App crashes at some point when canvas are created

Question

This is a bit difficult to describe... I've built a number of canvases (20-100 canvases) inside of a scroll pane. At the beginning it all works fine but after I change the number of canvases (e.g. 20 -> 40 -> 80 -> 100 -> ... etc.) I get the following NullPointerException at some point.

java.lang.NullPointerException
at com.sun.javafx.sg.prism.NGCanvas$RenderBuf.validate(NGCanvas.java:213)
at com.sun.javafx.sg.prism.NGCanvas.initCanvas(NGCanvas.java:640)
at com.sun.javafx.sg.prism.NGCanvas.renderContent(NGCanvas.java:603)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.renderForClip(NGNode.java:2294)
at com.sun.javafx.sg.prism.NGNode.renderRectClip(NGNode.java:2188)
at com.sun.javafx.sg.prism.NGNode.renderClip(NGNode.java:2214)
at com.sun.javafx.sg.prism.CacheFilter.impl_renderNodeToCache(CacheFilter.java:671)
at com.sun.javafx.sg.prism.CacheFilter.render(CacheFilter.java:575)
at com.sun.javafx.sg.prism.NGNode.renderCached(NGNode.java:2358)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2044)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:235)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:577)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2053)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1945)
at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:477)
at com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:323)
at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:125)
at java.lang.Thread.run(Thread.java:748)

I did some research and found this Cannot use large Canvas as ScrollPane. The canvases, that I create, have a width of 1338 and a height 326 (or 54). I thought that maybe the size of the canvases get bigger by changing a number of canvases I need, so that the error appears, but this is not happening.

a colleague of mine told me to add "-Dprism.order=sw" in the run configurations and it works, but the performance is a bit slower than before. — Yupp, Jan 10 '19 at 10:56
Not surprising; as suggested [here](https://stackoverflow.com/a/44141878/230513), continually (re-) rendering a `Canvas` is expensive, while displaying a flat image is cheap; more [here](https://stackoverflow.com/a/45685372/230513). — trashgod, Jan 10 '19 at 11:17
Also consider a `ListView` with a custom cell factory; see `fixedCellSize` about performance. — trashgod, Jan 10 '19 at 11:29
So after I have drawn everything into the canvas I would take a snapshot of it? I gonna try it out and see if It works. — Yupp, Jan 14 '19 at 06:40

App crashes at some point when canvas are created

0 Answers0