Java Raster.getPixel方法代码示例

import java.awt.image.Raster; //导入方法依赖的package包/类
/**
 * Trims the transparent pixels from the given {@link BufferedImage} (returns a sub-image).
 *
 * @param source The source image.
 * @return A new, trimmed image, or the source image if no trim is performed.
 */
public static BufferedImage trimmedImage(BufferedImage source) {
    final int minAlpha = 1;
    final int srcWidth = source.getWidth();
    final int srcHeight = source.getHeight();
    Raster raster = source.getRaster();
    int l = srcWidth, t = srcHeight, r = 0, b = 0;
    int alpha, x, y;
    int[] pixel = new int[4];
    for (y = 0; y < srcHeight; y++) {
        for (x = 0; x < srcWidth; x++) {
            raster.getPixel(x, y, pixel);
            alpha = pixel[3];
            if (alpha >= minAlpha) {
                l = Math.min(x, l);
                t = Math.min(y, t);
                r = Math.max(x, r);
                b = Math.max(y, b);
            }
        }
    }
    if (l > r || t > b) {
        // No pixels, couldn't trim
        return source;
    }
    return source.getSubimage(l, t, r - l + 1, b - t + 1);
}
 

import java.awt.image.Raster; //导入方法依赖的package包/类
public void runTest(Object context, int numReps) {
    Raster ras = ((Context) context).ras;
    int pixeldata[] = ((Context) context).pixeldata;
    do {
        ras.getPixel(numReps&7, 0, pixeldata);
    } while (--numReps > 0);
}
 

import java.awt.image.Raster; //导入方法依赖的package包/类
private List<Ruling> getHorizontalRulings(BufferedImage image) {

        // get all horizontal edges, which we'll define as a change in grayscale colour
        // along a straight line of a certain length
        ArrayList<Ruling> horizontalRulings = new ArrayList<>();

        Raster r = image.getRaster();
        int width = r.getWidth();
        int height = r.getHeight();

        for (int x = 0; x < width; x++) {

            int[] lastPixel = r.getPixel(x, 0, (int[]) null);

            for (int y = 1; y < height - 1; y++) {

                int[] currPixel = r.getPixel(x, y, (int[]) null);

                int diff = Math.abs(currPixel[0] - lastPixel[0]);
                if (diff > GRAYSCALE_INTENSITY_THRESHOLD) {
                    // we hit what could be a line
                    // don't bother scanning it if we've hit a pixel in the line before
                    boolean alreadyChecked = false;
                    for (Line2D.Float line : horizontalRulings) {
                        if (y == line.getY1() && x >= line.getX1() && x <= line.getX2()) {
                            alreadyChecked = true;
                            break;
                        }
                    }

                    if (alreadyChecked) {
                        lastPixel = currPixel;
                        continue;
                    }

                    int lineX = x + 1;

                    while (lineX < width) {
                        int[] linePixel = r.getPixel(lineX, y, (int[]) null);
                        int[] abovePixel = r.getPixel(lineX, y - 1, (int[]) null);

                        if (Math.abs(linePixel[0] - abovePixel[0]) <= GRAYSCALE_INTENSITY_THRESHOLD
                                || Math.abs(currPixel[0] - linePixel[0]) > GRAYSCALE_INTENSITY_THRESHOLD) {
                            break;
                        }

                        lineX++;
                    }

                    int endX = lineX - 1;
                    int lineWidth = endX - x;
                    if (lineWidth > HORIZONTAL_EDGE_WIDTH_MINIMUM) {
                        horizontalRulings.add(new Ruling(new Point2D.Float(x, y), new Point2D.Float(endX, y)));
                    }
                }

                lastPixel = currPixel;
            }
        }

        return horizontalRulings;
    }
 

import java.awt.image.Raster; //导入方法依赖的package包/类
private List<Ruling> getVerticalRulings(BufferedImage image) {

        // get all vertical edges, which we'll define as a change in grayscale colour
        // along a straight line of a certain length
        ArrayList<Ruling> verticalRulings = new ArrayList<>();

        Raster r = image.getRaster();
        int width = r.getWidth();
        int height = r.getHeight();

        for (int y = 0; y < height; y++) {

            int[] lastPixel = r.getPixel(0, y, (int[]) null);

            for (int x = 1; x < width - 1; x++) {

                int[] currPixel = r.getPixel(x, y, (int[]) null);

                int diff = Math.abs(currPixel[0] - lastPixel[0]);
                if (diff > GRAYSCALE_INTENSITY_THRESHOLD) {
                    // we hit what could be a line
                    // don't bother scanning it if we've hit a pixel in the line before
                    boolean alreadyChecked = false;
                    for (Line2D.Float line : verticalRulings) {
                        if (x == line.getX1() && y >= line.getY1() && y <= line.getY2()) {
                            alreadyChecked = true;
                            break;
                        }
                    }

                    if (alreadyChecked) {
                        lastPixel = currPixel;
                        continue;
                    }

                    int lineY = y + 1;

                    while (lineY < height) {
                        int[] linePixel = r.getPixel(x, lineY, (int[]) null);
                        int[] leftPixel = r.getPixel(x - 1, lineY, (int[]) null);

                        if (Math.abs(linePixel[0] - leftPixel[0]) <= GRAYSCALE_INTENSITY_THRESHOLD
                                || Math.abs(currPixel[0] - linePixel[0]) > GRAYSCALE_INTENSITY_THRESHOLD) {
                            break;
                        }

                        lineY++;
                    }

                    int endY = lineY - 1;
                    int lineLength = endY - y;
                    if (lineLength > VERTICAL_EDGE_HEIGHT_MINIMUM) {
                        verticalRulings.add(new Ruling(new Point2D.Float(x, y), new Point2D.Float(x, endY)));
                    }
                }

                lastPixel = currPixel;
            }
        }

        return verticalRulings;
    }