Fix gesture trail width calculation (92aee352) · Commits · e / os / android_packages_inputmethods_LatinIME

java/src/com/android/inputmethod/keyboard/internal/GesturePreviewTrail.java

+27 −9

Original line number	Diff line number	Diff line
		@@ -101,6 +101,16 @@ final class GesturePreviewTrail {
		}
		}

		/**
		* Calculate the alpha of a gesture trail.
		* A gesture trail starts from fully opaque. After mFadeStartDelay has been passed, the alpha
		* of a trail reduces in proportion to the elapsed time. Then after mFadeDuration has been
		* passed, a trail becomes fully transparent.
		*
		* @param elapsedTime the elapsed time since a trail has been made.
		* @param params gesture trail display parameters
		* @return the width of a gesture trail
		*/
		private static int getAlpha(final int elapsedTime, final Params params) {
		if (elapsedTime < params.mFadeoutStartDelay) {
		return Constants.Color.ALPHA_OPAQUE;
		@@ -111,10 +121,19 @@ final class GesturePreviewTrail {
		return Constants.Color.ALPHA_OPAQUE - decreasingAlpha;
		}

		/**
		* Calculate the width of a gesture trail.
		* A gesture trail starts from the width of mTrailStartWidth and reduces its width in proportion
		* to the elapsed time. After mTrailEndWidth has been passed, the width becomes mTraiLEndWidth.
		*
		* @param elapsedTime the elapsed time since a trail has been made.
		* @param params gesture trail display parameters
		* @return the width of a gesture trail
		*/
		private static float getWidth(final int elapsedTime, final Params params) {
		return Math.max((params.mTrailLingerDuration - elapsedTime)
		* (params.mTrailStartWidth - params.mTrailEndWidth)
		/ params.mTrailLingerDuration, 0.0f);
		final int deltaTime = params.mTrailLingerDuration - elapsedTime;
		final float deltaWidth = params.mTrailStartWidth - params.mTrailEndWidth;
		return (deltaTime * deltaWidth) / params.mTrailLingerDuration + params.mTrailEndWidth;
		}

		private final RoundedLine mRoundedLine = new RoundedLine();
		@@ -154,7 +173,7 @@ final class GesturePreviewTrail {
		final RoundedLine line = mRoundedLine;
		int p1x = getXCoordValue(xCoords[startIndex]);
		int p1y = yCoords[startIndex];
		int lastTime = sinceDown - eventTimes[startIndex];
		final int lastTime = sinceDown - eventTimes[startIndex];
		float maxWidth = getWidth(lastTime, params);
		float r1 = maxWidth / 2.0f;
		// Initialize bounds rectangle.
		@@ -167,20 +186,19 @@ final class GesturePreviewTrail {
		final float r2 = width / 2.0f;
		// Draw trail line only when the current point isn't a down point.
		if (!isDownEventXCoord(xCoords[i])) {
		final int alpha = getAlpha(elapsedTime, params);
		paint.setAlpha(alpha);
		final Path path = line.makePath(p1x, p1y, r1, p2x, p2y, r2);
		if (path != null) {
		final int alpha = getAlpha(elapsedTime, params);
		paint.setAlpha(alpha);
		canvas.drawPath(path, paint);
		outBoundsRect.union(p2x, p2y);
		}
		// Take union for the bounds.
		outBoundsRect.union(p2x, p2y);
		maxWidth = Math.max(maxWidth, width);
		}
		}
		p1x = p2x;
		p1y = p2y;
		r1 = r2;
		lastTime = elapsedTime;
		}
		// Take care of trail line width.
		final int inset = -((int)maxWidth + 1);