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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);
}
protected static float[] shortestVectorFromPointToLine(float[] point, float[] l1, float[] l2) {
float x1 = l1[0];
float x2 = l2[0];
float y1 = l1[1];
float y2 = l2[1];
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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