Merge "Avoid drawing too long gesture preview trails"
diff --git a/java/src/com/android/inputmethod/keyboard/internal/GestureStrokeWithPreviewPoints.java b/java/src/com/android/inputmethod/keyboard/internal/GestureStrokeWithPreviewPoints.java
index 235bcd7..7a51e25 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/GestureStrokeWithPreviewPoints.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/GestureStrokeWithPreviewPoints.java
@@ -34,14 +34,18 @@
private int mLastY;
private double mMinPreviewSamplingDistance;
private double mDistanceFromLastSample;
+ private double mInterpolationDistanceThreshold;
// TODO: Move these constants to resource.
+ // TODO: Use "dp" instead of ratio to the keyWidth because table has rather large keys.
// The minimum trail distance between sample points for preview in keyWidth unit when using
// interpolation.
private static final float MIN_PREVIEW_SAMPLING_RATIO_TO_KEY_WIDTH = 0.2f;
// The angular threshold to use interpolation in radian. PI/12 is 15 degree.
private static final double INTERPOLATION_ANGULAR_THRESHOLD = Math.PI / 12.0d;
- private static final int MAX_INTERPOLATION_PARTITION = 4;
+ // The distance threshold to use interpolation in keyWidth unit.
+ private static final float INTERPOLATION_DISTANCE_THRESHOLD_TO_KEY_WIDTH = 0.5f;
+ private static final int MAX_INTERPOLATION_PARTITIONS = 6;
public GestureStrokeWithPreviewPoints(final int pointerId, final GestureStrokeParams params) {
super(pointerId, params);
@@ -66,6 +70,7 @@
public void setKeyboardGeometry(final int keyWidth, final int keyboardHeight) {
super.setKeyboardGeometry(keyWidth, keyboardHeight);
mMinPreviewSamplingDistance = keyWidth * MIN_PREVIEW_SAMPLING_RATIO_TO_KEY_WIDTH;
+ mInterpolationDistanceThreshold = keyWidth * INTERPOLATION_DISTANCE_THRESHOLD_TO_KEY_WIDTH;
}
private boolean needsSampling(final int x, final int y) {
@@ -138,14 +143,20 @@
mInterpolator.setInterval(p0, p1, p2, p3);
final double m1 = Math.atan2(mInterpolator.mSlope1Y, mInterpolator.mSlope1X);
final double m2 = Math.atan2(mInterpolator.mSlope2Y, mInterpolator.mSlope2X);
- final double dm = Math.abs(angularDiff(m2, m1));
- final int partition = Math.min((int)Math.ceil(dm / INTERPOLATION_ANGULAR_THRESHOLD),
- MAX_INTERPOLATION_PARTITION);
+ final double deltaAngle = Math.abs(angularDiff(m2, m1));
+ final int partitionsByAngle = (int)Math.ceil(
+ deltaAngle / INTERPOLATION_ANGULAR_THRESHOLD);
+ final double deltaDistance = Math.hypot(mInterpolator.mP1X - mInterpolator.mP2X,
+ mInterpolator.mP1Y - mInterpolator.mP2Y);
+ final int partitionsByDistance = (int)Math.ceil(deltaDistance
+ / mInterpolationDistanceThreshold);
+ final int partitions = Math.min(MAX_INTERPOLATION_PARTITIONS,
+ Math.max(partitionsByAngle, partitionsByDistance));
final int t1 = eventTimes.get(d1);
final int dt = pt[p2] - pt[p1];
d1++;
- for (int i = 1; i < partition; i++) {
- final float t = i / (float)partition;
+ for (int i = 1; i < partitions; i++) {
+ final float t = i / (float)partitions;
mInterpolator.interpolate(t);
eventTimes.add(d1, (int)(dt * t) + t1);
xCoords.add(d1, (int)mInterpolator.mInterpolatedX);