Jframe canvas

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. It works, but the JFrame is not adapting to the Canvas. I have to manually resize the window to see the objects. How can I pack it so that JFrame automatically encompasses the Canvas?

EDIT: That's really weird. While frame. What I did was change the start method and turn it into a constructor, like that:. Gameso I followed it's tip and changed to:.

I don't know what it is you're trying to do, but you should NEVER be calling paint and especially not pass it null. In order to get the window to size to you component, you need to provide it some important information. While Window pack is the method you are looking for, it will not help you unless you provide appropriate sizing hints. In this case, you need to override the getPreferredSize method of you component and provide an appropriate size value. Window pack will use this value to determine what size it needs to be in order to accommodate it.

The paint chain is very important and you should avoid breaking it at all coasts. Make sure you always call super.

Use java. Learn more. Asked 6 years, 8 months ago. Active 6 years, 8 months ago. Viewed 27k times. GREEN ; g. BLACK ; g. Add frame. Don't mix AWT and Swing components needlessly.

YOu should be drawing on a JPanel and in its paintCompoment Active Oldest Votes. BorderLayout; import java. Color; import java. Dimension; import java. EventQueue; import java. Graphics; import javax. JFrame; import javax. JPanel; import javax. UIManager; import javax. MadProgrammer MadProgrammer k 18 18 gold badges silver badges bronze badges. Sign up or log in Sign up using Google.The Java library includes a simple package for drawing 2D graphics, called java.

There are several ways to create graphics in Java; the simplest way is to use java. Canvas and java. A Canvas is a blank rectangular area of the screen onto which the application can draw. The Graphics class provides basic drawing methods such as drawLinedrawRectand drawString.

The Drawing class extends Canvasso it has all the methods provided by Canvasincluding setSize. Once the frame is visible, the paint method is called whenever the canvas needs to be drawn; for example, when the window is moved or resized.

If you run this code, you should see a black circle on a gray background.

Game programming: JFrame, JPanel, paint method

You are probably used to Cartesian coordinateswhere x and y values can be positive or negative. In contrast, Java uses a coordinate system where the origin is in the upper-left corner. That way, x and y are always positive integers. Graphical coordinates are measured in pixels ; each pixel corresponds to a dot on the screen.

To draw on the canvas, you invoke methods on a Graphics object.

jframe canvas

The four parameters specify a bounding boxwhich is the rectangle in which the oval is drawn. To choose the color of a shape, invoke setColor on the Graphics object:. The setColor method determines the color of everything that gets drawn afterward. Other colors include:. You can create your own colors by specifying the red, green, and blue RGB components.

jframe canvas

For example:. Each value is an integer in the range 0 darkest to lightest. You can set the background color of the Canvas by invoking setBackground :. We can use the oval we just drew as the face, and then add two ears.

The first line draws the face. The next three lines create a smaller rectangle for the ears. We translate the rectangle up and left for the first ear, then to the right for the second ear. See the exercises at the end of this appendix for more example drawings. The code for this chapter is in the ap02 directory of ThinkJavaCode. See page?? Before you start the exercises, we recommend that you compile and run the examples.

Hint: You should only have to add or modify a few lines of code. Here is an example program that draws a circle using the fillOval method: import java. Canvas; import java. Graphics; import javax. In the main method, we: Create a JFrame object, which is the window that will contain the canvas. Create a Drawing object which is the canvasset its width and height, and add it to the frame.

Pack the frame resize it to fit the canvas, and display it on the screen. Figure B.An application must subclass the Canvas class in order to get useful functionality such as creating a custom component.

The paint method must be overridden in order to perform custom graphics on the canvas. Since: JDK1. Component Component. BaselineResizeBehaviorComponent. BltBufferStrategyComponent. Parameters: config - a reference to a GraphicsConfiguration object. This peer allows you to change the user interface of the canvas without changing its functionality. CanvasComponent. Most applications that subclass Canvas should override this method in order to perform some useful operation typically, custom painting of the canvas.

The default operation is simply to clear the canvas. Applications that override this method need not call super.

Урок №132. Java. Рисование в JFrame

This method is called in response to a call to repaint. The canvas is first cleared by filling it with the background color, and then completely redrawn by calling this canvas's paint method.

Note: applications that override this method should either call super. Multi-buffering is useful for rendering performance. This method attempts to create the best strategy available with the number of buffers supplied. It will always create a BufferStrategy with that number of buffers.

A page-flipping strategy is attempted first, then a blitting strategy using accelerated buffers. Finally, an unaccelerated blitting strategy is used. Each time this method is called, the existing buffer strategy for this component is discarded. Parameters: numBuffers - number of buffers to create, including the front buffer Throws: IllegalArgumentException - if numBuffers is less than 1.

IllegalStateException - if the component is not displayable Since: 1. This is useful, for example, if only accelerated memory or page flipping is desired as specified by the buffer capabilities. Parameters: numBuffers - number of buffers to create caps - the required capabilities for creating the buffer strategy; cannot be null Throws: AWTException - if the capabilities supplied could not be supported or met; this may happen, for example, if there is not enough accelerated memory currently available, or if page flipping is specified but not possible.

IllegalArgumentException - if numBuffers is less than 1, or if caps is null Since: 1. This method will return null if a BufferStrategy has not yet been created or has been disposed. Returns: the buffer strategy used by this component Since: 1. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy. Object java. Component java. Canvas All Implemented Interfaces: ImageObserverMenuContainerSerializableAccessible public class Canvas extends Component implements Accessible A Canvas component represents a blank rectangular area of the screen onto which the application can draw or from which the application can trap input events from the user.

Creates a new strategy for multi-buffering on this component with the required buffer capabilities. Creates the peer of the canvas. Paints this canvas.Canvas class is a part of Java AWT. Canvas is a blank rectangular area where the user can draw or trap input from the user. Canvas class inherits the Component class. Program 2: To create a canvas and add mouse listener to the canvas a circle of radius 5 will appear at the points where mouse are clicked or dragged on the canvas.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute. See your article appearing on the GeeksforGeeks main page and help other Geeks. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Writing code in comment? Please use ide. Constructor of the Canvas class are : Canvas : Creates a new blank canvas.

Canvas GraphicsConfiguration c : Creates a new canvas with a specified graphics configuration. Commonly used Methods in Canvas Class. Canvas c. Class class in Java Set 2 Java. Class class in Java Set 1. Check out this Author's contributed articles. Improved By : ManasChhabra2. Load Comments. Creates a new strategy for multi-buffering on this component with the required buffer capabilities.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Using JPanel as a canvas : JPanel « Swing « Java Tutorial

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I must say, It would have been simpler if you had just extended JFrame unless you want to extend something else. You need to understand that for code readability and reuseability, you need to follow conventional Java rules and best practices.

Hovercraft Full Of Eels has explained all you need above. All I do here is to set you right by example so there is no need duplicating what he has said. FlowLayout may be the easiest and simplest layout manager in Java but it is not that very powerful compared to say GridLayout or GrdiBagLayout. Here is the code:. Learn more. Java jframe adding canvas and jpanel to it Ask Question. Asked 3 years, 8 months ago. Active 3 years, 8 months ago.

Viewed 3k times. Try adding your canvas to the panel, instead of directly to the frame. Active Oldest Votes. When you add two components in a default fashion to any container that uses BorderLayout, such as a JFrame's, both are added by default in the BorderLayout.

CENTER postion and the second component covers the first, and so here the JPanel covers the Canvas, and since the Canvas is not displayed, its preferred size is ignored. You will instead want to figure out exactly where you want components relative to each other, specifically the JPanel, the Canvas and how they're placed in the JFrame, and then use the layout managers to their advantage rather than fighting the layout manager as your code currently does.

It's usually a bad idea to mix AWT and Swing components. Are you absolutely positive that you need to use Canvas? JPanels are double buffered by default and that usually smooths out any animation if that's your goal. Hovercraft Full Of Eels k 22 22 gold badges silver badges bronze badges.

It's almost always better not to extend JFrame, not unless you are planning on changing the innate behavior of the JFrame, such as override one of its methods.The JFrame class is slightly incompatible with Frame.

The content pane provided by the root pane should, as a rule, contain all the non-menu components displayed by the JFrame.

jframe canvas

This is different from the AWT Frame case. As a conveniance add and its variants, remove and setLayout have been overridden to forward to the contentPane as necessary. This means you can write: frame. The content pane will always be non-null. Attempting to set it to null will cause the JFrame to throw an exception. The default content pane will have a BorderLayout manager set on it. Unlike a Framea JFrame has some notion of how to respond when the user attempts to close the window.

The default behavior is to simply hide the JFrame when the user closes the window.

Java AWT | Canvas Class

To change the default behavior, you invoke the method setDefaultCloseOperation int. In a multi-screen environment, you can create a JFrame on a different screen device. See Frame for more information.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy. Warning: Serialized objects of this class will not be compatible with future Swing releases.

The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1. Please see XMLEncoder. Frame Frame. Window Window.To paint something we first need a surface where to paint on. This surface or canvas where we are going to paint our first example is a JPanel object. In the same way a canvas needs a frame to hold it, our JPanel will be framed in a window made by the JFrame class. The following code creates a window "Mini Tennis" of pixels by pixels.

When we create a JFrame object we start an engine which manages the user interface. This engine communicates with the operative system both to paint in the screen as to receive information from the keyboard and from the mouse. In the first java versions only AWT existed and then Swing was added. This engine uses several threads. A program is executed by just one processor, line by line.

Threads allow a program to start several executions at the same time. This is as if, there were several processors running at the same time their own sequence of instructions.

Even though threads and concurrence are very powerful tools, there can be problems when two threads enter the same variables. It is interesting to think that two threads can be running the same code at the same time. We can think that a thread is like a cook preparing a dish reading a recipe. Two concurrent threads would be like two cooks working in the same kitchen, preparing one dish with the same recipe o with differents recipes. The problems come when both try to use the same frying pan at the same time.

The AWT Engine starts several threads which can be seen if we start the aplication with debug and we go to the debug perspective. Each thread is as if it was an independent program running at the same time as the other threads. Further on we will see more about threads, meanwhile I am only interested that you remember the third thread we see in the debug view called "Thread [AWT-EventQueue-0]" this thread is the one in charge of painting the screen and receiving the mouse and keyboard events.

We extend the JPanel class to be able to overwrite the paint method which is the method called by the AWT Engine to paint what appears in the screen. The paint method receives by parameter a Graphics2D object which extends from Graphics. Graphics is an old class used by AWT which has been replaced with Graphics2D which has more and better functionality.

Once we have g2d we can use all the Graphics2D methods to draw. The first thing we do is choose the colour we use to draw: "g2d. RED ;". After, we draw circles and squares.

jframe canvas

To draw something inside the canvas we should indicate in which position we are going to start painting. For this, each of the points in the canvas has an associated position x,y being 0,0 the point of the top-left corner.


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