
The ASL Library and 2.1
=======================

(c) Copyright 1992-93 Commodore-Amiga, Inc.  All Rights Reserved

Among the many improvements to the 2.1 version of the operating system,
the ASL library now has a new type of requester: the screen mode
requester.  There are also many new tags and new header files.  The
purpose of this article is to summarize the changes in the 2.1 version of
the ASL library. 


The Screen Mode Requester
=========================

The Screeen Mode requester provides application writers with a convenient
way to ask the user for their screen display preferences.  You create an
ASL screen mode requester the same way you create an ASL file requester or
font requester; only the tags and structures used are different. 

There are three main functions to call:

· AllocAslRequest() 	Sets up the ScreenModeRequester structure you need. 

· AslRequest()      	Displays the requester you have set up with
			AllocAslRequest(). 

· FreeAslRequest()  	Frees the ScreenModeRequester structure and
			other resources.

The first step is to set up a ScreenModeRequester structure with the
AllocAslRequest() function.  The ScreenModeRequester structure is defined
in <libraries/asl.h> as follows:

 struct ScreenModeRequester {
     ULONG sm_DisplayID;            /* Display mode ID                  */
     ULONG sm_DisplayWidth;         /* Width of display in pixels       */
     ULONG sm_DisplayHeight;        /* Height of display in pixels      */
     UWORD sm_DisplayDepth;         /* Number of bit-planes of display  */
     UWORD sm_OverscanType;         /* Type of overscan of display      */
     BOOL  sm_AutoScroll;           /* Display should auto-scroll?      */
     ULONG sm_BitMapWidth;          /* Used to create your own BitMap   */
     ULONG sm_BitMapHeight;
     WORD  sm_LeftEdge;             /* Coordinates of requester on exit */
     WORD  sm_TopEdge;
     WORD  sm_Width;
     WORD  sm_Height;
     BOOL  sm_InfoOpened;           /* Info window opened on exit?      */
     WORD  sm_InfoLeftEdge;         /* Last coordinates of Info window  */
     WORD  sm_InfoTopEdge;
     WORD  sm_InfoWidth;
     WORD  sm_InfoHeight;
     APTR  sm_UserData;             /* You can store your own data here */
 };

The fields in this structure will be filled in with information obtained
from the user.  This information can then be used in your application to
create the type of screen that the user prefers. 


Note that for most programs, the user's preferred screen mode can be
determined from the Amiga's Preferences subsystem.  You do not have to use
a screen mode requester.  Consider carefully whether it is more
appropriate to use an ASL requester or to obtain the information directly
from the settings in Overscan and ScreenMode Preferences. 
 
Listed below is a simple program that displays the new ASL screen mode
requester including depth, width and height gadgets.  (This program
requires the 2.1 version of the Amiga OS.)
 
;/*
LC -b1 -cfistq -v -y -j73 aslsm.c
Blink FROM LIB:c.o,aslsm.o TO aslsm library LIB:lc.lib,lib:amiga.lib
quit
*/


#include <clib/all_protos.h>
#include <exec/types.h>
#include <libraries/asl.h>
#include <utility/tagitem.h>

#define SMRTITLE ("Simplest ScreenMode Requester")

UBYTE *vers="\0$VER: ASL_ScreenMode_Requester 0.01 (8.7.92)";

struct Library *AslBase;


void
main(int argc, char **argv)
{

struct ScreenModeRequester *smr;
struct TagItem smrtags[5];

if( AslBase=OpenLibrary("asl.library", 38L) )
    {
    smrtags[0].ti_Tag=ASLSM_TitleText;
    smrtags[0].ti_Data=(ULONG)SMRTITLE;

    smrtags[1].ti_Tag=ASLSM_DoWidth;
    smrtags[1].ti_Data=TRUE;

    smrtags[2].ti_Tag=ASLSM_DoHeight;
    smrtags[2].ti_Data=TRUE;

    smrtags[3].ti_Tag=ASLSM_DoDepth;
    smrtags[3].ti_Data=TRUE;

    smrtags[4].ti_Tag=TAG_DONE;

    if( smr = (struct ScreenModeRequester *)
          AllocAslRequest(ASL_ScreenModeRequest, smrtags) )
        {
        if( AslRequest(smr, 0L) )
            {
            printf("Display type: $%lx (see graphics/displayinfo.h)\n",
                    smr->sm_DisplayID);
            printf("Display width: %ld, height: %ld, depth: %d\n",
                   smr->sm_DisplayWidth, smr->sm_DisplayHeight,
                   smr->sm_DisplayDepth);
            }              
        else
            printf("User cancelled or error...\n");  
        
        FreeAslRequest(smr);
        }
    CloseLibrary(AslBase);
    }
}


As with other ASL requesters, the attributes of the screen mode requester
are established using tag items when AllocAslRequest() is called.  These
attributes can later be changed by using different tag items in the
AslRequest() call. 

For instance, in the example above, tag items are used to specify that the
screen mode requester should include gadgets for setting the display
height (ASLSM_DoHeight), width (ASLSM_DoWidth) and depth (ASLSM_DoDepth). 


Screen Mode Requester Tags
==========================

Here's a brief summary of the tag items that apply only to the ASL screen
mode requester.  For a complete listing of all ASL tag items, refer to the
ASL include files and Autodocs.

Screen Mode Tag Name			Used For
--------------------			--------
/* Window control */
#define ASLSM_Window	      		Parent window
#define ASLSM_Screen	      		Screen to open on if no window
#define ASLSM_PubScreenName   		Name of public screen
#define ASLSM_PrivateIDCMP    		Allocate private IDCMP?
#define ASLSM_IntuiMsgFunc    		Function to handle IntuiMessages
#define ASLSM_SleepWindow     		Block input in ASLSM_Window?
#define ASLSM_UserData	   		What to put in sm_UserData

/* Text display */
#define ASLSM_TextAttr	      		Text font to use for gadget text
#define ASLSM_Locale	        	Locale ASL should use for text
#define ASLSM_TitleText       		Title of requester
#define ASLSM_PositiveText    		Positive gadget text
#define ASLSM_NegativeText      	Negative gadget text

/* Initial settings */
#define ASLSM_InitialLeftEdge 		Initial requester coordinates
#define ASLSM_InitialTopEdge
#define ASLSM_InitialWidth		Initial requester dimensions
#define ASLSM_InitialHeight
#define ASLSM_InitialDisplayID		Initial display mode id
#define ASLSM_InitialDisplayWidth  	Initial display width
#define ASLSM_InitialDisplayHeight 	Initial display height
#define ASLSM_InitialDisplayDepth  	Initial display depth
#define ASLSM_InitialOverscanType  	Initial type of overscan
#define ASLSM_InitialAutoScroll    	Initial autoscroll setting
#define ASLSM_InitialInfoOpened    	Info window initially opened?
#define ASLSM_InitialInfoLeftEdge 	Initial Info window coords.
#define ASLSM_InitialInfoTopEdge

/* Options */
#define ASLSM_DoWidth         		Display Width gadget?
#define ASLSM_DoHeight        		Display Height gadget?
#define ASLSM_DoDepth         		Display Depth gadget?
#define ASLSM_DoOverscanType  		Display Overscan Type gadget?
#define ASLSM_DoAutoScroll    		Display AutoScroll gadget?

/* Filtering */
#define ASLSM_PropertyFlags   		Must have these Property flags
#define ASLSM_PropertyMask    		Only these should be looked at
#define ASLSM_MinWidth	      		Minimum display width to allow
#define ASLSM_MaxWidth	      		Maximum display width to allow
#define ASLSM_MinHeight       		Minimum display height to allow
#define ASLSM_MaxHeight       		Maximum display height to allow
#define ASLSM_MinDepth	      		Minimum display depth
#define ASLSM_MaxDepth	      		Maximum display depth
#define ASLSM_FilterFunc      		Function to filter mode id's

#define ASLSM_CustomSMList    		Exec list of struct DisplayMode



Other New ASL Tags in 2.1
=========================

The tag items used to control the behavior of ASL requesters have been
overhauled for the 2.1 release of the Amiga OS.  This section summarizes
the new 2.1 tags. 


New ASL Tags Used by All Requester Types
========================================

These tags apply to all three types of ASL requesters: the file requester,
the font requester and the new screen mode requester.  Each tag in the
list below is prepended with ASLxx_.  The actual tag names used by ASL
will be prepended with ASLFR_, ASLFO_ or ASLSM_ depending on what type of
requester is being used. 

New 2.1 Tag Name    	Used For
----------------	--------
ASLxx_PubScreenName 	Name of a public screen on which to open the
			requester. 
ASLxx_Screen        	Pointer to a screen on which to open the requester. 
ASLxx_PrivateIDCMP  	Specifies separate IDCMP for the requester
			window (this replaces
			the FILF_NEWIDCMP and FONF_NEWIDCMP flags in the
 			ASL_FuncFlags tag used in V37).  
ASLxx_IntuiMsgFunc  	Function to call when an unknown message arrives
			at a shared IDCMP used by the requester window
			(this replaces the ASL_HookFunc tag and the
			FILF_DOMSGFUNC and FONF_DOMSGFUNC flags in the
			ASL_FuncFlags used in V37). 
ASLxx_SleepWindow   	Modal requester.  Specifies that input should be
			blocked in the parent window.
ASLxx_UserData      	A 32-bit value copied into the user data field of
			the requester structure. 
ASLxx_TextAttr      	Font to use for requester window gadgets and menus.
ASLxx_Locale        	Locale (and language) to use for the requester
			window. 
ASLxx_FilterFunc    	Function to call for each item (file, font or
			mode) encountered.  If the function returns TRUE,
			the item is displayed in the list view gadget,
			otherwise it is rejected and not displayed.
			(This replaces the ASL_HookFunc tag and the
			FILF_DOWILDFUNC and FONF_DOWILDFUNC flags in
			ASL_FuncFLags used in V37.)



New ASL Tags Used by the File Requester
=======================================

These new 2.1 tag items apply only to file requesters:
        
New 2.1 Tag Name    	Used For
----------------	--------
ASLFR_DoSaveMode    	Specifies that this file requester is a save
			requester (this replaces the FILF_SAVE flag in
			the ASL_FuncFlags tag used in V37).
ASLFR_DoMultiSelect 	Enables multiple selection of files
			(this replaces the FILF_MULTISELECT flag in
			ASL_FuncFlags used in V37).
ASLFR_DoPatterns    	Causes a pattern gadget to be included in the
			requester (this replaces the FILF_PATGAD flag
			in ASL_FuncFlags used in V37). 
ASLFR_DrawersOnly   	Causes the requester to only display drawers
			(this replaces the FIL1F_NOFILES flag in
			ASL_ExtFlags1 used in V37).
ASLFR_RejectIcons   	Causes the requester not to display Workbench icons. 
ASLFR_RejectPattern 	Specifies an AmigaDOS pattern used to reject files. 
ASLFR_AcceptPattern 	Specifies an AmigaDOS pattern used to accept files. 
ASLFR_FilterDrawers 	Makes ASLFR_RejectPattern and ASLFR_AcceptPattern
 			apply to drawer names.



New ASL Tags Used by the Font Requester
=======================================

These new 2.1 tags apply only to font requesters.  The ASL Autodocs list
most of these as new tag items for V38.  However there are no new features
with most of these tags, just new, more consistent names. 

New 2.1 Tag Name      	Used For
----------------	--------
ASLFO_DoFrontPen 	Causes the requester to display the Front Color
			selection gadget
			(this replaces the FONF_FRONTCOLOR flag in
			ASL_FuncFlags used in V37). 
ASLFO_DoBackPen		Causes the requester to display the Back Color
			selection gadget (this replaces the FONF_BACKCOLOR
			flag in ASL_FuncFlags used in V37). 
ASLFO_DoStyle 		Causes the requester to display Style checkbox
			gadgets (this replaces the FONF_STYLES flag in
			ASL_FuncFlags used in V37).
ASLFO_DoDrawMode	Causes the requester to display the Mode cycle
			gadget.(this replaces the FONF_DRAWMODE flag in
			ASL_FuncFlags used in V37).
ASLFO_FixedWidthOnly	Causes the requester to list only fixed-width
			fonts (this replaces the FONF_FIXEDWIDTH flag
			in ASL_FuncFlags  used in V37).
ASLFO_InitialDrawMode 	Initial setting of the font Mode gadget.




New Tag Names for Old Features
==============================
Many of the new tag items in the asl.h header file do not provide any new
2.1 features.  They just make the naming conventions used by ASL more
consistent.  This section lists the new tag names along with the
corresponding tag name used previously in V37 and earlier versions of the
OS. 

In this first list each tag is prepended with ASLxx_.  The actual tag
names used by ASL will be prepended with ASLFR_, ASLFO_ or ASLSM_
depending on what type of requester is being used. 

New 2.1 Tag Name      	Old Tag Name	Used For
----------------	------------	--------
ASLxx_Window          	ASL_Window	Specifies the parent window of
					the requester.
ASLxx_TitleText       	ASL_Hail       	String to use for the requester
					title.
ASLxx_PositiveText    	ASL_OKText 	String to use for the OK button.
ASLxx_NegativeText    	ASL_CancelText	String to use for the  Cancel
					button.

ASLxx_InitialLeftEdge 	ASL_LeftEdge	These specify the size and
ASLxx_InitialTopEdge 	ASL_TopeEdge	position of the requester.
ASLxx_InitialWidth    	ASL_Width
ASLxx_InitialHeight   	ASL_Height





This set of ASL tags apply only to file requesters:

New 2.1 Tag Name      	Old Tag Name    Used For
----------------	------------	--------
ASLFR_InitialFile	ASL_File	Initial file name selection.
ASLFR_InitialDrawer	ASL_Dir		Initial directory name selection.
ASLFR_InitialPattern	ASL_Pattern	Initial pattern-matching string.
ASLFR_Flags1		ASL_Flags	Various file requester options.
ASLFR_Flags2		ASL_ExtFlags1	Various file requester options.
ASLFR_HookFunc		ASL_HookFunc	User function for inspecting list
					view gadget entries or handling
					shared IDCMP messages.



This set of ASL tags applies only to font requesters:

New 2.1 Tag Name      	Old Tag Name    Used For
----------------	------------	--------
ASLFO_InitialName	ASL_FontName    Initial font name selection.
ASLFO_InitialSize     	ASL_FontHeight  Initial font size.
ASLFO_InitialFrontPen 	ASL_FrontPen    Initial setting of Front Color
					gadget. 
ASLFO_InitialBackPen  	ASL_BackPen     Initial setting of Back Color
					gadget.
ASLFO_InitialStyle    	ASL_FontStyles  Initial setting of font Style
					gadget.
ASLFO_ModeList        	ASL_ModeList    Alternate strings for Mode
					cycle gadget.
ASLFO_MaxHeight       	ASL_MaxHeight   Specifies the maximum height of
					fonts to be listed.
ASLFO_MinHeight       	ASL_MinHeight   Specifies the minimum height of
					fonts to be listed.
ASLFO_HookFunc        	ASL_HookFunc    User function for inspecting
					list view gadget entries or
					handling shared IDCMP messages.
ASLFO_Flags           	ASL_Flags       Various font requester options.





The ASL Library and Amiga OS 2.1
================================

Developer Release NotesThe ASL Library and 2.1Amiga OS 2.1

Release Notes

This is the initial setting of the display Mode list view gadget.
(Display mode IDs are defined in <graphics/displayinfo.h>.)
    

These tags specify whether the screen mode requester should include a
width numeric slider gadget and what values to use for its initial,
maximum and minimum setting. 

These tags specify whether the screen mode requester should include a
height numeric gadget and what values to use for its initial, maximum and
minimum setting. 


These tags specify whether the screen mode requester should include a
depth numeric gadget and what values to use for its initial, maximum and
minimum setting. 

These tags specify whether the screen mode requester should include an
Overscan Type cycle gadget and what its initial setting should be. 

These tags specify whether the screen mode requester should include an
Autoscroll checkbox gadget and its initial state. 

These tags specify whether the screen mode requester should appear with
the Property window open and the values to use for its initial position.
Note that this window is always accesible from the screen mode requester's
menu. 

These two tags together provide a way to filter the display mode
properties that will appear in the Property window. 

A custom Exec list of modes to let the user choose from.
