No_internal_or_system_editor

This problem is typically encountered during a fresh install of
LateralGM on Linux, when the
user attempts to Edit a sprite subimage, a
background image, or a
sound's data. The user will click the button, and
the program will pause for a very brief moment, and then the program
will seem to behave as though the user never clicked the button.

Note that this problem can be avoided entirely by following the
#Workaround before ever attempting to edit
any images in LateralGM.

Stack Trace

The keen user might notice the terminal will dump the following lovely
stack
trace:

Exception in thread "AWT-EventQueue-0" java.lang.UnsupportedOperationException: no internal or system sprite editor
        at org.lateralgm.subframes.SpriteFrame$ImageEditor.start(SpriteFrame.java:1054)
        at org.lateralgm.subframes.SpriteFrame$ImageEditor.<init>(SpriteFrame.java:1042)
        at org.lateralgm.subframes.SpriteFrame.editSubimage(SpriteFrame.java:988)
        at org.lateralgm.subframes.SpriteFrame.handleToolbarEvent(SpriteFrame.java:834)
        at org.lateralgm.subframes.SpriteFrame.actionPerformed(SpriteFrame.java:819)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
        at java.awt.Component.processMouseEvent(Component.java:6504)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
        at java.awt.Component.processEvent(Component.java:6269)
        at java.awt.Container.processEvent(Container.java:2229)
        at java.awt.Component.dispatchEventImpl(Component.java:4860)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Component.dispatchEvent(Component.java:4686)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
        at java.awt.Container.dispatchEventImpl(Container.java:2273)
        at java.awt.Window.dispatchEventImpl(Window.java:2713)
        at java.awt.Component.dispatchEvent(Component.java:4686)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
        at java.awt.EventQueue.access$000(EventQueue.java:101)
        at java.awt.EventQueue$3.run(EventQueue.java:666)
        at java.awt.EventQueue$3.run(EventQueue.java:664)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:680)
        at java.awt.EventQueue$4.run(EventQueue.java:678)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Caused by: java.lang.UnsupportedOperationException: The EDIT action is not supported on the current platform!
        at java.awt.Desktop.checkActionSupport(Desktop.java:225)
        at java.awt.Desktop.edit(Desktop.java:300)
        at org.lateralgm.subframes.SpriteFrame$ImageEditor.start(SpriteFrame.java:1050)
        ... 40 more

The two unindented lines are the ones that tell the story:

UnsupportedOperationException: no internal or system sprite editor
Caused by: UnsupportedOperationException: The EDIT action is not supported on the current platform!

Explanation

The Stack Trace Exception is just telling you that you have specified
that LGM should use an external sprite editor (the default behavior for
LGM), but your operating system/platform does not support the EDIT
action. This is a known Java bug
7035369
that affects Linux platforms (especially Debian-based).

Unfortunately, the bug has been there for ages, and it doesn't seem like
any effort is being put into correcting it, so we have to provide a
workaround. Since there's not a nice way to figure out what your image
editor on Linux is (the nice way would have been the EDIT action...),
and we cannot assume that you have a specific editor installed (we used
to assume the GIMP, but Ubuntu stopped shipping with that, so now Ubuntu
pretty much doesn't have an image editor), which means that you, the
user, must specify a desired image editor.

Workaround

LateralGM allows you to specify a desired resource editor in its
Settings/Preferences. Please see Overriding
settings. The properties that you would
wish to modify are:

• externalBackgroundEditorCommand
• externalSpriteEditorCommand
• externalSoundEditorCommand

And a typical value for, say, Gimp, would be: gimp %s

Long Term Solution

A long term solution is planned by simply providing an image editor with
LateralGM (similar to what Game Maker does). In order for it to be
included, however, it would need to meet several criteria.

• It would need to be small in filesize. LateralGM is only 1-2 MB, and
  it seems ridiculous to include an image editor that is larger than
  LGM itself - which already rules out most of the existing image
  editors.
• It would need to be GNU GPL 3+ compatible, as this is the
  license LGM is written in. This rules out
  several more image editors.
• It would need to be cross-platform, as LGM is cross-platform. A good
  way to achieve this would be to be written in Java.
• It is preferred that it is written in Java, so
  that it can be completely internal, rather than having to launch an
  external program. This pretty much rules out the rest of them.

Seeing as we've pretty much ruled out every image editor in existence,
this leaves the final solution: build our own. And that's exactly what
we've proposed. Enter Java Easy Image Editor (JEIE).