TweetFollow Us on Twitter

Cursor Control 1
Volume Number:6
Issue Number:6
Column Tag:abC

Related Info: TextEdit Quickdraw

Cursor Control

By Bob Gordon, Minneapolis, MN

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Managing Cursors

I know how to curse

Shakespeare, The Tempest (Act 1, Scene 2)

If you remember from last time, I had introduced the idea of adding some additional data structures at the end of the window record to aid in keeping track of the data that hangs around with a window. At the end of that article I said we would illustrate the use of the added data in managing the cursor. We will cover that, but first I would like to comment on a nice piece of work by John Nairn in the April issue.

John has presented a full-blown Scrolling Manager to handle all the issues involved with creating and maintaining scrolling windows. While there are a number of differences between what he has done and what I am describing in this column, a couple common points are worth mentioning. First, the approach is to isolate the user interface control from the actual application. That is, as much as possible, develop generic code to handle the basic operation of the windows (or menus or dialogs, for that matter). Second, this generic code will probably require some place to keep the information it uses; develop a data structure to hold this, and attach it in some way to the window (or menu or dialog). There is actually a bit more commonality (I have the advantage of being able to see the parts I have written but not yet published), and we will explore one of those in this article.

One point of difference. John uses the window’s refCon to hold his additional data structure. His new data structure includes its own refCon for the window’s contents. I added the data on to the end of the window’s structure itself. I feel this simplifies things somewhat, and at least for now it does not seem to violate any rules. If you liked John’s article as I did, you certainly have my permission to use the technique I’ve outlined in implementing it. While I haven’t met John, I’m reasonably sure he won’t mind.

Cursors

The cursor attached to the mouse changes its shape as you move the mouse around the screen. In addition, the user can often affect its shape directly by selecting a tool from a toolbox (usually found in graphics or page layout applications). The problem we deal with this month is how to manage the cursor so it is handled as automatically as possible.

The first issue is getting cursors. There are five built in to the Mac: arrow, crosshairs, plus, clock, i-beam. You can also make your own with ResEdit or some other resource tool. Once we have decided the cursors to use (and made their resources), we need to control the appearance on the screen. What I will describe this month is one way to manage the change of cursor shape as the user moves the mouse around the screen. I am not covering the setting of the cursor’s via tool box or menus.

In June I suggested the use of window margins. The window margin is that area between the window’s frame, which is handled by the Macintosh toolbox routines, and the window’s actual contents, which is what your application is about. The objects that might be in a window margin include scroll bars, rulers, and tool boxes. These are such common components of windows that they can be handled by generic code apart from your application. The other property of the window margin is that the cursor typically changes into the arrow as it is moved into the scroll bar, ruler, etc.

Cursorhelp

Cursorhelp consists of three functions and an include file to aid in the setting and automatic changing of cursors. These functions assume the window structure described in June. The window margins (mtop,mbottom, mright, mleft) are stored with the window. More importantly, the rectangle that surrounds the actual window contents (cursrt) is also stored (I assume rectangular windows). This rectangle is the area in which the cursor is the shape the user selected (i beam, cross, etc.). I put it in the window structure simply to avoid having to calculate it each time. The final piece is the cursor itself (mouser). That is, the cursor’s shape as selected by the user is a property of the window. With a multi-window application the user can have one window editing text, another editing a graphic, and a third editing a spreadsheet (I am not suggesting anyone actually write something like this), and the appropriate cursor will be displayed automatically as the user selects each window. The main loop need know nothing of the cursors.

The main loop does need to set the cursor. There are two places where this can occur: the users specifies a cursor in some way or, the application displays the watch (or other indicator) to indicate the passage of time. The program calls CursorToUse passing the window and the number of the desired cursor.

The program also needs to set the cursor rectangle. This must be done every time the window’s size is changed or the window margins are changed (for example, choosing to show rulers or not).A call to CursorRect() does that. Note that the window margins must have been previously set.

To actually control the cursor, the program calls CursorMaintain() as it runs through the event loop.

Include Files
/*windowhelp.h */
#include “TextEdit.h”
 
#ifndef WINDOWHELP_H
#define WINDOWHELP_H
#include“abc.h”    /* window add-on structure */

#define WindowStruct struct w_struct
WindowStruct
 {
 WindowRecord  wr;  /* the original window record */
 uchar  mtop;    /* margin indents */
 uchar  mleft;
 uchar  mbottom;
 uchar  mright;
 Rect   cursrt;    /* used for cursor control */
 char   mouser;  /* mouse pointer id  */
 char   changed; /* if contents were changed */
 long   ckind;   /* kind of contents */
 short  fileref; /* associated file, if any */
 TEHandle curtext; /* handle to current text */
 };
 
WindowStruct*WindowNew();

#define Woffset  18
#define SBarWidth 15

/* these definitions allow easy generation of the four square cornered 
titled windows. The basic (simplest) window is the WDOC (NoGrowDocProc). 
To this optionally add WGROW to add a grow box and/or WZOOM to add a 
zoom box.
 */
#define WDOC4
#define WGROW    -4
#define WZOOM    8
#define WVBAR    16
#define WHBAR    32

/* Value placed in windowKind field of WindowRecord by WindowNew if the 
window has a grow box. This is used by routines that redraw the window 
to decide whether to draw the grow box or not 
 */
#define HASGROW  9

#endif

/* cursorhelp.h
 * header file for cursorhelp
 */
 
 #defineARROW  0
 #defineIBEAM  1
 #defineCROSS  2
 #definePLUS3
 #defineWATCH  4
CursorHelp Functions
#include“abc.h”
#include“Quickdraw.h”
#include“windowMgr.h”
#include“windowhelp.h”
#include“cursorhelp.h”

/* CursorMaintain
 * Adjusts the cursor according to the value
 * set in the window and the rectangle currect.
 * If the mouse is in the rectangle, the cursor 
 * set to the current cursor, otherwise it is
 * set to the arrow.
 * The if statement checks to see if there is a 
 * valid window and if the window belongs to the
 * application. If it does not belong to the application
 * it is a DA. If the DA is controlling the cursor, there
 * will be a conflict as both programs attempt to control
 * it.
 */
CursorMaintain(ws)
 WindowStruct  *ws;
{
 Point  pt;
 CursHandle curs;
 short  curcursor; /* current cursor */
 
 if (ws && (((WindowRecord *)ws)->windowKind > 7) )
 {
 GetMouse(&pt);
 curcursor = ws->mouser;  /* cursor kind is stored in the window struct 
*/
 if ((PtInRect(pt, &(ws->cursrt))) && (curcursor))
 {
 curs = (Cursor **)GetCursor(curcursor);     
 SetCursor(*curs); 
 }
 else if (curcursor != WATCH)
 {
 InitCursor();
 }
 }
 if (ws == NIL)
 InitCursor();
}

/* CursorRect
 * Uses the portRect of the window passed in
 * to set the current rectangle.  Adjusts the size
 * of the rectangle to account for window margins.
 * By keeping the rectangle around, we eliminate doing
 * this each time through the event loop.
 */
 
CursorRect(ws)
 WindowStruct    *ws;
{
 ws->cursrt = ((GrafPort *)ws)->portRect;
 AdjustRect(&(ws->cursrt),ws->mtop,ws->mleft,ws->mbottom,ws->mright);
}

/* CursorToUse
 * Sets the cursor to be displayed in the
 * rectangle of the current window.
 * Either pass a pointer to the window struct
 * or a NULL pointer. If a NULL pointer is passed,
 * CursorToUse() will use the front window. 
 * Note: At least one window must exist for this
 * to work, but if no windows exist, it
 * will not hurt.
 */
CursorToUse(ws,c)
 WindowStruct  *ws;/* window struct to set cursor for */
 short  c;/* cursor code to use */
{
 if (!ws)
 ws = (WindowStruct *)FrontWindow();
 if (ws)
 ws->mouser = c;
}

Using CursorMaintain()

The following fragment shows the call to CursorMaintain() in the main event loop.

EventLoop()
{
 EventRecordtheEvent;
 char   c;
 short  windowcode;
 WindowPtrwp;
 WindowStruct  *ws;
 
 while(True)
 {
 wp = FrontWindow();
 SystemTask();
 CursorMaintain(wp); 
 if (wp)
 {
 AppTask(wp);
 } 
 if (GetNextEvent(everyEvent,&theEvent))
 switch(theEvent.what)

Other Comments

Check John Nairn’s article for other things to do to automate cursor control. You will note he checks for certain keys being pressed to change the cursor to allow window scrolling (e.g. with a hand).

Last Time

I have a minor error in June’s column. I included some space in the window structure to handle window zooming. These are not needed as zooming is fully supported by the Mac Toolbox. I hadn’t used them for anything yet.

Next Time

Next time I am going to show a quick and very dirty way to help deal with menus.

P.S. Comments are welcome. Send your notes to MacTutor, and please include a phone number.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Monolingual 1.6.4 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. If you use your computer in only one (human) language, you... Read more
CleanApp 5.0 - Application deinstaller a...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Fantastical 2.0 - Create calendar events...
Fantastical is the Mac calendar you'll actually enjoy using. Creating an event with Fantastical is quick, easy, and fun: Open Fantastical with a single click or keystroke Type in your event details... Read more
Cocktail 8.2 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
Direct Mail 4.0.4 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for OS X. It lets you create and send great looking email campaigns. Start your newsletter by selecting from a gallery... Read more
jAlbum Pro 12.6 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.6 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
Lyn 1.5.9 - Lightweight image browser an...
Lyn is a lightweight and fast image browser and viewer designed for photographers, graphic artists and Web designers. Featuring an extremely versatile and aesthetically pleasing interface, it... Read more
Sublime Text 3080 - Sophisticated text e...
Sublime Text is a sophisticated text editor for code, markup, and prose. You'll love the slick user interface, extraordinary features, and amazing performance. Goto Anything. Use Goto Anything to... Read more
WALTR 1.0.11 - Drag-and-drop any media f...
WALTR is designed to make it easy to upload and convert any music or video file to an iPad or iPhone format for native playback. It supports a huge variety of media file types, including MP3, MP4,... Read more

MLB Manager 2015 (Games)
MLB Manager 2015 5.0.14 Device: iOS Universal Category: Games Price: $4.99, Version: 5.0.14 (iTunes) Description: Guide your favorite MLB franchise to glory! MLB Manager 2015, officially licensed by MLB.com and based on the award-... | Read more »
Breath of Light (Games)
Breath of Light 1.0.1421 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.1421 (iTunes) Description: Hold a quiet moment. Breath of Light is a meditative and beautiful puzzle game with a hypnotic soundtrack by... | Read more »
WWE WrestleMania Tags into the App Store
Are You ready to rumble? The official WWE WrestleMania app, by World Wrestling Entertainment, is now available. Now you can get all your WrestleMania info in one place before anyone else. The app offers details on superstar signings, interactive... | Read more »
Bio Inc's New Expansion is Infectin...
Bio Inc., by DryGin Studios, is the real time strategy game where you infect a human body with the worst virus your evil brain can design. Recently, the game was updated to add a whole lot of new features. Now you can play the new “Lethal”... | Read more »
The Monocular Minion is Here! Despicable...
Despicable Me: Minion Rush, by Gameloft, is introducing a new runner to the mix in their latest update. Now you can play as Carl, the prankster minion. Carl has a few new abilities to play with, including running at a higher speed from the start.... | Read more »
Dungeon of Madness (Games)
Dungeon of Madness 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: Dungeon of Madness is an action game where you rotate tiles to create our own route. Help the hero by connecting the... | Read more »
Filters for iPhone (Photography)
Filters for iPhone 1.0 Device: iOS iPhone Category: Photography Price: $.99, Version: 1.0 (iTunes) Description: | Read more »
Jump'N'Shoot Attack (Games)
Jump'N'Shoot Attack 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: A mobile game for gamers! Join Louise Lightfoot, the legendary "Master of Jumping and Shooting", on her mission to save... | Read more »
Space Bounties Inc. (Games)
Space Bounties Inc. 1.4 Device: iOS Universal Category: Games Price: $1.99, Version: 1.4 (iTunes) Description: SuperGameDroid: 4/5 "Satisfying futuristic RPG combat, high replay value, and a heavy dose of nostalgia make Space... | Read more »
Gamebook: Pocket RPG (Games)
Gamebook: Pocket RPG 1.0.11 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.11 (iTunes) Description: Walk into the Land of Lanthir Lamath ruled by wicked skeletons and fight for your life in a thrilling adventure.... | Read more »

Price Scanner via MacPrices.net

Logitech Says MX Master Is Its Most Advanced...
Logitech’s new MX Master Wireless Mouse incorporates the best of Logitech’s many computer mouse innovations into a striking hand-sculpted design. The company claims that the MX Master creates a new... Read more
Save up to $300 on a new Mac, $30 on an iPad,...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Apple refurbished 2014 MacBook Airs available...
The Apple Store lowered prices on Apple Certified Refurbished 2014 MacBook Airs recently, with models now available starting at $679. An Apple one-year warranty is included with each MacBook, and... Read more
Mac Notebook Evolution; A Desktop Replacement...
More often than not right from the beginning, Apple’s Macs have tended to skew toward small. The original Macs were called “compacts,”, and notwithstanding a few exceptions like the honking Big Mac... Read more
13-inch 1.4GHz/128GB MacBook Air (Apple refur...
The Apple Store has Apple Certified Refurbished 2014 13″ 1.4GHz/128GB MacBook Airs available for $759 including free shipping plus Apple’s standard one-year warranty. Their price is $240 off original... Read more
YEP! Alternative Browser for iOS Now Supports...
Pfaeffikon, Switzerland based Power App AG has announced the release of an update to their Yep! Web Browser (v1.3.0) for iOS8 iPhone and iPad. Yep! hit the App Store shortly after the release of iOS... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $250 off MSRP for a limited time. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $... Read more
Clearance 13-inch Retina MacBook Pros availab...
B&H Photo has leftover 2014 13″ Retina MacBook Pros on sale for up to $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.6GHz/128GB Retina MacBook Pro: $1098... Read more
Clearance 2014 MacBook Airs on sale for up to...
B&H Photo has MacBook Airs on sale for up to $180 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 11″ 128GB MacBook Air: $789.99 110 off original MSRP - 11″ 256GB... Read more
Apple refurbished Time Capsules available for...
The Apple Store has certified refurbished Time Capsules available for $100 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $199, $100... Read more

Jobs Board

*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - D...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Systems Engineer - Pre Sales, Educat...
…is responsible for proactively providing technical expertise to drive sales of Apple solutions into assigned accounts. The SE architects, validates, and assists in Read more
Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.