TweetFollow Us on Twitter

January 92 - UOrnaments: Half-price Icons

UOrnaments: Half-price Icons

Thomas E. Burns

What if you want to display a bunch of icons, but find that TIcons are too big and slow? This type of situation calls for a class of objects that know how to draw themselves, but don't process events. To minimize memory usage, it's nice if these classes require only one instance per icon, no matter how many places an icon appears within a view.

I developed two classes for this purpose, TOrnament and TOrnamentServer, have proven useful. TOrnament is a simple abstract class that defines objects that know how to draw themselves within a view, but do not respond to events. Because of their simplicity, ornaments are about twice as fast at drawing and consume far less memory than similar views. TOrnamentServers make using ornaments easy and efficient by managing their creation and imaging.

Using ornaments

Adding ornaments to a view is straight-forward. First, by modifying your ISomeView and IRes methods, ask the appropriate OrnamentServer, gPictureOrnamentServer for pictures or gIconOrnamentServer for icons, to load the ornament. The AddOrnament method will either create and initialize the ornament, if it hasn't already been created, or increment the ornament's reference count.
gPictureOrnamentServer->AddOrnament( kTestPicture );

Then add code to your view's Draw method that draws the ornament. This example draws the ornament kTestPicture in your view(this) at location where with highlighting hlOff:

gPictureOrnamentServer->Draw( this, kTestPicture, where, hlOff );

The final step is to delete the ornament in the view's free method. DeleteOrnament will decrement the ornament's reference count and, if the reference count is zero, free the ornament.

gPictureOrnamentServer->DeleteOrnament( kTestPicture );

Even though ornaments do a lot of work for you, only four methods are needed to implement a new subclass. I will stroll through the implementation of TPictureOrnament and TPictureOrnamentServer to demonstrate the creation of new ornament subclasses.

Implementing TPictureOrnament

Subclasses of TOrnament are used to implement specific, resource-based images, such as pictures and icons. Because TOrnament implements the methods used for reference counting, Add and Delete, its subclasses need to implement only three methods: IPictureOrnament, Draw and GetExtent.

The IPictureOrnament calls IOrnament and then loads the picture resource. IOrnament merely calls IObject, sets the reference count to zero and sets fRsrcId to rsrcId. The essential code (without failure handling) for the IPictureOrnament method is:

virtual pascal void
    short   rsrcId
    this->IOrnament( pictureRsrcId );
    fPicture = GetPicture( fRsrcId );   // fPicture holds the
                                        // picture
    FailNILResource( (Handle)fPicture );

The Draw method is the core of an ornament. Its implementation will, of course, vary greatly for different classes of ornaments. Typically, a Draw method will call inherited::Draw (which calls PenNormal()), load and make unpurgeable the ornament's resource, and then draw with the appropriate highlighting. Because the code for drawing pictures is rather long and specific for 'PICT' resources, I will only show the definition for the method.

virtual pascal void
    TView*              theView,    // view to draw in
    const VPoint&       where,      // top,left corner to draw at
    HLState             hilite      // the hilite to use

The next method, GetExtent, returns an ornament's size in a Point. This method is usually very similar to Draw. It must load and make unpurgeable the ornament's resource and then calculate its extent. Here's TOrnament's definition of this method:

virtual pascal Point

The next step for creating a new ornament is to make a subclass of TOrnamentServer that overrides the DoMakeOrnament method. The function of TOrnamentServers is to manage the interactions between views and ornaments. A view never needs to refer to an ornament directly; it always uses an ornaments resource number instead. The advantages of this setup are:

  • A view can assume that it always needs to load and unload an ornament because TOrnamentServer will only do what is necessary. TOrnamentServer loads an ornament only once and then unloads it only after all views are finished with it.
  • There is no need for a view to add instance variables just to keep track of all the ornaments it is using.
  • Memory is saved because an ornament is loaded only once, no matter how many views are using it.

TOrnamentServers need to create ornaments when a new one is added to its list. To maintain the "object-oriented" nature of this unit, I didn't want to make TOrnamentServer know about all the possible types of ornaments. Therefore, TOrnamentServer has a DoMakeOrnament method that returns a new TOrnament of the appropriate subclass. This method for TPictureOrnamentServer is:

pascal TOrnament*
    short       rsrcId
    TPictureOrnament*       pictureOrnament;

    pictureOrnament = new TPictureOrnament;
    pictureOrnament->IPictureOrnament( rsrcId );
    return( pictureOrnament );

As an optional last step, write the InitPictureOrnamentServer function. This function creates and initializes an instance of the TPictureOrnamentServer class.

pascal void
    if ( gPictureOrnamentServer == NULL )
        gPictureOrnamentServer = new TPictureOrnamentServer;

Good indications

While it only required a couple of hours to write the original UOrnaments unit, it has proven to be a useful tool. The project I was working on when creating this unit, a robot controller, requires frequent use of indicators that can appear many, many times within a view. Full fledged views would be too big and slow to be practical. I hope ornaments prove to be as useful for you.

Community Search:
MacTech Search:

Software Updates via MacUpdate

The best games like Animal Crossing on m...
Animal Crossing amiibo Festival is out right now for the Wii U, reminding us of just how much fun that world can be. Or at least to go back and check in on our villages once in a while. [Read more] | Read more »
Between 2 Taps - Tap for Tap interview M...
Hello, and welcome back to Between 2 Taps, Tap for Tap’s Indie Dev interview series. [Read more] | Read more »
Facility 47 (Games)
Facility 47 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: You wake up alone and freezing in an icy cell. You try the cell door but it’s locked, it seems that you are stuck with no... | Read more »
The best Photoshop alternative on iPad
Instagram and Lightroom are great and all, but sometimes people need to get extra creative with their image editing.Like, Photoshop creative. If you're one of these people, take a look at our pick for the best mobile Photoshop experience on iPad... | Read more »
The Walking Dead: No Man’s Land guide -...
A new update for The Walking Dead: No Man’s Land was released last week, making it the perfect time for you to head back to your base and take out some walkers. Here’s the lowdown on what’s new to the game, and how to take advantage. [Read more] | Read more »
Goat Rider guide - Tips and tricks to st...
We've all been there. One second, we're riding high on a crazed goat, and the next, we've been tossed off it like someone who's no good at goat ridin'. [Read more] | Read more »
Real Boxing 2 CREED: How to become a gre...
Just in time for Rocky fans who can’t wait to see CREED, the latest movie, we have the official tie-in game,Real Boxing 2 CREED. It builds on the success of its predecessor and there’s lots to take in so we at 148apps thought we’d run you through... | Read more »
CoinOp Heroes 2 guide - How to build an...
CoinOp Heroes 2 justlaunched and, like all clickers, it's dangerously addictive stuff. You have to furiously tap your screen to defeat wave after wave of foes and earn an insane amount of cash to spend on character upgrades and an army of minions... | Read more »
Dr. Panda Firefighters (Education)
Dr. Panda Firefighters 1.0.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0.1 (iTunes) Description: FIGHT FIRES AND SAVE THE DAY!Work together with Dr. Panda and his firefighting team to rescue his trapped... | Read more »
Puddle + (Games)
Puddle + 1.0 Device: iOS iPhone Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Puddle is back in a new "+" edition featuring enhanced graphics, new videos and Apple TV support ! No IAP and No Ads. Dive into Puddle... | Read more »

Price Scanner via

Save $30-$40 on new Apple TVs after rebate
Adorama has new Apple TVs on sale for up to $40 off MSRP after mail-in rebate, good through December 15th. Shipping is free, and Adorama charges NY & NJ sales tax only: - 32GB Apple TV: $119.99... Read more
13-Inch Haswell MacBook Air At Two Years – Th...
The 13-inch mid-2013 “Haswell” MacBook Air I ordered in Apple’s November 2013 Black Friday sale was my first new Mac in four and a half years — the longest interval I’ve gone between system upgrades... Read more
Target Black Friday Early Access deals: $100...
Target is offering early access to their Black Friday deals on Apple products on their online store for today, the 25th, only. Choose free shipping or free local store pickup (if available): - Apple... Read more
BlackBerry Q3 Mobility Index Report Finds iOS...
BlackBerry has announced results of its thirteenth Good Mobility Index Report, showing that organizations are increasingly building custom secure apps. Among Good Powered by BlackBerry (formerly Good... Read more
Wednesday roundup of early Black Friday Mac s...
Save up to $500 on a new Mac with these early Black Friday deals from Apple resellers, currently the lowest prices available for these models: (1) B&H Photo has all new Macs on sale for up to $... Read more
iPod nano on sale for $119, $30 off MSRP
Walmart has the 16GB iPod nano (various colors) on sale for $119.20 on their online store for a limited time. That’s $30 off MSRP. Choose free shipping or free local store pickup (if available). Sale... Read more
Adorama Black Friday deals: Up to $400 off Ma...
Adorama has released their Black Friday deals for 2015. Save up to $400 on MacBook Pros, $200 on MacBooks and MacBook Airs, and $270 on iMacs. Use code RYBFDEAL during checkout to see these prices.... Read more
B&H Photo Deals: $200 off 12-inch 1.2GHz...
In addition to the B&H Photo Black Friday week sales we posted yesterday, B&H has lowered their price on two products to $200 off MSRP: - 12″ 1.2GHz Gray Retina MacBook: $1399 save $200 - 13... Read more
Best Buy Early Access: Today only, Up to $125...
Best Buy has iPad Air 2s on sale for up to $125 off MSRP and Apple Watch models on sale on their online store for up to $100 off MSRP with special codes through midnight CT tonight. Choose free... Read more
UPPERCASE DESIGNS Premium Ultra Thin Keyboard...
UPPERCASE Designs today announced its new Premium Ultra Thin Keyboard Protector and its Palm Rest Protector Set for the 12-inch MacBook. The accessories provide durable protection for the 12-inch... Read more

Jobs Board

Hardware Systems Integration Engineer - *App...
# Hardware Systems Integration Engineer - Apple Watch Job Number: 39380139 Santa Clara Valley, Califo ia, United States Posted: Apr. 23, 2015 Weekly Hours: **Job Read more
Sr. Technical/Project Manager, *Apple* Educ...
# Sr. Technical/Project Manager, Apple Education Job Number: 36588557 New York City, New York, United States Posted: Jul. 30, 2015 Weekly Hours: 40.00 **Job Summary** 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
Merchant Operations Manager: *Apple* Pay -...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
*Apple* Pay QA Manager - Apple Inc. (United...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.