How to add an image to a JPanel

Question

I have a JPanel to which I d like to add JPEG and PNG images that I generate on the fly   All the examples I ve seen so far in the Swing Tutorials  specially in the Swing examples use ImageIcons   I m generating these images as byte arrays  and they are usually larger than the common icon they use in the examples  at 640x480    Is there any  performance or other  problem in using the ImageIcon class to display an image that size in a JPanel  What s the usual way of doing it  How to add an image to a JPanel without using the ImageIcon class    Edit  A more careful examination of the tutorials and the API shows that you cannot add an ImageIcon directly to a JPanel  Instead  they achieve the same effect by setting the image as an icon of a JLabel  This just doesn t feel right

User · Answer

JLabel imgLabel   new JLabel new ImageIcon  path to image png

User · Answer

If you are using JPanels  then are probably working with Swing   Try this   BufferedImage myPicture   ImageIO read new File  path-to-file     JLabel picLabel   new JLabel new ImageIcon myPicture    add picLabel     The image is now a swing component   It becomes subject to layout conditions like any other component

User · Answer

Here s how I do it  with a little more info on how to load an image    import java awt Graphics  import java awt image BufferedImage  import java io File  import java io IOException  import java util logging Level  import java util logging Logger  import javax imageio ImageIO  import javax swing JPanel   public class ImagePanel extends JPanel       private BufferedImage image       public ImagePanel            try                             image   ImageIO read new File  image name and path              catch  IOException ex                   handle exception                         Override     protected void paintComponent Graphics g            super paintComponent g           g drawImage image  0  0  this      see javadoc for more info on the parameters

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I think there is no need to subclass of anything  Just use a Jlabel  You can set an image into a Jlabel  So  resize the Jlabel then fill it with an image  Its OK  This is the way I do

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I m doing something very similar in a private project I m working on  Thus far I ve generated images up to 1024x1024 without any problems  except memory  and can display them very quickly and without any performance problems    Overriding the paint method of JPanel subclass is overkill and requires more work than you need to do    The way I do it is    Class MapIcon implements Icon         OR  Class MapIcon extends ImageIcon         The code you use to generate the image will be in this class  I use a BufferedImage to draw onto then when the paintIcon   is called  use g drawImvge bufferedImage   This reduces the amount of flashing done while you generate your images  and you can thread it    Next I extend JLabel   Class MapLabel extends Scrollable  MouseMotionListener         This is because I want to put my image on a scroll pane  I e  display part of the image and have the user scroll around as needed    So then I use a JScrollPane to hold the MapLabel  which contains only the MapIcon    MapIcon map   new MapIcon      MapLabel mapLabel   new MapLabel  map   JScrollPane scrollPane   new JScrollPane     scrollPane getViewport    add  mapLabel     But for your scenario  just show the whole image every time   You need to add the MapLabel to the top JPanel  and make sure to size them all to the full size of the image  by overriding the GetPreferredSize

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You can avoid using own Components and SwingX library and ImageIO class     File f   new File  hello jpg    JLabel imgLabel   new JLabel new ImageIcon file getName

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JPanel is almost always the wrong class to subclass  Why wouldn t you subclass JComponent   There is a slight problem with ImageIcon in that the constructor blocks reading the image  Not really a problem when loading from the application jar  but maybe if you re potentially reading over a network connection  There s plenty of AWT-era examples of using MediaTracker  ImageObserver and friends  even in the JDK demos

User · Answer

You can subclass JPanel - here is an extract from my ImagePanel  which puts an image in any one of 5 locations  top left  top right  middle middle  bottom left or bottom right   protected void paintComponent Graphics gc        super paintComponent gc        Dimension                           cs getSize                                 component size      gc gc create        gc clipRect insets left insets top  cs width-insets left-insets right   cs height-insets top-insets bottom        if mmImage  null    gc drawImage mmImage    cs width-mmSize width  2         mmHrzShift     cs height-mmSize height  2          mmVrtShift  null         if tlImage  null    gc drawImage tlImage  insets left                        tlHrzShift   insets top                            tlVrtShift  null         if trImage  null    gc drawImage trImage  cs width-insets right-trSize width trHrzShift   insets top                            trVrtShift  null         if blImage  null    gc drawImage blImage  insets left                        blHrzShift   cs height-insets bottom-blSize height blVrtShift  null         if brImage  null    gc drawImage brImage  cs width-insets right-brSize width brHrzShift   cs height-insets bottom-brSize height brVrtShift  null

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There shouldn t be any problem  other than any general problems you might have with very large images   If you re talking about adding multiple images to a single panel  I would use ImageIcons  For a single image  I would think about making a custom subclass of JPanel and overriding its paintComponent method to draw the image   see 2

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Fred Haslam s way works fine   I had trouble with the filepath though  since I want to reference an image within my jar   To do this  I used   BufferedImage wPic   ImageIO read this getClass   getResource  snow png     JLabel wIcon   new JLabel new ImageIcon wPic      Since I only have a finite number  about 10  images that I need to load using this method  it works quite well   It gets file without having to have the correct relative filepath

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I m doing something very similar in a private project I m working on  Thus far I ve generated images up to 1024x1024 without any problems  except memory  and can display them very quickly and without any performance problems    Overriding the paint method of JPanel subclass is overkill and requires more work than you need to do    The way I do it is    Class MapIcon implements Icon         OR  Class MapIcon extends ImageIcon         The code you use to generate the image will be in this class  I use a BufferedImage to draw onto then when the paintIcon   is called  use g drawImvge bufferedImage   This reduces the amount of flashing done while you generate your images  and you can thread it    Next I extend JLabel   Class MapLabel extends Scrollable  MouseMotionListener         This is because I want to put my image on a scroll pane  I e  display part of the image and have the user scroll around as needed    So then I use a JScrollPane to hold the MapLabel  which contains only the MapIcon    MapIcon map   new MapIcon      MapLabel mapLabel   new MapLabel  map   JScrollPane scrollPane   new JScrollPane     scrollPane getViewport    add  mapLabel     But for your scenario  just show the whole image every time   You need to add the MapLabel to the top JPanel  and make sure to size them all to the full size of the image  by overriding the GetPreferredSize

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Create a source folder in your project directory  in this case I called it Images    JFrame snakeFrame   new JFrame    snakeFrame setBounds 100  200  800  800   snakeFrame setVisible true   snakeFrame add new JLabel new ImageIcon  Images Snake png      snakeFrame pack

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You can subclass JPanel - here is an extract from my ImagePanel  which puts an image in any one of 5 locations  top left  top right  middle middle  bottom left or bottom right   protected void paintComponent Graphics gc        super paintComponent gc        Dimension                           cs getSize                                 component size      gc gc create        gc clipRect insets left insets top  cs width-insets left-insets right   cs height-insets top-insets bottom        if mmImage  null    gc drawImage mmImage    cs width-mmSize width  2         mmHrzShift     cs height-mmSize height  2          mmVrtShift  null         if tlImage  null    gc drawImage tlImage  insets left                        tlHrzShift   insets top                            tlVrtShift  null         if trImage  null    gc drawImage trImage  cs width-insets right-trSize width trHrzShift   insets top                            trVrtShift  null         if blImage  null    gc drawImage blImage  insets left                        blHrzShift   cs height-insets bottom-blSize height blVrtShift  null         if brImage  null    gc drawImage brImage  cs width-insets right-brSize width brHrzShift   cs height-insets bottom-brSize height brVrtShift  null

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I m doing something very similar in a private project I m working on  Thus far I ve generated images up to 1024x1024 without any problems  except memory  and can display them very quickly and without any performance problems    Overriding the paint method of JPanel subclass is overkill and requires more work than you need to do    The way I do it is    Class MapIcon implements Icon         OR  Class MapIcon extends ImageIcon         The code you use to generate the image will be in this class  I use a BufferedImage to draw onto then when the paintIcon   is called  use g drawImvge bufferedImage   This reduces the amount of flashing done while you generate your images  and you can thread it    Next I extend JLabel   Class MapLabel extends Scrollable  MouseMotionListener         This is because I want to put my image on a scroll pane  I e  display part of the image and have the user scroll around as needed    So then I use a JScrollPane to hold the MapLabel  which contains only the MapIcon    MapIcon map   new MapIcon      MapLabel mapLabel   new MapLabel  map   JScrollPane scrollPane   new JScrollPane     scrollPane getViewport    add  mapLabel     But for your scenario  just show the whole image every time   You need to add the MapLabel to the top JPanel  and make sure to size them all to the full size of the image  by overriding the GetPreferredSize

User · Answer

This answer is a complement to  shawalli s answer     I wanted to reference an image within my jar too  but instead of having a BufferedImage  I simple did this    JPanel jPanel   new JPanel           jPanel add new JLabel new ImageIcon getClass   getClassLoader   getResource  resource images polygon jpg

User · Answer

You can subclass JPanel - here is an extract from my ImagePanel  which puts an image in any one of 5 locations  top left  top right  middle middle  bottom left or bottom right   protected void paintComponent Graphics gc        super paintComponent gc        Dimension                           cs getSize                                 component size      gc gc create        gc clipRect insets left insets top  cs width-insets left-insets right   cs height-insets top-insets bottom        if mmImage  null    gc drawImage mmImage    cs width-mmSize width  2         mmHrzShift     cs height-mmSize height  2          mmVrtShift  null         if tlImage  null    gc drawImage tlImage  insets left                        tlHrzShift   insets top                            tlVrtShift  null         if trImage  null    gc drawImage trImage  cs width-insets right-trSize width trHrzShift   insets top                            trVrtShift  null         if blImage  null    gc drawImage blImage  insets left                        blHrzShift   cs height-insets bottom-blSize height blVrtShift  null         if brImage  null    gc drawImage brImage  cs width-insets right-brSize width brHrzShift   cs height-insets bottom-brSize height brVrtShift  null

User · Answer

You can subclass JPanel - here is an extract from my ImagePanel  which puts an image in any one of 5 locations  top left  top right  middle middle  bottom left or bottom right   protected void paintComponent Graphics gc        super paintComponent gc        Dimension                           cs getSize                                 component size      gc gc create        gc clipRect insets left insets top  cs width-insets left-insets right   cs height-insets top-insets bottom        if mmImage  null    gc drawImage mmImage    cs width-mmSize width  2         mmHrzShift     cs height-mmSize height  2          mmVrtShift  null         if tlImage  null    gc drawImage tlImage  insets left                        tlHrzShift   insets top                            tlVrtShift  null         if trImage  null    gc drawImage trImage  cs width-insets right-trSize width trHrzShift   insets top                            trVrtShift  null         if blImage  null    gc drawImage blImage  insets left                        blHrzShift   cs height-insets bottom-blSize height blVrtShift  null         if brImage  null    gc drawImage brImage  cs width-insets right-brSize width brHrzShift   cs height-insets bottom-brSize height brVrtShift  null

User · Answer

You can avoid using own Components and SwingX library and ImageIO class     File f   new File  hello jpg    JLabel imgLabel   new JLabel new ImageIcon file getName

User · Answer

I can see many answers  not really addressing the three questions of the OP   1  A word on performance  byte arrays are likely unefficient unless you can use an exact pixel byte ordering which matches to your display adapters current resolution and color depth    To achieve the best drawing performance  simply convert your image to a BufferedImage which is generated with a type corresponding to your current graphics configuration  See createCompatibleImage at https   docs oracle com javase tutorial 2d images drawonimage html   These images will be automatically cached on the display card memory after drawing a few times without any programming effort  this is standard in Swing since Java 6   and therefore the actual drawing will take negligible amount of time - if you did not change the image    Altering the image will come with an additional memory transfer between main memory and GPU memory - which is slow  Avoid  redrawing  the image into a BufferedImage therefore  avoid doing getPixel and setPixel at all means    For example  if you are developing a game  instead of drawing all the game actors to a BufferedImage and then to a JPanel  it is a lot faster to load all actors as smaller BufferedImages  and draw them one by one in your JPanel code at their proper position - this way there is no additional data transfer between the main memory and GPU memory except of the initial transfer of the images for caching   ImageIcon will use a BufferedImage under the hood - but basically allocating a BufferedImage with the proper graphics mode is the key  and there is no effort to do this right   2  The usual way of doing this is to draw a BufferedImage in an overridden paintComponent method of the JPanel  Although Java supports a good amount of additional goodies such as buffer chains controlling VolatileImages cached in the GPU memory  there is no need to use any of these since Java 6 which does a reasonably good job without exposing all of these details of GPU acceleration   Note that GPU acceleration may not work for certain operations  such as stretching translucent images    3  Do not add  Just paint it as mentioned above    Override protected void paintComponent Graphics g        super paintComponent g       g drawImage image  0  0  this         Adding  makes sense if the image is part of the layout  If you need this as a background or foreground image filling the JPanel  just draw in paintComponent  If you prefer brewing a generic Swing component which can show your image  then it is the same story  you may use a JComponent and override its paintComponent method  - and then add this to your layout of GUI components   4  How to convert the array to a Bufferedimage  Converting your byte arrays to PNG  then loading it is quite resource intensive  A better way is to convert your existing byte array to a BufferedImage   For that  do not use for loops and copy pixels  That is very very slow  Instead    learn the preferred byte structure of the BufferedImage  nowadays it is safe to assume RGB or RGBA  which is 4 bytes per pixel  learn the scanline and scansize in use  e g  you might have a 142 pixels wide image - but in the real life that will be stored as a 256 pixel wide byte array since it is faster to process that and mask the unused pixes by the GPU hardware  then once you have an array build according to these principles  the setRGB array method of the BufferedImage can copy your array to the BufferedImage

User · Answer

If you are using JPanels  then are probably working with Swing   Try this   BufferedImage myPicture   ImageIO read new File  path-to-file     JLabel picLabel   new JLabel new ImageIcon myPicture    add picLabel     The image is now a swing component   It becomes subject to layout conditions like any other component

User · Answer

JPanel is almost always the wrong class to subclass  Why wouldn t you subclass JComponent   There is a slight problem with ImageIcon in that the constructor blocks reading the image  Not really a problem when loading from the application jar  but maybe if you re potentially reading over a network connection  There s plenty of AWT-era examples of using MediaTracker  ImageObserver and friends  even in the JDK demos

User · Answer

I m doing something very similar in a private project I m working on  Thus far I ve generated images up to 1024x1024 without any problems  except memory  and can display them very quickly and without any performance problems    Overriding the paint method of JPanel subclass is overkill and requires more work than you need to do    The way I do it is    Class MapIcon implements Icon         OR  Class MapIcon extends ImageIcon         The code you use to generate the image will be in this class  I use a BufferedImage to draw onto then when the paintIcon   is called  use g drawImvge bufferedImage   This reduces the amount of flashing done while you generate your images  and you can thread it    Next I extend JLabel   Class MapLabel extends Scrollable  MouseMotionListener         This is because I want to put my image on a scroll pane  I e  display part of the image and have the user scroll around as needed    So then I use a JScrollPane to hold the MapLabel  which contains only the MapIcon    MapIcon map   new MapIcon      MapLabel mapLabel   new MapLabel  map   JScrollPane scrollPane   new JScrollPane     scrollPane getViewport    add  mapLabel     But for your scenario  just show the whole image every time   You need to add the MapLabel to the top JPanel  and make sure to size them all to the full size of the image  by overriding the GetPreferredSize

User · Answer

JLabel imgLabel   new JLabel new ImageIcon  path to image png

User · Answer

This answer is a complement to  shawalli s answer     I wanted to reference an image within my jar too  but instead of having a BufferedImage  I simple did this    JPanel jPanel   new JPanel           jPanel add new JLabel new ImageIcon getClass   getClassLoader   getResource  resource images polygon jpg

User · Answer

Here s how I do it  with a little more info on how to load an image    import java awt Graphics  import java awt image BufferedImage  import java io File  import java io IOException  import java util logging Level  import java util logging Logger  import javax imageio ImageIO  import javax swing JPanel   public class ImagePanel extends JPanel       private BufferedImage image       public ImagePanel            try                             image   ImageIO read new File  image name and path              catch  IOException ex                   handle exception                         Override     protected void paintComponent Graphics g            super paintComponent g           g drawImage image  0  0  this      see javadoc for more info on the parameters

User · Answer

You can avoid rolling your own Component subclass completely by using the JXImagePanel class from the free SwingX libraries   Download

User · Answer

I think there is no need to subclass of anything  Just use a Jlabel  You can set an image into a Jlabel  So  resize the Jlabel then fill it with an image  Its OK  This is the way I do

User · Answer

JPanel is almost always the wrong class to subclass  Why wouldn t you subclass JComponent   There is a slight problem with ImageIcon in that the constructor blocks reading the image  Not really a problem when loading from the application jar  but maybe if you re potentially reading over a network connection  There s plenty of AWT-era examples of using MediaTracker  ImageObserver and friends  even in the JDK demos

User · Answer

There shouldn t be any problem  other than any general problems you might have with very large images   If you re talking about adding multiple images to a single panel  I would use ImageIcons  For a single image  I would think about making a custom subclass of JPanel and overriding its paintComponent method to draw the image   see 2

User · Answer

Create a source folder in your project directory  in this case I called it Images    JFrame snakeFrame   new JFrame    snakeFrame setBounds 100  200  800  800   snakeFrame setVisible true   snakeFrame add new JLabel new ImageIcon  Images Snake png      snakeFrame pack

User · Answer

JPanel is almost always the wrong class to subclass  Why wouldn t you subclass JComponent   There is a slight problem with ImageIcon in that the constructor blocks reading the image  Not really a problem when loading from the application jar  but maybe if you re potentially reading over a network connection  There s plenty of AWT-era examples of using MediaTracker  ImageObserver and friends  even in the JDK demos

User · Answer

You can avoid rolling your own Component subclass completely by using the JXImagePanel class from the free SwingX libraries   Download

User · Answer

There shouldn t be any problem  other than any general problems you might have with very large images   If you re talking about adding multiple images to a single panel  I would use ImageIcons  For a single image  I would think about making a custom subclass of JPanel and overriding its paintComponent method to draw the image   see 2

User · Answer

You can avoid rolling your own Component subclass completely by using the JXImagePanel class from the free SwingX libraries   Download

User · Answer

You can avoid rolling your own Component subclass completely by using the JXImagePanel class from the free SwingX libraries   Download

User · Answer

Here s how I do it  with a little more info on how to load an image    import java awt Graphics  import java awt image BufferedImage  import java io File  import java io IOException  import java util logging Level  import java util logging Logger  import javax imageio ImageIO  import javax swing JPanel   public class ImagePanel extends JPanel       private BufferedImage image       public ImagePanel            try                             image   ImageIO read new File  image name and path              catch  IOException ex                   handle exception                         Override     protected void paintComponent Graphics g            super paintComponent g           g drawImage image  0  0  this      see javadoc for more info on the parameters

User · Answer

There shouldn t be any problem  other than any general problems you might have with very large images   If you re talking about adding multiple images to a single panel  I would use ImageIcons  For a single image  I would think about making a custom subclass of JPanel and overriding its paintComponent method to draw the image   see 2

User · Answer

I can see many answers  not really addressing the three questions of the OP   1  A word on performance  byte arrays are likely unefficient unless you can use an exact pixel byte ordering which matches to your display adapters current resolution and color depth    To achieve the best drawing performance  simply convert your image to a BufferedImage which is generated with a type corresponding to your current graphics configuration  See createCompatibleImage at https   docs oracle com javase tutorial 2d images drawonimage html   These images will be automatically cached on the display card memory after drawing a few times without any programming effort  this is standard in Swing since Java 6   and therefore the actual drawing will take negligible amount of time - if you did not change the image    Altering the image will come with an additional memory transfer between main memory and GPU memory - which is slow  Avoid  redrawing  the image into a BufferedImage therefore  avoid doing getPixel and setPixel at all means    For example  if you are developing a game  instead of drawing all the game actors to a BufferedImage and then to a JPanel  it is a lot faster to load all actors as smaller BufferedImages  and draw them one by one in your JPanel code at their proper position - this way there is no additional data transfer between the main memory and GPU memory except of the initial transfer of the images for caching   ImageIcon will use a BufferedImage under the hood - but basically allocating a BufferedImage with the proper graphics mode is the key  and there is no effort to do this right   2  The usual way of doing this is to draw a BufferedImage in an overridden paintComponent method of the JPanel  Although Java supports a good amount of additional goodies such as buffer chains controlling VolatileImages cached in the GPU memory  there is no need to use any of these since Java 6 which does a reasonably good job without exposing all of these details of GPU acceleration   Note that GPU acceleration may not work for certain operations  such as stretching translucent images    3  Do not add  Just paint it as mentioned above    Override protected void paintComponent Graphics g        super paintComponent g       g drawImage image  0  0  this         Adding  makes sense if the image is part of the layout  If you need this as a background or foreground image filling the JPanel  just draw in paintComponent  If you prefer brewing a generic Swing component which can show your image  then it is the same story  you may use a JComponent and override its paintComponent method  - and then add this to your layout of GUI components   4  How to convert the array to a Bufferedimage  Converting your byte arrays to PNG  then loading it is quite resource intensive  A better way is to convert your existing byte array to a BufferedImage   For that  do not use for loops and copy pixels  That is very very slow  Instead    learn the preferred byte structure of the BufferedImage  nowadays it is safe to assume RGB or RGBA  which is 4 bytes per pixel  learn the scanline and scansize in use  e g  you might have a 142 pixels wide image - but in the real life that will be stored as a 256 pixel wide byte array since it is faster to process that and mask the unused pixes by the GPU hardware  then once you have an array build according to these principles  the setRGB array method of the BufferedImage can copy your array to the BufferedImage

User · Answer

Here s how I do it  with a little more info on how to load an image    import java awt Graphics  import java awt image BufferedImage  import java io File  import java io IOException  import java util logging Level  import java util logging Logger  import javax imageio ImageIO  import javax swing JPanel   public class ImagePanel extends JPanel       private BufferedImage image       public ImagePanel            try                             image   ImageIO read new File  image name and path              catch  IOException ex                   handle exception                         Override     protected void paintComponent Graphics g            super paintComponent g           g drawImage image  0  0  this      see javadoc for more info on the parameters

User · Answer

Fred Haslam s way works fine   I had trouble with the filepath though  since I want to reference an image within my jar   To do this  I used   BufferedImage wPic   ImageIO read this getClass   getResource  snow png     JLabel wIcon   new JLabel new ImageIcon wPic      Since I only have a finite number  about 10  images that I need to load using this method  it works quite well   It gets file without having to have the correct relative filepath

[java] How to add an image to a JPanel?

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