PngInfo.java

net.minecraft.util.PngInfo

信息

• 全限定名：net.minecraft.util.PngInfo
• 类型：public record
• 包：net.minecraft.util
• 源码路径：src/main/java/net/minecraft/util/PngInfo.java
• 起始行号：L11
• 职责：

  TODO

字段/常量

• FORMAT

  • 类型: HexFormat
  • 修饰符: private static final
  • 源码定位: L12
  • 说明:

    TODO

• PNG_HEADER

  • 类型: long
  • 修饰符: private static final
  • 源码定位: L13
  • 说明:

    TODO

• IHDR_TYPE

  • 类型: int
  • 修饰符: private static final
  • 源码定位: L14
  • 说明:

    TODO

• IHDR_SIZE

  • 类型: int
  • 修饰符: private static final
  • 源码定位: L15
  • 说明:

    TODO

内部类/嵌套类型

• 无

构造器

• 无

方法

下面的方法块按源码顺序生成。

public static PngInfo fromStream(InputStream inputStream) @ L17

• 方法名：fromStream
• 源码定位：L17
• 返回类型：PngInfo
• 修饰符：public static

参数:

• inputStream: InputStream

说明:

TODO

public static PngInfo fromBytes(byte[] bytes) @ L39

• 方法名：fromBytes
• 源码定位：L39
• 返回类型：PngInfo
• 修饰符：public static

参数:

• bytes: byte[]

说明:

TODO

public static void validateHeader(ByteBuffer buffer) @ L43

• 方法名：validateHeader
• 源码定位：L43
• 返回类型：void
• 修饰符：public static

参数:

• buffer: ByteBuffer

说明:

TODO

代码

public record PngInfo(int width, int height) {
    private static final HexFormat FORMAT = HexFormat.of().withUpperCase().withPrefix("0x");
    private static final long PNG_HEADER = -8552249625308161526L;
    private static final int IHDR_TYPE = 1229472850;
    private static final int IHDR_SIZE = 13;
 
    public static PngInfo fromStream(InputStream inputStream) throws IOException {
        DataInputStream stream = new DataInputStream(inputStream);
        long magic = stream.readLong();
        if (magic != -8552249625308161526L) {
            throw new IOException("Bad PNG Signature: " + FORMAT.toHexDigits(magic));
        } else {
            int headerSize = stream.readInt();
            if (headerSize != 13) {
                throw new IOException("Bad length for IHDR chunk: " + headerSize);
            } else {
                int headerType = stream.readInt();
                if (headerType != 1229472850) {
                    throw new IOException("Bad type for IHDR chunk: " + FORMAT.toHexDigits(headerType));
                } else {
                    int width = stream.readInt();
                    int height = stream.readInt();
                    return new PngInfo(width, height);
                }
            }
        }
    }
 
    public static PngInfo fromBytes(byte[] bytes) throws IOException {
        return fromStream(new ByteArrayInputStream(bytes));
    }
 
    public static void validateHeader(ByteBuffer buffer) throws IOException {
        ByteOrder order = buffer.order();
        buffer.order(ByteOrder.BIG_ENDIAN);
        if (buffer.limit() < 16) {
            throw new IOException("PNG header missing");
        } else if (buffer.getLong(0) != -8552249625308161526L) {
            throw new IOException("Bad PNG Signature");
        } else if (buffer.getInt(8) != 13) {
            throw new IOException("Bad length for IHDR chunk!");
        } else if (buffer.getInt(12) != 1229472850) {
            throw new IOException("Bad type for IHDR chunk!");
        } else {
            buffer.order(order);
        }
    }
}

引用的其他类

• 无