In this tutorial, we’ll learn how to use AS3 to create an RIA that can modify the color properties of an image, such as Brightness, Contrast, Hue and Saturation. Read on!
Final Result Preview
Let’s take a look at the final result we will be working towards:
Step 1: Brief Overview
We will use a native ActionScript Class that will get new values from a Slider Component and then apply them to the target image using the ColorMatrixFilter class.
Step 2: Flash Document SettingsLaunch Flash and create a new document. Set the stage size to 557x400px, and the frame rate to 24fps.
The interface will be very simple; just an image in the stage that will be then modified by the Sliders Components in the Adjust Color Panel.
Step 4: Demo ImageWe’ll need an image to test our application, choose it from your personal collection or download one for testing.
This is the image from the demo, obtained from Flickr, with a Creative Commons License.
Flower by Antonio ManchadoStep 5: Instance Names
Create a panel and four Sliders with instance names as seen in the following image:
You can add bars above the Sliders as shown to improve the appearance.
Step 6: Slider ValuesLet’s set the Slider components’ values.
These are obtained from the minimum and maximum valid values of the AdjustColor class, which we will use to adjust each property:
brightSL: -100 to 100contSL: -100 to 100hueSL: -180 to 180satSL: -100 to 100Step 7: New ActionScript ClassCreate a new ActionScript 3.0 Class (Cmd + N) and save it as Main.as in your class folder.
Create your basic class structure to begin writing your code.
>package{import flash.display.Sprite;public class Main extends Sprite{public function Main():void{// constructor code}}}Step 9: Required ClassesThese are the classes we’ll need to import for our class to work; the import directive makes externally defined classes and packages available to your code.
import flash.display.Sprite;import fl.motion.AdjustColor;import flash.filters.ColorMatrixFilter;import fl.events.SliderEvent;Step 10: VariablesThese are the variables we’ll use; read the comments in the code to learn more about them.
private var color:AdjustColor = new AdjustColor(); //This object will hold the color propertiesprivate var filter:ColorMatrixFilter; //Will store the modified color filter to change the imageStep 11: ConstructorThe constructor is a function that runs when an object is created from a class; this code is the first to execute when you make an instance of an object, or in this case it is run when the SWF is loaded, as it is in the document class.
It will perform the neccesary actions to start the application.
public final function Main():void{//Code}Step 12: Initial MatrixThe color matrix will be generated by the values stored in the AdjustColor properties; we need to set initial values to these properties in order to get a correct matrix. If we don’t do this, an array with null values will be generated.
/* Required to create initial Matrix */color.brightness = 0;color.contrast = 0;color.hue = 0;color.saturation = 0;/* This function will add the necessary event listeners */addListeners();Step 13: Add Slider ListenersThis function adds listeners to the Slider components in order to call certain functions whenever their values change.
private final function addListeners():void{colorPanel.brightSL.addEventListener(SliderEvent.CHANGE, adjustBrightness);colorPanel.contSL.addEventListener(SliderEvent.CHANGE, adjustContrast);colorPanel.hueSL.addEventListener(SliderEvent.CHANGE, adjustHue);colorPanel.satSL.addEventListener(SliderEvent.CHANGE, adjustSaturation);}Step 14: BrightnessThis function modifies the Brightness value, getting its data from the brightSL slider component.
private final function adjustBrightness(e:SliderEvent):void{color.brightness = e.target.value;update();}Step 15: ContrastThis function modifies the Contrast value, getting its data from the contSL slider component.
private final function adjustContrast(e:SliderEvent):void{color.contrast = e.target.value;update();}Step 16: HueThis function modifies the Hue value, getting its data from the hueSL slider component.
private final function adjustHue(e:SliderEvent):void{color.hue = e.target.value;update();}When you modify the hue of a color, you move it around the color wheel by the specified number of degrees.
Step 17: SaturationThis function modifies the Saturation value, getting its data from the satSL slider component.
private final function adjustSaturation(e:SliderEvent):void{color.saturation = e.target.value;update();}When you modify the saturation of a color, you move it towards or away from the center of the color wheel.
Step 18: Update FunctionThis function is called in every slider change. It renews the ColorMatrixFilter value and applies it to the image in stage.
private final function update():void{filter = new ColorMatrixFilter(color.CalculateFinalFlatArray());image.filters = [filter];}Step 19: Set Main ClassWe’ll make use of the Document Class in this tutorial, if you don’t know how to use it or are a bit confused please read this QuickTip.
Step 20: TestYou’re ready to test — press Cmd+Return to export your application and see it working!
You’ve learned an excellent technique of image manipulation, experiment with it!
Thanks for reading this tutorial, I hope you’ve found it useful!
More Colorful Resources on Activetuts+Manipulate Visual Effects With the ColorMatrixFilter and ConvolutionFilterComparing Filters in Flash Create a Brightness Editor in ActionScript 3Quick Tip: Whipping up Real Time Motion Trails Harness the Power of Palette Mapping to Customize Game Characters – Active PremiumSubscribe to our RSS Feed, Follow us on Twitter or simply recommend us to friends and colleagues!
TweetCarlos is a Web/Logo Designer, Flash Developer with passion for great designs and cool applications.
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Related PostsAny chance you could be nice and save the Demo Files as CS5? Right now, they REQUIRE you to have CS5.5.
ReplyDone :)
ReplyNice introductory tut. For people who don’t know how to use the slider component, it would be nice to have a link to the component tut series here at activetuts (http://active.tutsplus.com/tutorials/tools-tips/quick-introduction-flash-numericstepper-slider-and-progressbar-components/).
Be aware that the AdjustColor class shows some unexpected behavior. Try to build a reset button:
1. Create the needed sprite (instance btReset)
2. Add to Main.as at the appropriate places something like that:
btReset.addEventListener(MouseEvent.MOUSE_DOWN,downReset);
private final function downReset(e:MouseEvent){
resetPict();
}
private final function resetPict(){
brightSL.value = 0;
color.brightness = brightSL.value;
//the same for the other props as well
update();
}
3. Test it:
a. change the saturation and contrast. Then click the reset button and feel happy.
b. change the brightness and / or hue and click again the reset button. Your happiness will melt away.
Inside the AdjustColor class, the setter for brightness and hue do ignore values of 0. If you don’t want to look into that class directly, test it out inside the update function by tracing the resulting 4 x 5 matrix with:
trace(color.CalculateFinalFlatArray());
The 5th, 10th and 15th value represent the brightness setting. They won’t ever change to 0 (with the honorable exception of starting the app). It is not possible to directly access the brightness (or hue) property since that is write-only.
If you don’t want to touch (or break) the AdjustColor class, use a very small number like 0.001 for brightness and hue to reset the values.
ReplyAwesome, thanks for the tip, Peter!
ReplyActually, I am not sure if we can intentionally break the default classes (am a very brave developer so I didn’t try it; use your friends’ computer to test it out). There are a lot of swc files lurking around, i.e., common/configuration/ActionScript 3.0/libs/flash.swc. An swc is just a zip that can be opened by whatever unzip programm you use (7zip goes fine). Maybe Flash does load precompiled classes out of swc files?
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