Formulas.java

/*
 * Copyright 2010-2011 Øyvind Berg (elacin@gmail.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 org.elacin.pdfextract.formula;

import org.elacin.pdfextract.content.StyledText;
import org.elacin.pdfextract.geom.HasPosition;
import org.elacin.pdfextract.style.TextUtils;
import org.jetbrains.annotations.NotNull;

import java.util.Collection;

import static org.elacin.pdfextract.style.Style.GRAPHIC_MATH_BAR;

/**
 * Created by IntelliJ IDEA. User: elacin Date: 29.11.10 Time: 01.30 To change this template use
 * File | Settings | File Templates.
 */
public class Formulas {

// -------------------------- PUBLIC STATIC METHODS --------------------------
    public static boolean stringContainsMath(@NotNull final String text1) {

        for (int i = 0; i < text1.length(); i++) {
            if (Character.getType(text1.codePointAt(i)) == Character.MATH_SYMBOL) {
                return true;
            }
        }

        return false;
    }

    public static boolean textContainsMath(@NotNull StyledText text) {

        if (text.getStyle().isMathFont()) {
            return true;
        }

        return stringContainsMath(text.getText());
    }

    public static boolean textSeemsToBeFormula(@NotNull Collection<? extends HasPosition> contents) {

        if (contents.size() < 4) {
            return false;
        }

        if (!TextUtils.listContainsStyledText(contents)) {
            return false;
        }

        int looksLikeMath     = 0;
        int wordCount         = 0;
        int containedGraphics = 0;

        for (HasPosition content : contents) {
            if (!(content instanceof StyledText)) {
                continue;
            }

            StyledText word = (StyledText) content;

            if (word.getStyle().equals(GRAPHIC_MATH_BAR)) {
                containedGraphics++;

                continue;
            }

            wordCount += word.getText().length();

            /* first check whether the whole word seems to be formatted in a math font */
            if (word.getStyle().isMathFont()) {
                looksLikeMath += 3 * word.getText().length();

                continue;
            }

            for (int i = 0; i < word.getText().length(); i++) {
                final char c = word.getText().charAt(i);

                if (Character.getType(c) == (int) Character.MATH_SYMBOL) {
                    looksLikeMath += 3;
                } else if (Character.isDigit(c)) {
                    looksLikeMath += 1;
                }
            }
        }

        looksLikeMath += containedGraphics * looksLikeMath * 0.1f;

        return looksLikeMath > wordCount;
    }
}