Amiga Plus Extra 1997 #2

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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/MUIM_Group_Sort 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 Group.mui/MUIM_Group_Sort NAME MUIM_Group_Sort (V4 ) SYNOPSIS DoMethod(obj,MUIM_Group_Sort,Object *obj[1]); FUNCTION This method rearranges the order of the children stored in a group object. INPUTS - all objects of the group, terminated by NULL. RESULT The result value is currently undefined. NOTES You must always pass all objects of your group! EXAMPLE hgr = HGroup, Child, o1 = ..., Child, o2 = ..., Child, o3 = ..., Child, o4 = ..., End; DoMethod(hgr,MUIM_Group_Sort,o4,o3,o2,o1,NULL);