TweetFollow Us on Twitter

Selective Color
Volume Number:10
Issue Number:1
Column Tag:C Workshop

Related Info: Dialog Manager

Selective Color

Using custom color buttons on color and black and white Macs

By Mark W. Batten, Washington, D.C.

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

Custom color buttons enliven any application, but if the programmer is writing software that must run on both black-and-white and color machines (as most of us are), it may seem daunting to write code that will draw the button different ways on differently configured machines. This article demonstrates a simple scheme to create buttons that are smart enough to be custom-drawn on color machines, and as regular Toolbox buttons on black-and-white machines.

The key to the technique is the Toolbox routine SetDItem. Although generally used only to change a dialog item’s rectangle, SetDItem is actually quite powerful; it lets you change just about everything associated with a dialog item. In this example, we’ll use it to point the Mac to our own CDEF to draw the button on color machines.

Setting Up The Resources

First, you need to create the CDEF that draws the color button. At the end of this article is source code for a sample button with a nice 3-D appearance.

(This particular CDEF uses an “auxiliary control record” (as described in Inside Macintosh, Vol. 5, pp. 216-18) to tell it what colors to draw the control in. If you’ve never encountered these arcane things, don’t worry; you don’t need to understand them to implement the scheme described in the article).

Second, create a dialog (DLOG) and a dialog item list (DITL) for your application as you normally would. Be sure that your DLOG will not be displayed when it’s loaded (in ResEdit, be sure the “Initially visible” box is unchecked). The DITL should use normal, vanilla buttons for OK and Cancel. That way, the resource is all set up to run normally on black-and-white machine, without any more work.

For this example, you also need to create two other resources: a dialog color table (‘dctb’) and a control color table (‘cctb’). (The correct values for the sample are listed at the end of this article). The ‘dctb’ serves two functions here: first, when you call GetNewDialog to read in a dialog, the Mac will automatically make it a color dialog, based on a CGrafPort, if the Mac finds a ‘dctb’ with the same ID as the DLOG resource. Second, the ‘dctb’ colors the content area of the dialog, which makes our button look better. The CDEF uses the ‘cctb’ resource to determine what colors to use when drawing the custom button.

Making The Switch

On a black-and-white Mac, the dialog will perform as it’s supposed to, without any special code in your application. To do something fancier on color machines, your application just has to alert the Dialog Manager to use our custom CDEF instead of the standard one. Here are the necessary steps.

1. In your application’s initialization routines, load the CDEF resource and the cctb color table into variables, like this:


/* 1 */

 Handle myCDEF;  /* handle to our custom CDEF */
 CTabHandle CtrlCTab;/* handle to colors for our control */

 myCDEF=GetResource('CDEF',32); 
 CtrlCTab=(CTabHandle)GetResource('cctb',128);

2. When you’re ready to create the dialog, load it with GetNewDialog (or build it from scratch with NewDialog). Then call the following routine, which uses SetDItem to tell the Mac where to find our custom code. Pass the DialogPtr in d and the item number of the button you want to convert in i:

/* 2 */

ConvertToColorButtons(d,i)
DialogPtr d;
int i; 
{
 int j; 
 Handle tItem; 
 Rect box; 
 char n[31];

 GetDItem(d,i,&j,&tItem,&box);
 if(j==ctrlItem+btnCtrl || 
 j==ctrlItem+btnCtrl+itemDisable){
 SetCtlColor(tItem,CtrlCTab);
 (**((ControlHandle)tItem)).contrlDefProc=myCDEF;
 j&=127;
 SetDItem(d,i,j,tItem,&box); 
 }
}
 Here's the CDEF code.

pascal long main(var,CH,msg,par)
int msg,var;
ControlHandle CH;
long par;
{
 long l;

 l=0L;
 switch(msg){
 case 0: 
 doDraw(CH); 
 break;
 case 1: 
 l=(long)doTest(par,CH); 
 break;
 case 2: 
 doCalc(par,CH); 
 break;
 }
 return l;
}

doTest(par,CH)
long par;
ControlHandle CH;
{
 Point pt;

 pt.v=HiWord(par); 
 pt.h=LoWord(par);
 return (int)PtInRect(pt,&((**CH).contrlRect));
}

doCalc(par,CH)
RgnHandle par;
ControlHandle CH;
{
 par=(RgnHandle)((long)par&0x7FFFFFFF);
 RectRgn(par,&((**CH).contrlRect));
}

doDraw(CH)
ControlHandle CH;
{
 int j,k,*p;
 Handle tItem;
 Rect r;
 RGBColor rgb,rgb1,rgb2; 
 AuxCtlHandle ax;
 FontInfo inf;
 
 r=(**CH).contrlRect; 
 j=StringWidth((**CH).contrlTitle); 
 GetFontInfo(&inf); 
 k=inf.ascent+inf.descent;
 k=(r.top+r.bottom+k)/2;
 MoveTo((r.left+r.right-j)/2,k-inf.descent);
 DrawString((**CH).contrlTitle);
 GetAuxCtl(CH,&ax);
 
 p=(int *)&(**(**ax).acCTable).ctTable[0].rgb.red; 
 rgb.red=p[0];   /* 21845, 0x5555*/
 rgb.green=p[1]; /* 21845, 0x5555*/
 rgb.blue=p[2];  /* 21845, 0x5555*/
 rgb1.red=p[4];  /* 34952, 0x8888*/
 rgb1.green=p[5];/* 34952, 0x8888*/
 rgb1.blue=p[6]; /* 34952, 0x8888*/
 rgb2.red=rgb2.green=rgb2.blue=0xFFFF;
 
 PenSize(2,2);
 RGBForeColor(&rgb);
 MoveTo(r.right-2,r.top); 
 LineTo(r.left,r.top);
 LineTo(r.left,r.bottom-2); 
 RGBForeColor(&rgb2);
 MoveTo(r.right-2,r.top+1);
 LineTo(r.right-2,r.bottom-2);
 LineTo(r.left,r.bottom-2); 
 rgb2.red=rgb2.green=rgb2.blue=0;
 RGBForeColor(&rgb2);
 InsetRect(&r,2,2);
 FrameRect(&r);

 InsetRect(&r,2,2);
 if(!(**CH).contrlHilite){
 PenSize(1,1);
 RGBForeColor(&rgb);
 MoveTo(r.left,r.top);
 LineTo(r.left,r.bottom-2);
 PenSize(2,2); 
 LineTo(r.right-2,r.bottom-2);
 Move(0,-1);
 PenSize(1,1);
 RGBForeColor(&rgb1);
 LineTo(r.left+1,r.bottom-3);
 LineTo(r.left+1,r.top);
 LineTo(r.right-1,r.top);
 Move(0,1);
 rgb2.red=rgb2.green=rgb2.blue=0xFFFF; 
 RGBForeColor(&rgb2);
 LineTo(r.left+2,r.top+1);
 }
 else {
 MoveTo(r.right-2,r.top);
 RGBForeColor(&rgb);
 LineTo(r.left,r.top);
 PenSize(1,1);
 LineTo(r.left,r.bottom-3);
 PenSize(3,3);
 LineTo(r.right-3,r.bottom-3); 
 PenSize(1,1);
 Move(2,-1);
 RGBForeColor(&rgb1); 
 LineTo(r.left+1,r.bottom-4);
 LineTo(r.left+1,r.top+2);
 LineTo(r.right-1,r.top+2);
 }
 rgb2.red=rgb2.green=rgb2.blue=0;
 RGBForeColor(&rgb2); 
}

The values for the color table resources for the example are as follows:

The control color table (type 'cctb') has two entries. The part codes are just 0 and 1 (the CDEF doesn't really use these) and the colors are { 0x5555,0x5555,0x5555 } and { 0x8888,0x8888,0x8888 }.

The dialog color table (type 'dctb') must have five entries, with part codes of 0-4, and colors as follows: { 0xAAAA,0xAAAA,0xAAAA }, { 0x5555,0x5555, 0x5555 }, { 0,0,0 }, { 0,0,0 }, { 0,0,0 }.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Black Hole Joyrider (Games)
Black Hole Joyrider 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Guide your spacecraft through the gravity well of a powerful black hole using only your retro-thrusters and dwindling fuel... | Read more »
My Koi (Games)
My Koi 1.0 Device: iOS iPhone Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: My Koi is a beautiful and relaxing fish pond app. Customise and name each fish. Feed them daily. Watch them grow. Collect new fish.... | Read more »
Never Gone (Games)
Never Gone 1.0.2 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.2 (iTunes) Description: ###IMPPORTANT### Never Gone's HD art resources require devices with more than 1GB RAM, so please note that iPhone 4/4s, iPad 2/... | Read more »
INKS. (Games)
INKS. 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: From the makers of BAFTA-winning Lumino City comes INKS. INKS updates pinball for a new generation. It combines the joy of pinball with... | Read more »
How to maximise your profits in Bakery B...
Running a bakery can be an expensive venture. You’ll need to continuously upgrade your oven, your kitchen supplies, and even your ingredients to keep customers happy. Most of these renovations in Bakery Blitz cost a pretty penny, but we have a few... | Read more »
How to manage your time in Bakery Blitz
It can be tricky, especially when you risk burning your kitchen to the ground if you forget a cake in the oven, so make sure to use these time management tricks to keep your bakery running smoothly. Don’t collect the money right away [Read more] | Read more »
Model 15 (Music)
Model 15 1.0 Device: iOS iPhone Category: Music Price: $29.99, Version: 1.0 (iTunes) Description: The Moog Model 15 App is the first Moog modular synthesizer and synthesis educational tool created exclusively for iPad, iPhone and... | Read more »
How to deal with wind in Angry Birds Act...
Angry Birds Action! is a physics-based puzzler in which you're tasked with dragging and launching birds around an obstacle-littered field to achieve a set objective. It's simple enough at first, but when wind gets introduced things can get pretty... | Read more »
How to get three stars in every level of...
Angry Birds Action! is, essentially, a pinball-style take on the pull-and-fling action of the original games. When you first boot it up, you'll likely be wondering exactly what it is you have to do to get a good score. Well, never fear as 148Apps... | Read more »
The beginner's guide to Warbits
Warbits is a turn-based strategy that's clearly inspired by Nintendo's Advance Wars series. Since turn-based strategy games can be kind of tricky to dive into, see below for a few tips to help you in the beginning. Positioning is crucial [Read... | Read more »

Price Scanner via MacPrices.net

12-inch 128GB iPad Pros on sale for up to $10...
B&H Photo has 12″ 128GB WiFi iPad Pros on sale for up to $100 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 12″ Space Gray 128GB WiFi iPad Pro: $899 $50 off MSRP... Read more
Global Tablet Sales Slump Continues, iPad’s F...
Another miserable showing for the global slate tablet category in calendar Q1/16, with global tablet shipments falling another 1ten percent to 46.5 million units during the according to Strategy... Read more
Revel Systems to Showcase iPad POS Platform w...
Revel Systems, specialists in iPad Point of Sale management solution for brick-and-mortar retail, food businesses and more, today announced that it will showcase its innovative iPad Point of Sale... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Apple refurbished 2015 iMacs available for up...
Apple now has a full line of Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are... Read more
Indian Smartphone Market Grows Annually by 12...
India’s smartphone market grew by 12 percent year-over-year, with 24.4 million units shipping in Q1 2016. The top five vendors stayed the same, with Samsung in the lead, followed by Micromax, Intex... Read more
Get Notifications When Your Friend’s Phone Ba...
Calgary, Canada based Stonelight Pictures has announced the release of Battery Share 1.0.1, its new utility for iOS 9 supported devices. The company notes that people are spending more time on their... Read more
11-inch 1.6GHz/128GB MacBook Air on sale for...
Amazon has the current-generation 11″ 1.6GHz/128GB MacBook Air (sku MJVM2LL/A) on sale for $749.99 for a limited time. Their price is $150 off MSRP, and it’s the lowest price available for this model... Read more
Price drops on clearance 2015 13-inch MacBook...
B&H Photo has dropped prices on clearance 2015 13″ MacBook Airs by up to $250. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/4GB/128GB MacBook Air (MJVE2LL/A): $799, $200... Read more
Mac minis on sale for up to $100 off MSRP
B&H Photo has Mac minis on sale for up to $100 off MSRP including free shipping plus NY sales tax only: - 1.4GHz Mac mini: $449 $50 off MSRP - 2.6GHz Mac mini: $649 $50 off MSRP - 2.8GHz Mac mini... Read more

Jobs Board

*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
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Automotive Sales Consultant - Apple Ford Linc...
…you. The best candidates are smart, technologically savvy and are customer focused. Apple Ford Lincoln Apple Valley is different, because: $30,000 annual salary Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Simply Mac *Apple* Specialist- Service Repa...
Simply Mac is the largest premier retailer of Apple products in the nation. In order to support our growing customer base, we are currently looking for a driven Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.