Why does this image rendering benchmark crash on IOS but not in the simulator? - codenameone

Question

I tried to get a grasp of image rendering performance and created some code which draws full screen images using mutable images and PNGs.
The code runs fine in the simulator but on an iPhone SE it crashes after 50 seconds or short before a million images.
Is it a bug or is there another explanation since it doesn't crash in the simulator and I cannot see a memory leak in jvisualvm?
Here is the code:
public class FormMeasureImage extends Form implements Painter {
abstract class Wallpaper implements Painter {
private Component componentParent;
public Wallpaper(Component aComponentParent) {
componentParent = aComponentParent;
}
public void paint(Graphics aGraphics, Rectangle aRectangle) {
aGraphics.drawImage(
getImage(new Dimension(componentParent.getWidth(), componentParent.getHeight())),
0,
0);
}
public abstract Image getImage(Dimension aDimension);
}
class WallpaperTiledIcons extends Wallpaper {
private Image image;
private Dimension dimension;
public WallpaperTiledIcons(Component aComponentParent) {
super(aComponentParent);
}
public Image getImage(Dimension aDimension) {
if ((null == image || !dimension.equals(aDimension)) && null != aDimension) {
dimension = new Dimension(aDimension);
Label labelPattern = new Label("1234567890");
Style styleLabelPattern = labelPattern.getAllStyles();
styleLabelPattern.setBorder(Border.createEmpty());
styleLabelPattern.setMargin(0, 0, 0, 0);
// byte[] bytes = new byte[4];
// Arrays.fill(bytes, Style.UNIT_TYPE_PIXELS);
// styleLabelPattern.setPaddingUnit(bytes);
styleLabelPattern.setPadding(0, 0, 0, 1);
Dimension preferredSizeLabelPattern = labelPattern.getPreferredSize();
labelPattern.setSize(preferredSizeLabelPattern);
Image imagePattern = Image.createImage(
preferredSizeLabelPattern.getWidth(),
preferredSizeLabelPattern.getHeight(),
0x00000000);
Graphics graphicsImagePattern = imagePattern.getGraphics();
graphicsImagePattern.setAlpha(255);
labelPattern.paint(graphicsImagePattern);
image = Image.createImage(
aDimension.getWidth(),
aDimension.getHeight(),
0xff606060);
Graphics graphics = image.getGraphics();
if (graphics.isAntiAliasingSupported()) {
graphics.setAntiAliased(true);
}
int canvasWidth = preferredSizeLabelPattern.getWidth(), canvasHeight = preferredSizeLabelPattern.getHeight();
int[] clip = graphics.getClip();
Rectangle rectangleClip = new Rectangle(clip[0], clip[1], clip[2], clip[3]);
int columns = (rectangleClip.getX() + rectangleClip.getWidth()) / canvasWidth + 1;
int rows = (rectangleClip.getY() + rectangleClip.getHeight()) / canvasHeight + 1;
for (int row = 0; row < rows; row++) {
for (int column = 0; column < columns; column++) {
int x = canvasWidth * column;
int y = canvasHeight * row;
Rectangle rectangle = new Rectangle(x, y, canvasWidth, canvasHeight);
if (!rectangleClip.intersects(rectangle)) {
continue;
}
graphics.drawImage(imagePattern, x, y);
}
}
}
return image;
}
}
abstract class Stage {
long millisTotal;
long tally;
TextArea textArea;
public Stage(String aName) {
textArea = new TextArea();
textArea.setEditable(false);
getContentPane().add(textArea);
stages.add(this);
}
abstract void perform();
abstract boolean isPainted();
}
private Wallpaper wallpaper;
private List<Stage> stages = new ArrayList<>();
private Iterator<Stage> iteratorStages;
private Image imageEncoded;
public FormMeasureImage() {
super("FormMeasureImage", new BoxLayout(BoxLayout.Y_AXIS));
setScrollableX(false);
setScrollableY(true);
Style styleForm = getAllStyles();
styleForm.setBgTransparency(255);
styleForm.setBgPainter(this);
TextArea textArea = new TextArea();
textArea.setEditable(false);
textArea.setText("Measuring image throughput.");
add(textArea);
}
#Override
public void paint(Graphics aGraphics, Rectangle aRectangle) {
if (null == iteratorStages) {
new Stage("create") {
void perform() {
long millisBefore = System.currentTimeMillis();
wallpaper = new WallpaperTiledIcons(FormMeasureImage.this);
wallpaper.getImage(aRectangle.getSize());
millisTotal += System.currentTimeMillis() - millisBefore;
tally++;
textArea.setText("create: " + millisTotal + " / " + tally);
}
boolean isPainted() {
return false;
}
};
new Stage("mutable") {
void perform() {
long millisBefore = System.currentTimeMillis();
for (int index = 0; index < 1000; index++) {
wallpaper.paint(aGraphics, aRectangle);
tally++;
}
millisTotal += System.currentTimeMillis() - millisBefore;
textArea.setText("mutable: " + millisTotal + " / " + tally);
}
boolean isPainted() {
return true;
}
};
new Stage("encoding") {
void perform() {
long millisBefore = System.currentTimeMillis();
try {
millisBefore = System.currentTimeMillis();
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.getImageIO().save(wallpaper.getImage(null), byteArrayOutputStream, ImageIO.FORMAT_PNG, 1);
byteArrayOutputStream.close();
imageEncoded = Image.createImage(new ByteArrayInputStream(byteArrayOutputStream.toByteArray()));
tally++;
millisTotal += System.currentTimeMillis() - millisBefore;
textArea.setText("encoding: " + millisTotal + " / " + tally);
} catch (IOException e) {
throw new RuntimeException(e.toString());
}
millisTotal += System.currentTimeMillis() - millisBefore;
tally++;
textArea.setText("encoding: " + millisTotal + " / " + tally);
}
boolean isPainted() {
return false;
}
};
new Stage("encoded") {
void perform() {
long millisBefore = System.currentTimeMillis();
for (int index = 0; index < 1000; index++) {
aGraphics.drawImage(
imageEncoded,
0,
0);
tally++;
}
millisTotal += System.currentTimeMillis() - millisBefore;
textArea.setText("encoded: " + millisTotal + " / " + tally);
}
boolean isPainted() {
return true;
}
};
iteratorStages = stages.iterator();
}
while (!perform().isPainted()) {;}
}
private Stage perform() {
if (!iteratorStages.hasNext()) {
iteratorStages = stages.iterator();
}
Stage stage = iteratorStages.next();
stage.perform();
return stage;
}
}

Answer 1

It seems that the test case included an EDT violation of decoding off the EDT. This can work for some cases but because of the heavy usage it crashes.
Making UI code threadsafe is a difficult task which is doubly so cross platforms.