The QB Times

Issue: 1

Contents:

• Introduction
  
• Projects
  
• Site Reviews
  
  • Future Software
    
  • Nemesis Software
    
• Hex Tutorial by @bionnn
  
• Shorts
  
• First Impression
  
  • 3Des Designer
    
  • Project RT
    
• Writing your own scripting language by Nightwolf
  
• ASM in QB by @bionnn
  
• Ramblings of a Crazed Programmer: Advanced Quest Design by DarkAges
  
• In the Spotlight by Viper
  
• File Formats: The BMP Format
  
• Closing Words
  
• Credits
  

Introduction

Welcome to the first issue of The QB Times. I'll try to make this magazine as informative as possible with articles on all kinds of things like scripting, on how to use different file formats in QBasic, assembly and all other kinds of things. Also I'll do site reviews in The QB Times. Another item is projects; here I'll tell on updates from other programmer's projects and new projects. In shorts I'll tell about the news from the QB world. I also do First Impressions on upcoming projects and last but not least I've some people writing articles for me! So, that's all for the introduction this time... Have fun with this issue!!

-Nightwolf

Projects

In this section there will be updates on QBasic programmers projects, or new projects.
• Tek's RPG, Indigo Moon, is being recoded. Tek told us that he has shops and spell casting done. The battle engine is going to be next and then he'll add midi music.
  
• Tsugumo is working on a new project! It's called ThiefRPG.
  
• Viper and Marcade are working on a chat program called NemChat it's made in VB 5.0; version 2 is out and available for download on the Nemesis Software page. Version 3 is still in the works and is delayed due to a bug!
  
• Marcade and Tomahawk are working on a new RPG! It doesn't have a new yet. But the early screenshot I saw looked good. It ran at 300 FPS at a PII 400, but it'll probably run on about 100 FPS on a normal computer. Tomahawk originally started the game, but soon Marcade took over the programming. Tomahawk is doing the graphics now. It will have SoundBlaster music (either QMidi or BWSB), a good storyline and astonishing graphics. The QB Times will keep you informed!
• BlackBird is working on a QB IDE for Windows, I saw an early screenshot and it's really looking good! Check out BlackBird's Site for more info.
• Also BlackBird is working on a 3D object creator, I've seen a very beta version. Check my First Impressions below.
• Dark Knight Software, the makers of DarkAges II, has released a demo of the engine. The way the mouse is used to walk around is really good and original.
• Angelo Motolla & Petter Holmberg are working on a 3D game in QB; it's called Project RT. I saw some early screenshots and it looked very good! It's also very fast.
• Danny Gump, creator of The Mystical Journey and Dash, told us that he is going to recode his RPG, The Mystical Journey. He is going to redo the battles and the engine and he'll be using the Dash 3D subs to add 3D effects to the battles.
• Yoda and Caylo are working on Pokemon 2: Xenophobic Continuum. Here is a description of the project which Yoda has written:

  Pokemon 2: Xenophobic Continuum, once it is completed will be an advanced tile game, with high adventure, obscure puzzles to solve, and many strange places to explore. The raw power of the game engine and the limitless possibilities of gameplay, along with the sparkling wonder of the graphics, will leave any gameplayer wondering if this game was really programmed in simple QuickBasic. By using an innovative technique, Pokemon 2: Xenophobic Continuum has virtually no limits to the amount of tiles that can be used, giving the game a more appealing look and feel. With powerful NPC scripting, the people you meet will seem as alive as must of your friends or family. The player interface is highly configurable, to allow the game to be played without the interface being in the way. And with on the fly configurability, the player can set the way the game plays, to best meet the speed of there computer. Unfortunately, Pokemon 2 is still under development, with the development team working hard to bring you this unique game. As of now, the game engine is 20% complete, but you can still check the progress made on the game so far by downloading the Pre-Alpha Demo release, which be available shortly at www.quickbasic.com This very early demo shows the powerful NPC capabilities of the Pokemon 2 engine. This Demo release also features a surprise appearance by the venerable Jedi Master Yoda.

Site Review

Here I'll do site reviews. After this issue it'll be taken over by Viper.

Future Software
Future Software is one of the mayor QB sites out there. When you enter Future software you come to a page that ask you to bookmark it and then says that all QBasic programmers can enter... Well since I'm a QB programmer I entered. The first thing I noticed is the great layout! There is a nice looking navigation bar on the left of the page, two search engines in the bottom and the navigation for the files page is on top in a pulldown window, this is really good! On to the page, Future Software has more than 400 files, a really neat QB sites search engine, a message board, site reviews and some information about them. Ok, that's about the introduction now read the scores!
.
General Appearance:	80/100	A well thought out layout, also the Files pull-down menu is really nice. The MsgBoard & Guestbook are all local CGI-Script, heavily modified by Future Software.
Images:	95/100	Just great looking images!!
Sound:	N/A	No sound
Programs/Links:	90/100	Lots of files and a good search engine with many sites!!
QBasic:	95/100	All about QBasic!
Unique:	75/100	Well the search engine is pretty unique but that's all...
Total:	87/100	A good site to bookmark and come back often!

Nemesis Software
Nemesis Software is a fairly new page, it has a really good layout; the page title is in a top frame, there's a body frame with some borders around it, and a bottom frame with a menu. Whenever a topic you select from the menu has categories a little menu frame pops up at the top of the body frame which keeps the page clearly structures. There is a banner exchange, some links, awards page, about 60 files, some Q&A question, and their programs and information about Nemesis Software
General Appearance:	87/100	A very good layout, very clear and easy to navigate. There are some JavaScripts on Nemesis Software all written by themself.
Images:	80/100	Just 3 words: Simple but nice!
Sound:	N/A	No Sound
Programs/Links:	77/100	Not so much programs and only a few links, but there is a search engine with more links.
QBasic:	82/100	There are lots of things about QBasic but also lots of things not about QBasic.
Unique:	80/100	The Banner Exchange and the Search Engine are pretty unique.
Total:	80/100	A good looking page with not too much programs and links but with some unique features.

Shorts

NES Emulators in QBasic!

No, I'm not kidding! There are two NES emulators written in QBasic now! The first is called: uNESsential and the second if called DRR-Nes. DRR-NES now emulates some games. But not that many... uNESsential emulates also very little games.

More people moving to .quickbasic.com

Many QBasic sites are moving to a new .quickbasic.com address. This includes NeoZones, QBasic The Magazine, Enchanted Creations and Alternatelogic. If you want your own .quickbasic.com address go to Darkelf Productions

Qlympics STILL in Preliminary Rounds

As of now the Qlympics are still in Preliminary Rounds. It's almost two months since the Preliminary Rounds have started. When will the real voting on the Qlympics begin? The QB Times will keep you informed

First Impression

3Des Designer

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3Des Designer is a 3D object creator. It has a real nice interface and you can have lots and lots of planes in your object. It comes with a very neat help system which is almost like a HTML page! It also has a renderer where you can view your object rotating in 3D with realtime shadowing!

You can make objects by placing planes in the workarea. Then you can shape up the plane. You can edit in 3 views: top view, front view and side view. You need to fool around a bit but when you get the hang of it it's really cool!

The version avaible on the internet is version 0.42B. The version I reviewed was version 0.43B. I really liked the interface of 3DES Designer, it's very clear. The pre-made objects made by BlackBird are also very nice to look at. I think if this program continues it could be one of the best QB programs ever made!

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Project RT

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Project RT, one of the most anticipated projects of the year so far. And we are the first to bring you an official playtest ! Many rumours have been spread about the engine being incrdibly fast, some even saying that the engine got 60 FPS on a 133 !!! well i can now tell you that each and every one of these rumours are true ! the turbo charged ASM engine flys on my 300 at a speed which is almost unplayable ! The incredible engine supports texture mapped walls and 256 objects on the screen at any one time. At the moment Peter is waiting for angelo's door routines so the project can continue, but as Angelo's net connection is down, RT has been put on hold for the next couple of days. Just to clear up a couple of wild rumours, someone said that you played cuby and coby in a doom style wetspot 3, this is very not true. Peter has said that Angelo and he have not discussed anything of the sort ! For all the latest news read The QB Times

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The author of this article is Greg McAusland ( Maz )

Hex Tutorial

Warning: This is meant for advanced QB users or advanced C/C++ users wanting to expand their knowledge and make their own libraries. QB beginners beware; this would be a frighting scare!

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Level One: One and only

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People how worked with HEX numbers before don't have to read this. Basically as 19day says, run away run away! =) Actually you might find this a bit or two interesting (just keep it under 32-bit please =)

We'll start with showing how about digits and stuff of the sort,

	Base 1:		Base 2:		Base 8:		Base 10:
	0		01		01234567	0123456789
	

OK there you have is some different numbering systems. As you can see Base 1, has only one possibility, it is useless and wont be used. Base 2 has 2, from where you get 'bi', therefor getting the word binary. Base 8 has 8,from where you get 'oct', therefor giving you octal. And obviously comes good old base 10 (the one you should use in your head.) from where you get 'dec', therefor giving you decimal.

Now you might already know all that, but why I'm here is to show you how to count in HEXADECIMAL. It's a Base 16 numbering system.

        Base 16:
	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
	----------------------------------------------
	0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
	

There you have it, now you know what all those As Bs and Cs are! You might be asking how to count double hexadigits. Well it's simple, let's take 11 as an example.

(First digit*16)+(second digit)
	

Which gives us 17. Simple? Sure is, a similar concept applies to quad hexadigits.

(First digit*4096)+(Second digit*256)+(Third digit*16)+Fourth digit
	

Or you could just use calculator to give you the answer, but I'm sure it's too hard to press Start, Programs, Accessories, Calculator ... no no no ... What's the world coming to??? So back to the real world lets take 2222 as an example, you get 8738! Simple right? Try making your own functions if you want, although it will be useless, there's always HEX$. Now that over, you could go back to whatever you were reading and finish this tutorial! =)

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The author can be contacted at: abionnnn@geocities.com

Writing your own scripting language

Introduction

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Well, this article is about creating a scripting language for your game. But what exactly is a scripting language? A scripting language is that you type in commands in, for example, a text-file and the program reads the text-file and knows what to do from the commands it reads from the text-file. I'll give an example:

OPENBOX
DISPLAYTEXT Hi! This text is written in a box
WAITKEY
CLOSEBOX
END
        

That are some simple instructions you can make a program respond on. Like, with OPENBOX it opens a box, then displays the text, waits for a key to be pressed, closes the box and ends. How do you make this stuff with QBasic? Well, that's why I'm writing this, to explain that to you!

A simple scripting language

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Ok, first we'll start with the basics like calling a PRINT command from an external file. Ok, lets say we want to call the command to PRINT a text: DISPLAYTEXT. Create a new file in Notepad and write this in it:

CLEARSCREEN
DISPLAYTEXT Wow! This is my first scripting language!!
DISPLAYTEXT Press any key to end...
WAITFORKEY
DISPLAYTEXT You pressed a key and now the program ends!
ENDSCRIPT
DISPLAYTEXT This action will NOT be executed because there
DISPLAYTEXT is an ENDSCRIPT command before it!

        

Save it as script.dat. So now we have some commands in an external file. But QBasic can't do anything with that so we need to make a program that reads the script-file and ports it so QBasic can understand it. A good way is to read the script-file line by line, then check if the line contains commands and what they are, if there are any expressions after the command store them in a temporarily variable and then execute the command. For example to let the program execute the commands we just used you could use this code:

OPEN "script.dat" FOR INPUT AS #1
 DO
  INPUT #1, ReadLine$
  ReadLine$ = LTRIM$(RTRIM$(ReadLine$)
  IF LEFT$(ReadLine$, 11) = "DISPLAYTEXT" THEN
   Temp1$ = RIGHT$(ReadLine$, LEN(ReadLine$) - 12)
   PRINT Temp1$
  END IF
  IF LEFT$(ReadLine$, 7) = "WAITKEY" THEN
   WHILE INKEY$ = "": WEND
  END IF
  IF LEFT$(ReadLine$, 9) = "ENDSCRIPT" THEN
   EXIT DO
  END IF
  LOOP UNTIL EOF(1)
CLOSE #1
        

I'll discuss the code line by line now:

OPEN "script.dat" FOR INPUT AS #1
        

Opens our scripting file 'script.dat' for reading as file #1

DO
        

Start the Do...Loop event that runs until the file ends

INPUT #1, ReadLine$
        

Reads a single line from the file.

ReadLine$ = LTRIM$(RTRIM$(ReadLine$)
        

Removes all the spaces from the left and right of the line.

IF LEFT$(ReadLine$, 11) = "DISPLAYTEXT" THEN
        

If the first 11 characters from the line we just read form the word DISPLAYTEXT the DISPLAYTEXT command is run.

Temp1$ = RIGHT$(ReadLine$, LEN(ReadLine$) - 12)
        

The DISPLAYTEXT command contains one expression so we just read the right part of the line we took minus twelve character (the DISPLAYTEXT command + the space).

PRINT Temp1$
        

We PRINT the expression we just took.

END IF
        

End the IF...THEN command

IF LEFT$(ReadLine$, 7) = "WAITKEY" THEN
        

If the first 7 characters from the line we read are WAITKEY we run it.

WHILE INKEY$ = "": WEND
        

We wait until a key is pressed

END IF
        

End the IF...THEN command IF LEFT$(ReadLine$, 9) = "ENDSCRIPT" THEN If the first 9 characters from the line we read are ENDSCRIPT we run the command.

EXIT DO
        

We exit the DO...LOOP event.

END IF
        

End the IF...THEN command

LOOP UNTIL EOF(1)
        

Loop back to the DO

CLOSE #1
        

We close the file.

Now you have your first (small) scripting language! Now onto the harder things!

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Adding comments

Well, this isn't exactly hard but I still wanted to include it. I'll now explain on how to add QBasic like comments (the little ' thing). Add a line with a command somewhere in the 'script.dat' file before the ENDSCRIPT command.

Ok, now add this 2 lines somewhere in the do loop:

IF LEFT$(ReadLine$,1) = "'" THEN
END IF
        

This checks if the first command is a ' and if it is, it just does nothing because a comment does nothing. Good, now you can have comments in your scripts!

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Next time

Next time I'll talk about variables and IF...THEN commands. Maybe also about DO...LOOPs and FOR...NEXTs. Until then, enjoy the rest of the issue!

ASM in QBasic

Hello, and welcome to my first article in this small serie. As you know the future of QBasic/QuickBasic relies on the extensive use of ASM. But the problem is that the QBasic community doesn't have enough qualified programmers to "drive" this complicated machine. Well, I want to change all that today. = ) Before you start reading this I must warn you, this is pretty heavy stuff to start on, if you're only starting on QBasic now is the time to back out. Don't say I didn't warn you ; ) And for ASM pros, don't read this either, because I'll end up insulting your intelligence and you'll end up hating me. The first thing you need to get to start ASMing is an assembler, a debugger, and a guide. You probably have the last one (your reading it right now), but if you need to get the other two, hop down to http://www.quickbasic.com/ and get yourself "The ATK V2.01" (If ChUcK put it up there, if he didn't email me and I'll put it up there, in the mean time download the atk v1.0). Got everything? Good. Here we go:

Lesson no.1 The 4 basic registers

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First I'd like to start with a brief explaination of variables in ASM. ASM is very diffrent from QB and high-level languages, as it doesn't use variable names. (well assemblers do in their way, but at a pure level there is no variable naming system) Of course, you can store data in the computers memory, but it wont be "tagged" with a variable name like i% or num1.

When fooling around with asm, you get many preset (variables) to temporarly hold critical data. The first four registers we will learn today are:

AX 16-bit register BX 16-bit register CX 16-bit register DX 16-bit register

Well you see AX, BX, CX and DX are all really integers (can have a value between -32766 to 32767) inside your CPU. You're probably thinking "4 integers! How am I ment to work with that many variables!" You see that's the art of ASM (ofcourse there are more than 4 registers but I'll introduce them later) you must challenge your self programming in it! If you don't want to be challenged and you just want to use other people's librarys, please stop now and spare yourself some precious time, ASM is not for everybody.

Lesson no.2 Some very basic commands

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Before starting this section, read the HEX tutorial if you have no previous knowledge of using hexadecimal.

In order to give a register a value, you must "move" the value into the register. It's simpler than you think, here is an example:

        MOV AX,1
        

that command tells the CPU to assign register AX a value of &H1. So in other words ax% = &H1. Here's another example:

        MOV CX,32
        

That command tells the CPU to assign register CX a value of &H32. that mean cx% = &H32.

You can also assign values from one register to another like so:

        MOV BX,DX
        

This give BX the value of DX. As you can see it's easier than you probably thought, Moving a value from one register to another, or assigning a value to a register takes a bit of time, but when I say a bit of time I mean 2 clocks* on a 80286 (really old processor) or 1 clock on a 486/Pentium.

To add a value to register you use the simple "add" code like so:

        ADD AX,4
        

This increases the value of AX by &H4. You can also add another register to an other register like you would when "mov"ing. Heres an example code :

        MOV AX,3
        MOV DX,AX
        ADD DX,4
        ADD AX,DX
        

What does the value of AX end up? Simple, &H7! Look at the code carefully if you don't agree with my calculations.

Well that's it for this artical, in part two we'll be discussing some more productive methods of using ASM.

* A Clock cycical is used to mesure time taken by the processor to process a command, to find the nanosecond taken you use this simple command : (1000Mhz/(n Mhz))=X nanoseconds Where n is the Mhz speed of the computer.

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The author of this article can be contacted at: abionnnn@geocities.com

Ramblings of a Crazed RPG Programmer: Advanced Quest Design

Greetings Everyone! For those of you who have not managed to read something of mine or bump into me in a QB chatroom, I'm fairly laid back and informal. So, without any noticable transition, let me tell you about a problem that many first-time RPG programmers run into. Simply put, they have the engine, they have the art, the person walks and talks, now how do you force him to conduct a series of actions and thus perform a quest?

I suppose in its simplest form a quest follows these steps:

1. Attain quest - usually by talking to a non-player character (NPC)
2. Perform quest - do the action commanded by the NPC
3. Accept reward - get something in return for completing the quest


To give an example of the above steps as they should appear in your game commands, here is what happens: Store a variable in your code called BEARQUEST. Set it's value to 0. You talk to the village elder (an NPC) who's code is partitioned in this manner:

If BEARQUEST =0 then say a$
If BEARQUEST =1 then say b$
If BEARQUEST =2 then say c$
If BEARQUEST =3 then say d$
        

Since your BEARQUEST variable is 0 at the moment, he says a$ which could be this. "A bear is eating all the children. If you slay him, I will reward you with 500 gold coins." Once the text is said, have the code change BEARQUEST to 1. If you now talk to the elder, he will say b$, which could be "Please hurry in your quest." At this point the player wanders all around the game until the bear is found. Once killed change BEARQUEST to 2. Now return to the village elder who now says c$, "You've saved us! Here is 500 gold coins!" Now to complete the quest, change BEARQUEST to 3 so that from now on, everytime you talk to the elder he will say d$, "Thank you for saving the children. Good luck in all your future adventures." Congratulations if you could follow that, it's all there is to making a quest.

Now you're probably thinking, "That's not hard at all! I thought this was advanced quest design!" Don't worry, I'm not finished yet. The above design was more or less what was used in Dark Ages I. Its brilliance is in its simplicity (and that it works), but its drawbacks are impracticality, informal structure, and wasted space. While programming Dark Ages II, I discovered something better structured, external, and more malleable is necessary for what is going to be a much larger and more complex program. Using the basic concepts of the above example and integrating better structured coding such as scripting, I believe I have come up with a great quest system.

In order for this to make sense, you need to be familiar with scripting. I can't give you a good impression of it here, but it's basically a few lines of code that get their data from external files (usually .txt) and perform the actions based on the data read. The advantages are almost essential in programming because they save a lot of code space, structure your program, and organize what would otherwise be an uncontrollable amount of variables. In my strategy, quest coding requires three things: speech scripting, object scripting, and a universal variable dimension. The universal variable dimension (UVD) is a simple integer dimension from 1 to whatever, where each number represents a variable and could have a value from 0 to whatever. Now here comes the surprise, this strategy is advanced, yet amazingly simple. My speech script contains the following necessities, but yours could be modified to your needs. It contains the variables required, the text that is spoken, and the variables that are changed. The text scripting code would be read whenever a player attempts to talk to someone.

Let's look at some pseudo code of my script:

*"1","0"
*"1","1"
*"Help me, I have a horrible disease and need a magic cure potion!"
*"1","1"

*"1","2"
*"Thank you for saving my life. Take this magic item as thanks."
*"1","3"
*"2","1"

*"1","3"
*"I'll never forget how you saved my life."
        

Here's how it works. Variable 1 from your UVD currently has a value of 0. According to the above script, if it has a value of 0 or 1, the text would read, "Help me, I have a...etc." and then change variable 1 to have a value of 1 (obviously if it was 1 already, changing it to 1 would mean keeping it the same). If it had a value of 2, it would read the corresponding text, change it to 3, then change varialbe 2 (perhaps a magic sword variable) to have a value of 1. After that, every time the text is read, it would find variable 1, value 3 and read that corresponding text, never making any more changes.

"Hold up! Where did variable 1, value 2 come from?" Ahh, good question! Here's where object scripting comes in. Object scripting is in many ways similar to text scripting. The basics that I have integrated are type of object, variables required, text to be read, and variables changed when activated.

Let's look at some object pseudo code:

*"1"
*"1","1"
*"You have found a magic cure potion."
*"1","2"
        

Unlike text scripting, object scripting needs to be read twice in the game. The first time it is read is when the map loads. You have to write a script that will search your file for the objects that will show up on the map, then a separate script for what happens when you manipulate those objects while playing the game. In the case of the above code, the first "1" represents that the object is something that you pick up if the UVD variable 1 has a value of 1 (as shown in the second line of code above). If you had a value of "2" for the first line, it could be an object that you activate, but do not pick up, like a lever or switch. In this manner, if you load the map before you have been given the quest to find the magic cure potion, then your UVD variable 1 would have a value of 0 and the potion would not appear on the map. But if you have been given the quest, then your UVD variable 1 would have a value of 1 and the potion would appear. The third line of code is what appears signifying you have picked up the potion and the fourth line gives variable 1 a value of 2. Now if you redraw your map and check your object script, it will no longer draw the object because your UVD variable 1 has a value other than 1. If you've been following all this then you will notice that variable 1, value 2 is the key to finishing the quest you started in the scripting code. You can now return to the NPC who sent you on the quest and get your reward.

Obviously this is a very basic example of advanced quest programming. Your scripts may contain up to 20 lines, and manage up to 10 variables as some of mine do in DA2. It just depends on how complex of an engine you desire. But hopefully you've picked up what a quest is in an RPG computer game. Simply put, a quest is just the manipulation of people and objects in the game. You could even go so far as to create your own program to manage your NPC and object scripts while you write them.

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The author of this article is: Michael Hoopmann aka DarkAges

In the Spotlight

That's right, I have my own article here every time the QB Times comes out.. =) Well, here i'm going to discuss a site, each time the QBT comes out a different site, the site for this issue of the QBT is: (P.S. Want your site here? Mail me at viper2@cyberdude.com)

The IFace Warehouse

The I-Face Warehouse is a site about graphics, web-design, etc. They provide you with a huge collection of interfaces you can freely use on your site! (like Future Software did) They also have tons of website templates, all top-notch design! Now, see how many points they scored:

Topic:	Mark:	Description:
Design:	7.3	Could have been better, if their menu was in a side-frame, while the content was in the main-frame.. Also, i would have used another font, like Verdana, and not the standard one..
Compatibility:	7.0	This site works just fine with with a resolution of 800x600, and higher, but not when you're viewing the site with a resolution of 640x480..
Content:	9.5	This site is really filled with lots of good, useable information and cool interfaces, banners, website-templates, etc...
Updating:	9.0	This guy updates his site a lot, that's all I can say here..
Overall:	8.2

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The author of this article is Viper who can be contacted at: viper2@cyberdude.com

File Formats: BMP

Note: This document is for advanced programmers! You need a good understanding of binary files and the different kinds of variables!

This topic describes the graphics-file formats used by the Microsoft Windows operating system. Graphics files include bitmap files, icon-resource files, and cursor-resource files.

Bitmap-File Formats

Windows bitmap files are stored in a device-independent bitmap (DIB) format that allows Windows to display the bitmap on any type of display device. The term "device independent" means that the bitmap specifies pixel color in a form independent of the method used by a display to represent color. The default filename extension of a Windows DIB file is .BMP.

Bitmap-File Structures

Each bitmap file contains a bitmap-file header, a bitmap-information header, a color table, and an array of bytes that defines the bitmap bits. The file has the following form:

BITMAPFILEHEADER bmfh;
BITMAPINFOHEADER bmih;
RGBQUAD          aColors[];
BYTE             aBitmapBits[];
        

The bitmap-file header contains information about the type, size, and layout of a device-independent bitmap file. The header is defined as a BITMAPFILEHEADER structure.

The bitmap-information header, defined as a BITMAPINFOHEADER structure, specifies the dimensions, compression type, and color format for the bitmap.

The color table, defined as an array of RGBQUAD structures, contains as many elements as there are colors in the bitmap. The color table is not present for bitmaps with 24 color bits because each pixel is represented by 24-bit red-green-blue (RGB) values in the actual bitmap data area. The colors in the table should appear in order of importance. This helps a display driver render a bitmap on a device that cannot display as many colors as there are in the bitmap. If the DIB is in Windows version 3.0 or later format, the driver can use the biClrImportant member of the BITMAPINFOHEADER structure to determine which colors are important.

The BITMAPINFO structure can be used to represent a combined bitmap-information header and color table. The bitmap bits, immediately following the color table, consist of an array of BYTE values representing consecutive rows, or "scan lines," of the bitmap. Each scan line consists of consecutive bytes representing the pixels in the scan line, in left-to-right order. The number of bytes representing a scan line depends on the color format and the width, in pixels, of the bitmap. If necessary, a scan line must be zero-padded to end on a 32-bit boundary. However, segment boundaries can appear anywhere in the bitmap. The scan lines in the bitmap are stored from bottom up. This means that the first byte in the array represents the pixels in the lower-left corner of the bitmap and the last byte represents the pixels in the upper-right corner.

The biBitCount member of the BITMAPINFOHEADER structure determines the number of bits that define each pixel and the maximum number of colors in the bitmap. These members can have any of the following values:

Value	Meaning
1	Bitmap is monochrome and the color table contains two entries. Each bit in the bitmap array represents a pixel. If the bit is clear, the pixel is displayed with the color of the first entry in the color table. If the bit is set, the pixel has the color of the second entry in the table.
4	Bitmap has a maximum of 16 colors. Each pixel in the bitmap is represented by a 4-bit index into the color table. For example, if the first byte in the bitmap is 0x1F, the byte represents two pixels. The first pixel contains the color in the second table entry, and the second pixel contains the color in the sixteenth table entry.
8	Bitmap has a maximum of 256 colors. Each pixel in the bitmap is represented by a 1-byte index into the color table. For example, if the first byte in the bitmap is 0x1F, the first pixel has the color of the thirty-second table entry.
24	Bitmap has a maximum of 2^24 colors. The bmiColors (or bmciColors) member is NULL, and each 3-byte sequence in the bitmap array represents the relative intensities of red, green, and blue, respectively, for a pixel.

The biClrUsed member of the BITMAPINFOHEADER structure specifies the number of color indexes in the color table actually used by the bitmap. If the biClrUsed member is set to zero, the bitmap uses the maximum number of colors corresponding to the value of the biBitCount member. An alternative22 form of bitmap file uses the BITMAPCOREINFO, BITMAPCOREHEADER, and RGBTRIPLE structures.

Bitmap Compression

Windows versions 3.0 and later support run-length encoded (RLE) formats for compressing bitmaps that use 4 bits per pixel and 8 bits per pixel. Compression reduces the disk and memory storage required for a bitmap.

Compression of 8-Bits-per-Pixel Bitmaps

When the biCompression member of the BITMAPINFOHEADER structure is set to BI_RLE8, the DIB is compressed using a run-length encoded format for a 256-color bitmap. This format uses two modes: encoded mode and absolute mode. Both modes can occur anywhere throughout a single bitmap.

Encoded Mode

A unit of information in encoded mode consists of two bytes. The first byte specifies the number of consecutive pixels to be drawn using the color index contained in the second byte. The first byte of the pair can be set to zero to indicate an escape that denotes the end of a line, the end of the bitmap, or a delta. The interpretation of the escape depends on the value of the second byte of the pair, which must be in the range 0x00 through 0x02. Following are the meanings of the escape values that can be used in the second byte:

Absolute Mode

Absolute mode is signaled by the first byte in the pair being set to zero and the second byte to a value between 0x03 and 0xFF. The second byte represents the number of bytes that follow, each of which contains the color index of a single pixel. Each run must be aligned on a word boundary. Following is an example of an 8-bit RLE bitmap (the two-digit hexadecimal values in the second column represent a color index for a single pixel):

Second byte	Meaning
0	End of line.
1	End of bitmap.
2	Delta. The two bytes following the escape contain unsigned values indicating the horizontal and vertical offsets of the next pixel from the current position.

Compressed data	Expanded data
03 04	04 04 04
05 06	06 06 06 06 06
00 03 45 56 67 00	45 56 67
02 78	78 78
00 02 05 01	Move 5 right and 1 down
02 78	78 78
00 00	End of line
09 1E	1E 1E 1E 1E 1E 1E 1E 1E 1E
00 01	End of RLE bitmap

Compression of 4-Bits-per-Pixel Bitmaps

When the biCompression member of the BITMAPINFOHEADER structure is set to BI_RLE4, the DIB is compressed using a run-length encoded format for a 16-color bitmap. This format uses two modes: encoded mode and absolute mode.

Encoded Mode

A unit of information in encoded mode consists of two bytes. The first byte of the pair contains the number of pixels to be drawn using the color indexes in the second byte.

The second byte contains two color indexes, one in its high-order nibble (that is, its low-order 4 bits) and one in its low-order nibble.

The first pixel is drawn using the color specified by the high-order nibble, the second is drawn using the color in the low-order nibble, the third is drawn with the color in the high-order nibble, and so on, until all the pixels specified by the first byte have been drawn.

The first byte of the pair can be set to zero to indicate an escape that denotes the end of a line, the end of the bitmap, or a delta. The interpretation of the escape depends on the value of the second byte of the pair. In encoded mode, the second byte has a value in the range 0x00 through 0x02. The meaning of these values is the same as for a DIB with 8 bits per pixel.

Absolute Mode

In absolute mode, the first byte contains zero, the second byte contains the number of color indexes that follow, and subsequent bytes contain color indexes in their high- and low-order nibbles, one color index for each pixel. Each run must be aligned on a word boundary.

Following is an example of a 4-bit RLE bitmap (the one-digit hexadecimal values in the second column represent a color index for a single pixel):

Compressed data	Expanded data
03 04	0 4 0
05 06	0 6 0 6 0
00 06 45 56 67 00	4 5 5 6 6 7
04 78	7 8 7 8
00 02 05 01	Move 5 right and 1 down
04 78	7 8 7 8
00 00	End of line
09 1E	1 E 1 E 1 E 1 E 1
00 01	End of RLE bitmap

Bitmap Example

The following example is a text dump of a 16-color bitmap (4 bits per pixel):

Win3DIBFile
   BitmapFileHeader
                  Type       19778
                  Size       3118
                  Reserved1  0
                  Reserved2  0
                  OffsetBits 118
   BitmapInfoHeader
                  Size            40
                  Width           80
                  Height          75
                  Planes          1
                  BitCount        4
                  Compression     0
                  SizeImage       3000

                  XPelsPerMeter   0
                  YPelsPerMeter   0
                  ColorsUsed      16
                  ColorsImportant 16
   Win3ColorTable
                          Blue  Green  Red  Unused
        [00000000]        84    252    84   0
        [00000001]        252   252    84   0
        [00000002]        84    84     252  0
        [00000003]        252   84     252  0
        [00000004]        84    252    252  0
        [00000005]        252   252    252  0
        [00000006]        0     0      0    0
        [00000007]        168   0      0    0
        [00000008]        0     168    0    0
        [00000009]        168   168    0    0
        [0000000A]        0     0      168  0
        [0000000B]        168   0      168  0
        [0000000C]        0     168    168  0
        [0000000D]        168   168    168  0
        [0000000E]        84    84     84   0
        [0000000F]        252   84     84   0
   Image
        .
        .                                           Bitmap data
        .

Icon-Resource File Format

An icon-resource file contains image data for icons used by Windows applications. The file consists of an icon directory identifying the number and types of icon images in the file, plus one or more icon images. The default filename extension for an icon-resource file is .ICO.

Icon Directory

Each icon-resource file starts with an icon directory. The icon directory, defined as an ICONDIR structure, specifies the number of icons in the resource and the dimensions and color format of each icon image. The ICONDIR structure has the following form:

typedef struct ICONDIR {
    WORD          idReserved;
    WORD          idType;
    WORD          idCount;
    ICONDIRENTRY  idEntries[1];
} ICONHEADER;
        

Following are the members in the ICONDIR structure:

Member	Description
idReserved	Reserved; must be zero.
idType	Specifies the resource type. This member is set to 1.
idCount	Specifies the number of entries in the directory.
idEntries	Specifies an array of ICONDIRENTRY structures containing information about individual icons. The idCount member specifies the number of structures in the array.

The ICONDIRENTRY structure specifies the dimensions and color format for an icon. The structure has the following form:

struct IconDirectoryEntry {
    BYTE  bWidth;
    BYTE  bHeight;
    BYTE  bColorCount;
    BYTE  bReserved;
    WORD  wPlanes;
    WORD  wBitCount;
    DWORD dwBytesInRes;
    DWORD dwImageOffset;
};

Following are the members in the ICONDIRENTRY structure:

Member	Description
bWidth	Specifies the width of the icon, in pixels. Acceptable values are 16, 32, and 64.
bHeight	Specifies the height of the icon, in pixels. Acceptable values are 16, 32, and 64.
bColorCount	Specifies the number of colors in the icon. Acceptable values are 2, 8, and 16.
bReserved	Reserved; must be zero.
wPlanes	Specifies the number of color planes in the icon bitmap.
wBitCount	Specifies the number of bits in the icon bitmap.
dwBytesInRes	Specifies the size of the resource, in bytes.
dwImageOffset	Specifies the offset, in bytes, from the beginning of the file to the icon image.

Icon Image

Each icon-resource file contains one icon image for each image identified in the icon directory. An icon image consists of an icon-image header, a color table, an XOR mask, and an AND mask. The icon image has the following form:

BITMAPINFOHEADER    icHeader;
RGBQUAD             icColors[];
BYTE                icXOR[];
BYTE                icAND[];
        

The icon-image header, defined as a BITMAPINFOHEADER structure, specifies the dimensions and color format of the icon bitmap. Only the biSize through biBitCount members and the biSizeImage member are used. All other members (such as biCompression and biClrImportant) must be set to zero.

The color table, defined as an array of RGBQUAD structures, specifies the colors used in the XOR mask. As with the color table in a bitmap file, the biBitCount member in the icon-image header determines the number of elements in the array. For more information about the color table, see Section 1.1, "Bitmap-File Formats."

The XOR mask, immediately following the color table, is an array of BYTE values representing consecutive rows of a bitmap. The bitmap defines the basic shape and color of the icon image. As with the bitmap bits in a bitmap file, the bitmap data in an icon-resource file is organized in scan lines, with each byte representing one or more pixels, as defined by the color format. For more information about these bitmap bits, see Section 1.1, "Bitmap-File Formats."

The AND mask, immediately following the XOR mask, is an array of BYTE values, representing a monochrome bitmap with the same width and height as the XOR mask. The array is organized in scan lines, with each byte representing 8 pixels.

When Windows draws an icon, it uses the AND and XOR masks to combine the icon image with the pixels already on the display surface. Windows first applies the AND mask by using a bitwise AND operation; this preserves or removes existing pixel color. Windows then applies the XOR mask by using a bitwise XOR operation. This sets the final color for each pixel.

The following illustration shows the XOR and AND masks that create a monochrome icon (measuring 8 pixels by 8 pixels) in the form of an uppercase K:

Windows Icon Selection

Windows detects the resolution of the current display and matches it against the width and height specified for each version of the icon image. If Windows determines that there is an exact match between an icon image and the current device, it uses the matching image. Otherwise, it selects the closest match and stretches the image to the proper size.

If an icon-resource file contains more than one image for a particular resolution, Windows uses the icon image that most closely matches the color capabilities of the current display. If no image matches the device capabilities exactly, Windows selects the image that has the greatest number of colors without exceeding the number of display colors. If all images exceed the color capabilities of the current display, Windows uses the icon image with the least number of colors.

Cursor-Resource File Format

A cursor-resource file contains image data for cursors used by Windows applications. The file consists of a cursor directory identifying the number and types of cursor images in the file, plus one or more cursor images. The default filename extension for a cursor-resource file is .CUR.

Cursor Directory

Each cursor-resource file starts with a cursor directory. The cursor directory, defined as a CURSORDIR structure, specifies the number of cursors in the file and the dimensions and color format of each cursor image. The CURSORDIR structure has the following form:

typedef struct _CURSORDIR {
    WORD           cdReserved;
    WORD           cdType;
    WORD           cdCount;
    CURSORDIRENTRY cdEntries[];
} CURSORDIR;

Following are the members in the CURSORDIR structure:

Member	Description
cdReserved	Reserved; must be zero.
cdType	Specifies the resource type. This member must be set to 2.
cdCount	Specifies the number of cursors in the file.
cdEntries	Specifies an array of CURSORDIRENTRY structures containing information about individual cursors. The cdCount member specifies the number of structures in the array.

A CURSORDIRENTRY structure specifies the dimensions and color format of a cursor image. The structure has the following form:

typedef struct _CURSORDIRENTRY {
    BYTE  bWidth;
    BYTE  bHeight;
    BYTE  bColorCount;
    BYTE  bReserved;
    WORD  wXHotspot;
    WORD  wYHotspot;
    DWORD lBytesInRes;
    DWORD dwImageOffset;
} CURSORDIRENTRY;

Following are the members in the CURSORDIRENTRY structure:

Member	Description
bWidth	Specifies the width of the cursor, in pixels.
bHeight	Specifies the height of the cursor, in pixels.
bColorCount	Reserved; must be zero.
bReserved	Reserved; must be zero.
wXHotspot	Specifies the x-coordinate, in pixels, of the hot spot.
wYHotspot	Specifies the y-coordinate, in pixels, of the hot spot.
lBytesInRes	Specifies the size of the resource, in bytes.
dwImageOffset	Specifies the offset, in bytes, from the start of the file to the cursor image.

Cursor Image Each cursor-resource file contains one cursor image for each image identified in the cursor directory. A cursor image consists of a cursor-image header, a color table, an XOR mask, and an AND mask. The cursor image has the following form:

BITMAPINFOHEADER    crHeader;
RGBQUAD             crColors[];
BYTE                crXOR[];
BYTE                crAND[];
        

The cursor hot spot is a single pixel in the cursor bitmap that Windows uses to track the cursor. The crXHotspot and crYHotspot members specify the x- and y-coordinates of the cursor hot spot. These coordinates are 16-bit integers.

The cursor-image header, defined as a BITMAPINFOHEADER structure, specifies the dimensions and color format of the cursor bitmap. Only the biSize through biBitCount members and the biSizeImage member are used. The biHeight member specifies the combined height of the XOR and AND masks for the cursor. This value is twice the height of the XOR mask. The biPlanes and biBitCount members must be 1. All other members (such as biCompression and biClrImportant) must be set to zero.

The color table, defined as an array of RGBQUAD structures, specifies the colors used in the XOR mask. For a cursor image, the table contains exactly two structures, since the biBitCount member in the cursor-image header is always 1.

The XOR mask, immediately following the color table, is an array of BYTE values representing consecutive rows of a bitmap. The bitmap defines the basic shape and color of the cursor image. As with the bitmap bits in a bitmap file, the bitmap data in a cursor-resource file is organized in scan lines, with each byte representing one or more pixels, as defined by the color format. For more information about these bitmap bits, see Section 1.1, "Bitmap-File Formats."

The AND mask, immediately following the XOR mask, is an array of BYTE values representing a monochrome bitmap with the same width and height as the XOR mask. The array is organized in scan lines, with each byte representing 8 pixels.

When Windows draws a cursor, it uses the AND and XOR masks to combine the cursor image with the pixels already on the display surface. Windows first applies the AND mask by using a bitwise AND operation; this preserves or removes existing pixel color. Window then applies the XOR mask by using a bitwise XOR operation. This sets the final color for each pixel.

The following illustration shows the XOR and the AND masks that create a cursor (measuring 8 pixels by 8 pixels) in the form of an arrow:

Following are the bit-mask values necessary to produce black, white, inverted, and transparent results:

Pixel result	AND mask	XOR mask
Black	0	0
White	0	1
Transparent	1	0
Inverted1	1

Windows Cursor Selection

If a cursor-resource file contains more than one cursor image, Windows determines the best match for a particular display by examining the width and height of the cursor images.

---

BITMAPFILEHEADER (3.0)

typedef struct tagBITMAPFILEHEADER {    /* bmfh */
    UINT    bfType;
    DWORD   bfSize;
    UINT    bfReserved1;
    UINT    bfReserved2;
    DWORD   bfOffBits;
} BITMAPFILEHEADER;

The BITMAPFILEHEADER structure contains information about the type, size, and layout of a device-independent bitmap (DIB) file.

Member	Description
bfType	Specifies the type of file. This member must be BM.
bfSize	Specifies the size of the file, in bytes.
bfReserved1	Reserved; must be set to zero.
bfReserved2	Reserved; must be set to zero.
bfOffBits	Specifies the byte offset from the BITMAPFILEHEADER structure to the actual bitmap data in the file.

Comments

A BITMAPINFO or BITMAPCOREINFO structure immediately follows the BITMAPFILEHEADER structure in the DIB file.

See Also

BITMAPCOREINFO, BITMAPINFO

---

BITMAPINFO (3.0)

typedef struct tagBITMAPINFO {  /* bmi */
    BITMAPINFOHEADER    bmiHeader;
    RGBQUAD             bmiColors[1];
} BITMAPINFO;

The BITMAPINFO structure fully defines the dimensions and color information for a Windows 3.0 or later device-independent bitmap (DIB).

Member	Description
bmiHeader	Specifies a BITMAPINFOHEADER structure that contains information about the dimensions and color format of a DIB.
bmiColors	Specifies an array of RGBQUAD structures that define the colors in the bitmap.

Comments

A Windows 3.0 or later DIB consists of two distinct parts: a BITMAPINFO structure, which describes the dimensions and colors of the bitmap, and an array of bytes defining the pixels of the bitmap. The bits in the array are packed together, but each scan line must be zero-padded to end on a LONG boundary. Segment boundaries, however, can appear anywhere in the bitmap. The origin of the bitmap is the lower-left corner.

The biBitCount member of the BITMAPINFOHEADER structure determines the number of bits which define each pixel and the maximum number of colors in the bitmap. This member may be set to any of the following values:

Value	Meaning
1	The bitmap is monochrome, and the bmciColors member must contain two entries. Each bit in the bitmap array represents a pixel. If the bit is clear, the pixel is displayed with the color of the first entry in the bmciColors table. If the bit is set, the pixel has the color of the second entry in the table.
4	The bitmap has a maximum of 16 colors, and the bmciColors member contains 16 entries. Each pixel in the bitmap is represented by a four-bit index into the color table. For example, if the first byte in the bitmap is 0x1F, the byte represents two pixels. The first pixel contains the color in the second table entry, and the second pixel contains the color in the sixteenth table entry.
8	The bitmap has a maximum of 256 colors, and the bmciColors member contains 256 entries. In this case, each byte in the array represents a single pixel.
24	The bitmap has a maximum of 2^24 colors. The bmciColors member is NULL, and each 3-byte sequence in the bitmap array represents the relative intensities of red, green, and blue, respectively, of a pixel.

The biClrUsed member of the BITMAPINFOHEADER structure specifies the number of color indexes in the color table actually used by the bitmap. If the biClrUsed member is set to zero, the bitmap uses the maximum number of colors corresponding to the value of the biBitCount member.

The colors in the bmiColors table should appear in order of importance. Alternatively, for functions that use DIBs, the bmiColors member can be an array of 16-bit unsigned integers that specify an index into the currently realized logical palette instead of explicit RGB values. In this case, an application using the bitmap must call DIB functions with the wUsage parameter set to DIB_PAL_COLORS.

Note: The bmiColors member should not contain palette indexes if the bitmap is to be stored in a file or transferred to another application. Unless the application uses the bitmap exclusively and under its complete control, the bitmap color table should contain explicit RGB values.

See Also

BITMAPINFOHEADER, RGBQUAD

---

BITMAPINFOHEADER (3.0)

typedef struct tagBITMAPINFOHEADER {    /* bmih */
    DWORD   biSize;
    LONG    biWidth;
    LONG    biHeight;
    WORD    biPlanes;
    WORD    biBitCount;
    DWORD   biCompression;
    DWORD   biSizeImage;
    LONG    biXPelsPerMeter;
    LONG    biYPelsPerMeter;
    DWORD   biClrUsed;
    DWORD   biClrImportant;
} BITMAPINFOHEADER;

The BITMAPINFOHEADER structure contains information about the dimensions and color format of a Windows 3.0 or later device-independent bitmap (DIB).

Member	Description
biSize	Specifies the number of bytes required by the BITMAPINFOHEADER structure.
biWidth	Specifies the width of the bitmap, in pixels. biHeightSpecifies the height of the bitmap, in pixels.
biPlanes	Specifies the number of planes for the target device. This member must be set to 1.
biBitCount	Specifies the number of bits per pixel. This value must be 1, 4, 8, or 24.
biCompression	Specifies the type of compression for a compressed bitmap. It can be one of the following values:

Member	Description
BI_RGB	Specifies that the bitmap is not compressed.
BI_RLE8	Specifies a run-length encoded format for bitmaps with 8 bits per pixel. The compression format is a 2-byte format consisting of a count byte followed by a byte containing a color index. For more information, see the following Comments section.
BI_RLE4	Specifies a run-length encoded format for bitmaps with 4 bits per pixel. The compression format is a 2-byte format consisting of a count byte followed by two word-length color indexes. For more information, see the following Comments section.
biSizeImage	Specifies the size, in bytes, of the image. It is valid to set this member to zero if the bitmap is in the BI_RGB format.
biXPelsPerMeter	Specifies the horizontal resolution, in pixels per meter, of the target device for the bitmap. An application can use this value to select a bitmap from a resource group that best matches the characteristics of the current device.
biYPelsPerMeter	Specifies the vertical resolution, in pixels per meter, of the target device for the bitmap.
biClrUsed	Specifies the number of color indexes in the color table actually used by the bitmap. If this value is zero, the bitmap uses the maximum number of colors corresponding to the value of the biBitCount member. For more information on the maximum sizes of the color table, see the description of the BITMAPINFO structure earlier in this topic. If the biClrUsed member is nonzero, it specifies the actual number of colors that the graphics engine or device driver will access if the biBitCount member is less than 24. If biBitCount is set to 24, biClrUsed specifies the size of the reference color table used to optimize performance of Windows color palettes. If the bitmap is a packed bitmap (that is, a bitmap in which the bitmap array immediately follows the BITMAPINFO header and which is referenced by a single pointer), the biClrUsed member must be set to zero or to the actual size of the color table.
biClrImportant	Specifies the number of color indexes that are considered important for displaying the bitmap. If this value is zero, all colors are important

Comments

The BITMAPINFO structure combines the BITMAPINFOHEADER structure and a color table to provide a complete definition of the dimensions and colors of a Windows 3.0 or later DIB. For more information about specifying a Windows 3.0 DIB, see the description of the BITMAPINFO structure.

An application should use the information stored in the biSize member to locate the color table in a BITMAPINFO structure as follows:

pColor = ((LPSTR) pBitmapInfo + (WORD) (pBitmapInfo->bmiHeader.biSize))
        

Windows supports formats for compressing bitmaps that define their colors with 8 bits per pixel and with 4 bits per pixel. Compression reduces the disk and memory storage required for the bitmap. The following paragraphs describe these formats.

BI_RLE8

When the biCompression member is set to BI_RLE8, the bitmap is compressed using a run-length encoding format for an 8-bit bitmap. This format may be compressed in either of two modes: encoded and absolute. Both modes can occur anywhere throughout a single bitmap.

Encoded mode consists of two bytes: the first byte specifies the number of consecutive pixels to be drawn using the color index contained in the second byte. In addition, the first byte of the pair can be set to zero to indicate an escape that denotes an end of line, end of bitmap, or a delta. The interpretation of the escape depends on the value of the second byte of the pair. The following list shows the meaning of the second byte:

Value	Meaning
0	End of line.
1	End of bitmap.
2	Delta. The two bytes following the escape contain unsigned values indicating the horizontal and vertical offset of the next pixel from the current position.

Absolute mode is signaled by the first byte set to zero and the second byte set to a value between 0x03 and 0xFF. In absolute mode, the second byte represents the number of bytes that follow, each of which contains the color index of a single pixel. When the second byte is set to 2 or less, the escape has the same meaning as in encoded mode. In absolute mode, each run must be aligned on a word boundary. The following example shows the hexadecimal values of an 8-bit compressed bitmap:

03 04 05 06 00 03 45 56 67 00 02 78 00 02 05 01
02 78 00 00 09 1E 00 01
        

This bitmap would expand as follows (two-digit values represent a color index for a single pixel):

04 04 04
06 06 06 06 06
45 56 67
78 78
move current position 5 right and 1 down
78 78
end of line
1E 1E 1E 1E 1E 1E 1E 1E 1E
end of RLE bitmap
        

BI_RLE4

When the biCompression member is set to BI_RLE4, the bitmap is compressed using a run-length encoding (RLE) format for a 4-bit bitmap, which also uses encoded and absolute modes. In encoded mode, the first byte of the pair contains the number of pixels to be drawn using the color indexes in the second byte. The second byte contains two color indexes, one in its high-order nibble (that is, its low-order four bits) and one in its low-order nibble. The first of the pixels is drawn using the color specified by the high-order nibble, the second is drawn using the color in the low-order nibble, the third is drawn with the color in the high-order nibble, and so on, until all the pixels specified by the first byte have been drawn. In absolute mode, the first byte contains zero, the second byte contains the number of color indexes that follow, and subsequent bytes contain color indexes in their high- and low-order nibbles, one color index for each pixel. In absolute mode, each run must be aligned on a word boundary. The end-of-line, end-of-bitmap, and delta escapes also apply to BI_RLE4.

The following example shows the hexadecimal values of a 4-bit compressed bitmap:

03 04 05 06 00 06 45 56 67 00 04 78 00 02 05 01
04 78 00 00 09 1E 00 01
        

This bitmap would expand as follows (single-digit values represent a color index for a single pixel):

0 4 0
0 6 0 6 0
4 5 5 6 6 7
7 8 7 8
move current position 5 right and 1 down
7 8 7 8
end of line
1 E 1 E 1 E 1 E 1
end of RLE bitmap
        

See Also BITMAPINFO

---

RGBQUAD (3.0)

typedef struct tagRGBQUAD {     /* rgbq */
    BYTE    rgbBlue;
    BYTE    rgbGreen;
    BYTE    rgbRed;
    BYTE    rgbReserved;
} RGBQUAD;
        

The RGBQUAD structure describes a color consisting of relative intensities of red, green, and blue. The bmiColors member of the BITMAPINFO structure consists of an array of RGBQUAD structures.

Member	Description
rgbBlue	Specifies the intensity of blue in the color.
rgbGreen	Specifies the intensity of green in the color.
rgbRed	Specifies the intensity of red in the color.
rgbReserved	Not used; must be set to zero.

See Also

BITMAPINFO

---

RGB (2.x)

COLORREF RGB(cRed, cGreen, cBlue)

BYTE cRed;      /* red component of color       */
BYTE cGreen;    /* green component of color     */
BYTE cBlue;     /* blue component of color      */

The RGB macro selects an RGB color based on the parameters supplied and the color capabilities of the output device.

Parameter	Description
cRed	Specifies the intensity of the red color field.
cGreen	Specifies the intensity of the green color field.
cBlue	Specifies the intensity of the blue color field.

Returns

The return value specifies the resultant RGB color.

Comments

The intensity for each argument can range from 0 through 255. If all three intensities are specified as zero, the result is black. If all three intensities are specified as 255, the result is white.

Comments

The RGB macro is defined in WINDOWS.H as follows:

#define RGB(r,g,b)   ((COLORREF)(((BYTE)(r)|((WORD)(g)<<8))| \
    (((DWORD)(BYTE)(b))<<16)))
        

See Also GetBValue, GetGValue, GetRValue, PALETTEINDEX, PALETTERGB

---

BITMAPCOREINFO (3.0)

typedef struct tagBITMAPCOREINFO {  /* bmci */
    BITMAPCOREHEADER bmciHeader;
    RGBTRIPLE        bmciColors[1];
} BITMAPCOREINFO;
        

The BITMAPCOREINFO structure fully defines the dimensions and color information for a device-independent bitmap (DIB). Windows applications should use the BITMAPINFO structure instead of BITMAPCOREINFO whenever possible.

Member	Description
bmciHeader	Specifies a BITMAPCOREHEADER structure that contains information about the dimensions and color format of a DIB.
bmciColors	Specifies an array of RGBTRIPLE structures that define the colors in the bitmap.

Comments

The BITMAPCOREINFO structure describes the dimensions and colors of a bitmap. It is followed immediately in memory by an array of bytes which define the pixels of the bitmap. The bits in the array are packed together, but each scan line must be zero-padded to end on a LONG boundary. Segment boundaries, however, can appear anywhere in the bitmap. The origin of the bitmap is the lower-left corner.

The bcBitCount member of the BITMAPCOREHEADER structure determines the number of bits that define each pixel and the maximum number of colors in the bitmap. This member may be set to any of the following values:

Value	Meaning
1	The bitmap is monochrome, and the bmciColors member must contain two entries. Each bit in the bitmap array represents a pixel. If the bit is clear, the pixel is displayed with the color of the first entry in the bmciColors table. If the bit is set, the pixel has the color of the second entry in the table.
4	The bitmap has a maximum of 16 colors, and the bmciColors member contains 16 entries. Each pixel in the bitmap is represented by a four-bit index into the color table. For example, if the first byte in the bitmap is 0x1F, the byte represents two pixels. The first pixel contains the color in the second table entry, and the second pixel contains the color in the sixteenth table entry.
8	The bitmap has a maximum of 256 colors, and the bmciColors member contains 256 entries. In this case, each byte in the array represents a single pixel.
24	The bitmap has a maximum of 2^24 colors. The bmciColors member is NULL, and each 3-byte sequence in the bitmap array represents the relative intensities of red, green, and blue, respectively, of a pixel.

The colors in the bmciColors table should appear in order of importance. Alternatively, for functions that use DIBs, the bmciColors member can be an array of 16-bit unsigned integers that specify an index into the currently realized logical palette instead of explicit RGB values. In this case, an application using the bitmap must call DIB functions with the wUsage parameter set to DIB_PAL_COLORS.

Note: The bmciColors member should not contain palette indexes if the bitmap is to be stored in a file or transferred to another application. Unless the application uses the bitmap exclusively and under its complete control, the bitmap color table should contain explicit RGB values.

See Also BITMAPINFO, BITMAPCOREHEADER, RGBTRIPLE

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P> BITMAPCOREHEADER (3.0)

typedef struct tagBITMAPCOREHEADER {    /* bmch */
    DWORD   bcSize;
    short   bcWidth;
    short   bcHeight;
    WORD    bcPlanes;
    WORD    bcBitCount;
} BITMAPCOREHEADER;
        

The BITMAPCOREHEADER structure contains information about the dimensions and color format of a device-independent bitmap (DIB). Windows applications should use the BITMAPINFOHEADER structure instead of BITMAPCOREHEADER whenever possible.

Member	Description
bcSize	Specifies the number of bytes required by the BITMAPCOREHEADER structure.
bcWidth	Specifies the width of the bitmap, in pixels. bcHeightSpecifies the height of the bitmap, in pixels.
bcPlanes	Specifies the number of planes for the target device. This member must be set to 1.
bcBitCount	Specifies the number of bits per pixel. This value must be 1, 4, 8, or 24.

Comments

The BITMAPCOREINFO structure combines the BITMAPCOREHEADER structure and a color table to provide a complete definition of the dimensions and colors of a DIB. See the description of the BITMAPCOREINFO structure for more information about specifying a DIB.

An application should use the information stored in the bcSize member to locate the color table in a BITMAPCOREINFO structure with a method such as the following:

lpColor = ((LPSTR) pBitmapCoreInfo + (UINT) (pBitmapCoreInfo->bcSize))
        

See Also

BITMAPCOREINFO, BITMAPINFOHEADER, BITMAPINFOHEADER

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RGBTRIPLE (3.0)

typedef struct tagRGBTRIPLE {   /* rgbt */
    BYTE    rgbtBlue;
    BYTE    rgbtGreen;
    BYTE    rgbtRed;
} RGBTRIPLE;
        

The RGBTRIPLE structure describes a color consisting of relative intensities of red, green, and blue. The bmciColors member of the BITMAPCOREINFO structure consists of an array of RGBTRIPLE structures. Windows applications should use the BITMAPINFO structure instead of BITMAPCOREINFO whenever possible. The BITMAPINFO structure uses an RGBQUAD structure instead of the RGBTRIPLE structure.

Member	Description
rgbtBlue	Specifies the intensity of blue in the color.
rgbtGreen	Specifies the intensity of green in the color.
rgbtRed	Specifies the intensity of red in the color.

See Also BITMAPCOREINFO, BITMAPINFO, RGBQUAD

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Closing Words

Well, that's it for the first issue of The QB Times. I hope you enjoyed reading it and that you found use of any of the articles in this issue. The next issue is schedueld for somewhere the next 3 or 4 weeks. Again I hope you enjoyed this issue and I hope to see you again next issue!

-Nightwolf

Credits

Editor:	Regular Writers:	Submissions:
Nightwolf	Masamune_Q Abionnnn Nightwolf Viper DarkAges	Yoda