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

Printopia 3.0.4 - Share Mac printers wit...
Run Printopia on your Mac to share its printers to any capable iPhone, iPad, or iPod Touch. Printopia will also add virtual printers, allowing you to save print-outs to your Mac and send to apps.... Read more
Tinderbox 7.3.1 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
ExpanDrive 6.1.6 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Printopia 3.0.4 - Share Mac printers wit...
Run Printopia on your Mac to share its printers to any capable iPhone, iPad, or iPod Touch. Printopia will also add virtual printers, allowing you to save print-outs to your Mac and send to apps.... Read more
Tinderbox 7.3.1 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
ExpanDrive 6.1.6 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
VOX 3.0.1 - Music player that supports m...
VOX just sounds better! The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features and support for all audio formats you should ever need.... Read more
Merlin Project 4.3.3 - $289.00
Merlin Project is the leading professional project management software for OS X. If you plan complex projects on your Mac, you won’t get far with a simple list of tasks. Good planning raises... Read more
Mac DVDRipper Pro 7.1 - Copy, backup, an...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
iMazing 2.5.2 - Complete iOS device mana...
iMazing (was DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and from... Read more

Latest Forum Discussions

See All

148Apps' Ultimate Guide to Black Fr...
Black Friday is here, and there are a whole lot of discounts running right now for folks on the lookout for new mobile devices, accessories, and yes, even games. Here's a helpful rundown of what you'll find both in stores and online. Happy... | Read more »
The best Black Friday mobile game deals
Black Friday's upon us, and if you've happened to nab a fancy new phone during the week's big savings, you might be searching for some new games to fill up space on your new gadget. There are a lot of great games on sale right now for Black Friday... | Read more »
The best mobile games to play while your...
Thanksgiving is a time to reconnect with loved ones, eat lots of food, and all of that jazz, but once the festivities start to wind down, folks tend to head to the couch to watch whatever football is happening for Turkey Day. | Read more »
The best Black Friday deals for Apple ga...
Black Friday is hours away at this point, but many popular retailers are getting a jump on things with plenty of pre-Black Friday sales already available. Many of those early bird sales including some sharp discounts on the latest Apple phones... | Read more »
The Inner World 2 (Games)
The Inner World 2 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Solve mind-bending puzzles in a world full of mystery and save the family of the flute-noses! Their dynasty has been... | Read more »
warbot.io wants you for the robot wars
Fans of epic gundam-style battles will find a lot to love in warbot.io, the first game for up and coming developer Wondersquad. The game saw a lot of success when it first launched for browsers and Facebook, and now even more people are getting the... | Read more »
Uncover alien mysteries in cross-genre s...
If the Alien franchise taught us anything, it’s that landing on a strange planet at the behest of a faceless corporation is probably asking for trouble. And Eldritch Game’s Deliria doesn’t prove otherwise. In 2107, Dimension LG7 is rich with... | Read more »
The best mobile games to play during dre...
| Read more »
Animal Crossing: Pocket Camp beginner...
Animal Crossing: Pocket Camp, was just announced yesterday, but it's already in soft launch in Australia. No matter where you are in the world, you can still get access to the soft launch on iOS, so we've devised a few beginner tips for folks who... | Read more »
The mobile gamer's guide to Black F...
We're starting to catch wind of some exciting deals in the mobile gaming space for Black Friday. There are big discounts on mobile phones and accessories cropping up already, so you might want to get a move on things ahead of the big day. It's... | Read more »

Price Scanner via MacPrices.net

Apple Black Friday sale for 2017: $150 Apple...
BLACK FRIDAY Apple has posted their Black Friday deals for 2017. Receive a $150 Apple gift card with the purchase of select Macs and up to $100 with various iPads, iPhones, and Apple Watches. The... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has 15″ and 13″ MacBook Pros on sale for up to $200 off MSRP as part of the Black Friday and Holiday sale. Shipping is free, and B&H charges sales tax for NY & NJ residents only... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has 12″ MacBooks on sale for $150 off MSRP as part of the Black Friday and Holiday sale. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 12″ 1.2GHz... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has 10.5″ iPad Pros in stock today and on sale for up to $130 off MSRP. Each iPad includes free shipping, and B&H charges sales tax in NY & NJ only: – 10.5″ 64GB WiFi iPad Pro... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has 13″ MacBook Airs on sale for up to $150 off MSRP as part of the Black Friday and Holiday sale. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 13″... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has 27″ and 21″ iMacs on sale for up to $200 off MSRP as part of the Black Friday and Holiday sale. Shipping is free, and B&H charges sales tax for NY & NJ residents only: – 27... Read more
Black Friday 2017: Where to find the best dea...
B&H Photo has Mac minis on sale for $100 off MSRP as part of their Black Friday sale, each including free shipping plus NY & NJ sales tax only: – 1.4GHz Mac mini: $399 $100 off MSRP – 2.6GHz... Read more
Black Friday 2017: Find the best deals and lo...
Scan our exclusive price trackers for the latest Black Friday 2017 sales & deals and the lowest prices available on Apple Macs, iPads, and gear from Apple’s authorized resellers. We update the... Read more
Black Friday: 27″ 3.4GHz iMac for $1599, save...
Amazon has the 27″ 3.4GHz Apple iMac on sale for $1599.99 as part of their Black Friday sale. That’s $200 off MSRP, and shipping is free. Their price is currently the lowest price available for this... Read more
Black Friday: 13″ 2.3GHz/256GB MacBook Pro fo...
Amazon has the 13″ 2.3GHz/256GB Apple MacBook Pro on sale for $1299.99 as part of their Black Friday sale. Shipping is free: – 13-inch 2.3GHz/256GB Space Gray MacBook Pro (MPXT2LL/A): $1299.99 $200... Read more

Jobs Board

Business Development Manager, *Apple* Pay -...
# Business Development Manager, Apple Pay Job Number: 112919084 Santa Clara Valley, California, United States Posted: 18-Aug-2017 Weekly Hours: 40.00 **Job Summary** Read more
Digital Marketing Media Planner, *Apple* Se...
# Digital Marketing Media Planner, Apple Services Job Number: 113080212 Culver City, California, United States Posted: 03-Oct-2017 Weekly Hours: **Job Summary** Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Business Development Manager, *Apple* Pay -...
# Business Development Manager, Apple Pay Job Number: 112919084 Santa Clara Valley, California, United States Posted: 18-Aug-2017 Weekly Hours: 40.00 **Job Summary** Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 56553863 North Wales, Pennsylvania, United States Posted: 17-Jun-2017 Weekly Hours: 40.00 **Job Summary** Are you passionate Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.