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/*
* Copyright 2012 AndroidPlot.com
*
* 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.androidplot.util;
import android.graphics.PointF;
import android.graphics.RectF;
/**
* Utility methods for converting pixel coordinates into real values and vice versa.
*/
public class ValPixConverter {
private static final int ZERO = 0;
public static float valToPix(double val, double min, double max, float lengthPix, boolean flip) {
if(lengthPix <= ZERO) {
throw new IllegalArgumentException("Length in pixels must be greater than 0.");
}
double range = range(min, max);
double scale = lengthPix / range;
double raw = val - min;
float pix = (float)(raw * scale);
if(flip) {
pix = (lengthPix - pix);
}
return pix;
}
public static double range(double min, double max) {
return (max-min);
}
public static double valPerPix(double min, double max, float lengthPix) {
double valRange = range(min, max);
return valRange/lengthPix;
}
/**
* Convert a value in pixels to the type passed into min/max
* @param pix
* @param min
* @param max
* @param lengthPix
* @param flip True if the axis should be reversed before calculated. This is the case
* with the y axis for screen coords.
* @return
*/
public static double pixToVal(float pix, double min, double max, float lengthPix, boolean flip) {
if(pix < ZERO) {
throw new IllegalArgumentException("pixel values cannot be negative.");
}
if(lengthPix <= ZERO) {
throw new IllegalArgumentException("Length in pixels must be greater than 0.");
}
float pMult = pix;
if(flip) {
pMult = lengthPix - pix;
}
double range = range(min, max);
return ((range / lengthPix) * pMult) + min;
}
/**
* Converts a real value into a pixel value.
* @param x Real d (domain) component of the point to convert.
* @param y Real y (range) component of the point to convert.
* @param plotArea
* @param minX Minimum visible real value on the d (domain) axis.
* @param maxX Maximum visible real value on the y (domain) axis.
* @param minY Minimum visible real value on the y (range) axis.
* @param maxY Maximum visible real value on the y (range axis.
* @return
*/
public static PointF valToPix(Number x, Number y, RectF plotArea, Number minX, Number maxX, Number minY, Number maxY) {
float pixX = ValPixConverter.valToPix(x.doubleValue(), minX.doubleValue(), maxX.doubleValue(), plotArea.width(), false) + (plotArea.left);
float pixY = ValPixConverter.valToPix(y.doubleValue(), minY.doubleValue(), maxY.doubleValue(), plotArea.height(), true) + plotArea.top;
return new PointF(pixX, pixY);
}
}