我在将图像转换为 byte[] 并反转时遇到一个问题:
我有 2 个函数将图像转换为 byte[],如下所示
public byte[] extractBytes2 (String ImageName) throws IOException {
File imgPath = new File(ImageName);
BufferedImage bufferedImage = ImageIO.read(imgPath);
WritableRaster raster = bufferedImage .getRaster();
DataBufferByte data = (DataBufferByte) raster.getDataBuffer();
return ( data.getData() );
}
和
public byte[] extractBytes (String ImageName) throws IOException
{
Path path = Paths.get(ImageName);
byte[] data = Files.readAllBytes(path);
return data;
}
我会有byte[] byteArray
byteArray = extractBytes2("image/pikachu.png");
或
byteArray = extractBytes("image/pikachu.png");
当我将 byte[] 转换为我使用的图像时
Graphics g = panelMain.getGraphics();
Graphics2D g2D = (Graphics2D) g;
try {
InputStream in = new ByteArrayInputStream(byteArray);
BufferedImage image = ImageIO.read(in);
g2D.drawImage(image, 0, 0, GiaoDienChinh.this);
g2D.setPaint(Color.BLACK);
panelMain.setOpaque(true);
panelMain.paintComponents(g2D);
}
catch ( Exception e ) {
}
finally {
}
但我只使用 byteArray 绘制,使用函数“extractBytes”而不是“extractBytes2”!!!
任何人都可以向我解释如何使用从“extractByte2”获得的 byteArray 绘制图像?
感谢大家的支持!
最佳答案
让我们从绘制代码开始。
ImageIO.read(in)
需要一种有效的图像格式,它的一个可插入服务提供知道如何读取和转换为 BufferedImage
。
当您从 extractBytes
传递字节时,您只是传回代表实际图像文件的字节数组。我会说 Image.read(new File("image/pikachu.png"))
但是,从您的 extractBytes2
返回的数据缓冲区正在返回图像数据的内部表示,ImageIO
可能无法“读取”它。
已更新
A BufferedImage is an accessible buffer of image data, essentially pixels, and their RGB colors. The BufferedImage provides a powerful way to manipulate the Image data. A BufferedImage object is made up of two parts a ColorModel object and a Raster object.
引用自 here
已更新
我在回家的路上想到了如何将 BufferedImage
转换为字节数组的古怪想法...
基本思路是使用ImageIO.write
将BufferedImage
写出到ByteOutputStream
...
public static byte[] extractBytes2(String ImageName) throws IOException {
File imgPath = new File(ImageName);
BufferedImage bufferedImage = ImageIO.read(imgPath);
ByteOutputStream bos = null;
try {
bos = new ByteOutputStream();
ImageIO.write(bufferedImage, "png", bos);
} finally {
try {
bos.close();
} catch (Exception e) {
}
}
return bos == null ? null : bos.getBytes();
}
这是我的测试...
public class TestByteImage {
public static void main(String[] args) {
new TestByteImage();
}
public static byte[] extractBytes2(String ImageName) throws IOException {
File imgPath = new File(ImageName);
BufferedImage bufferedImage = ImageIO.read(imgPath);
ByteOutputStream bos = null;
try {
bos = new ByteOutputStream();
ImageIO.write(bufferedImage, "png", bos);
} finally {
try {
bos.close();
} catch (Exception e) {
}
}
return bos == null ? null : bos.getBytes();
}
public TestByteImage() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new ImagePane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ImagePane extends JPanel {
private BufferedImage original;
private byte[] byteData;
private BufferedImage fromBytes;
public ImagePane() {
String name = "/path/to/your/image";
try {
original = ImageIO.read(new File(name));
byteData = extractBytes2(name);
} catch (IOException ex) {
ex.printStackTrace();
}
setFont(UIManager.getFont("Label.font").deriveFont(Font.BOLD, 48f));
}
@Override
public Dimension getPreferredSize() {
return original == null ? super.getPreferredSize() : new Dimension(original.getWidth() * 2, original.getHeight());
}
protected void drawText(Graphics2D g2d, String text, int x, int width) {
BufferedImage img = new BufferedImage(width, getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D tmpg = img.createGraphics();
tmpg.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
tmpg.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
tmpg.setFont(g2d.getFont());
tmpg.setColor(Color.RED);
FontMetrics fm = tmpg.getFontMetrics();
int xPos = ((width - fm.stringWidth(text)) / 2);
int yPos = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent();
tmpg.drawString(text, xPos, yPos);
tmpg.dispose();
AffineTransform transform = g2d.getTransform();
g2d.setTransform(AffineTransform.getRotateInstance(Math.toRadians(-10), x + (x + width) / 2, getHeight() / 2));
g2d.drawImage(img, x, 0, this);
g2d.setTransform(transform);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (original != null) {
g.drawImage(original, 0, 0, this);
drawText((Graphics2D) g, "Original", 0, original.getWidth());
}
if (byteData != null && fromBytes == null) {
try {
fromBytes = ImageIO.read(new ByteInputStream(byteData, byteData.length));
} catch (IOException exp) {
exp.printStackTrace();
}
}
if (fromBytes != null) {
g.drawImage(fromBytes, getWidth() - fromBytes.getWidth(), 0, this);
drawText((Graphics2D) g, "From Bytes", getWidth() - fromBytes.getWidth(), fromBytes.getWidth());
}
}
}
}
关于java - 关于在 Java 中将 Image 转换为 byte[] 和反转,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13282740/