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TABLE OF CONTENTS select.gadget/--background-- select.gadget/select.gadget select.gadget/ClearSelectGadget select.gadget/GetSGAttr select.gadget/InitSelectGadgetA select.gadget/ObtainSelectGClass select.gadget/SetSGAttrsA select.gadget/--background-- select.gadget/--background-- DESCRIPTION The select.gadget is a shared library which, when opened, adds to the system a public BOOPSI gadget class called "selectgclass". This class implements a button-like selection gadget, with features similar to those of a traditional GadTools cycle gadget, but with the additional ability to open, when pressed, a pop-up menu which allows the user to pick his choice more easily. The look and behavior of the gadget and its pop-up menu can be configured using the attribute tags of the class. The library is freeware; if you use it, you are allowed to distribute it with your software. Some highlights: - A delay can be set for the appearance of the pop-up menu, allowing for a gadget which reacts like a normal cycle gadget upon "quick" clicks, and like a pop-up gadget if the mouse button is kept pressed a little longer. - The pop-up menu can appear and disappear with a vertical "zoom" effect whose duration is configurable. - It is optionally possible to have a "sticky" pop-up menu which remains open when the mouse button is released. - The gadget can be made "quiet", that is, the currently selected item can be not displayed. Useful to attach a small pop-up button to string gadgets. - The gadget can be configured to always behave like a cycle gadget, and even like a plain button gadget. - The gadget can broadcast changes in its value to target objects via the BOOPSI notification system. - All changes done with SetGadgetAttrsA() to the gadget's position, size and look are visually executed in real-time. - The gadget's dispatcher is able to swap the stack when needed. - The gadget can be added to requesters and window borders. - The pop-up menu can have a drop shadow. - The gadget's "pop-up" symbol can be placed at the left side, at the right side, or it can also not appear at all; its width is also configurable. The gadget's default imagery for the symbol is fully scalable, and it can be replaced by the application with a custom image. - The default values for unspecified attributes can be globally set by the user with an ASCII preferences file; the changes are applied in real-time (to gadgets created afterwards) via file notification. Furthermore, the library offers some functions which allow to "transform" a normal gadget into a custom gadget having (almost) the same features of the "selectgclass" gadgets. This way it's possible, for example, to create GadTools GENERIC_KIND gadgets and turn them into pop-up gadgets, obtaining all the benefits of this type of gadgets while also keeping the benefits of the GadTools automatic gadget creation (and deletion) system. Lastly, this gadget class supports VisualPrefs and takes full advantage of the graphic enhancements it brings to the system. CLASS DOCUMENTATION Class: selectgclass Superclass: gadgetclass Include File: <gadgets/select.h> A BOOPSI popup gadget which can also behave as a GadTools-like cycle gadget or even as a normal button gadget. The selectgclass gadget keeps its current active item value in its SGA_Active attribute, and when it changes because of user's interaction a notification message is sent to its target and also (optionally) an IDCMP_GADGETUP message is sent to its window's UserPort. New Methods: None. Changed Methods: OM_NEW - After creation of the gadget by the superclass, this method initializes the "selectgclass" instance data on the basis of the contents of the attributes tag list. OM_DISPOSE - This method frees all the resources allocated in the OM_NEW method. OM_SET, OM_UPDATE - The gadget will automatically refresh its graphic appearance to reflect any changes to visual attributes, such as the active item, the gadget position and size, and the gadget text. In particular, when the gadget is moved, it first erases itself at the old position. GM_RENDER - The rendering of the various "selectgclass" gadget components (frame, symbol, label, text) is made in a very optimized way. The gadget clips its graphics at the window borders, and avoids as much as possible to redraw a single pixel more than once. If gpRender.gpr_Redraw has the value GREDRAW_UPDATE the gadget redraws only the frame and its contents, otherwise it also redraws the text. GM_HITTEST - This method currently always returns GMR_GADGETHIT, but don't count on this being the case also in future versions. GM_GOACTIVE - In this method some precalculations are made and cached, to speed up the GM_HANDLEINPUT method. GM_HANDLEINPUT - If the user clicks with the mouse select button on the "pop-up" zone of the gadget (which can be the entire gadget box, or just a part of it, depending on the value of the SGA_FullPopUp tag), an internal timer starts. If the button is released before the pop-up delay (set with SGA_PopUpDelay) expires, the gadget behaves exactly as a GadTools cycle gadget would: if the mouse pointer was within the gadget box when the button was released, the gadget's active item changes, and the change is reported to the application via an IDCMP_GADGETUP IntuiMessage and/or to the gadget's target object via an OM_UPDATE message. If, instead, the mouse button is kept pressed long enough, a pop-up menu appears, showing all the available items. However, it the gadget has too few items (the threshold can be set with the SGA_MinItems tag) the menu doesn't appear, and the gadget keeps behaving like a cycle gadget. When the menu is displayed, the user can select any of the displayed items just by moving the mouse pointer on it and releasing the mouse select button. Alternatively, if the pop-up menu is of the "sticky" type, the user must first release the mouse button, then move the pointer on the desired choice and press the button again. If the selected item is different from the previously active one, or if the SGA_ReportAll attribute is set to TRUE, the new active value is reported to the application via an IDCMP_GADGETUP IntuiMessage and/or to the gadget's target object via an OM_UPDATE message. If the mouse select button is initially clicked with the pointer not on the "pop-up" zone of the gadget, the pop-up menu doesn't appear, and the gadget behaves like a GadTools cycle gadget, no matter how long the button is kept pressed. As with GadTools, a SHIFT qualifier causes the gadget to cycle backwards. The gadget reports changes in its SGA_Active attribute value to the application by sending an IDCMP_GADGETUP IntuiMessage to the UserPort of its window. The IntuiMessage.Code field contains the new value of the attribute. The gadget reports changes in its SGA_Active attribute value to its target object by sending it an OM_UPDATE message. The message's attribute tag list contains the new value of the attribute and the ID of the gadget. Any operation being made with the "selectgclass" gadget can always be aborted by pressing the right (menu) button of the mouse. GM_GOINACTIVE - This method does a clean-up after the GM_GOACTIVE method. GM_LAYOUT - In this method, a "selectgclass" gadget does all necessary calculations to prepare itself for rendering and user interaction. This method fully support the Intuition relativity flags (GFLG_RELRIGHT, GFLG_RELBOTTOM, GFLG_RELWIDTH and GFLG_RELHEIGHT). Attributes: GA_Image (IS) - The image the gadget will use to render its frame. If this attribute is not specified, or if it's NULL, a default image will be used (namely, an instance of "frameiclass"). If it's set to ~0 (or -1) no image will be rendered. The gadget renders its frame image with the IM_DRAWFRAME method when possible, so it would be a good idea to have your custom image support this. Changing this attribute causes the gadget to be redrawn. GA_Text, GA_IntuiText, GA_LabelImage (IS) - The gadget supports all of these methods of specifying a text. Changing one of these attributes causes the gadget to be redrawn. See also SGA_TextPlace (below). GA_Left, GA_RelRight, GA_Top, GA_RelBottom (IS) - The gadget supports both absolute and relative positioning. Changing one of these attributes causes the gadget to be redrawn, with its old imagery being erased first. GA_Width, GA_RelWidth, GA_Height, GA_RelHeight (IS) - The gadget supports both absolute and relative sizing. Changing one of these attributes causes the gadget to be redrawn, with its old imagery being erased first. GA_DrawInfo (I) - A pointer to your screen's DrawInfo structure. If this attribute is specified, and the tag list doesn't contain any explicit information about the gadget's size, the gadget will automatically size itself just large enough to frame its contents. This can work for just one axis, or both, depending on which ones have an explicitly specified size. This attribute is only valid at creation time; you don't need to specify it if you do not want the automatic sizing feature. SGA_Active (ISGNU) - The index number (starting from zero) of the current active item. The default value is zero. Changing this attribute causes the gadget to be redrawn. SGA_Labels (ISU) - A NULL-terminated string array containing all the item labels for the gadget. It can safely be empty. If this attribute is not specified, or if it's NULL, the gadget will look and behave like a traditional button gadget. Changing this attribute causes the gadget to be redrawn. SGA_MinItems (ISGU) - The minimum number of items the gadget must have for the pop-up menu to appear. If the items are fewer than this, the gadget will always behave like a traditional GadTools cycle gadget. The default is zero. SGA_FullPopUp (ISU) - If TRUE, clicking anywhere on the gadget box will cause the pop-up menu to appear (after the requested delay). If FALSE, clicking on the "symbol box" (if one exists) will make the gadget behave like a GadTools cycle gadget. Defaults to FALSE. SGA_PopUpDelay (ISU) - The amount of time (in milliseconds) the gadget must remain pressed for the pop-up menu to appear. If this is zero, the pop-up menu will appear immediately and the gadget won't even change to its "pressed" state. Defaults to zero. SGA_PopUpPos (ISU) - This attribute determines where the pop-up menu is to appear, relative to the gadget's position. It may have four different values: SGPOS_ONITEM - position the menu so that the the active item is under the mouse pointer. SGPOS_ONTOP - always align the top edge of the menu with the top edge of the gadget. SGPOS_BELOW - place the menu just below the gadget. SGPOS_RIGHT - place the menu at the right side of gadget, aligning its top edge with the gadget's top edge. With the exception of SGPOS_RIGHT, all the values center the menu horizontally on the "popup" zone of the gadget. The default is SGPOS_ONITEM. SGA_MinTime (ISU) - The minimum duration of the menu panel's opening/closing animation effect, in milliseconds. You can set this to a value greater than zero to make sure the effect can be noticed even with gadgets having a very small number of items. The default is zero. (V40.14) SGA_MaxTime (ISU) - The maximum duration of the menu panel's opening/closing animation effect, in milliseconds. You can set this to a small value to make sure the effect doesn't take too much time with gadgets having a very large number of items. If set to zero, the effect doesn't take place at all. The default is zero. (V40.14) SGA_Sticky (ISU) - If FALSE, the pop-up menu will close as soon as the user releases the mouse button. If TRUE, the menu will remain open after the button is released, and will close when the user clicks on it to select an item, or somewhere else to abort the operation. Defaults to FALSE. Changing this attribute causes the gadget to be redrawn (to change the symbol image), unless you are using a custom symbol. SGA_PanelMode (ISU) - This attribute specifies the way the menu panel will be rendered to the screen. It can have three different values: SGPM_WINDOW - the panel will be a normal Intuition window. This is the most system-friendly mode, and does not block graphic output to the screen, but it's also slower and more sluggish than the other two modes. SGPM_DIRECT_NB - the panel will be rendered directly to the screen's bitmap, without blocking graphic output to the screen. SGPM_DIRECT_B - the panel will be rendered directly to the screen's bitmap, blocking graphic output to the screen. The last two modes give a very smoother visual feedback (especially with the opening/closing animation effect) but might also cause unexpected results under some rare circumstances. The default is SGPM_WINDOW. (V40.14) SGA_TextAttr (ISU) - Pointer to a TextAttr structure describing the font to be used for the gadget's text and labels. The font must be already in memory and openable with OpenFont(); if not, the screen font will be used instead. This attribute is overridden by SGA_TextFont. Changing this attribute causes the gadget to be redrawn, unless there's a valid font specified with SGA_TextFont. SGA_TextFont (ISU) - Pointer to a TextFont structure which is to be used for rendering the gadget's text and labels. This overrides the SGA_TextAttr attribute. If both attributes are NULL or not specified, the screen font will be used. The font whose pointer you pass with this tag must remain open for the whole life of the gadget. Changing this attribute causes the gadget to be redrawn. SGA_TextPlace (ISGU) - The position at which the gadget's text is to be rendered. It can assume one of the five PLACETEXT_#? values defined in <libraries/gadtools.h>. If this is not specified, PLACETEXT_LEFT is assumed, unless the gadget has no items (that is, it's a button gadget) in which case PLACETEXT_IN is assumed. This works also if the text is really an image label. Changing this attribute causes the gadget to be redrawn, with the text in the new position. Note: currenty this attribute MUST be specified if the gadget uses an IntuiText for its text, whereas it can be optional if the text is a string or an image label. SGA_Underscore (ISU) - The symbol preceding the character in the gadget text to be underscored. This can be to indicate keyboard equivalents for gadgets (note that "selectgclass" does not process the keys; it just displays the underscore). This attribute is only used if the gadget text is a simple string; if you use an IntuiText or an image, you must provide your own underscoring. The value of this attribute is a simple UBYTE. Changing this attribute causes the gadget to be redrawn. SGA_Justify (ISU) - The alignment of the active label within the "text zone" of the gadget box. It can be SGJ_LEFT, SGJ_CENTER or SGJ_RIGHT. The default is SGJ_CENTER. Changing this attribute causes the gadget to be redrawn. Note: SGJ_RIGHT is not yet implemented. SGA_Quiet (ISU) - If TRUE, the gadget's active label will not be displayed within the gadget box. Defaults to FALSE. Changing this attribute causes the gadget to be redrawn. SGA_Symbol (ISU) - Pointer to a standard or BOOPSI image structure, to be used as the "pop-up" symbol (akin to the "cycle" symbol of GadTools cycle gadgets) which is usually displayed at the left or right side of a "selectgclass" gadget. The image, if BOOPSI, is rendered within the symbol box using the IM_DRAWFRAME method, so try to support this. If NULL or not specified, a default (scalable) internal image will be used, whose look depends on the gadget type (sticky or non-sticky). If this is ~0 (or -1) no symbol will be displayed. Changing this attribute causes the gadget to be redrawn. SGA_SymbolWidth (ISGU) - The width of the "symbol box", that is, the part of the gadget box (usually delimited by a separator line) which contains the "pop-up" symbol. It is advised not to make it too wide, or there could be insufficient room for the gadget's active label. The default is 21 (like for GadTools cycle gadgets). Changing this attribute causes the gadget to be redrawn. SGA_SymbolOnly (ISU) - If TRUE, only the symbol box will be selectable, while the rest of the gadget will appear recessed and will be read-only. Defaults to FALSE. Changing this attribute causes the gadget to be redrawn. SGA_Separator (ISU) - If TRUE, a recessed separator line will be drawn between the symbol and the active label in the gadget box. Defaults to TRUE. Changing this attribute causes the gadget to be redrawn. SGA_ListFrame (ISU) - Pointer to a standard or BOOPSI image to be used as the background of the pop-up menu panel. When possible it is rendered with the IM_DRAWFRAME method, so try to support this. If NULL or not specified, a default image will be used (an instance of "frameiclass"). SGA_DropShadow (ISU) - If TRUE, a four-pixel thick dithered drop shadow will appear under the pop-up menu. Defaults to FALSE. SGA_ItemSpacing (ISU) - The number of pixels which is to be added to the gadget's font height in order to determine the height of an item in the pop-up menu. The result of the sum will be ignored if it is smaller than the value of the SGA_ItemHeight attribute (see below). The default is zero. SGA_ItemHeight (ISU) - The exact height of each item in the pop-up menu. It can never be less than the gadget's font height plus the value of the SGA_ItemSpacing attribute. Defaults to the gadget's font height plus the value of the SGA_ItemSpacing attribute. SGA_ListJustify (ISU) - The alignment of labels within the pop-up menu panel. It can be SGJ_LEFT, SGJ_CENTER or SGJ_RIGHT. The default is SGJ_CENTER. Note: SGJ_RIGHT is not yet implemented. SGA_ActivePens (ISU) - Pointer to an array of four UWORDs containing the pen numbers to be used for rendering the active item in the pop-up menu panel. The meaning of the array index is: 0 - color of the text; 1 - color of the background; 2 - color of the bright edges; 3 - color of the dark edges. These are actual color numbers, not Intuition pen numbers. Defaults to using the colors of FILLTEXTPEN, FILLPEN, SHINEPEN and SHADOWPEN (although the presence of the VisualPrefs patch might change these defaults). SGA_ActiveBox (ISU) - If this is not zero, the active item in the pop-up menu panel will have a 3D frame around it. The frame will be recessed if this attribute is -1, otherwise it will be raised. The colors are determined with the SGA_ActivePens tag. Defaults to zero (no frame). SGA_BorderSize (ISU) - The thickness of the border to be left between the edges of the pop-up menu panel and the displayed labels. If it is set to -1, a suitable value will be chosen automatically. Defaults to -1. SGA_FullWidth (ISU) - If TRUE, the pop-up menu will have the same width of the entire gadget; if FALSE, it will have the width of the gadget minus the width of the symbol box. Defaults to FALSE. SGA_FollowMode (ISU) - Determines the behavior of the pop-up menu when the mouse pointer goes out of its boundaries. There are three possible values: SGFM_NONE - the active item becomes not highlighted. SGFM_KEEP - the active item remains highlighted, but doesn't change until the pointer returns on the panel. SGFM_FULL - the active item remains highlighted, and can also change if the user moves the pointer up and down, even if outside of the menu panel. If the gadget is not sticky, and the user lets go of the mouse select button while the pointer is outside of the menu panel, the currently highlighted item will be selected, if there is one. The default is SGFM_NONE. SGA_ReportAll (ISU) - If TRUE, the gadget reports the selection of an item even if it was already the active item. If FALSE, a selection is only reported when the active item actually changes. Defaults to FALSE. Note: if there are no items (that is, if the gadget is really a button gadget) this attribute is currently ignored, and assumed TRUE. SGA_Refresh (SU) - This is not a real attribute; if you pass this tag with a value of TRUE, it will force an immediate refresh of the gadget's imagery. This is only useful for custom select gadgets obtained with the InitSelectGadgetA() function, as the usual RefreshGadgets() and RefreshGList() functions aren't always sufficient to refresh them correctly. Real "selectgclass" BOOPSI gadgets shouldn't need this tag. USER CONFIGURATION AND PROGRAMMING STYLE Although the "selectgclass" class offers many attributes to customize its look and behavior, programmers should not explicitly set the value of the ones which don't influence the working of their applications, or else the user would be confused by a multitude of differently-looking gadgets. Usually, the only attributes you really need to specify in your code are SGA_Active, SGA_Labels, SGA_TextPlace, SGA_Underscore, SGA_Quiet, SGA_Symbol, SGA_ListFrame and SGA_ReportAll (plus the various GA_#? ones). If you also use SGA_TextAttr or SGA_TextFont, it would be a good idea to offer the user a way to choose the font and size to be used. Of course, nothing stops you from using other attributes too, but it's a better style to do so only when it's really needed. For attributes which are transparent to your application, it is advised that you respect the default values. Such default values, for the most significant attributes defining the look and feel of the gadgets, can be globally set by the user in a preferences file, called "ENV:Gadgets/select.prefs". The attribute values found in the preferences file override the built-in default values for the corresponding tags; if an attribute isn't present in the file, or if the file is not found, it will keep using the value most recently set (the initial one being the built-in default). As the preferences file is just ASCII text, the user can edit it by hand to change the desired attributes. The format of the file is very simple; it is a list of tool types named exactly like the corresponding "selectgclass" tags, minus the SGA_ prefix. An example of file would be: ItemSpacing=3 FullWidth=1 PopUpDelay=250 As of now, the attributes settable by the user are the following ones ("inf" means "infinite"): Attribute Range Type Default MinItems [ 1..inf] (integer) 1 FullPopUp [ 0, 1 ] (boolean) 0 PopUpDelay [ 0..inf] (integer) 0 PopUpPos [ 0..3 ] (integer) 0 Sticky [ 0, 1 ] (boolean) 0 Justify [ 0..2 ] (integer) 1 Separator [ 0, 1 ] (boolean) 1 DropShadow [ 0, 1 ] (boolean) 0 ItemSpacing [ 0..inf] (integer) 0 ListJustify [ 0..2 ] (integer) 1 ActiveBox [-1..1 ] (integer) 0 BorderSize [-1..inf] (integer) -1 FullWidth [ 0, 1 ] (boolean) 0 FollowMode [ 0..2 ] (integer) 0 PanelMode [ 0..2 ] (integer) 0 MinTime [ 0..Inf] (integer) 0 MaxTime [ 0..Inf] (integer) 0 TO DO Future releases should add the following features: o More attributes globally settable by the user. o Ability to display read-only pop-up menus. o Ability to generate "repeat" messages if the gadget is kept pressed for a while (only when it's a button gadget). Useful for making arrow buttons. o Ability to only display the menu on a button release. Would make sense for "sticky" gadgets. o Text clipping for the gadget item labels. o Some more code optimization. HISTORY 40.15 (19.6.99) Now the gadget preserves the pen color of any IntuiText passed to it rather than incorrectly changing it to TEXTPEN. 40.14 (14.1.99) - Added the ability to do direct bitmap rendering (instead of opening a window) for the pop-up menu panel, which gives a much smoother visual feedback. - Now the menu panel can have an opening/closing "zoom" effect with a configurable duration. - The drop shadow edges have now the correct shape when the "round edges" option of VisualPrefs is active. - Now the background process handling global preferences has a name. 40.13 (17.11.98) Slightly enhanced the GM_RENDER method. 40.12 (25.5.98) First public release. select.gadget/select.gadget select.gadget/select.gadget NAME select.gadget -- create a pop-up, cycle or button BOOPSI gadget FUNCTION The select.gadget shared library implements a public BOOPSI gadget class, called "selectgclass", which provides gadgets with the ability to display a pop-up menu allowing the user to pick up a choice among a number of alternatives. The "selectgclass" gadgets can also be used as standard GadTools-like cycle gadgets, or even as simple button gadgets. Nearly every aspect of their look and behavior can be configured using tag items which give access to the class attributes. For a complete description of the "selectgclass" class and its features, see the class reference documentation in the --background-- paragraph. The library also supplies some functions allowing to modify an existing, non-BOOPSI gadget in order to make it a custom gadget using the hook function of "selectgclass". This makes it possible to use normal gadgets, such as GadTools GENERIC_KIND ones, as if they were "selectgclass" BOOPSI gadgets (with some minor limitations, mainly the lack of notification abilities). To be able to create and use "selectgclass" objects in an application, you first have to open the select.gadget library with OpenLibrary(). Once you have done this, you shouldn't close the library until all of your "selectgclass" objects have been freed. TAGS For the full list of "selectgclass" attributes, see the class reference documentation in the --background-- paragraph. NOTES The "selectgclass" gadget class currently does not support adding gadgets to a screen titlebar. This feature shouldn't be needed anyway. WARNING Don't close the select.gadget library if you still have some instances of "selectgclass" gadgets hanging around! BUGS None known. select.gadget/ClearSelectGadget select.gadget/ClearSelectGadget NAME ClearSelectGadget -- strip a gadget of all additional information. SYNOPSIS ClearSelectGadget(gadget); A0 void ClearSelectGadget(struct Gadget *); FUNCTION Strips a gadget of all the addition information which was added by InitSelectGadgetA(), and restores it (as much as possible) to its former state. You should only call this function on gadgets that were successfully modified by InitSelectGadgetA(), and call it only once. INPUTS gadget - pointer to a custom gadget initialized by InitSelectGadgetA() NOTES Once cleared, the gadget can still be used as a traditional gadget, although in most cases this probably won't make much sense. BUGS None known. SEE ALSO InitSelectGadgetA() select.gadget/GetSGAttr select.gadget/GetSGAttr NAME GetSGAttr -- get value of an attribute of a non-BOOPSI select gadget. SYNOPSIS result = GetSGAttr(attrid, gadget, storageptr); D0 D0 A0 A1 ULONG GetSGAttr(ULONG, struct Gadget *, ULONG *); FUNCTION Inquires from the specified gadget the value of the specified attribute. The gadget must be a non-BOOPSI gadget successfully modified by InitSelectGadgetA(), and the attribute must be specific to "selectgclass". Do not attempt to get standard "gadgetclass" attributes with this function. You always pass the address of a LONG variable, which will receive the same value that would be passed to SetSGAttrsA() in the ti_Data portion of a TagItem element. Not all attributes will respond to this function. Those which do are marked with the "G" applicability flag in the "Attributes" list found in the class reference documentation (see --background-- paragraph). INPUTS attrid - an attribute tag ID understood by "selectgclass" gadget - pointer to a custom select gadget storageptr - pointer to appropriate storage for the answer RESULT result - FALSE if the inquiries of the specified attribute are not provided by "selectgclass", TRUE otherwise NOTES Don't call this function on real BOOPSI "selectgclass" objects; use intuition.library/GetAttr() instead. BUGS None known. SEE ALSO InitSelectGadgetA(), ClearSelectGadget(), SetSGAttrsA() select.gadget/InitSelectGadgetA select.gadget/InitSelectGadgetA NAME InitSelectGadgetA -- change a gadget into a "selectgclass"-like gadget. InitSelectGadget -- varargs stub for InitSelectGadgetA(). SYNOPSIS success = InitSelectGadgetA(gadget, flags, taglist) D0 A0 D0 A1 ULONG InitSelectGadgetA(struct Gadget *, ULONG, struct TagItem *); success = InitSelectGadget(gadget, flags, firsttag, ...) ULONG InitSelectGadget(struct Gadget *, ULONG, Tag, ...); FUNCTION The purpose of this function is to modify an already existing gadget in order to make it a custom gadget which uses the same hook function used by the "selectgclass" BOOPSI gadgets. This function can be very useful if you have already written a program using a non-BOOPSI framework for its GUI (such as GadTools), as it allows you to make your program use the "select" gadgets without having to intermix BOOPSI code with the already existing non-BOOPSI code. In the case of GadTools, for example, you could create GENERIC_KIND gadgets instead of CYCLE_KIND gadgets, and later use InitSelectGadgetA() to turn them into pop-up gadgets. You would then continue handling your interface exactly as before, and once you are done with your gadgets you would just have to restore them to their original state (using the ClearSelectGadget() function) before deleting them as usual with gadtools.library/FreeGadgets(). InitSelectGadgetA() does all necessary allocations, and appends some information to the gadget structure. This information is initialized on the basis of the attribute/value couples you pass in the tag list. The tag list can only contain attributes specific to "selectgclass" (SGA_#?), with the _only_ exception being the "gadgetclass" GA_Image attribute, which can be passed to the function. Every other "standard" gadget attribute (GA_#?) can't be passed to InitSelectGadgetA(), but must be set in the gadget structure by hand. However, once the structure has been modified by InitSelectGadgetA(), and until it is restored by ClearSelectGadget(), some restrictions apply to what you're allowed to do with its fields. More precisely, you may read and write the following fields ONLY: NextGadget LeftEdge, TopEdge, Width, Height GadgetText GadgetID UserData BoundsLeftEdge, BoundsTopEdge, BoundsWidth, BoundsHeight You may also read, set and clear the following flag bits: GFLG_RELBOTTOM, GFLG_RELRIGHT, GFLG_RELWIDTH, GFLG_RELHEIGHT GFLG_DISABLED GFLG_LABELSTRING, GFLG_LABELIMAGE GACT_RELVERIFY GMORE_GADGETHELP The following flag bits are read-only: GFLG_IMAGEDISABLE GFLG_EXTENDED GACT_LEFTBORDER, GACT_TOPBORDER, GACT_RIGHTBORDER, GACT_BOTTOMBORDER GACT_ENDGADGET GTYP_SCRGADGET (not supported yet) GTYP_GZZGADGET GTYP_REQGADGET GMORE_BOUNDS All the above public fields and flag bits, even the read-only ones, may be set BEFORE calling InitSelectGadgetA(), which will preserve them. The only exception is the GACT_RELVERIFY bit: the function will always set it, but you can clear it later (doesn't make much sense though, as you would be no longer able to hear anything from the gadget). Note well: all remaining fields and flag bits are considered PRIVATE and should NOT be used nor relied on. To set/change the gadget's image, always use the GA_Image tag. Don't touch the GadgetRender field! Also, if you modify by hand some values in the gadget structure which could cause a change in the gadget visual appearance, such as its position, size or text, you can force a refresh of the gadget by calling SetSGAttrsA() with the couple { SGA_Refresh, TRUE }. Using RefreshGadgets() or RefreshGList() is not sufficient in this case. Once your custom select gadget is no longer needed, you should strip it of all the added information by using the ClearSelectGadget() function. This will turn the gadget back into whatever it was before you called InitSelectGadgetA(). INPUTS gadget - pointer to a non-BOOPSI gadget which will be transformed into a custom gadget using the hook function of "selectgclass"; it can safely be NULL, in which case the function returns failure flags - reserved for future use; please set this to zero for now taglist - pointer to an array of tags providing extra parameters, or NULL TAGS For the full list of "selectgclass" attributes, see the class reference documentation in the --background-- paragraph. RESULT success - TRUE if all went ok, FALSE otherwise. If FALSE the gadget has not been changed, so you don't have to clear it with ClearSelectGadget() EXAMPLE Your already existing GadTools code might be looking like this: ... newgadget.ng_GadgetText = "Qualifier:"; newgadget.ng_Flags = PLACETEXT_ABOVE; ... gad = CreateGadget(CYCLE_KIND,gad,&newgadget,GTCY_Labels,labels, GTCY_Active,active, TAG_END); ... To use the "selectgclass" features, you could modify it this way: ... newgadget.ng_GadgetText = "Qualifier:"; ... gad = CreateGadget(GENERIC_KIND,gad,&newgadget,TAG_END); if (!InitSelectGadget(gad,0L,SGA_Labels,labels, SGA_Active,active, SGA_TextPlace,PLACETEXT_ABOVE, TAG_END)) { gad = NULL; // From now on, all CreateGadget() calls will fail } ... BUGS None known. SEE ALSO ClearSelectGadget() select.gadget/ObtainSelectGClass select.gadget/ObtainSelectGClass NAME ObtainSelectGClass -- return a pointer to "selectgclass". SYNOPSIS sgclass = ObtainSelectGClass() D0 Class *ObtainSelectGClass(void); FUNCTION Returns a pointer to the class implemented by the select.gadget, called "selectgclass". Use this pointer with care, and do not reference it after you've closed the select.gadget library. INPUTS none RESULT sgclass - pointer to the class BUGS None known. SEE ALSO select.gadget/SetSGAttrsA select.gadget/SetSGAttrsA NAME SetSGAttrsA -- change the attributes of a non-BOOPSI select gadget. SetSGAttrs -- varargs stub for SetSGAttrsA(). SYNOPSIS result = SetSGAttrsA(gadget, window, requester, flags, taglist) D0 A0 A1 A2 D0 A3 ULONG SetSGAttrsA(struct Gadget *, struct Window *, struct Requester *, ULONG, struct TagItem *); result = SetSGAttrs(gadget, window, requester, flags, firsttag, ...) ULONG SetSGAttrs(struct Gadget *, struct Window *, struct Requester *, ULONG, Tag, ...); FUNCTION Changes the attributes of a gadget modified by InitSelectGadgetA(), according to the attributes chosen in the tag list. If an attribute is not provided in the tag list, its value remains unchanged. This function is only able to change the attributes which are specific to "selectgclass", as well as the GA_Image attribute. Any other standard "gadgetclass" attribute is not recognized, so do NOT pass such attributes to SetSGAttrsA(). The gadget will refresh its imagery to reflect changes to visual attributes, such as the active item, the "pop-up" symbol or the gadget's frame image. If you also want to change standard gadget attributes (like position, size and gadget text), first change them by hand in the gadget structure, then call this function with the tag item { SGA_Refresh, TRUE }, which will force a refresh. See the documentation of InitSelectGadgetA() for a list of the fields in the gadget structure that you are allowed to change by hand. This function is provided to let you change the special attributes of non-BOOPSI gadgets that were initialized by InitSelectGadgetA(); you may not call intuition.library/SetGadgetAttrsA() on this special kind of gadgets. The opposite is also true: this function must not be used with real BOOPSI gadgets (not even "selectgclass" ones). INPUTS gadget - pointer to a custom gadget initialized by InitSelectGadgetA(). It may be NULL, in which case this function does nothing window - pointer to the window containing the gadget. It may be NULL, in which case the internal attributes of the gadget are altered but no rendering occurs requester - pointer to the requester containing the gadget, required only for REQGADGETs flags - reserved for future use; please set this to zero for now taglist - array of TagItem structures with attribute/value pairs TAGS For the full list of "selectgclass" attributes, see the class reference documentation in the --background-- paragraph, and only consider the attributes with the "S" applicability flag. RESULT result - TRUE if all went ok, or FALSE if there was an error (usually a failure in some memory allocation) NOTES Never, ever call this function with real "selectgclass" BOOPSI gadgets; use intuition.library/SetGadgetAttrsA() instead. BUGS None known. SEE ALSO InitSelectGadgetA(), ClearSelectGadget(), GetSGAttr()