public double getAlpha(int var1) {
        final double cAlphaStart = -20.0D;
        final double cAlphaStep = 0.2D;
        return cAlphaStart + (double) var1 * cAlphaStep;
    }
Copied and pasted from Tess4j (https://sourceforge.net/projects/tess4j/)
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-ocr-module/src/main/java/org/apache/tika/parser/ocr/tess4j/ImageDeskew.java