Graphics2D, setting AlphaComposite, drawing Background and Image doesn't work

[augustas656]

Hello!

I'm making an RPG Game and my main game class extends Canvas, and it also uses JFrame. I have a tick loop, that my game updates every 60 seconds and renders either every 60 seconds or as fast as the computer can handle, I have a boolean variable that defines whether rendering is limited or unlimited. I am having issues with rendering, especially, working with Alpha Composite. First I'll show related snippets of my code:

Some object definitions in the main class:

private BufferedImage testImage = GraphicsHandler.getImage("Test Image.png");
private Graphics2D gfx;
private BufferStrategy strategy;
private AlphaComposite composite = AlphaComposite.getInstance(AlphaComposite.DST_IN, 1.0F);
public static Color gameStageColor = new Color(66, 255, 66, 0); //For the alpha (last integer arguement) I tried 0, 128 and 255.

Render method, called rapidly by the game loop:

strategy = getBufferStrategy();
if (strategy == null) { createBufferStrategy(3); return; }
gfx = (Graphics2D) strategy.getDrawGraphics();

gfx.setComposite(composite);
gfx.setColor(gameStageColor);
gfx.fillRect(0, 0, gameWidth, gameHeight);
gfx.drawImage(testImage, 100, 100, 148, 148, null);
gfx.dispose();
strategy.show();

What I'm trying to achieve here:
Firstly, the background color is drawn, the stage color, which I defined 66, 255, 66, 0, this being a shade of green. Then overlapped in position X: 100 to 148 and Y: 100 to 148, I want a test image to be drawn. This image has been loaded with ImageIO.read(imageFile), and the image file exists in a Java Build Path: Class Folder, linked folder to the project. The test image is a PNG image with some semi-transperant areas, now I want these areas to mix with the green background. Instead of that, all I get is a black screen, I tried Color.RED instead of gameStageColor and I got a Black and White rapidly flashing screen.

What's the problem with this?
How do I get it to do what I want it to do?

Regards
Augustas656

[DarrylBurke]

Thread moved from New to Java.

Have you discovered the Oracle tutorials? Compositing Graphics (The Javaâ„¢ Tutorials > 2D Graphics > Advanced Topics in Java2D)

db

[jim829]

Although I have used the AlphaComposite class I am not sufficiently versed in it to help you with what you submitted.
If you could submit a http:/SSCCE.org which demonstrates the problem I may be able to help. However, why are you
using Canvas? That is AWT and you are mixing it with Swing (e.g. JFrame). Probably not a good idea. You should just
use JPanels and do your painting in them.

Regards,
Jim

[augustas656]

I'm using Canvas so I can make the Buffer Strategy triple buffering rather than the integrated double buffering in JPanels. It's just the problem with AlphaComposite