6f46ed3177
git-svn-id: svn://svn.code.sf.net/p/writer2latex/code/trunk@256 f0f2a975-2e09-46c8-9428-3b39399b9f3c
212 lines
7.5 KiB
Java
212 lines
7.5 KiB
Java
/************************************************************************
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*
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* Calc.java
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License version 2.1, as published by the Free Software Foundation.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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* Copyright: 2002-2015 by Henrik Just
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*
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* All Rights Reserved.
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*
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* Version 1.6 (2015-02-19)
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*
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*/
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package writer2latex.util;
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/** A collection of static methods used to perform calculations on strings representing floating point numbers
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* with units or percentages. In the JavaDoc, a length refers to a string like e.g. "21.7cm" and percent refers
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* to a string like e.g. "2.5%".
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*/
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public class Calc {
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/** Get a float value from a string (e.g. "218.86" returns 218.86F)
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*
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* @param sFloat the string to parse
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* @param fDefault a default value to return if the string cannot be parsed as a float
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* @return the float value of the string
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*/
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public static final float getFloat(String sFloat, float fDefault){
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float f;
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try {
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f=Float.parseFloat(sFloat);
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}
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catch (NumberFormatException e) {
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return fDefault;
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}
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return f;
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}
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/** Replace the unit inch with in on a length (e.g. "17.5inch" returns "17.5in")
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*
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* @param sValue the length
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* @return the truncated length
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*/
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public static String truncateLength(String sValue) {
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if (sValue.endsWith("inch")) {
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// Cut of inch to in
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return sValue.substring(0,sValue.length()-2);
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}
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else {
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return sValue;
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}
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}
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/** Checks whether a given length is zero within a tolerance of 0.001 (e.g. "0.0005cm" returns true)
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*
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* @param sValue the length to check
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* @return true if the value is close to zero
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*/
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public static boolean isZero(String sValue) {
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return Math.abs(getFloat(sValue.substring(0, sValue.length()-2),0))<0.001;
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}
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// Return units per inch for some unit
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private static final float getUpi(String sUnit) {
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if ("in".equals(sUnit)) { return 1.0F; }
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else if ("mm".equals(sUnit)) { return 25.4F; }
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else if ("cm".equals(sUnit)) { return 2.54F; }
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else if ("pc".equals(sUnit)) { return 6F; }
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else { return 72; } // pt or unknown
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}
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/** Convert a length to px assuming 96ppi; cf. the CSS spec (e.g. "0.1in" returns "9.6px").
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* Exception: Never return less than 1px
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*
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* @param sLength the length to convert
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* @return the converted length
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*/
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public static final String length2px(String sLength) {
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if (sLength.equals("0")) { return "0"; }
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float fLength=getFloat(sLength.substring(0,sLength.length()-2),1);
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String sUnit=sLength.substring(sLength.length()-2);
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float fPixels = 96.0F/getUpi(sUnit)*fLength;
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if (Math.abs(fPixels)<0.01) {
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// Very small, treat as zero
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return "0";
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}
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else if (fPixels>0) {
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// Never return less that 1px
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return Float.toString(fPixels<1 ? 1 : fPixels)+"px";
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}
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else {
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// Or above -1px
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return Float.toString(fPixels>-1 ? -1 : fPixels)+"px";
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}
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}
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/** Divide dividend by divisor and return the quotient as an integer percentage
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* (e.g. "0.5cm" divided by "2cm" returns "25%").
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* Exception: Never returns below 1% except if the dividend is zero.
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*
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* @param sDividend the length to use as dividend
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* @param sDivisor the length to use as divisor
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* @return the quotient percentage
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*/
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public static final String divide(String sDividend, String sDivisor) {
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return divide(sDividend,sDivisor,false);
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}
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/** Divide dividend by divisor and return the quotient as an integer percentage
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* (e.g. "0.5cm" divided by "2cm" returns "25%").
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* Exception: Never returns below 1% except if the dividend is zero, and never returns above 100%
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* if last parameter is true.
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*
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* @param sDividend the length to use as dividend
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* @param sDivisor the length to use as divisor
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* @param bMax100 true if a maximum of 100% should be returned
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* @return the quotient percentage
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*/
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public static final String divide(String sDividend, String sDivisor, boolean bMax100) {
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if (sDividend.equals("0")) { return "0%"; }
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if (sDivisor.equals("0")) { return "100%"; }
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float fDividend=getFloat(sDividend.substring(0,sDividend.length()-2),1);
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String sDividendUnit=sDividend.substring(sDividend.length()-2);
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float fDivisor=getFloat(sDivisor.substring(0,sDivisor.length()-2),1);
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String sDivisorUnit=sDivisor.substring(sDivisor.length()-2);
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int nPercent = Math.round(100*fDividend*getUpi(sDivisorUnit)/fDivisor/getUpi(sDividendUnit));
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if (bMax100 && nPercent>100) {
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return "100%";
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}
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else if (nPercent>0) {
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return Integer.toString(nPercent)+"%";
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}
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else {
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return "1%";
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}
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}
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/** Multiply a length by a percentage (e.g. "150%" multiplied with "2.5mm" returns "3.75cm")
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*
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* @param sPercent the percentage
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* @param sLength the length
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* @return the product length
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*/
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public static final String multiply(String sPercent, String sLength){
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if (sLength.equals("0")) { return "0"; }
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float fPercent=getFloat(sPercent.substring(0,sPercent.length()-1),1);
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float fLength=getFloat(sLength.substring(0,sLength.length()-2),1);
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String sUnit=sLength.substring(sLength.length()-2);
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return Float.toString(fPercent*fLength/100)+sUnit;
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}
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/** Add two lengths (e.g. "2.5cm" added to "1.08cm" returns "3.58cm")
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*
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* @param sLength1 the first length term
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* @param sLength2 the second length term
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* @return the sum (as a length with the same unit as the first term)
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*/
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public static final String add(String sLength1, String sLength2){
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if (sLength1.equals("0")) { return sLength2; }
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if (sLength2.equals("0")) { return sLength1; }
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float fLength1=getFloat(sLength1.substring(0,sLength1.length()-2),1);
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String sUnit1=sLength1.substring(sLength1.length()-2);
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float fLength2=getFloat(sLength2.substring(0,sLength2.length()-2),1);
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String sUnit2=sLength2.substring(sLength2.length()-2);
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// Use unit from sLength1:
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return Float.toString(fLength1+getUpi(sUnit1)/getUpi(sUnit2)*fLength2)+sUnit1;
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}
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/** Subtract two lengths (e.g. "2.5cm" subtracted by "1.08cm" returns "1.42cm")
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*
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* @param sLength1 the first length term
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* @param sLength2 the second length term
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* @return the difference (as a length with the same unit as the first term)
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*/
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public static final String sub(String sLength1, String sLength2){
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return add(sLength1,multiply("-100%",sLength2));
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}
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/** Test whether a given length is smaller than another length
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* (e.g. "2.5cm" compared to "2.6cm" returns true;
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*
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* @param sThis is this length the smaller?
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* @param sThat is this length the larger?
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* @return true is the first length is smaller than the second length
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*/
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public static boolean isLessThan(String sThis, String sThat) {
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return sub(sThis,sThat).startsWith("-");
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}
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/** Get the absolute value of a length (e.g. "-2.5cm" returns "2.5cm")
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*
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* @param sLength the length
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* @return the absolute value
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*/
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public static String abs(String sLength) {
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return sLength.startsWith("-") ? sLength.substring(1) : sLength;
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}
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}
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