TweetFollow Us on Twitter

Sep 96 Tips
Volume Number:12
Issue Number:9
Column Tag:Tips & Tidbits

Tips & Tidbits

By Steve Sisak

Did You Take Out the Garbage?

A somewhat obscure but useful way of determing whether objects are getting deleted in C++ is to do this:

1. In the class implementation (usually in the header file), add a destructor:

class MyClass
{
public:
   virtual ~MyClass();

2. Don’t implement the destructor; i.e., don’t write the actual code for the destructor method.

3. Run the project. If you get link errors for the destructors, this means that the destructors are getting called (i.e. the objects are getting deleted), which is what you want. If you don’t get a link error, this means that the object never gets deleted, which could signify a possible memory leak.

Jeremy Vineyard

Pre-Flighting EditText

For a program I recently wrote, I wanted to do user input checking for a dialog box as the user was typing into an EditText field. I wrote a routine that figures out what the contents of a specific EditText box will be if the current event is allowed to be processed. I then called the routine from my custom dialog event proc, and analyzed the results. That way, I could easily decide if the user’s action would produce valid results, or if I needed to abort the current event.

IsDlgControl is a simple check for control characters we always want to process. DivineNewItemString is the routine that does all the work. PStrCopy is a little routine for copying Pascal strings; I’m sure other people have better ways of doing this.

Michael Trent

// some control key constants.
#define kEnterKey               3
#define kBackspace              8
#define kTab                    9
#define kReturnKey              13
#define kEscapeKey              27
#define kLeftKey                28
#define kRightKey               29
#define kUpKey                  30
#define kDownKey                31
#define kDelete                 0xFF

/* IsDlgControl
 * Returns true if c is a special control key (say an arrow key, or escape).
 * Otherwise returns false.
 */
Boolean IsDlgControl(char c)
{
        if ((c >= kEscapeKey) && (c <= kDownKey)) return true;
        if ((c == kReturnKey) || (c == kEnterKey) 
        || (c == kDelete) || (c == kBackspace) || (c == kTab))
                  return true;

        return false;
}

/* PStrCpy
 * A little routine to copy Pascal strings. Provided for those people who don’t
 * already use BlockMove() to do this for them ...
 */
void PStrCpy(Str255 s, const Str255 t)
{
        short i;

        for (i=0; i<=s[0]; i++) {
                s[i]=t[i];
        }
}

/* DivineNewItemString
 * Given a DialogPtr, EventPtr and an item number for the active EditText DLOG
 * Item, it returns what the string will be if the current event is processed.
 * It should be called from a custom dialog event proc.
 */
void DivineNewItemString (
     DialogPtr d, EventRecord *e, short item, Str255 output)
{
        short           *TEScrpLength = (short *)0x0AB0;
        DialogRecord    *dr;
        TEHandle        teh;
        char            c;
        Str255          input, text;
        short           selStart, selEnd;
        short           i;
        short           outStrIdx=0;

        short           iType;
        Handle          iHandle;
        Rect            iRect;

                  // get the text string
        GetDItem(d,item,&iType,&iHandle,&iRect);
        GetIText(iHandle,text);

                 // Set the input string
        c = (e->message & charCodeMask);

        if (IsDlgControl(c)) {  // if it’s a control char, return the
                                // item’s text.
                PStrCpy(output,text);
                return;
        } else if (e->modifiers & cmdKey) {
                if  ((c == 'v') || (c == 'V')) {
                // if pasting, get the pasted string.
                        (void)TEFromScrap();
                        HLock(iHandle);
                        iHandle = TEScrapHandle();
                        for (i=0; i< *TEScrpLength; i++) {
                                input[i+1]=((unsigned char *)
                                        (*iHandle))[i];
                        }
                        input[0]=*TEScrpLength;
                        HUnlock(iHandle);
                } else { // if any other command stroke
                        PStrCpy(output,text);
                        return;
                }
        } else {
                  // else, set the input string equal to the new character
                input[0]=1;
                input[1]=(unsigned char) c;
        }

        // get the selection point from the TERec
        dr = (DialogRecord *)d;
        teh = dr->textH;
        selStart=(*teh)->selStart;
        selEnd=(*teh)->selEnd;

        // generate output string:
        //  copy the first bit of text
        for (i=1; i<=selStart; i++) {
                output[++outStrIdx]=text[i];
        }
        //  copy the input string
        for (i=1; i<=input[0]; i++) {
                output[++outStrIdx]=input[i];
        }
        //  copy the last part of text
        for (i=selEnd+1; i<=text[0]; i++) {
                output[++outStrIdx]=text[i];
        }
        //  lastly, set the length
        output[0] = outStrIdx;
}


A Free Tool From Apple

You can use the Finder’s “About this Macintosh” window to see the size your application’s heap, and the amount of free memory that is available in your heap. This information is only updated during idle time, though, so don’t count on it to always be accurate. [Here’s the real tip: use Balloon Help to get a numeric representation of the information. - sgs]

David Lawrence


Avoiding the Menu Item Gotcha

Watch out when using AppendMenu or InsertMenuItem. I’m using AppendMenu to create a popup menu based on user input. Since AppendMenu interprets certain characters as menu attributes (such as command-key equivalents, menu dimming, etc.), if a user enters one of these characters, you will run into a problem with your menu. To avoid this, call AppendMenu or InsertMenuItem with a dummy string such as "\p " (the string must not be empty), and then call SetMenuItemText using the real string, like so:

Str255 theUserName;

// Get the string to display in the menu
theUser->GetUserName (theUserName);

// Append an empty string to the menu
AppendMenu (theMenuHandle, "p\ ");

// Change the menu item to the userName
SetMenuItemText (theMenuHandle, theIndex, theUserName);

Tim Pedone

World’s Most Original Use of ResEdit

If you are looking in the code of a PICT, you can often see a color table with 256 colors even if you use only 2 or 3 colors. This can represent a massive waste of disk space. I tried to find an app to compact the color table but I couldn’t find one - until finally I found ResEdit!

My trick: create a 'cicn' resource in ResEdit, paste in your PICT or draw it, select the part for using in the PICT, copy and paste it into an actual PICT. The only limitation is the maximum size: 64 by 64.

Henri Clerc

No, Wait -
World’s Most Truly Totally Original Use Of ResEdit

This might be one everybody knows, but I just figured it out and it’s saved me a load of time, so here goes.

ResEdit is a Drag-and-Drop application!!! This works for any type of file. No longer must eons be frittered away navigating through countless folders in open dialog boxes to access resource forks of files hidden deep within the murky depths of your hard drive. Just do a Find in the Finder and drag it to ResEdit - I keep an alias on my desktop. Happy hacking!

Joshua “Vampiric Bunny” Glazer

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Drop to GIF 1.28 - Drag-and-drop creatio...
Drag to GIF means zero-click movie-to-GIF conversion. Select a folder to watch and every movie saved or moved into that folder will be converted to an animated GIF. Features Dragging - Drag a movie... Read more
BetterTouchTool 3.158 - Customize multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom)... Read more
NeoFinder 7.4.1 - Catalog your external...
NeoFinder (formerly CDFinder) rapidly organizes your data, either on external or internal disks, or any other volumes. It catalogs and manages all your data, so you stay in control of your data... Read more
Tunnelblick 3.8.0 - GUI for OpenVPN.
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
Tweetbot 3 for Twitter 3.3.1 - Popular T...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
Monosnap 3.5.9 - Versatile screenshot ut...
Monosnap lets you capture screenshots, share files, and record video and .gifs. Features Capture Capture full screen, just part of the screen, or a selected window Make your crop area pixel... Read more
Monosnap 3.5.9 - Versatile screenshot ut...
Monosnap lets you capture screenshots, share files, and record video and .gifs. Features Capture Capture full screen, just part of the screen, or a selected window Make your crop area pixel... Read more
Tweetbot 3 for Twitter 3.3.1 - Popular T...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
Tunnelblick 3.8.0 - GUI for OpenVPN.
Tunnelblick is a free, open source graphic user interface for OpenVPN on OS X. It provides easy control of OpenVPN client and/or server connections. It comes as a ready-to-use application with all... Read more
Bookends 13.2.5 - Reference management a...
Bookends is a full-featured bibliography/reference and information-management system for students and professionals. Bookends uses the cloud to sync reference libraries on all the Macs you use.... Read more

Latest Forum Discussions

See All

Void Tyrant guide - Tips and tricks for...
Void Tyrant continues to get a lot of play in these parts. Probably because the game is just so deep and varied. The next stop on our guide series for Void Tyrant is class-specific guides. First up is the Knight, as it’s the first class anyone has... | Read more »
Summon beasts and battle evil in epic re...
Imagine a tale of conlict between factions of good and evil, where rogueish heroes summon beasts to aid them in them in warfare and courageously battle dragons over fields of scorched earth and brimstone - that's exactly the essence of epic fantasy... | Read more »
Upcoming visual novel Arranged shines a...
If you’re in the market for a new type of visual novel designed to inform and make you think deeply about its subject matter, then Arranged by Kabuk Games could be exactly what you’re looking for. It’s a wholly unique take on marital traditions in... | Read more »
TEPPEN guide - The three best decks in T...
TEPPEN’s unique take on the collectible card game genre is exciting. It’s just over a week old, but that isn’t stopping lots of folks from speculating about the long-term viability of the game, as well as changes and additions that will happen over... | Read more »
Intergalactic puzzler Silly Memory serve...
Recently released matching puzzler Silly Memory is helping its fans with their intergalactic journeys this month with some very special offers on in-app purchases. In case you missed it, Silly Memory is the debut title of French based indie... | Read more »
TEPPEN guide - Tips and tricks for new p...
TEPPEN is a wild game that nobody asked for, but I’m sure glad it exists. Who would’ve thought that a CCG featuring Capcom characters could be so cool and weird? In case you’re not completely sure what TEPPEN is, make sure to check out our review... | Read more »
Dr. Mario World guide - Other games that...
We now live in a post-Dr. Mario World world, and I gotta say, things don’t feel too different. Nintendo continues to squirt out bad games on phones, causing all but the most stalwart fans of mobile games to question why they even bother... | Read more »
Strategy RPG Brown Dust introduces its b...
Epic turn-based RPG Brown Dust is set to turn 500 days old next week, and to celebrate, Neowiz has just unveiled its biggest and most exciting update yet, offering a host of new rewards, increased gacha rates, and a brand new feature that will... | Read more »
Dr. Mario World is yet another disappoin...
As soon as I booted up Dr. Mario World, I knew I wasn’t going to have fun with it. Nintendo’s record on phones thus far has been pretty spotty, with things trending downward as of late. [Read more] | Read more »
Retro Space Shooter P.3 is now available...
Shoot-em-ups tend to be a dime a dozen on the App Store, but every so often you come across one gem that aims to shake up the genre in a unique way. Developer Devjgame’s P.3 is the latest game seeking to do so this, working as a love letter to the... | Read more »

Price Scanner via MacPrices.net

13″ 1.8GHz MacBook Air on sale again for only...
Amazon has the 2017 13″ 1.8GHz/128GB MacBook Air on sale today for only $749.99 shipped. That’s $250 off Apple’s original MSRP for this model and the cheapest MacBook Air available from any Apple... Read more
Apple’s $1489 clearance price on refurbished...
Apple has Certified Refurbished 2018 13″ 2.3GHz 4-Core Touch Bar MacBook Pros available starting at $1489. Apple’s one-year warranty is included, shipping is free, and each MacBook has a new outer... Read more
New 2019 13″ 2.4GHz 4-Core MacBook Pros on sa...
Apple resellers B&H Photo and Amazon are offering the new 2019 13″ 2.4GHz 4-Core Touch Bar MacBook Pros for $150 off Apple’s MSRP. These are the same MacBook Pros sold by Apple in its retail and... Read more
B&H drops prices another $50 on clearance...
B&H Photo has dropped prices on clearance 2018 13″ MacBook Airs by a further $50 with models now available for $250 off Apple’s original MSRP. Overnight shipping, or expedited shipping, is free... Read more
Find the best sales & lowest prices on Ap...
Our Apple award-winning price trackers are the best place to look for the best sales and lowest prices on Apple gear. Scan our price trackers for the latest information on sales, bundles, and... Read more
Apple has clearance 2018 13″ MacBook Airs now...
Apple has Certified Refurbished 2018 13″ MacBook Airs available starting at only $849. Each MacBook features a new outer case, comes with a standard Apple one-year warranty, and is shipped free. The... Read more
Save $400 on the 8-Core iMac Pro today at Ama...
Amazon has the base 8-core iMac Pro on sale today for $4599 including free shipping. Their price is $400 off Apple’s MSRP, and it’s the currently lowest price available for an iMac Pro. For the... Read more
Flash sale! New 11″ 1TB WiFi iPad Pros for th...
Amazon has the 11″ 1TB WiFi iPad Pro on sale today for only $1199.99 including free shipping. Their price is $350 off Apple’s MSRP for this model, and it’s the lowest price ever for a 1TB 11″ iPad... Read more
Weekend Deal: 2018 13″ MacBook Airs starting...
B&H Photo has clearance 2018 13″ MacBook Airs available starting at only $999 with all models now available for $200 off Apple’s original MSRP. Overnight shipping, or expedited shipping, is free... Read more
Apple has clearance 10.5″ iPad Pros available...
Apple has Certified Refurbished 2017 10.5″ iPad Pros available starting at $469. An Apple one-year warranty is included with each iPad, outer shells are new, and shipping is free: – 64GB 10″ iPad Pro... Read more

Jobs Board

Best Buy *Apple* Computing Master - Best Bu...
**711495BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 000882-Waterfront-Store **Job Description:** The Read more
Best Buy *Apple* Computing Master - Best Bu...
**711597BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000873-Colma CA-Store **Job Description:** **What does a Read more
Best Buy *Apple* Computing Master - Best Bu...
**711346BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Location Number:** 001095-Chesterfield-Store **Job Description:** Read more
Best Buy *Apple* Computing Master - Best Bu...
**704899BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000135-Pleasant Hill-Store **Job Description:** **What does Read more
Best Buy *Apple* Computing Master - Best Bu...
**707083BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Location Number:** 000045-Rockford-Store **Job Description:** **What does a Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.