learning by sample gdi+ - lines
DESCRIPTION
For more tutorial visit www.bukansembarang.infoTRANSCRIPT
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GDI+ : Lines
Learning By Sample Series
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Foreword
Learning By Sample ?
So, why should I made this tutorial freely accessed by everyone ? Well, surely I
am just nobody, I also just another ordinary person with ordinary knowledge. However,
I always feel that some persons in the internet giving away their tutorial for free and I
feel being helped by them. Then, I remember one of my senior wisdom words : “If you
want to be given more, then start to give more”. And of course, I really believe those
words, since that I already proof it to be right all the time.
Also, I’m not an English native speaker, however, I just try to improve my
English in any other way, especially in written format. Thus, I think writing is the best
practice to improve my English freely. However, you will find many grammatical errors
in my tutorial, so please send me comments and also suggestion to improve it.
Then, why the format using Learning By Sample series ? Is it really different with
other tutorials out there ? Ehm, I already wrote three books (in Indonesian) using this
kind of format, and many readers already contact me about how this format really help
them to learn from the scratch. So, why in the world I’m not re-create it in English
format, right ? Eventhough actually, it is similar with Hands On Lab series which
already famous in Microsoft site previously.
All of my lesson also being designed as short samples and short time exercise.
Thus, I hope that each of tutorial series would take only at least 10-15 minutes
maximum to learn. Why keep it short ? Because many beginner (and even expert) will
find boring whenever they must keep studying more than 15 minutes (but you will
never get bored when you online in such time right ?).
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Another reason is just because many of samples in this series come up from my
lecturing task exercise. So, I just try to compile all my lab exercises in order to keep it
tidy and also reusable for my students. That’s why you will find many unsorted course
material inside these series, however, just take a seat and enjoy the ride !
Requirements
In this series, I try to give simple example about GDI+. So what is GDI+ anyway ?
GDI+ or GraphicsDrawing Interface is merely part of .NET Framework which entirely
purposed in manipulating graphics. However I’m not going to make you understand
complex theory about this class. I just try to make you understand it in very simple and
stupid way.
All of my samples in this series use Visual Web Developer 2010 Express edition
however you can also do it all using Visual Studio. If you really want to follow this
series, then you should aware that basic programming knowledge is needed. You
should also familiar with ASP .NET especially for version 3.5 above.
FYI, I’m a VB guy, so please don’t complaint if I use VB entirely in this series. But
nowadays, there’s no such useful things if we argue about language differences,
because I just try to share something that I know. So, if you don’t like VB and want to
have another tutorial with your own favourit language, then I’d be happy to read it.
Now, let’s get started…….
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Let’s Get Started
1. First, ensure that you already open Visual Web Developer 2010 Express Edition
2. Create a newly blank website and give it a name
3. Now, let’s create a new blank web page
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4. Next, put a text for labelling with a Textbox and a Button. Also add an Image
control right below. Thus, the web page should be look like this picture :
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5. Very simple right ? Then let’s go on to next step. Just double click at the Button to
go to Code Editor, and type this code :
6. Some errors showing ? Don’t worry, just type this reference command at the top of
your code :
7. So, what is really happen in those lines of code ? Here is the explanation :
a. First, we must import reference of System.Drawing at top of all code to use
GDI+
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b. Then we must declare a Bitmap with certain dimension (in this sample I use
300x 300, but you can modify it of course). Just assume that this Bitmap is
like your canvas which will be ready to be painted later.
c. Now take a look at Graphics variable which took place from Bitmap object.
This Graphics object then being cleared using White background color.
d. Then using simple looping, we just create Line object in Black color.
e. Afterward, just save the result into a temporary image file named as
test.png. This technique absolutely not an efficient one, however, this is just
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the beginning and I will show you later the other technique in other tutorial
chapter.
f. So, we already got the result, then just display it into Image control.
g. Also don’t forget to dispose all the previos declared object, thus we can
execute this web page over and over again.
8. Now, let’s execute this simple web page, just press Ctrl+F5 and see what happen :
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9. Don’t you think it’s very quick and easy ? Well, it’s late midnight and my filter
kretek is running out, see you in following tutorial then…..