Amiga Format CD 5/amigaformatcd05.iso/mui/developer/autodocs/mui_group.doc

Text File | 1996-08-13 | 16KB | 550 lines

TABLE OF CONTENTS

Group.mui/Group.mui
Group.mui/MUIA_Group_ActivePage
Group.mui/MUIA_Group_Child
Group.mui/MUIA_Group_ChildList
Group.mui/MUIA_Group_Columns
Group.mui/MUIA_Group_Horiz
Group.mui/MUIA_Group_HorizSpacing
Group.mui/MUIA_Group_LayoutHook
Group.mui/MUIA_Group_PageMode
Group.mui/MUIA_Group_Rows
Group.mui/MUIA_Group_SameHeight
Group.mui/MUIA_Group_SameSize
Group.mui/MUIA_Group_SameWidth
Group.mui/MUIA_Group_Spacing
Group.mui/MUIA_Group_VertSpacing
Group.mui/MUIM_Group_ExitChange
Group.mui/MUIM_Group_InitChange
Group.mui/Group.mui

    Group class is responsible for the complete layout
    of a MUI window. A group may contain any number of
    child objects, maybe buttons, cycle gadgets or
    even other groups.

    Some attributes of group class define how the children
    of a group are layouted. You can e.g. tell your group
    to place its children horizontally (in a row) or
    vertically (in a column). Since every MUI object knows
    about its minimum and maximum dimensions, group class
    has everything it needs to do that job.

    More sophisticated layout is possible by assigning
    different weights to objects in a group or by
    making a group two-dimensional.

    Beneath the layout issues, a group object passes
    attributes and methods through to all of its
    children. Thus, you can talk and listen to any
    child of a group by talking and listening to the
    group itself.
Group.mui/MUIA_Group_ActivePage

    NAME
    MUIA_Group_ActivePage -- (V5 ) [ISG], LONG

    SPECIAL INPUTS
    MUIV_Group_ActivePage_First
    MUIV_Group_ActivePage_Last
    MUIV_Group_ActivePage_Prev
    MUIV_Group_ActivePage_Next
    MUIV_Group_ActivePage_Advance

    FUNCTION
    Set (or get) the active page of a page group.
    Only this active page is displayed, all others
    are hidden.

    The value may range from 0 (for the first child)
    to numchildren-1 (for the last child). Children are
    adressed in the order of creation:

    PageGroup,
       Child, Page_0_Object,
       Child, Page_1_Object,
       Child, Page_2_Object,
       Child, Page_3_Object,
       End;

    Note: You may *never* supply an incorrect page value!

    SEE ALSO
    MUIA_Group_PageMode
Group.mui/MUIA_Group_Child

    NAME
    MUIA_Group_Child -- (V4 ) [I..], Object *

    FUNCTION
    You supply a pointer to a previously created MUI object
    here. This object will be treated as child of the group,
    the group is responsible for positioning the object.

    Of course you can specify any number of child objects,
    limited only by available memory.

    Normally, the value for a MUIA_Group_Child tag is
    a direct call to another MUI_NewObject(), children
    are generated "on the fly".

    When a group is disposed, all of its children will also
    get deleted. If you supply a NULL pointer as child,
    the group object will fail and previously dispose all
    valid children found in the taglist.

    This behaviour makes it possible to generate a complete
    application within one single (but long) MUI_NewObject()
    call. Error checking is not necessary since every error,
    even if it occurs in a very deep nesting level, will
    cause the complete call to fail without leaving back
    any previously created object.

   EXAMPLES
    Please have a look at some of the supplied example
    programs.

   SEE ALSO
    MUIA_Group_Horiz
Group.mui/MUIA_Group_ChildList

    NAME
    MUIA_Group_ChildList -- (V4 ) [..G], struct List *

    FUNCTION
    This attribute returns a pointer to a struct List in which
    a group manages its children.

    The only thing you are allowed to do with this list is
    to traverse through the children. You *must* use
    intuition.library/NextObject() for this purpose!

    Never add or remove member directly, use the
    OM_ADDMEMBER/OM_REMMEMBER methods instead!

    SEE ALSO
    MUIA_Group_Child
Group.mui/MUIA_Group_Columns

    NAME
    MUIA_Group_Columns -- (V4 ) [IS.], LONG

    FUNCTION
    Indicate number of columns in a two dimensional group.
    If you use this tag, the total number of children must
    be dividable by the number of columns.

    The children will be positioned in a two dimensional
    array, e.g. allowing easy creation of button fields
    (maybe for calculator).

    The children in your taglist are always read line
    by line.

    When MUI layouts two-dimensional groups, it does
    actually two layout calculations, one for the rows
    and one the columns. Parameters like weights and
    dimensions are handled this way:

    - the minimum width of a column/row is the maximum
      minimum width of all objects in this column/row.

    - the maximum width of a column/row is the minimum
      maximum width of all objects in this column/row.

    - the weight of a column/row is the sum of all
      objects in this column/row.

    Actually, there is no difference if you use
    MUIA_Group_Columns or MUIA_Group_Rows.

    EXAMPLE

    /* group of labeled string gadgets */

    GroupObject,
       MUIA_Group_Columns, 2,
       MUIA_Group_Child  , label1,
       MUIA_Group_Child  , string1,
       MUIA_Group_Child  , label2,
       MUIA_Group_Child  , string2,
       MUIA_Group_Child  , label3,
       MUIA_Group_Child  , string3,
           ...
       End;

    SEE ALSO
    MUIA_Group_Rows, MUIA_Group_Horiz
Group.mui/MUIA_Group_Horiz

    NAME
    MUIA_Group_Horiz -- (V4 ) [I..], BOOL

    FUNCTION
    Boolean value to indicate whether the objects in
    this group shall be layouted horizontally or
    vertically. Defaults to FALSE.

    This is the easy way of telling your group how
    it has to look like. If you want two-dimensional
    groups, you have to use MUIA_Group_Columns
    or MUIA_Group_Rows.

    EXAMPLE
    GroupObject,
       MUIA_Group_Horiz, TRUE,
       MUIA_Group_Child, obj1,
       MUIA_Group_Child, obj2,
       MUIA_Group_Child, obj3,
       End;

    SEE ALSO
    MUIA_Group_Columns, MUIA_Group_Rows, MUIA_Group_Child
Group.mui/MUIA_Group_HorizSpacing

    NAME
    MUIA_Group_HorizSpacing -- (V4 ) [ISG], LONG

    FUNCTION
    Number of pixels to be inserted between horizontal
    elements of a group.

    Please use this tag wisely, you will override the
    user's prefered default setting!

    SEE ALSO
    MUIA_Group_Spacing, MUIA_Group_VertSpacing
Group.mui/MUIA_Group_LayoutHook

    NAME
    MUIA_Group_LayoutHook -- (V11) [I..], struct Hook *

    FUNCTION
    Since version 11 of muimaster.library, you have the
    ability to customize the way objects are placed in a
    group. Altough MUI features a very powerful builtin
    layout algorithm which serves well for almost all
    GUI related purposes, it might sometimes become
    handy to override this with custom code.

    Imagine you want to build a multimedia document
    viewer which contains text objects, bitmap objects
    and buttons. An easy way for doing this is to simply
    create a sub class of group class which contains all
    the documents elements as MUI objects and which
    specifies a custom layout hook for the parent group.
    This hook is then responsible for placing the
    objects within the bounds of the parent group.

    As soon as you specify a MUIA_Group_LayoutHook, the
    builtin layout calculation is skipped and your hook
    is called whenever MUI needs some information.
    Register A2 will contain a pointer to the parent
    group object and register A1 will contain a pointer
    to a struct MUI_LayoutMsg. The lm_Type field of
    this structure determines which kind of action MUI
    wants you to perform (see below), the lm_Children
    field is a pointer to a list of your groups
    children. By traversing through list list with the
    intuition function NextObject(), you can retrieve
    the children of the group.

    If lm_Type == MUILM_ASKMINMAX, MUI wants you to
    calculate your groups minimum, maximum and default
    sizes. At this time, the children of your group have
    already been asked for their dimensions. This allows
    you to traverse through the list of children and do
    some calculations depending on their min/max sizes.
    Use the macros _minwidth(child), _maxwidth(child),
    _minheight(child), _maxheight(child) for this
    purpose. Place the result of your calculations in
    the structure lm_MinMax of the MUI_LayoutMsg and
    exit your hook with a return value of 0.

    If lm_Type == MUILM_LAYOUT, MUI has already placed
    the group object somewhere in a window and now wants
    you to place the children of this group. You have to
    traverse through the child list and calculate
    positions and sizes for each child. Use the function
    MUI_Layout() to tell the child where it should
    appear. You have to make sure that you don't place
    child objects outside of the parent group and you
    should generally avoid overlapping objects. Return
    TRUE if all children are placed, return FALSE if you
    were for some reasons unable to place your children.

    If your previous min/max calculations were correct,
    your algorithms should not have problems to place
    all the children in the rectangle defined by the
    parent group. Its size will never be smaller as your
    specified minimum dimensions and never be larger as
    your specified maximum dimensions.

    If your group is a virtual group, the width
    and height your layout hook receives are as big as
    the *visible* part of the virtual group. In this
    case, you are allowed to position your objects
    outside of the visible part, i.e. you are not
    limited to keep your objects inside the given width
    and height. Place them where you wish and set
    lm_Layout.Width and lm_Layout.Height to the width
    and height you really need for your objects before
    exiting. The virtual width and height of your group
    will be adjusted accordingly.

    EXAMPLE
    see MUI demo program Layout.c

    SEE ALSO
    muimaster.library/MUI_Layout()
Group.mui/MUIA_Group_PageMode

    NAME
    MUIA_Group_PageMode -- (V5 ) [I..], BOOL

    FUNCTION
    Settings this attribute to TRUE makes the current group a page
    group. Page groups always display only one of their children,
    which one can be adjusted with the MUIA_Group_ActivePage
    attribute.

    Imagine you have a preferences window with several different
    pages, e.g. the MUI preferences with object, frame, image,
    font, screen, keyboard and system prefs. Instead of one
    separate window for each group, you could put all pages into
    one page group and have a cycle gadget for page switching.
    This will make your program easier to use since the user
    won't have to handle a lot of windows. However, he will not
    be able to work with more than one page at the same time.

    Sizes are calculated as follows:

    The minimum width/height of a page group is the maximum
    minimum width/height of all its children.

    The maximum width/height of a page group is the minimum
    maximum width/height of all its children.

    When the maximum width/height of a child in a page group is
    smaller than the minimum width/height of the page group
    (since it contains another child with big minimum width/height),
    the child be centered.

    Page groups are not limited in depth, children of a page
    group may of course be other page groups.

    If you want to have a gadget only visible under certain
    conditions, you could make a page group containing this
    gadget and an empty rectangle object.

    If you want TAB cycling for the objects in a page group,
    simply include all objects in the cycle chain (as if
    they all were visible at the same time).

    EXAMPLE
    demo program "Pages.c"

    SEE ALSO
    MUIA_Group_ActivePage
Group.mui/MUIA_Group_Rows

    NAME
    MUIA_Group_Rows -- (V4 ) [IS.], LONG

    FUNCTION
    Indicate number of rows in a two dimensional group.
    If you use this tag, the total number of children must
    be dividable by the number of rows.

    The children will be positioned in a two dimensional
    array, e.g. allowing easy creation of button fields
    (maybe for calculator).

    The children in your taglist are always read line
    by line.

    When MUI layouts two-dimensional groups, it does
    actually two layout calculations, one for the rows
    and one the columns. Parameters like weights and
    dimensions are handled this way:

    - the minimum width of a column/row is the maximum
      minimum width of all objects in this column/row.

    - the maximum width of a column/row is the minimum
      maximum width of all objects in this column/row.

    - the weight of a column/row is the sum of all
      objects in this column/row.

    Actually, there is no difference if you use
    MUIA_Group_Columns or MUIA_Group_Rows.

    SEE ALSO
    MUIA_Group_Columns, MUIA_Group_Horiz
Group.mui/MUIA_Group_SameHeight

    NAME
    MUIA_Group_SameHeight -- (V4 ) [I..], BOOL

    FUNCTION
    Boolean value to indicate that all children of this
    group shall have the same height.

    BUGS
    Up to version 5 of groupclass, using MUIA_Group_SameHeight
    could make objects larger than their maximum height. This
    has been fixed for version 6.

    SEE ALSO
    MUIA_Group_SameSize, MUIA_Group_SameWidth
Group.mui/MUIA_Group_SameSize

    NAME
    MUIA_Group_SameSize -- (V4 ) [I..], BOOL

    FUNCTION
    This is a shorthand for MUIA_Group_SameWidth and
    MUIA_Group_SameHeight, it sets both of these
    attributes at once.

    Using MUIA_Group_SameSize, you won't need to think
    if your group is horizontal or vertical, both
    cases are handled automatically.

    Forcing all objects of a group to be the same size
    is e.g. useful for a row of buttons. It's visually
    more attractive when these buttons have equal sizes
    instead of being just as big as the text within.

    BUGS
    Up to version 5 of groupclass, using MUIA_Group_SameSize
    could make objects larger than their maximum size. This
    has been fixed for version 6.

    EXAMPLE

    /* three buttons, same size */

    GroupObject,
       MUIA_Group_Horiz   , TRUE,
       MUIA_Group_SameSize, TRUE,
       MUIA_Group_Child   , but1,
       MUIA_Group_Child   , but2,
       MUIA_Group_Child   , but3,
       End;

    SEE ALSO
    MUIA_Group_SameWidth, MUIA_Group_SameHeight
Group.mui/MUIA_Group_SameWidth

    NAME
    MUIA_Group_SameWidth -- (V4 ) [I..], BOOL

    FUNCTION
    Boolean value to indicate that all children of this
    group shall have the same width.

    BUGS
    Up to version 5 of groupclass, using MUIA_Group_SameWidth
    could make objects larger than their maximum width. This
    has been fixed for version 6.

    SEE ALSO
    MUIA_Group_SameSize, MUIA_Group_SameHeight
Group.mui/MUIA_Group_Spacing

    NAME
    MUIA_Group_Spacing -- (V4 ) [IS.], LONG

    FUNCTION
    This is a shorthand for MUIA_Group_HorizSpacing and
    MUIA_Group_VertSpacing, it sets both of these
    attributes at once.

    Using MUIA_Group_Spacing, you won't need to think
    if your group is horizontal or vertical, both
    cases are handled automatically.

    Note that setting a spacing value for a group
    overrides the user's default settings. Please
    use it only if you have a good reason.

    EXAMPLE

    /* no space between obj1 and obj2: */

    GroupObject,
       MUIA_Group_Horiz  , TRUE,
       MUIA_Group_Spacing, 0,
       MUIA_Group_Child  , obj1,
       MUIA_Group_Child  , obj2,
       End;

    SEE ALSO
    MUIA_Group_HorizSpacing, MUIA_Group_VertSpacing
Group.mui/MUIA_Group_VertSpacing

    NAME
    MUIA_Group_VertSpacing -- (V4 ) [ISG], LONG

    FUNCTION
    Number of pixels to be inserted between vertical
    elements of a group.

    Please use this tag wisely, you will override the
    user's prefered default setting!

    SEE ALSO
    MUIA_Group_Spacing, MUIA_Group_HorizSpacing
Group.mui/MUIM_Group_ExitChange

    NAME
    MUIM_Group_ExitChange (V11)

    SYNOPSIS
    DoMethod(obj,MUIM_Group_ExitChange,);

    FUNCTION
    Terminates MUIM_Group_InitChange state.

    SEE ALSO
    MUIM_Group_InitChange
Group.mui/MUIM_Group_InitChange

    NAME
    MUIM_Group_InitChange (V11)

    SYNOPSIS
    DoMethod(obj,MUIM_Group_InitChange,);

    FUNCTION
    Prepares a group for dynamic adding/removing of objects.
    MUI 3 offers the possibility to dynamically add/remove
    children from groups, even when the window that contains
    these objects is currently open. To be able to do this,
    you must first put the group into a special "exchange"
    state by using this method. Then, you can add/remove
    children at will. If you're done, use MUIM_Group_ExitChange
    to make MUI recalculate the display.

    RESULT
    returns NULL on failure.

    EXAMPLE
    /* remove two children, add another one */

    if (DoMethod(group,MUIM_Group_InitChange))
    {
       DoMethod(group,OM_REMMEMBER,somechild);
       DoMethod(group,OM_REMMEMBER,somechild2);

       DoMethod(group,OM_ADDMEMBER,somenewchild);

       DoMethod(group,MUIM_Group_ExitChange);
    }

    SEE ALSO
    MUIM_Group_InitChange