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
TPictureOrnament::IPictureOrnament
(
    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.

UOrnaments
virtual pascal void
Draw
(
    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
GetExtent
(
    void
);

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*
TPictureOrnamentServer::DoMakeOrnament
(
    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
InitPictureOrnamentServer
(
    void
)
{
    if ( gPictureOrnamentServer == NULL )
    {
        gPictureOrnamentServer = new TPictureOrnamentServer;
        gPictureOrnamentServer->IPictureOrnamentServer();
    }
}

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

Latest Forum Discussions

See All

Top Mobile Game Discounts
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links... | Read more »
Price of Glory unleashes its 1.4 Alpha u...
As much as we all probably dislike Maths as a subject, we do have to hand it to geometry for giving us the good old Hexgrid, home of some of the best strategy games. One such example, Price of Glory, has dropped its 1.4 Alpha update, stocked full... | Read more »
The SLC 2025 kicks off this month to cro...
Ever since the Solo Leveling: Arise Championship 2025 was announced, I have been looking forward to it. The promotional clip they released a month or two back showed crowds going absolutely nuts for the previous competitions, so imagine the... | Read more »
Dive into some early Magicpunk fun as Cr...
Excellent news for fans of steampunk and magic; the Precursor Test for Magicpunk MMORPG Crystal of Atlan opens today. This rather fancy way of saying beta test will remain open until March 5th and is available for PC - boo - and Android devices -... | Read more »
Prepare to get your mind melted as Evang...
If you are a fan of sci-fi shooters and incredibly weird, mind-bending anime series, then you are in for a treat, as Goddess of Victory: Nikke is gearing up for its second collaboration with Evangelion. We were also treated to an upcoming... | Read more »
Square Enix gives with one hand and slap...
We have something of a mixed bag coming over from Square Enix HQ today. Two of their mobile games are revelling in life with new events keeping them alive, whilst another has been thrown onto the ever-growing discard pile Square is building. I... | Read more »
Let the world burn as you have some fest...
It is time to leave the world burning once again as you take a much-needed break from that whole “hero” lark and enjoy some celebrations in Genshin Impact. Version 5.4, Moonlight Amidst Dreams, will see you in Inazuma to attend the Mikawa Flower... | Read more »
Full Moon Over the Abyssal Sea lands on...
Aether Gazer has announced its latest major update, and it is one of the loveliest event names I have ever heard. Full Moon Over the Abyssal Sea is an amazing name, and it comes loaded with two side stories, a new S-grade Modifier, and some fancy... | Read more »
Open your own eatery for all the forest...
Very important question; when you read the title Zoo Restaurant, do you also immediately think of running a restaurant in which you cook Zoo animals as the course? I will just assume yes. Anyway, come June 23rd we will all be able to start up our... | Read more »
Crystal of Atlan opens registration for...
Nuverse was prominently featured in the last month for all the wrong reasons with the USA TikTok debacle, but now it is putting all that behind it and preparing for the Crystal of Atlan beta test. Taking place between February 18th and March 5th,... | Read more »

Price Scanner via MacPrices.net

AT&T is offering a 65% discount on the ne...
AT&T is offering the new iPhone 16e for up to 65% off their monthly finance fee with 36-months of service. No trade-in is required. Discount is applied via monthly bill credits over the 36 month... Read more
Use this code to get a free iPhone 13 at Visi...
For a limited time, use code SWEETDEAL to get a free 128GB iPhone 13 Visible, Verizon’s low-cost wireless cell service, Visible. Deal is valid when you purchase the Visible+ annual plan. Free... Read more
M4 Mac minis on sale for $50-$80 off MSRP at...
B&H Photo has M4 Mac minis in stock and on sale right now for $50 to $80 off Apple’s MSRP, each including free 1-2 day shipping to most US addresses: – M4 Mac mini (16GB/256GB): $549, $50 off... Read more
Buy an iPhone 16 at Boost Mobile and get one...
Boost Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering one year of free Unlimited service with the purchase of any iPhone 16. Purchase the iPhone at standard MSRP, and then choose... Read more
Get an iPhone 15 for only $299 at Boost Mobil...
Boost Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering the 128GB iPhone 15 for $299.99 including service with their Unlimited Premium plan (50GB of premium data, $60/month), or $20... Read more
Unreal Mobile is offering $100 off any new iP...
Unreal Mobile, an MVNO using AT&T and T-Mobile’s networks, is offering a $100 discount on any new iPhone with service. This includes new iPhone 16 models as well as iPhone 15, 14, 13, and SE... Read more
Apple drops prices on clearance iPhone 14 mod...
With today’s introduction of the new iPhone 16e, Apple has discontinued the iPhone 14, 14 Pro, and SE. In response, Apple has dropped prices on unlocked, Certified Refurbished, iPhone 14 models to a... Read more
B&H has 16-inch M4 Max MacBook Pros on sa...
B&H Photo is offering a $360-$410 discount on new 16-inch MacBook Pros with M4 Max CPUs right now. B&H offers free 1-2 day shipping to most US addresses: – 16″ M4 Max MacBook Pro (36GB/1TB/... Read more
Amazon is offering a $100 discount on the M4...
Amazon has the M4 Pro Mac mini discounted $100 off MSRP right now. Shipping is free. Their price is the lowest currently available for this popular mini: – Mac mini M4 Pro (24GB/512GB): $1299, $100... Read more
B&H continues to offer $150-$220 discount...
B&H Photo has 14-inch M4 MacBook Pros on sale for $150-$220 off MSRP. B&H offers free 1-2 day shipping to most US addresses: – 14″ M4 MacBook Pro (16GB/512GB): $1449, $150 off MSRP – 14″ M4... Read more

Jobs Board

All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.