/**
* Render image consisting of computation result. This method will be run in background thread, so
* it can have a while. Implementation should periodically check if status.isCancelled() and abort
* (return null) if so.
*
* @param xAxis values for x dimension
* @param yAxis values for y dimension
* @param status status to be checked periodically
* @return computation result as two-dimensional array
* @throws Exception if computational error occurs
*/
public BufferedImage renderImage(
Axis<Number> xAxis, Axis<Number> yAxis, ImageRendererStatus status) throws Exception {
ImageResult result;
int width = (int) xAxis.getWidth();
int height = (int) yAxis.getHeight();
double xMin = xAxis.getValueForDisplay(0.0).doubleValue();
double xMax = xAxis.getValueForDisplay(width - 1).doubleValue();
double yMin = yAxis.getValueForDisplay(0.0).doubleValue();
double yMax = yAxis.getValueForDisplay(height - 1).doubleValue();
PreferencesWithAxes<P> pax =
new PreferencesWithAxes<P>(getPreferences(), width, height, xMin, xMax, yMin, yMax);
CachedImageResult<PreferencesWithAxes<P>> cache = cache_;
if (cache != null && cache.preferences.equals(pax)) {
result = cache.result;
} else {
result = compute(pax, status);
if (result == null) {
return null;
}
cache_ = new CachedImageResult<PreferencesWithAxes<P>>(pax, result);
}
BufferedImage image = new BufferedImage(pax.width, pax.height, BufferedImage.TYPE_INT_RGB);
if (result == null) {
return null;
}
double max = 0;
for (int ix = 0; ix < pax.width; ++ix) {
for (int iy = 0; iy < pax.height; ++iy) {
max = Math.max(max, result.values[ix][iy].abs());
}
}
int[] palette = palette_.getPalette();
boolean inverted = inverted_;
for (int ix = 0; ix < pax.width; ++ix) {
if (status.isCancelled()) {
return null;
}
for (int iy = 0; iy < pax.height; ++iy) {
double t = result.values[ix][iy].abs() / max;
if (inverted) {
t = 1.0 - t;
}
int value = palette[Math.min((int) Math.floor(t * palette.length), palette.length - 1)];
image.setRGB(ix, iy, value);
}
}
return image;
}
@Override
public Iterable<Data<X, Y>> getVisibleData() {
final Axis<X> xAxis = getChart().getXAxis();
final double width = xAxis.getWidth();
List<Data<X, Y>> visible =
getData()
.filtered(
new Predicate<Data<X, Y>>() {
@Override
public boolean test(Data<X, Y> item) {
final double p = xAxis.getDisplayPosition(item.getXValue());
return p >= 0 && p <= width;
}
});
return visible;
}