Using AWT, how do you import an image into a rectangle you have drawn? I want to assign the background to that particular rectangle only.
Set the Rectangle as the clipping region.
Draw the image at a point so (part of) it is inside the clipping region.
Clear the clip.
Draw the rectangle.
As seen in this answer (the shape here is of text, but same principle applies).
The most common approach is to override the the paint method in your component. Have a look at Graphics.drawImage(). Example: Drawing an Image
If you decide to move to Swing, you can take advantage of Swing's optimizied painting model, overriding paintComponent instead of paint.
See: Performing Custom Painting
Related
I want to draw a repeating image on a javafx canvas, is there any way to do it other than manually reapeatedly drawing the same image over and over?
This can be done by setting the Paint for filling some area. A subclass of Paint is
https://openjfx.io/javadoc/12/javafx.graphics/javafx/scene/paint/ImagePattern.html
which does exactly what you want.
I am developing a graphic project in java using swing and awt libraries. I am looking for a method that allow me to draw very fast on my JPanel. I tried various methods: overriding paintComponent, calling repaint(x, y, width, heigth).. But in all cases i have to repaint ALL the screen! I have a background and a small image in front of it that changes every few time. i am looking for a method that allow me to paint on the screen only the small image, i don't need to repaint the background too, because it is always the same, and the small image is always at the same coords. for example in C++ i painted the background and then i only painted the small images in front of it using putimage (graphics.h), so that it was very very fast. Do someone have some tips?
I've had some experience with game programming and usually a JPanel is used as canvas. Now to paint on it you would write a simple loop which continuously buffers an image and later paints it to the screen. So on initialisation you create a Graphics or Graphics2D object which is passed to a buffer() method. After painting a BufferedImage with the Instance of Graphics, some paint() method paints the BufferedImage to the screen.
When only painting the background once, previously drawn images will still be visible. If all your images are the same size, you don't have to bother but I still recommend repainting your background as well.
Have a look at the book Killer Game Programming In Java for further information, it's a great reference.
Tips:
Paint static images to a BufferedImage and then draw that within the paintComponent using Graphics#drawImage(...)
You do know that the repaint(...) method is overloaded and that one overload can accept a Rectangle parameter, limiting the area of repainting.
Making a paint-like application that works by saving mouse points in an arraylist. My idea is to have a "points" arraylist with all the previously drawn stuff, and a "temp" arraylist to get and modify the current brush stroke the user just entered. This is necessary as the user can change the color and size, so my idea is to modify the current brush stroke based off what buttons have been pressed, then add that brush stroke to the rest of the picture. I searched around StackOverflow and found some code but cant get it to work how I want to (assuming I found the right code).
#Override
public void paintComponent(Graphics g1) {
super.paintComponent(g1);
final Graphics2D g = (Graphics2D)g1.create();
try {
g.setColor(brushColor);
for (Point point : tempArrayList){
g.fillOval(point.x, point.y, brushSize, brushSize);
}
} finally {
g.dispose();
}
The problem is that I need to clear the tempArrayList for the next brush stroke, which I can do when they change the color/size, but then it erases what was previously there. I am starting to think that I don't even need the "points" arraylist as descibed above because I was hoping that the g1 graphic would just save what the g graphic created.
I guess I just need to figure out how to add the g graphic to g1
Painting is controlled by the Swing API, there is a expectation that whenever paintComponent is called, you will repaint the entire state of the component (as part of your component might have been damaged due to some system event), so the short answer is, no, you can't...however....
You Could...
Paint to a BufferedImage instead and paint the BufferedImage when paintComponent is called
You Could...
Establish a series of "paintable" objects which contain information about what is to be painted and how it is to the painted, including the brush stroke, stroke color and fill color.
These would then be added to some kind of List and "painted" when the paintComponent method is called
Check out Custom Painting Approaches for exampled of painting from:
A List of objects
A BufferedImage.
The examples show how to draw Rectangles of different colours.
Ok, I'm not even sure if that is the right question to ask.
I've been confused by what is A Graphics object for a while now, I used to think that it is simplly a tool to use to change colors and draw to specific container(ie JFrame, JPanel).
However, I've been studying buffering(triple, double, flipping...etc) and how it works for 3 days now, and my confusion has only increased. for instance, why when we need to draw to the buffer(ie BufferStrategy, BufferedImage) we get its own graphics object to draw to it and then we project it to the screen? does the Graphics Object represent the drawing surface (ie the JPanel it self if we're using one to draw custom painting via JPanel#paintComponent(Graphics g)) ?
and so when we're getting the graphics object of a buffer, do we actually get its drawing surface to paint on?
Please somebody explain, any help is appreciated
Thanks
From the API:
A Graphics object encapsulates state information needed for the basic
rendering operations that Java supports. This state information
includes the following properties:
The Component object on which to draw.
A translation origin for rendering and clipping coordinates.
The current clip.
The current color.
The current font.
The current logical pixel operation function (XOR or Paint).
The current XOR alternation color (see setXORMode(java.awt.Color)).
So a Graphics instance contains information about WHERE to draw (a component) as well as HOW to draw it (a color, font, etc). It then gives you methods so you can tell it WHAT to draw (a rectangle, circle, text, etc).
I'm working on a project for maze generation using Java, swing, and Java2D. I'm fairly new to Java2D so please excuse me if this question is newbish.
Basically, I have a successfully generated maze. I wish to draw this maze on a custom JPanel that I've set up and properly overridden PaintComponent on. The problem I have now is I currently have the ability to draw the maze, but every time I repaint it disappears. I've solved this by having it redraw the maze every time repaint() is called but this seems horribly inefficient. Since the maze doesn't change why should I have to redraw it?
So my question is this: is there any way to "cache" the drawing of the maze so I don't have to waste cycles redrawing it every time? I can see redrawing it every time for exceptionally large mazes being a major source of slow downs.
Thank you!
Draw the maze to a BufferedImage. Then in your paintComponent() method just paint the BufferedImage. Swing will determine whether the entire maze or just parts of it need to be repainted.
For an example painting onto a BufferedImage see the DrawOnImage example from Custom Painting Approaches.
If the maze never changes, you can initially draw it into a BufferedImage. You can use your same code you wrote for overriding paintComponent by creating a BufferedImage and calling image.createGraphics() on it to get a Graphics2D object. Any painting you do to the Graphics2D object returned from createGraphics() is added to the BufferedImage. You may have to extract your previous drawing code just for the maze into its own function which takes a Graphics2D object and draws to it.
Once you have your maze drawn into the BufferedImage, you can use any of the drawImage() functions in Graphics or Graphics2D. This avoids having to redraw the maze: now you are just drawing the already rendered image.