So, a little after I got a working player character in the Python version of RuntDeale, I started moving it to Java, and, progress has been pretty smooth. I got the window, icon, and the resources folders all working how they should.
But, when I tried making my own canvas implementation, it keeps blinking when I keep updating it. And if I don't update it, it just shows nothingness (just a white screen).
This is what the class looks like:
/**
* Calin Baenen's version of a canvas element.
*/
class CPane {
// Debug variables.
/**
* The canvas itself.
*/
private final JPanel canvas; // Canvas.
/**
* The buffer that adds data to the canvas.
*/
private BufferedImage buffer; // Buffer.
// Constructor.
public CPane(int width, int height) {
this(0, 0, width, height);
}
public CPane(int width, int height, Color initialColor) {
this(0, 0, width, height, initialColor);
}
public CPane(int x, int y, int width, int height) {
this(x, y, width, height, Color.WHITE);
}
public CPane(int x, int y, int width, int height, Color initialColor) {
this(x, y, width, height, initialColor, Color.WHITE);
}
public CPane(int x, int y, int width, int height, Color initialColor, Color baseColor) {
this.canvas = new JPanel(); // Make an element to display the drawing on.
canvas.setBounds(x, y, width, height); // Set the bounds of the canvas.
canvas.setBackground(baseColor); // Make the canvas white.
canvas.setDoubleBuffered(true); // Make the canvas double buffered.
buffer = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); // Set the buffer.
Graphics ctx = buffer.getGraphics(); // Get the graphics for the buffer.
// Paint the image with an initisl color.
ctx.setColor(initialColor); // Set color.
ctx.drawRect(0, 0, width, height); // Draw.
ctx.dispose(); // Dispose.
}
/**
* Draws a rectangle to the screen by filling an area with color.
*/
public void drawRect(int x, int y, int width, int height, Color color) {
Graphics ctx = buffer.getGraphics(); // Get the graphics.
ctx.setColor(color); // Set the context's color.
ctx.fillRect(x, y, width, height); // Draw a rectangle.
ctx.dispose(); // Dispose the graphics.
this.update(); // Update the canvas.
}
/**
* Draw an image to the canvas.
*/
public void drawImage(Image image, int x, int y) {
this.drawImage(image, x, y, image.getWidth(null), image.getHeight(null));
}
/**
* Draw an image to the canvas.
*/
public void drawImage(Image image, int x, int y, int width, int height) {
Image shot = image.getScaledInstance(width, height, Image.SCALE_FAST); // Get the scaled image to draw.
Graphics ctx = buffer.getGraphics(); // Get the graphics.
ctx.drawImage(shot, x, y, null); // Draw the image.
ctx.dispose(); // Dispose.
this.update(); // Update the canvas.
}
/**
* Update the graphics.
*/
public void update() {
try {
Graphics display = canvas.getGraphics(); // Get the display graphics.
display.drawImage(buffer, 0, 0, null); // Draw the bufer.
display.dispose(); // Dispose the display.
} catch(Exception error) {}
}
}
I know it's probably within the update method itself, but, how can I fix this bug?
Thanks!
Cheers!
Cheers!
Top comments (2)
It’s a Long time since I used Java and implemented double buffering. I’m not sure if I am correct. But my first finding, which I think is not necessary: you create and dispose the graphics ctx of the buffer. Just use the one you created in the constructor. And I don’t think you should dispose the panels Graphics. Just try it and observe for memory
Thanks for the tip. Though, when I tried this, the canvas didn't draw anything (it stayed white). Where previously, it displayed an image, then went to black (which is where the flickering started).