58 lines
1.6 KiB
Java
58 lines
1.6 KiB
Java
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package org.jcodec.scale;
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import org.jcodec.common.model.Size;
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public class BicubicResampler extends BaseResampler {
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private short[][] horizontalTaps;
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private short[][] verticalTaps;
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private static double alpha = 0.6D;
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public BicubicResampler(Size from, Size to) {
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super(from, to);
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this.horizontalTaps = buildFilterTaps(to.getWidth(), from.getWidth());
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this.verticalTaps = buildFilterTaps(to.getHeight(), from.getHeight());
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}
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private static short[][] buildFilterTaps(int to, int from) {
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double[] taps = new double[4];
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short[][] tapsOut = new short[to][4];
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double ratio = (double)from / (double)to;
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double toByFrom = (double)to / (double)from;
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double srcPos = 0.0D;
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for (int i = 0; i < to; i++) {
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double fraction = srcPos - (double)(int)srcPos;
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for (int t = -1; t < 3; t++) {
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double d = (double)t - fraction;
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if (to < from)
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d *= toByFrom;
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double x = Math.abs(d);
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double xx = x * x;
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double xxx = xx * x;
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if (d >= -1.0D && d <= 1.0D) {
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taps[t + 1] = (2.0D - alpha) * xxx + (-3.0D + alpha) * xx + 1.0D;
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} else if (d < -2.0D || d > 2.0D) {
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taps[t + 1] = 0.0D;
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} else {
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taps[t + 1] = -alpha * xxx + 5.0D * alpha * xx - 8.0D * alpha * x + 4.0D * alpha;
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}
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}
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normalizeAndGenerateFixedPrecision(taps, 7, tapsOut[i]);
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srcPos += ratio;
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}
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return tapsOut;
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}
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protected short[] getTapsX(int dstX) {
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return this.horizontalTaps[dstX];
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}
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protected short[] getTapsY(int dstY) {
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return this.verticalTaps[dstY];
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}
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protected int nTaps() {
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return 4;
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}
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}
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