/** * <a url=http://www.jdeskew.com/>JDeskew</a> */ package com.recognition.software.jdeskew; import java.awt.Color; import java.awt.Graphics2D; import java.awt.RenderingHints; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.awt.image.WritableRaster; import net.sourceforge.tess4j.util.LoggHelper; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class ImageUtil { private static final Logger logger = LoggerFactory.getLogger(new LoggHelper().toString()); /** * Whether the pixel is black. * * @param image source image * @param x * @param y * @return */ public static boolean isBlack(BufferedImage image, int x, int y) { if (image.getType() == BufferedImage.TYPE_BYTE_BINARY) { WritableRaster raster = image.getRaster(); int pixelRGBValue = raster.getSample(x, y, 0); return pixelRGBValue == 0; } int luminanceValue = 140; return isBlack(image, x, y, luminanceValue); } /** * Whether the pixel is black. * * @param image source image * @param x * @param y * @param luminanceCutOff * @return */ public static boolean isBlack(BufferedImage image, int x, int y, int luminanceCutOff) { int pixelRGBValue; int r; int g; int b; double luminance = 0.0; // return white on areas outside of image boundaries if (x < 0 || y < 0 || x > image.getWidth() || y > image.getHeight()) { return false; } try { pixelRGBValue = image.getRGB(x, y); r = (pixelRGBValue >> 16) & 0xff; g = (pixelRGBValue >> 8) & 0xff; b = (pixelRGBValue) & 0xff; luminance = (r * 0.299) + (g * 0.587) + (b * 0.114); } catch (Exception e) { logger.warn("", e); } return luminance < luminanceCutOff; } /** * Rotates image. * * @param image source image * @param angle by degrees * @param cx x-coordinate of pivot point * @param cy y-coordinate of pivot point * @return rotated image */ public static BufferedImage rotate(BufferedImage image, double angle, int cx, int cy) { int width = image.getWidth(null); int height = image.getHeight(null); int minX, minY, maxX, maxY; minX = minY = maxX = maxY = 0; int[] corners = {0, 0, width, 0, width, height, 0, height}; double theta = Math.toRadians(angle); for (int i = 0; i < corners.length; i += 2) { int x = (int) (Math.cos(theta) * (corners[i] - cx) - Math.sin(theta) * (corners[i + 1] - cy) + cx); int y = (int) (Math.sin(theta) * (corners[i] - cx) + Math.cos(theta) * (corners[i + 1] - cy) + cy); if (x > maxX) { maxX = x; } if (x < minX) { minX = x; } if (y > maxY) { maxY = y; } if (y < minY) { minY = y; } } cx = (cx - minX); cy = (cy - minY); BufferedImage bi = new BufferedImage((maxX - minX), (maxY - minY), image.getType()); Graphics2D g2 = bi.createGraphics(); g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC); g2.setBackground(Color.white); g2.fillRect(0, 0, bi.getWidth(), bi.getHeight()); AffineTransform at = new AffineTransform(); at.rotate(theta, cx, cy); g2.setTransform(at); g2.drawImage(image, -minX, -minY, null); g2.dispose(); return bi; } }