An encoder is an io.Writer that satisfies writes by writing PNG IDAT chunks, including an 8-byte header and 4-byte CRC checksum per Write call. Such c

The absolute value of a byte interpreted as a signed int8.

readImagePass reads a single image pass, sized according to the pass number.

Encode writes the Image m to w in PNG format.

Read presents one or more IDAT chunks as one continuous stream (minus the intermediate chunk headers and footers). If the PNG data looked like: ... le

Returns whether or not the image is fully opaque.

Encode writes the Image m to w in PNG format. Any Image may be encoded, but images that are not image.NRGBA might be encoded lossily.

decode decodes the IDAT data into an image.

Chooses the filter to use for encoding the current row, and applies it. The return value is the index of the filter and also of the row in cr that has

filterPaeth applies the Paeth filter to the cdat slice. cdat is the current row's data, pdat is the previous row's data.

This function is required because we want the zero value of Encoder.CompressionLevel to map to zlib.DefaultCompression.

mergePassInto merges a single pass into a full sized image.

paeth implements the Paeth filter function, as per the PNG specification.

wrapListener wraps l with an idle timeout, if possible. A zero timeout disables timeouts. If setting a timeout fails, the returned Listener falls back

Write the actual image data to one or more IDAT chunks.

Accept implements net.Conn. Connections returned by Accept are tracked. Once all active connections are closed and the idle timeout expires, Accept re

Decode reads a PNG image from r and returns it as an image.Image. The type of Image returned depends on the PNG contents.

DecodeConfig returns the color model and dimensions of a PNG image without decoding the entire image.