any of the following, with the stated meanings where applicable:

nil

Has no border.

t

Has a border.

:default

Use the default for the window type.

:outline

Add an outline border.

There are various platform/pane class combinations which do not respond to all values of visible-border . For instance, on Windows XP with the default theme, text-input-choice and option-pane always have a visible border regardless of the value of visible-border , while other classes including display-pane, text-input-pane, list-panel, editor-pane and graph-pane have three distinct border styles, with visible-border :default meaning the same as visible-border t.

If internal-border is non-nil, it should be a non-negative integer specifying the width of an empty region around the edge of the pane.

Description: Miscellaneous

automatic-resize makes the pane resize automatically. This has an effect only if it is placed inside a static-layout (including subclasses like pinboard-layout). The effect is that when the static-layout is resized then the pane also changes its geometry.

The value of automatic-resize defines how the pane's geometry changes. It must be a plist of keywords and values which match the keywords of the function set-object-automatic-resize and are interpreted in the same way.

If the pane is used in the toolbar-items list of an interface, then toolbar-title should be a short string that will be shown near to the pane if required for the toolbar.

Notes: Miscellaneous

1. In order to display a simple pane, it needs to be contained within an interface. In a real application you will will define your interface class, but for debugging and just playing around with pane the two convenience functions make-container and contain are provided to create an interface with enough support for that pane. The function make-container just returns a container for an element, and the function contain displays an interface created for the pane using make-container.
2. You can also control automatic resizing of a simple-pane using set-object-automatic-resize.

Example

(capi:contain (make-instance 'capi:output-pane

                  :background :red

                  :scroll-width 300

                  :horizontal-scroll t))

(setf ep

      (capi:contain

       (make-instance 'capi:editor-pane

                      :visible-border t)))

(setf (capi:simple-pane-cursor ep) :crosshair)

For an example illustrating the use of drag-callback , see:

(example-edit-file "capi/choice/drag-and-drop")

See also

contain
define-font-alias
set-object-automatic-resize
General Properties of CAPI Panes
Laying Out CAPI Panes
Adding Toolbars
Transparency and the alpha channel