TweetFollow Us on Twitter

HTML Rendering Volume Number: 16 (2000)
Issue Number: 8
Column Tag: Programming

HTML Rendering with FutureBASIC^3

By Chris Stasny

How to write a simple HTML Browser with FutureBASIC^3

East Meets South

We had been dealing with our Japanese distributors for about six years when their head honcho asked for a face-to-face. It's true that Thelma and I enjoy a life of bliss in our double wide, but I wasn't sure how these foreigners would take to a genuine Mississippi abode. They would have to circumnavigate several junk cars to reach the front door. They would have to sleep with ol' Blue and a half dozen of his flea-bitten companions who hold the existing claim to our guest bed. After a brief emailed discussion of accommodations, we decided to meet in a neutral country: California.

There was a second introduction stacked in the Tarot cards, but this one was binary. I was prodded into action when I discovered that the in-box had been overrun with requests for some method of displaying HTML code. And both of those emails were strongly worded! It was time for... Drum roll... Use deep voice... "FutureBASIC meets the HTML Renderer."

The first step was to locate documentation of the new manager. Apple's only documentation seems to be a terse little reference called HTML_RenderingLib.pdf. A quick search of the hard drive turned up another necessary component. It is an extension called HTMLRenderingLib, which seems to work well in both Systems 8.x and 9. It took me more than an hour to locate the carbon library on a monthly SDK CD that contained information on the constants and toolboxes. Another few minutes were required for converting the code from C to FB^3. These converted toolbox calls are now placed in a file named Tlbx HTML Rendering.Incl and can be found at stazsoftware.com, on the Release 3 CD, or with electronic versions of this publication. The routines are accessed by your program with the following line of code:

INCLUDE "Tlbx HTML Rendering.Incl"

When Cultures Collide

The whole thing about meeting those foreigners had me on pins and needles. My first faux pas came when they introduced themselves and handed me business cards. They do this by holding the card in both hands and bowing slightly when it is presented. I could tell right off that this was a big deal and I was anxious not to appear uncouth. (These guys were really couth.) I hastily extracted a card from my wallet and smoothed it out against my jeans. (This had the added benefit of wiping away some dirt and a few non-descript chicken parts that had adhered to the card.) I scratched out Bubba's Seafood and Shoe Repair, then carefully printed my name. I bowed and presented it to that foreign guy. Please note here that things did not work out exactly as I had envisioned. I am loath to admit it, but I believe that a recently consumed six pack of Bud may have been responsible for my falling against him and knocking down the entire Japanese contingent like a row of carefully placed dominoes.

The thought of working with the new HTML Rendering library had me on edge too. I soon discovered that a few simple toolbox calls would do the work for me. To simplify this example program, I decided to use the FutureBASIC II runtime (one of the many runtimes available under the Command menu). This allowed me to prune window, menu, and event handling so that the example could concentrate on the concepts of HTML rendering. The entire code set (sans remarks and white space) is just over 100 lines. It was written to work with almost any preference setting, but you will need to uncheck Toolboxes require "CALL" in the preferences window and make sure that you compile in PPC. (This particular set of routines does not include 68K inline code.) The program operates from a single window and contains a small set of globals.

BEGIN GLOBALS
	DIM AS LONG gHRref		// heavily used HR reference
	DIM AS LONG @gPort&		// "@" means don't use register
	DIM gResizeFlag 			// bool: window will be resized
	DIM gQuit						// flag says it's time to terminate
END GLOBALS

Program brevity may be contributed to the fact that we use only one window. Its pointer is held in gPort&. For non-FBers: You don't have to type class variables in FutureBASIC, though you can if you desire. There is no necessity for setting separate variables for a grafport and a window pointer, as they are (in System 9 and earlier) the same address. Another obvious difference from other languages is that a local function does not have to return a result. Even if it does return something, the caller does not have to accept the result. This makes for a bulletproof environment.

Almost every operation involving the HTML rendering library requires an HTML Rendering (HR) reference number. We start with a single gHRref and use it for the duration. The only remaining globals are two flags that indicate when to resize the rendering area and when to quit the application.

FN setHTMLrect

Three utility functions handle most of the work. The first sets the rectangle of the rendering area based on the size of the grafport. This is called when a window is resized and when the window is initially created.

/*
	This routine sets the size of the HTML
	rendering rect so that it fits in the 
	current grafport.
*/
LOCAL
DIM AS RECT renderRect
DIM err
LOCAL FN setHTMLrect
  gResizeFlag = _false
  renderRect  = @gPort&.portRect%
  OFFSETRECT(renderRect,1,0)
  INSETRECT(renderRect,0,-1)
  err = FN HRSetRenderingRect(gHRref,renderRect)
END FN

Because of automatic colorization and things not used in the formatting of code for this publication, you will see a significant difference in appearance (though not in content) between the printed code and the screen version.


The FB^3 Editor Window.

In FB^3, bookmarks are visible lines instead of obscure selection ranges. Indention and capitalization are automatic. Font, size, style, capitalization, and fore/background colors are user selectable for remarks, bookmarks, keywords, toolbox calls, quoted strings, constants and more. There are several ways of sorting the function menu and you may command-double-click a word to be transported to its definition.

FN showLocalURL

The most important routine calls the toolbox rendering library and handles necessary set up. In FN showLocalURL, we insure that the library is available, create the new HR reference, and open the file specified by name and volume reference number. Note that this particular example works on local files rather than web based files. This lends itself more readily to building HTML based help systems and handling local tests of a web site before uploading. I tested the project by opening a local copy of the STAZ web site and navigating hither and yon. Amazingly, clicking mail links launched my email program. Clicking links to remote locations opened the Netscape browser and took me to the site. If you wish to work from downloaded web pages instead of local files, you will need to review FN HRGoToURL.

/*
	Check to see if rendering is available.
	Create a new HR reference.
	Build a file spec to an HTML file.
	Render the file.
*/
LOCAL 
DIM spec AS fsspec
DIM err,wTitle$
LOCAL FN showLocalURL(theURL$,vRef%)
	LONG IF FN HRHTMLRenderingLibAvailable
		
		LONG IF gHRref = 0
			err = FN HRNewReference(gHRref,¬
							_kHRRendererHTML32Type,¬
							gPort&)
			FN setHTMLrect
		END IF

		LONG IF FN FSMAKEFSSPEC(vRef%,0,theURL$,spec) = _noErr
			LONG IF FN HRGoToFile(gHRref,spec,_false,¬
										_zTrue) = _noErr
				LONG IF FN HRGetTitle(gHRref,wTitle$) = _noErr
					SETWTITLE(gPort&,wTitle$)
				END IF
			END IF
		END IF
	END IF
END FN

FN terminate

A final library call performs the simple task of closing down the HR reference. It is called when the application quits.

/*
	On exit, dispose of the HR reference.
*/
LOCAL
DIM err
LOCAL FN terminate
	err = FN HRDisposeReference(gHRref)
END FN

This Is My Gift to You

Excuse my digression. Only moments ago, we were deeply involved in the tale of an important business meeting. During the last episode, the hero's (that would be me) denim-clad torso was sprawled across a pile of tailored Japanese suits. They declined my offer to help them back to a standing position and proceeded with the next part of eastern culture where we exchanged gifts. They presented a towel thing that had a bunch of that funny looking writing and a small collapsible fan. I wiped sweat from my brow, fanned myself, (to show appreciation) and donned a very large grin with a very small number of teeth. It was then that I realized I was not in possession of a reciprocating gift.

I had to think fast - like the time that Thelma found me in the barn with... (Never mind. I'll save that for another article.) Anyhow, luck was with me because I had just emptied and flattened a perfectly good spit cup prior to the meeting. I turned around, removed it from my shirt pocket, and stretched it back out. I did a perfect military about face in accordance with the pomp and circumstance of the occasion. (Unfortunately, the aforementioned six pack caused me to turn a lot farther than 180 degrees and took a significant number of tiny little baby steps to realign.) I bowed, and presented the head guy with a slightly used (but still perfectly good) spit cup.

Init Routines

The many runtimes of FB^3 are a gift that we programmers may accept without reciprocation. I mentioned earlier that I used the FBII emulation for this project. It allowed me to build and maintain a window with a single line of code. My total set is held in this simple fragment:

/*
	Init Everything
*/

_fileMenu = 1

BEGIN ENUM 1
	_openItem
	_quitItem
END ENUM

MENU _fileMenu,0        ,_enable,"File"
MENU _fileMenu,_openItem,_enable,"Open/O"
MENU _fileMenu,_quitItem,_enable,"Quit/Q"

WINDOW 1
GETPORT(gPort&)

Dialog Routines

The next task involves event handling. The program accepts the default behaviors for most user interaction, but process a few window message items specific to this type of application. During update events, a region is created and HRdraw is used to redraw the rendered area. When the window is activated or deactivated, HRactivate and HRdeactivate are called into action. When the window is closed, the gQuit Boolean is set and when it is about to be resized, gResizeFlag is set.

/*
	Handle window refresh, activate, deactivate,
	grow, and close.
*/
LOCAL
DIM act,ref,err
LOCAL FN doDialog
	act = DIALOG(0)
	ref = DIALOG(act)

	SELECT act 

		CASE _wndRefresh			// update
			DIM rgn&
			rgn& = FN NEWRGN
			rectrgn(rgn&,gPort&.portRect%)
			err = FN HRdraw(gHRref,rgn&)
			DISPOSERGN(rgn&)

		CASE _wndActivate			// activate/deactivate
			LONG IF ref > 0
				err = FN HRactivate(gHRref)
			XELSE
				err = FN HRdeactivate(gHRref)
			END IF

		CASE _wndClose				// close
			gQuit = _zTrue

		CASE _preview				// grow
			LONG IF ref = _preWndGrow 
				gResizeFlag = _zTrue
			END IF
	END SELECT

END FN

FN doEvent

The HR library is intelligent enough to handle its own events. We pass these through a raw event vector which receives events before FB^3 acts upon them.

/*
	Handle raw events before FB has a 
	opportunity to process them
*/
LOCAL
DIM err
LOCAL FN doEvent
	LONG IF FN HRIsHREvent(EVENT) 
		% EVENT,0
	XELSE
		IF gResizeFlag THEN FN setHTMLrect
	END IF
END FN

FN doMenu

Menu events are vectored to a single routine. The Quit item does nothing more than set a flag. The Open item displays a dialog, then vectors to the previously defined FN showLocalURL. Two things are noteworthy.

Noteworthy thing 1: FB^3 places variables in registers until all registers are used. This is an operation that is paramount for PPC speed and is OK until you encounter a parameter that is passed as a pointer to a variable. Registers are not memory locations and cannot themselves be passed as variable addresses. Earlier, we dimensioned @gPort& so that we could use GETPORT(gPort&) because gPort& is a variable that receives information. Similarly, vRef% is dimensioned with the @ symbol because it is a variable that will receive information from the FILES$ routine.

Noteworthy thing 2: Basic users normally use the LEN function to determine the length of a string. In FB^3, you may look at any character in a string by wrapping its offset in brackets. The use of fName$[0] accomplishes the same thing as LEN by extracting the length byte from a Pascal string.

/*
	Handle menu events
*/
LOCAL
DIM fName$
DIM @vRef%
LOCAL FN doMenu
	LONG IF MENU(_menuID) = _fileMenu
		SELECT MENU(_itemID)

			CASE _openItem
				fName$ = FILES$(_fOpen,"TEXT",,vRef%)
				LONG IF fName$[0]
					FN showLocalURL(fName$,vRef%)
				END IF

			CASE _quitItem
				gQuit = _zTrue

		END SELECT
	END IF
MENU
END FN

Event Loop

The final code fragment sets up vectors for those events that interest us, then falls into the event loop.

/*
' Event loop
*/

ON DIALOG FN dodialog
ON EVENT  FN doEvent
ON MENU   FN doMenu

DO
	HANDLEEVENTS
UNTIL gQuit

FN terminate

A Lean, Mean Rendering Machine

I tested the code by opening the index page in my local copy of a web site. The rendering was clean and generally fast, though background patterns seem to be imaged a bit slower in Apple's library than in Netscape's. Nevertheless, the rendering was exact. No pictures disappeared. No text or formatting was lost. Clicking a graphic or link worked just as it would in Netscape. I had never dreamed that the functionality of a browser could be reduced to a few lines of code just as I never dreamed that meeting a few guys from the other side of the pond would be so unnerving.


Screen Shot of FB^3 Simple Browser.

We have put on the blinders and walked a straight and simple path to the completion of this project. And while it is not your Father's Oldsmobrowser, it is certainly an exciting start into untested waters. Good luck in your quest.


The only things that Chris Stasny (a.k.a. The STAZ) enjoys more than sitting on the front porch of his trailer are programming his Mac and finding a good place to spit. He has several commercial products under his ample belt which include Classroom Publisher, FutureBASIC^3, and RedNeck Publisher. You can reach the STAZ tech team at tech@stazsoftware.com or visit their web site at http://www.stazsoftware.com.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Live Home 3D Pro 3.2.2 - $69.99
Live Home 3D Pro, a successor of Live Interior 3D, is the powerful yet intuitive home design software that lets you build the house of your dreams right on your Mac. It has every feature of Live Home... Read more
FileZilla 3.27.0.1 - Fast and reliable F...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface. Version 3.27.0.1: MSW: Add misssing file to .zip binary package... Read more
Spotify 1.0.59.395. - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
Sierra Cache Cleaner 11.0.6 - Clear cach...
Sierra Cache Cleaner is an award-winning general purpose tool for macOS X. SCC makes system maintenance simple with an easy point-and-click interface to many macOS X functions. Novice and expert... Read more
DiskCatalogMaker 7.1.2 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Live Home 3D Pro 3.1.2 - $69.99
Live Home 3D Pro, a successor of Live Interior 3D, is the powerful yet intuitive home design software that lets you build the house of your dreams right on your Mac. It has every feature of Live Home... Read more
Deeper 2.2.1 - Enable hidden features in...
Deeper is a personalization utility for macOS which allows you to enable and disable the hidden functions of the Finder, Dock, QuickTime, Safari, iTunes, login window, Spotlight, and many of Apple's... Read more
Pinegrow 3.04 - Mockup and design webpag...
Pinegrow (was Pinegrow Web Designer) is desktop app that lets you mockup and design webpages faster with multi-page editing, CSS and LESS styling, and smart components for Bootstrap, Foundation,... Read more
Deeper 2.2.1 - Enable hidden features in...
Deeper is a personalization utility for macOS which allows you to enable and disable the hidden functions of the Finder, Dock, QuickTime, Safari, iTunes, login window, Spotlight, and many of Apple's... Read more
Spotify 1.0.59.395. - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more

Latest Forum Discussions

See All

The best deals on the App Store this wee...
There are quite a few truly superb games on sale on the App Store this week. If you haven't played some of these, many of which are true classics, now's the time to jump on the bandwagon. Here are the deals you need to know about. [Read more] | Read more »
Realpolitiks Mobile (Games)
Realpolitiks Mobile 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: PLEASE NOTE: The game might not work properly on discontinued 1GB of RAM devices (iPhone 5s, iPhone 6, iPhone 6 Plus, iPad... | Read more »
Layton’s Mystery Journey (Games)
Layton’s Mystery Journey 1.0.0 Device: iOS Universal Category: Games Price: $15.99, Version: 1.0.0 (iTunes) Description: THE MUCH-LOVED LAYTON SERIES IS BACK WITH A 10TH ANNIVERSARY INSTALLMENT! Developed by LEVEL-5, LAYTON’S... | Read more »
Full Throttle Remastered (Games)
Full Throttle Remastered 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Originally released by LucasArts in 1995, Full Throttle is a classic graphic adventure game from industry legend Tim... | Read more »
Stunning shooter Morphite gets a new tra...
Morphite is officially landing on iOS in September. The game looks like the space shooter we've been needing on mobile, and we're going to see if it fits the bill quite shortly. The game's a collaborative effort between Blowfish Studios, We're Five... | Read more »
Layton's Mystery Journey arrives to...
As you might recall, Layton's Mystery Journey is headed to iOS and Android -- tomorrow! To celebrate the impending launch, Level-5's released a new trailer, complete with an adorable hamster. [Read more] | Read more »
Sidewords (Games)
Sidewords 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Grab a cup of coffee and relax with Sidewords. Sidewords is part logic puzzle, part word game, all original. No timers. No... | Read more »
Noodlecake Games' 'Leap On!...
Noodlecake Games is always good for some light-hearted arcade fun, and its latest project, Leap On! could carry on that tradition. It's a bit like high stakes tetherball in a way. Your job is to guide a cute little blob around a series of floating... | Read more »
RuneScape goes mobile later this year
Yes, RuneScape still exists. In fact, it's coming to iOS and Android in just a few short months. Jagex, creators of the hit fantasy MMORPG of yesteryear, is releasing RuneScape Mobile and Old School RuneScape for mobile devices, complete with... | Read more »
Crash of Cars wants you to capture the c...
Crash of Cars is going full on medieval in its latest update, introducing castles and all manner of new cars and skins fresh from the Dark Ages. The update introduces a new castle-themed map (complete with catapults) and a gladiator-style battle... | Read more »

Price Scanner via MacPrices.net

Save or Share
FotoJet Designer, is a simple but powerful new graphic design apps available on both Mac and Windows. With FotoJet Designer’s 900+ templates, thousands of resources, and powerful editing tools you... Read more
Logo Maker Shop iOS App Lets Businesses Get C...
A newly released app is designed to help business owners to get creative with their branding by designing their own logos. With more than 1,000 editable templates, Logo Maker Shop 1.0 provides the... Read more
Sale! New 15-inch MacBook Pros for up to $150...
Amazon has the new 2017 15″ MacBook Pros on sale for up to $150 off MSRP including free shipping: – 15″ 2.8GHz MacBook Pro Space Gray: $2249 $150 off MSRP – 15″ 2.89Hz MacBook Pro Space Gray: $2779 $... Read more
DEVONthink To Go 2.1.7 For iOS Brings Usabili...
DEVONtechnologies has updated DEVONthink To Go, the iOS companion to DEVONthink for Mac, with enhancements and bug fixes. Version 2.1.7 adds an option to clear the Global Inbox and makes the grid... Read more
15-inch 2.2GHz Retina MacBook Pro, Apple refu...
Apple has Certified Refurbished 2015 15″ 2.2GHz Retina MacBook Pros available for $1699. That’s $300 off MSRP, and it’s the lowest price available for a 15″ MacBook Pro. An Apple one-year warranty is... Read more
13-inch 2.3GHz Silver MacBook Pro on sale for...
B&H Photo has the new 2017 13″ 2.3GHz/256GB Silver MacBook Pro (MPXU2LL/A) on sale for $1399 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP. Read more
Apple Tackles Distracted Driving With iOS 11...
One of the most important new features coming in iOS 11 is Do Not Disturb while driving, intended to help drivers stay more focused on the road. With Do Not Disturb while driving, your iPhone can... Read more
iMazing Mini for Mac: Free Automatic and Priv...
Geneva, Switzerland-based indie developer DigiDNA has released iMazing Mini, their free macOS utility designed to automatically back up iOS devices over any local Wi-Fi network. The app offers users... Read more
Clearance 2016 13-inch MacBook Airs, Apple re...
Apple dropped prices recently on Certified Refurbished 2016 13″ MacBook Airs, with models now available starting at $809. An Apple one-year warranty is included with each MacBook, and shipping is... Read more
9.7-inch 2017 iPads available for $299, save...
B&H Photo has 2017 9.7″ 32GB WiFi iPads on sale for $30 off MSRP for a limited time. Shipping is free, and pay sales tax in NY & NJ only: – 32GB iPad WiFi: $299, $30 off Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions - Apple...
SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Senior Payments Architect - *Apple* Pay - A...
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 Read more
Frameworks Engineering Manager, *Apple* Wat...
Frameworks Engineering Manager, Apple Watch Job Number: 41632321 Santa Clara Valley, California, United States Posted: Jun. 15, 2017 Weekly Hours: 40.00 Job Summary Read more
Manager, *Apple* Media Products - Apple Inc...
Job Summary The Apple Media Products Discovery, Fraud and Abuse team is responsible for protecting the integrity of Apple services. As a manager of the team, you Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.