#37423 better signal rendering

.gitignore

@@ -24,6 +24,7 @@ svarog/output.bin
 # NetBeans configuration
 nb-configuration.xml
 nbactions.xml
+nbproject/
 
 # InteliJ
 .idea

svarog/src/main/java/org/signalml/app/view/signal/SignalPlot.java

@@ -4,7 +4,6 @@
 
 package org.signalml.app.view.signal;
 
-import static java.lang.String.format;
 import static org.signalml.app.util.i18n.SvarogI18n._;
 import static org.signalml.app.util.i18n.SvarogI18n._R;
 
@@ -21,7 +20,6 @@
 import java.awt.RenderingHints;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
-import java.awt.geom.GeneralPath;
 import java.awt.geom.Point2D;
 import java.beans.PropertyChangeEvent;
 import java.beans.PropertyChangeListener;
@@ -59,7 +57,6 @@
 import org.signalml.domain.montage.system.ChannelFunction;
 import org.signalml.domain.signal.SignalProcessingChain;
 import org.signalml.domain.signal.raw.RawSignalSampleSource;
-import org.signalml.domain.signal.samplesource.ChangeableMultichannelSampleSource;
 import org.signalml.domain.signal.samplesource.MultichannelSampleSource;
 import org.signalml.domain.signal.samplesource.OriginalMultichannelSampleSource;
 import org.signalml.domain.tag.StyledTagSet;
@@ -147,7 +144,7 @@
 	private int blocksPerPage;
 	private final long firstSampleTimestamp;
 
-	private GeneralPath generalPath = new GeneralPath(GeneralPath.WIND_EVEN_ODD,50000);
+	private final SignalRenderer renderer = new SignalRenderer();
 
 	private SignalPlotColumnHeader signalPlotColumnHeader = null;
 	private SignalPlotRowHeader signalPlotRowHeader = null;
@@ -805,7 +802,6 @@ private int computeVisibleChannelCount(int height) {
 	@Override
 	protected void paintComponent(Graphics gOrig) {
 
-		int i;
 		Graphics2D g = (Graphics2D)gOrig;
 		Rectangle clip = g.getClipBounds();
 
@@ -832,7 +828,7 @@ protected void paintComponent(Graphics gOrig) {
 			int endBlock = (int) Math.ceil(clipEndX / pixelPerBlock);
 
 			g.setColor(Color.GRAY);
-			for (i=startBlock; i <= endBlock; i++) {
+			for (int i=startBlock; i <= endBlock; i++) {
 				g.drawLine((int)(i * pixelPerBlock), clip.y, (int)(i * pixelPerBlock), clipEndY);
 			}
 		}
@@ -846,7 +842,7 @@ protected void paintComponent(Graphics gOrig) {
 			int endPage = (int) Math.ceil(clipEndX / pixelPerPage);
 
 			g.setColor(Color.RED);
-			for (i=startPage; i <= endPage; i++) {
+			for (int i=startPage; i <= endPage; i++) {
 				g.drawLine((int)(i * pixelPerPage), clip.y, (int)(i * pixelPerPage), clipEndY);
 			}
 		}
@@ -900,11 +896,6 @@ protected void paintComponent(Graphics gOrig) {
 			g.setComposite(AlphaComposite.SrcOver);
 		}
 
-		int firstSample, lastSample, length;
-		double realX, x, y;
-		double lastX = 0;
-		double lastY = 0;
-
 		visibleCount = 0;
 		channel=startChannel;
 		while (visibleCount < maxNumberOfChannels && channel<channelCount) {
@@ -915,12 +906,12 @@ protected void paintComponent(Graphics gOrig) {
 			visibleCount ++;
 			// those must be offset by one to get correct partial redraw
 			// offset again by one, this time in terms of samples
-			firstSample = (int) Math.max(0, Math.floor((clip.x-1) / timeZoomFactor) - 1);
-			lastSample = (int) Math.min(sampleCount[channel] - 1, Math.ceil((clipEndX+1) / timeZoomFactor) + 1);
+			int firstSample = (int) Math.max(0, Math.floor((clip.x-1) / timeZoomFactor) - 1);
+			int lastSample = (int) Math.min(sampleCount[channel] - 1, Math.ceil((clipEndX+1) / timeZoomFactor) + 1);
 			if (lastSample < firstSample) {
 				continue;
 			}
-			length = 1 + lastSample - firstSample;
+			int length = 1 + lastSample - firstSample;
 			if (samples == null || samples.length < length) {
 				samples = new double[length];
 			}
@@ -935,118 +926,14 @@ protected void paintComponent(Graphics gOrig) {
 				throw ex;
 			}
 
-			realX = firstSample * timeZoomFactor;
-
 			double pixelPerValueForChannel= channelsPlotOptionsModel.getPixelsPerValue(channel);
-			y = samples[0] * pixelPerValueForChannel;
-
-			if (clamped)
-			{
-				if (y > clampLimit) {
-					y = channelLevel[channel] - clampLimit;
-				} else if (y < -clampLimit) {
-					y = channelLevel[channel] + clampLimit;
-				} else {
-					y = channelLevel[channel] - y;
-				}
-			} else {
-				y = channelLevel[channel] - y;
-			}
-
-			generalPath.reset();
-
-			if (!antialiased) {
-
-				x = StrictMath.floor(realX + 0.5);
-				y = StrictMath.floor(y + 0.5);
-
-				generalPath.moveTo(x, y);
-
-				lastX = x;
-				lastY = y;
-
-			} else {
-
-				generalPath.moveTo(realX, y);
-
-			}
-
-			int sampleSkip = 1;
-
-			if (optimizeSignalDisplaying) {
-				//optimize signal display displays at most two sample for each pixel.
-				sampleSkip = (int) (1/timeZoomFactor);
-				sampleSkip /= 2;
-				if (sampleSkip < 1)
-					sampleSkip = 1;
-			}
-
-			//if the user selects a piece of the signal, we shouldn't break the rule
-			//that we always take the sampleSkip's sample!
-			int startingFrom = sampleSkip - firstSample % sampleSkip;
-			if (firstSample % sampleSkip == 0)
-				startingFrom = 0;
-
-			if (optimizeSignalDisplaying) {
-				//in each step we want to display the same samples even though few new were added
-				OriginalMultichannelSampleSource source = signalChain.getSource();
-				if (source instanceof ChangeableMultichannelSampleSource) {
-					ChangeableMultichannelSampleSource changeableSource = (ChangeableMultichannelSampleSource) source;
-					long addedSamples = changeableSource.getAddedSamplesCount();
-
-					int changeableCorrection = 0;
-					if (addedSamples % sampleSkip != 0)
-						changeableCorrection = (int) (sampleSkip - addedSamples % sampleSkip);
-					startingFrom += changeableCorrection;
-					if (startingFrom >= sampleSkip)
-						startingFrom -= sampleSkip;
-				}
-			}
-
-			for (i=startingFrom; i<length; i += sampleSkip) {
-
-				y = samples[i] * pixelPerValueForChannel;
-
-				if (clamped)
-				{
-					if (y > clampLimit) {
-						y = channelLevel[channel] - clampLimit;
-					} else if (y < -clampLimit) {
-						y = channelLevel[channel] + clampLimit;
-					} else {
-						y = channelLevel[channel] - y;
-					}
-				} else {
-					y = channelLevel[channel] - y;
-				}
-
-				realX = ((firstSample+i) * timeZoomFactor);
-
-				if (antialiased) {
-
-					generalPath.lineTo(realX, y);
 
-				} else {
-
-					// if not antialiased then round to integer in order to prevent aliasing affects
-					// (which cause slave plots to display the signal slightly differently)
-					// expand Math.round for performance, StrictMath.floor is native
-					x = StrictMath.floor(realX + 0.5);
-					y = StrictMath.floor(y + 0.5);
-
-					if (x != lastX || y != lastY) {
-						generalPath.lineTo(x, y);
-					}
-
-					lastX = x;
-					lastY = y;
-
-				}
-
-
-			}
+			renderer.render(
+					g, channel, samples, length, firstSample, clip,
+					channelLevel[channel], timeZoomFactor, pixelPerValueForChannel,
+					clamped ? clampLimit : null
+			);
 
-			g.draw(generalPath);
 			channel++;
 		}
 

svarog/src/main/java/org/signalml/app/view/signal/SignalRenderer.java

+package org.signalml.app.view.signal;
+
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.geom.GeneralPath;
+
+/**
+ * Class responsible for signal rendering.
+ * Objects of this class are instantiated and used by SignalPlot.
+ * This is a stateless object with respect to the render() method.
+ *
+ * @author piotr.rozanski@braintech.pl
+ */
+public class SignalRenderer {
+
+	private int pointCount = 0;
+	private Point.Double[] points;
+	private final GeneralPath shape = new GeneralPath(GeneralPath.WIND_EVEN_ODD, 2048);
+
+	/**
+	 * Perform signal rendering.
+	 * Only the signal itself (time vs value) will be rendered,
+	 * without any axes or additional labels.
+	 *
+	 * @param g  graphics object (canvas) to render the signal onto
+	 * @param channel  channel number (first channel = 0)
+	 * @param samples  array of sample values
+	 * @param sampleCount  number of samples to use (sampleCount ≤ samples.count)
+	 * @param firstSample  actual index of the first sample relative to the start of the signal
+	 * @param clip  clipping rectangle for rendering
+	 * @param channelLevel  vertical offset of channel in pixels
+	 * @param xScale  scale coefficient for time axis
+	 * @param yScale  scale coefficient for value axis
+	 * @param clampLimit  half of the channel height in pixels if signal is to be clamped, null otherwise
+	 */
+	public void render(Graphics2D g, int channel, double[] samples, int sampleCount, int firstSample, Rectangle clip, double channelLevel, double xScale, double yScale, Integer clampLimit) {
+		if (sampleCount > 2 * clip.width) {
+			// we have much more samples than pixels,
+			// so at each pixel we want to represent minimum and maximum values
+			setPointCount(2 * clip.width);
+			for (int p=0; p<clip.width; ++p) {
+				int x = clip.x + p;
+				// pixel at x corresponds to samples [i0..iN-1]
+				int i0 = Math.max(0, (int) Math.round((x - 0.5) / xScale) - firstSample);
+				int iN = Math.min(sampleCount-1, (int) Math.round((x + 0.5) / xScale) - firstSample);
+				double min, max;
+				min = max = samples[i0] * yScale;
+				for (int i=i0+1; i<iN; ++i) {
+					double sample = samples[i] * yScale;
+					min = Math.min(min, sample);
+					max = Math.max(max, sample);
+				}
+				int odd = p & 1;
+				int even = 1 - odd;
+				// if p is even, we draw a line from min to max
+				// if p is odd, we draw a line from max to min
+				points[2*p+odd].x = x;
+				points[2*p+odd].y = min;
+				points[2*p+even].x = x;
+				points[2*p+even].y = max;
+			}
+		} else {
+			// we have as much signal samples as pixels,
+			// so we draw a line with all samples
+			setPointCount(sampleCount);
+			for (int p=0; p<sampleCount; ++p) {
+				int i = p;
+				points[p].x = (firstSample+i) * xScale;
+				points[p].y = samples[i] * yScale;
+			}
+		}
+
+		// drawing line from points[]
+		shape.reset();
+		shape.moveTo(points[0].x, translateY(channelLevel, points[0].y, clampLimit));
+		for (int p=1; p<pointCount; ++p) {
+			double y = translateY(channelLevel, points[p].y, clampLimit);
+			shape.lineTo(points[p].x, y);
+		}
+		g.draw(shape);
+	}
+
+	private void setPointCount(int pointCount) {
+		this.pointCount = pointCount;
+		if (points == null || points.length < pointCount) {
+			points = new Point.Double[pointCount];
+			for (int i=0; i<pointCount; ++i) {
+				points[i] = new Point.Double();
+			}
+		}
+	}
+
+	private double translateY(double y0, double y, Integer clampLimit) {
+		if (clampLimit != null) {
+			if (y > clampLimit) {
+				y = clampLimit;
+			} else if (y < -clampLimit) {
+				y = -clampLimit;
+			}
+		}
+		return y0 - y;
+	}
+
+}