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

Vivaldi 1.0.118.19 - Lightweight browser...
Vivaldi browser. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind that users are... Read more
Stacks 2.6.11 - New way to create pages...
Stacks is a new way to create pages in RapidWeaver. It's a plugin designed to combine drag-and-drop simplicity with the power of fluid layout. Features: Fluid Layout: Stacks lets you build pages... Read more
xScope 4.1.3 - Onscreen graphic measurem...
xScope is powerful set of tools that are ideal for measuring, inspecting, and testing on-screen graphics and layouts. Its tools float above your desktop windows and can be accessed via a toolbar,... Read more
Cyberduck 4.7 - FTP and SFTP browser. (F...
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
Labels & Addresses 1.7 - Powerful la...
Labels & Addresses is a home and office tool for printing all sorts of labels, envelopes, inventory labels, and price tags. Merge-printing capability makes the program a great tool for holiday... Read more
teleport 1.2.1 - Use one mouse/keyboard...
teleport is a simple utility to let you use one single mouse and keyboard to control several of your Macs. Simply reach the edge of your screen, and your mouse teleports to your other Mac! The... Read more
Apple iMovie 10.0.8 - Edit personal vide...
With an all-new design, Apple iMovie lets you enjoy your videos like never before. Browse your clips more easily, instantly share your favorite moments, and create beautiful HD movies and Hollywood-... Read more
Box Sync 4.0.6233 - Online synchronizati...
Box Sync gives you a hard-drive in the Cloud for online storage. Note: You must first sign up to use Box. What if the files you need are on your laptop -- but you're on the road with your iPhone? No... Read more
Fantastical 2.0.3 - Create calendar even...
Fantastical 2 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... Read more
The Hit List 1.1.14 - Advanced reminder...
The Hit List manages the daily chaos of your modern life. It's easy to learn - it's as easy as making lists. And it's powerful enough to let you plan, then forget, then act when the time is right.... Read more

SoundHound + LiveLyrics is Making its De...
SoundHound Inc. has announced that SoundHound + LiveLyrics, will be one of the first third-party apps to hit the Apple Watch. With  SoundHound you'll be able to tap on your watch and have the app recognize the music you are listening to, then have... | Read more »
Adobe Joins the Apple Watch Lineup With...
A whole tidal wave of apps are headed for the Apple Watch, and Adobe has joined in with 3 new ways to enhance your creativity and collaborate with others. The watch apps pair with iPad/iPhone apps to give you total control over your Adobe projects... | Read more »
Z Steel Soldiers, Sequel to Kavcom'...
Kavcom has released Z Steel Soldiers, which continues the story of the comedic RTS originally created by the Bitmap Brothers. [Read more] | Read more »
Seene Lets You Create 3D Images With You...
Seene, by Obvious Engineering, is a 3D capture app that's meant to allow you to create visually stunning 3D images with a tap of your finger, and then share them as a 3D photo, video or gif. [Read more] | Read more »
Lost Within - Tips, Tricks, and Strategi...
Have you just downloaded Lost Within and are you in need of a guiding hand? While it’s not the toughest of games out there you might still want some helpful tips to get you started. [Read more] | Read more »
Entertain Your Pet With Your Watch With...
The Petcube Camera is a device that lets you use live video to check in on your pet, talk to them, and play with them using a laser pointer - all while you're away. And the Petcube app is coming to the Apple Watch, so you'll be able to hang out with... | Read more »
Now You Can Manage Your Line2 Calls With...
You'll be able to get your Line2 cloud phone service on the Apple Watch very soon. The watch app can send and receive messages using hands-free voice dictation, or by selecting from a list of provided responses. [Read more] | Read more »
R.B.I. Baseball 15 (Games)
R.B.I. Baseball 15 1.01 Device: iOS Universal Category: Games Price: $4.99, Version: 1.01 (iTunes) Description: The legendary Major League Baseball franchise returns to the diamond. Make History. ** ALL iPOD Touch, the iPad 2 and the... | Read more »
Here's How You Can Tell if an App W...
The Apple Watch is pretty much here, and that means a whole lot of compatible apps and games are going to be updated or released onto the App Store. That's okay though, beacause Apple has quietly updated their app description pages to make things... | Read more »
Forgotten Memories : Alternate Realities...
Forgotten Memories : Alternate Realities 1.0.1 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: + REDUCED PRICE ONLY THE LAUNCHING WEEK + "The most exciting horror game of 2015." - AppSpy... | Read more »

Price Scanner via MacPrices.net

Heal to Launch First One-Touch House Call Doc...
Santa Monica, California based Heal, a pioneer in on-demand personal health care services — will offer the first one-touch, on-demand house call doctor app for the Apple Watch. Heal’s Watch app,... Read more
Mac Notebooks: Avoiding MagSafe Power Adapter...
Apple Support says proper usage, care, and maintenance of Your Mac notebook’s MagSafe power adapter can substantially increase the the adapter’s service life. Of course, MagSafe itself is an Apple... Read more
12″ Retina MacBook In Shootout With Air And P...
BareFeats’ rob-ART morgan has posted another comparison of the 12″ MacBook with other Mac laptops, noting that the general goodness of all Mac laptops can make which one to purchase a tough decision... Read more
FileMaker Go for iPad and iPhone: Over 1.5 Mi...
FileMaker has announced that its FileMaker Go for iPad and iPhone app has surpassed 1.5 million downloads from the iTunes App Store. The milestone confirms the continued popularity of the FileMaker... Read more
Sale! 13-inch 2.7GHz Retina MacBook Pro for $...
 Best Buy has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale for $1099 – $200 off MSRP. Choose free shipping or free local store pickup (if available). Price for online orders only, in-... Read more
Minimalist MacBook Confirms Death of Steve Jo...
ReadWrite’s Adriana Lee has posted a eulogy for the “Digital Hub” concept Steve Jobs first proposed back in 2001, declaring the new 12-inch MacBook with its single, over-subscribed USB-C port to be... Read more
13-inch 2.7GHz Retina MacBook Pro for $1234 w...
Adorama has the 13″ 2.7GHz/128GB Retina MacBook Pro in stock for $1234.99 ($65 off MSRP) including free shipping plus a free LG external DVD/CD optical drive. Adorama charges sales tax in NY & NJ... Read more
13-inch 2.5GHz MacBook Pro available for $999...
 Adorama has the 13-inch 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store is offering Apple Certified Refurbished Mac Pros for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
Updated MacBook Price Trackers
We’ve updated our MacBook Price Trackers with the latest information on prices, bundles, and availability on 12″ MacBooks, MacBook Airs, and MacBook Pros from Apple’s authorized internet/catalog... Read more

Jobs Board

*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* Watch SW Application Project Manager...
**Job Summary** The Apple Watch software team is looking for an Application Engineering Project Manager to work on new projects for Apple . The successful candidate Read more
Map Services Frameworks Manager - *Apple* M...
Job Description: Apple 's Maps Evaluation Organization is seeking a Senior Manager to lead the Map services assertions and performance frameworks group. Key Read more
Shuttle Driver - APPLE EAST, APPLE EAST (Unit...
HERE WE GROW AGAIN!! We are adding to our team! Red Lion Chevrolet of Apple Automotive is growing and we are looking for a PART TIME SHUTTLE DRIVER/ PORTER FOR SERVICE Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.