我需要一些算法来使图书中的文字变粗。换句话说，我有一个书页的摄影图像，我想把文字加粗，以提高阅读能力。
我的图片是透明的，只包含文字，没有任何其他像素。
答案 0 :(得分：0)
使用较小的y差异多次绘制图像会使文本变为粗体。
class tmpPanel extends JPanel {
private File pngFile;
private int boldSize = 5;
public tmpPanel() {
addMouseListener(new MouseListener() {
@Override
public void mouseClicked(MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1) {
++boldSize;
repaint();
} else if (e.getButton() == MouseEvent.BUTTON3) {
--boldSize;
repaint();
}
}
@Override
public void mousePressed(MouseEvent e) {
mouseClicked(e);
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
}
@Override
public void mouseExited(MouseEvent e) {
}
});
}
public void setPngFile(File pngFile) {
this.pngFile = pngFile;
}
@Override
public void paint(Graphics g) {
try {
super.paint(g); //To change body of generated methods, choose Tools | Templates.
Graphics2D d = (Graphics2D) g;
g.setColor(Color.WHITE);
g.fillRect(0, 0, getWidth(), getHeight());
BufferedImage image = ImageIO.read(pngFile);
for (int i = 0; i < boldSize; ++i)
g.drawImage(image, 0, i, getWidth(), getHeight(), null);
} catch (IOException ex) {
Logger.getLogger(tmpPanel.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
答案 1 :(得分：0)
最佳解决方案：使用@ bazz-dee idea（扩张过滤器）：
它的时间是O（N ^ 2）和存储器4N其中N是一个图像的大小。代码取自http://blog.ostermiller.org/dilate-and-erode和此答案https://stackoverflow.com/a/17542851/3441905
class tmpPanel extends JPanel {
private File pngFile;
private int boldSize = 1;
boolean nightMode = true;
private static final int arr[][] = new int[1377][886]; //width, hight of image
public tmpPanel() {
addMouseListener(new MouseListener() {
@Override
public void mouseClicked(MouseEvent e) {
}
@Override
public void mousePressed(MouseEvent e) {
if (e.getButton() == MouseEvent.BUTTON1) {
++boldSize;
repaint();
} else if (e.getButton() == MouseEvent.BUTTON3) {
--boldSize;
repaint();
}
}
@Override
public void mouseReleased(MouseEvent e) {
}
@Override
public void mouseEntered(MouseEvent e) {
}
@Override
public void mouseExited(MouseEvent e) {
}
});
}
public void setPngFile(File pngFile) {
this.pngFile = pngFile;
}
private void dilate(int[][] image, int k) {
image = manhattan(image);
for (int i = 0; i < image.length; i++) {
for (int j = 0; j < image[i].length; j++) {
image[i][j] = (image[i][j] <= k) ? 1 : 0;
}
}
}
/**
* Converts an image to a binary one based on given threshold
*
* @param image the image to convert. Remains untouched.
* @param threshold the threshold in [0,255]
* @return a new BufferedImage instance of TYPE_BYTE_GRAY with only 0'S and
* 255's
*/
public BufferedImage thresholdImage(BufferedImage image, int threshold) {
BufferedImage result = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
result.getGraphics().drawImage(image, 0, 0, null);
WritableRaster raster = result.getRaster();
int[] pixels = new int[image.getWidth()];
for (int y = 0; y < image.getHeight(); y++) {
raster.getPixels(0, y, image.getWidth(), 1, pixels);
for (int i = 0; i < pixels.length; i++) {
if (pixels[i] < threshold) {
pixels[i] = 1;
} else {
pixels[i] = 0;
}
}
raster.setPixels(0, y, image.getWidth(), 1, pixels);
}
return result;
}
private int[][] manhattan(int[][] image) {
// traverse from top left to bottom right
for (int i = 0; i < image.length; i++) {
for (int j = 0; j < image[i].length; j++) {
if (image[i][j] == 1) {
// first pass and pixel was on, it gets a zero
image[i][j] = 0;
} else {
// pixel was off
// It is at most the sum of the lengths of the array
// away from a pixel that is on
image[i][j] = image.length + image[i].length;
// or one more than the pixel to the north
if (i > 0) {
image[i][j] = Math.min(image[i][j], image[i - 1][j] + 1);
}
// or one more than the pixel to the west
if (j > 0) {
image[i][j] = Math.min(image[i][j], image[i][j - 1] + 1);
}
}
}
}
// traverse from bottom right to top left
for (int i = image.length - 1; i >= 0; i--) {
for (int j = image[i].length - 1; j >= 0; j--) {
// either what we had on the first pass
// or one more than the pixel to the south
if (i + 1 < image.length) {
image[i][j] = Math.min(image[i][j], image[i + 1][j] + 1);
}
// or one more than the pixel to the east
if (j + 1 < image[i].length) {
image[i][j] = Math.min(image[i][j], image[i][j + 1] + 1);
}
}
}
return image;
}
@Override
public void paint(Graphics g) {
try {
super.paint(g); //To change body of generated methods, choose Tools | Templates.
BufferedImage image = ImageIO.read(pngFile);
BufferedImage res = new BufferedImage(image.getWidth(), image.getHeight(), image.getType());
Graphics2D d = (Graphics2D) res.createGraphics();
d.setColor(Color.WHITE);
d.fillRect(0, 0, res.getWidth(), res.getHeight());
d.drawImage(image, 0, 0, res.getWidth(), res.getHeight(), null);
res = thresholdImage(res, 128);
WritableRaster raster = res.getRaster();
if (boldSize > 0) {
for (int i = 0; i < res.getHeight(); ++i)
raster.getPixels(0, i, res.getWidth(), 1, arr[i]);
dilate(arr, boldSize);
for (int i = 0; i < res.getHeight(); ++i) {
for (int j = 0; j < res.getWidth(); ++j)
if (arr[i][j] == 1)
arr[i][j] = nightMode ? 255 : 0;
else
arr[i][j] = nightMode ? 0 : 255;
raster.setPixels(0, i, res.getWidth(), 1, arr[i]);
}
}
g.drawImage(res, 0, 0, getWidth(), getHeight(), null);
//for (int i = 0; i < boldSize; ++i)
//g.drawImage(image, 0, i, getWidth(), getHeight(), null);
} catch (IOException ex) {
Logger.getLogger(tmpPanel.class.getName()).log(Level.SEVERE, null, ex);
}
}
}