TABLE OF CONTENTS

propgclass/--datasheet--
propgclass/GM_HANDLEINPUT


propgclass/--datasheet--                                 propgclass/--datasheet--

    NAME
	propgclass -- proportional gadget class

    SUPERCLASS
	gadgetclass

    REQUIRES
	None

    DESCRIPTION
	A BOOPSI proportional ("prop") gadget. The BOOPSI prop gadget is
	similar to the conventional prop gadget but extends its
	function to make it easier to use. The BOOPSI prop gadget keeps
	its current integer value in its PGA_Top attribute.

    METHODS
	OM_NEW -- Create the propgclass object. Passed to superclass.

	OM_GET -- Obtain the value of an attribute. Passed to superclass.

	OM_SET -- Set object attributes. Passed to superclass first.

	OM_UPDATE -- Update object attributes. Passed to superclass first.

	GM_HITTEST -- Determine if gadget was hit.

	GM_RENDER -- Render the gadget with state.

	GM_GOACTIVE -- Activate the gadget.

	GM_GOINACTIVE -- Deactivate the gadget.

	GM_HANDLEINPUT -- Handle input while active.

	GM_EXTENT -- Inquire about rendering extent.

	GM_LAYOUT -- Calculate relative gadget coordinates.

	All other methods are passed to the superclass.

    ATTRIBUTES
	GA_Image (struct Image *)
	    Propgclass intercepts this gadgetclass attribute before
	    passing it on to gadgetclass. This attribute passes an
	    image for the prop gadget's knob which gets stored in the
	    propgclass object's Gadget.Image structure.

	    An AUTOKNOB automatically sizes itself according to how
	    large the range of the gadget is compared to the visible
	    range of the gadget. See the PGA_Visible and PGA_Total
	    attributes for more details.

	    Defaults to AUTOKNOB.

	    Applicability is (OM_NEW)

	GA_Border (struct Border *)
	    Propgclass intercepts this gadgetclass attribute to prevent
	    gadgetclass from setting up a border. If an application
	    tries to set this attribute for a propgclass gadget the
	    prop gadget turns itself into an AUTOKNOB gadget.

	    Applicability is (OM_NEW)

	GA_Highlight (uint16)
	    Propgclass intercepts this gadgetclass attribute before
	    passing it on to gadgetclass. It does this to make sure
	    the highlighting is not set to GADGHBOX. GADGHBOX will be
	    converted to GADGHCOMP.

	    Applicability is (OM_NEW)

	GA_SpecialInfo (APTR)
	    This tag is used for storing private propgclass object
	    information and will be overridden.

	    Applicability is (OM_NEW)

	PGA_Freedom (uint16)
	    This attribute tells a propgclass object on which axis
	    the gadget's knob is free to move (horizontal or vertical).
	    It is either FREEHORIZ or FREEVERT.

	    Defaults to FREEVERT.

	    Applicability is (OM_NEW, OM_GET)

	PGA_Borderless (BOOL)
	    This attribute corresponds to the PROPBORDERLESS flag of
	    the PropInfo structure's Flags field (defined in
	    <intuition/intuition.h>. If this attribute is TRUE the
	    new propgclass object will not have a border around it.
	    In an AUTOKNOB propgclass gadget, if the PROPNEWLOOK flag
	    is set as well (see the PGA_NewLook) the knob will have a
	    3D appearance.

	    Defaults to FALSE.

	    Applicability is (OM_NEW)

	PGA_NewLook (BOOL)
	    This attribute corresponds to the PROPNEWLOOK flag of the
	    PropInfo structure's Flags field (defined in
	    <intuition/intuition.h>). If this attribute is TRUE the
	    new propgclass object will use post Release 2 imagery
	    rather than the Release 1.3 imagery.

	    Defaults to FALSE.

	    Applicability is (OM_NEW)

	PGA_Total (uint32)
	PGA_Visible (uint32)
	PGA_Top (uint32)
	    These attributes replace the Pot and Body variables of
	    the Release 1.3 prop gadget. They are based on the use
	    of proportional gadgets to control scrolling text. When
	    scrolling 100 lines of text in a 25 line visible window,
	    you would set PGA_Total to 100, PGA_Visible to 25, and
	    watch PGA_Top run from 0 to 75 (top line of the last page).

	    If the user clicks in the prop gadget but not on the knob,
	    the entire knob jumps one "page" (the size of the visible
	    area minus one, PGA_Visible-1). The page jump will leave
	    an overlap of one line unless the value PGA_Visible is 1
	    in which case the prop gadget acts as an integer numeric
	    slider sliding from 0 to PGA_Total - 1.

	    Note that when PGA_Top changes the gadget sends itself
	    an OM_NOTIFY message about this attribute change (see the
	    propgclass description of GM_HANDLEINPUT for more
	    information).

	    Applicability is (OM_NEW, OM_SET, OM_UPDATE, OM_GET)
	    PGA_Top is also (OM_NOTIFY)

propgclass/GM_HANDLEINPUT                               propgclass/GM_HANDLEINPUT

    NAME
	GM_HANDLEINPUT -- Handle input while active.

    SYNOPSIS
	uint32 result = IDoMethodA(APTR obj, struct gpInput* msg);

    FUNCTION
	If the knob position changes sufficiently to change a
	propgclass object's PGA_Top attribute the gadget will send
	OM_NOTIFY message to itself which the propgclass dispatcher
	passes on to the gadgetclass dispatcher for processing
	(see the rootclass description of OM_NOTIFY and OM_UPDATE
	for more information).

	The OM_NOTIFY message will contain two attribute/value pairs,
	PGA_Top and GA_ID. While the prop gadget's PGA_Top is in a
	transitory state (while it is active and the user is moving
	the prop gadget's knob) the gadget sends interim OM_NOTIFY
	messages. The interim OM_NOTIFY messages have the OPUF_INTERIM
	flag of the opUpdate.opu_Flags field set. When the user finishes
	manipulating the gadget (by letting go of the knob) the gadget
	sends a final OM_NOTIFY message with a cleared OPUF_INTERIM flag.

    INPUTS
	obj - propgclass object pointer
	msg - pointer to fully initialized struct gpInput
	      (see <intuition/gadgetclass.h>)

    RESULT
	Returns a valid GMR_xxx combination.

    SEE ALSO
	gadgetclass/GM_HANDLEINPUT, rootclass/OM_NOTIFY