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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.gallery3d.filtershow.imageshow;
import android.graphics.Rect;
import android.graphics.RectF;
public class GeometryMath {
// Math operations for 2d vectors
public static float clamp(float i, float low, float high) {
return Math.max(Math.min(i, high), low);
}
public static float[] lineIntersect(float[] line1, float[] line2) {
float a0 = line1[0];
float a1 = line1[1];
float b0 = line1[2];
float b1 = line1[3];
float c0 = line2[0];
float c1 = line2[1];
float d0 = line2[2];
float d1 = line2[3];
float t0 = a0 - b0;
float t1 = a1 - b1;
float t2 = b0 - d0;
float t3 = d1 - b1;
float t4 = c0 - d0;
float t5 = c1 - d1;
float denom = t1 * t4 - t0 * t5;
if (denom == 0)
return null;
float u = (t3 * t4 + t5 * t2) / denom;
float[] intersect = {
b0 + u * t0, b1 + u * t1
};
return intersect;
}
public static float[] shortestVectorFromPointToLine(float[] point, float[] line) {
float x1 = line[0];
float x2 = line[2];
float y1 = line[1];
float y2 = line[3];
float xdelt = x2 - x1;
float ydelt = y2 - y1;
if (xdelt == 0 && ydelt == 0)
return null;
float u = ((point[0] - x1) * xdelt + (point[1] - y1) * ydelt)
/ (xdelt * xdelt + ydelt * ydelt);
float[] ret = {
(x1 + u * (x2 - x1)), (y1 + u * (y2 - y1))
};
float[] vec = {
ret[0] - point[0], ret[1] - point[1]
};
return vec;
}
// A . B
public static float dotProduct(float[] a, float[] b) {
return a[0] * b[0] + a[1] * b[1];
}
public static float[] normalize(float[] a) {
float length = (float) Math.sqrt(a[0] * a[0] + a[1] * a[1]);
float[] b = {
a[0] / length, a[1] / length
};
return b;
}
// A onto B
public static float scalarProjection(float[] a, float[] b) {
float length = (float) Math.sqrt(b[0] * b[0] + b[1] * b[1]);
return dotProduct(a, b) / length;
}
public static float[] getVectorFromPoints(float[] point1, float[] point2) {
float[] p = {
point2[0] - point1[0], point2[1] - point1[1]
};
return p;
}
public static float[] getUnitVectorFromPoints(float[] point1, float[] point2) {
float[] p = {
point2[0] - point1[0], point2[1] - point1[1]
};
float length = (float) Math.sqrt(p[0] * p[0] + p[1] * p[1]);
p[0] = p[0] / length;
p[1] = p[1] / length;
return p;
}
public static RectF scaleRect(RectF r, float scale) {
return new RectF(r.left * scale, r.top * scale, r.right * scale, r.bottom * scale);
}
// A - B
public static float[] vectorSubtract(float[] a, float[] b) {
int len = a.length;
if (len != b.length)
return null;
float[] ret = new float[len];
for (int i = 0; i < len; i++) {
ret[i] = a[i] - b[i];
}
return ret;
}
public static float vectorLength(float[] a) {
return (float) Math.sqrt(a[0] * a[0] + a[1] * a[1]);
}
public static float scale(float oldWidth, float oldHeight, float newWidth, float newHeight) {
if (oldHeight == 0 || oldWidth == 0)
return 1;
return Math.min(newWidth / oldWidth, newHeight / oldHeight);
}
public static Rect roundNearest(RectF r) {
Rect q = new Rect(Math.round(r.left), Math.round(r.top), Math.round(r.right),
Math.round(r.bottom));
return q;
}
}
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