Learn how to write skeleton code for creating a Bitmap object from an image file and how to display the bitmap. Learn two different ways to handle the image file, one of which results in a security issue that must be handled at compile time. Learn how to extract the BitmapData object from the Bitmap object and how to use the getPixels, setPixels, and setPixel32 methods to process the pixels in the bitmap. Learn how to apply a color inversion algorithm to invert the colors in a BitmapData object.
Click
Bitmap05 or
Bitmap06 to run the ActionScript programs from this lesson.
(Click the "Back" button in your browser
to return to this page.)
Table of contents
Preface
General
All references to ActionScript in this lesson arereferences to version 3 or later.
This tutorial lesson is
part of a series of lessons dedicated to object-oriented programming(OOP) with ActionScript.
Several ways to create and launch ActionScript
programs
There are several ways to
create and launch programs written in the ActionScript programming language.Many of the lessons in this series will use Adobe Flex as the launch pad for the
sample ActionScript programs.
An earlier lesson titled
The Default
Application Container provided information on how to get started programming
with Adobe's Flex Builder 3.
(See
Baldwin's Flex programming website .) You should study that lesson before embarking on the lessons in this series.
Some understanding of Flex MXML will be required
I also recommend that you
study all of the lessons on Baldwin's Flex programming website in parallel withyour study of these ActionScript lessons. Eventually you will probably need to
understand both ActionScript and Flex and the relationships that exist betweenthem in order to become a successful ActionScript programmer.
Will emphasize ActionScript code
It is often possible to use
either ActionScript code or Flex MXML code to achieve the same result. Insofaras this series of lessons is concerned, the emphasis will be on ActionScript
code even in those cases where Flex MXML code may be a suitable alternative.
Viewing tip
I recommend that you open another copy of this document in a separate browser
window and use the following links to easily find and view the figures andlistings while you are reading about them.
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Figure 1 . Screen output for both programs.
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Figure 2 . Program file structure for the program
named Bitmap05.
Listings
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Listing 1 . MXML code for the program named
Bitmap05.
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Listing 2 . Beginning of the ActionScript Driver
class.
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Listing 3 . Start the process of loading the image
file.
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Listing 4 . Beginning of the complete event
handler.
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Listing 5 . Encapsulate the Bitmap in an Image
object.
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Listing 6 . Clone the original Bitmap to create a
duplicate Bitmap.
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Listing 7 . Modify the duplicate Bitmap.
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Listing 8 . Beginning of the modify method.
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Listing 9 . Process pixels using the getPixels and
setPixels methods.
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Listing 10 . Modify the pixels in the rectangular
region.
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Listing 11 . Put the modified pixel data back
into the same rectangular region.
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Listing 12 . Process pixels using the setPixel32
method.
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Listing 13 . Put borders on the top and bottom
edges.
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Listing 14 . Return to the complete event
handler.
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Listing 15 . Beginning of the invert method.
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Listing 16 . Apply the inversion algorithm.
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Listing 17 . Put the modified pixel data back
into the BitmapData object.
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Listing 18 . Code that is different in the
program named Bitmap06.
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Listing 19 . MXML code for the program named
Bitmap05.
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Listing 20 . ActionScript code for the program
named Bitmap05.
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Listing 21 . ActionScript code for the program
named Bitmap06.
