我写了一个简单的任务来缩放我的图像，但它似乎对 PNG 文件有问题。
这是任务的内容[它的重要部分]：
<image srcdir="${imgResizeDir}" destdir="${imgResizeDir}/md" overwrite="yes" >
<scale width="75%" height="75%"/>
<regexpmapper from="^(.*)-hd\.(.*)$$" to="\1-md.\2"/>
</image>
当我运行它时，我最终遇到了这个错误：
Error: IOException occurs when search for propriate codecs.
Occurs in: com.sun.media.jai.codec.ImageCodec
java.io.IOException: Bad file descriptor
at java.io.RandomAccessFile.seek(Native Method)
at com.sun.media.jai.codec.FileSeekableStream.readPage(FileSeekableStream.java:141)
at com.sun.media.jai.codec.FileSeekableStream.read(FileSeekableStream.java:181)
at com.sun.media.jai.codec.SeekableStream.readFully(SeekableStream.java:327)
at com.sun.media.jai.codec.SeekableStream.readFully(SeekableStream.java:306)
at com.sun.media.jai.codec.ImageCodec.getDecoderNames(ImageCodec.java:274)
at com.sun.media.jai.opimage.StreamRIF.create(StreamRIF.java:80)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.media.jai.FactoryCache.invoke(FactoryCache.java:130)
at javax.media.jai.OperationRegistry.invokeFactory(OperationRegistry.java:1679)
at javax.media.jai.ThreadSafeOperationRegistry.invokeFactory(ThreadSafeOperationRegistry.java:481)
at javax.media.jai.registry.RIFRegistry.create(RIFRegistry.java:340)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:830)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:810)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:810)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.JAI.createNS(JAI.java:1103)
at javax.media.jai.JAI.create(JAI.java:977)
at javax.media.jai.JAI.create(JAI.java:1672)
at org.apache.tools.ant.taskdefs.optional.image.Image.processFile(Image.java:320)
at org.apache.tools.ant.taskdefs.optional.image.Image.processDir(Image.java:253)
at org.apache.tools.ant.taskdefs.optional.image.Image.execute(Image.java:374)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:390)
at org.apache.tools.ant.Target.performTasks(Target.java:411)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
at org.apache.tools.ant.Main.runBuild(Main.java:809)
at org.apache.tools.ant.Main.startAnt(Main.java:217)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.intellij.rt.ant.execution.AntMain2.main(AntMain2.java:29)
java.lang.RuntimeException: - Unable to render RenderedOp for this operation.
at org.apache.tools.ant.taskdefs.optional.image.Image.processFile(Image.java:343)
at org.apache.tools.ant.taskdefs.optional.image.Image.processDir(Image.java:253)
at org.apache.tools.ant.taskdefs.optional.image.Image.execute(Image.java:374)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:390)
at org.apache.tools.ant.Target.performTasks(Target.java:411)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
at org.apache.tools.ant.Main.runBuild(Main.java:809)
at org.apache.tools.ant.Main.startAnt(Main.java:217)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.intellij.rt.ant.execution.AntMain2.main(AntMain2.java:29)
Caused by: java.lang.RuntimeException: - Unable to render RenderedOp for this operation.
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:838)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:810)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.RenderedOp.createInstance(RenderedOp.java:810)
at javax.media.jai.RenderedOp.createRendering(RenderedOp.java:878)
at javax.media.jai.RenderedOp.getRendering(RenderedOp.java:899)
at javax.media.jai.JAI.createNS(JAI.java:1103)
at javax.media.jai.JAI.create(JAI.java:977)
at javax.media.jai.JAI.create(JAI.java:1672)
at org.apache.tools.ant.taskdefs.optional.image.Image.processFile(Image.java:320)
... 24 more
如果我从宽度和高度中删除 % 符号，我最终会得到具有适当尺寸的图像，但是 PNG 被搞砸了[它们看起来像是覆盖着半透明的黑色层]。大多数图像都是PNG，我必须使用％。
我在 MacOS Lion 上使用 Apache Ant 1.8.2 运行此任务。Java版本：1.6.0_31
我应该在我的蚂蚁中添加一些东西来完成这项工作吗？
谢谢