pngsheet

README

pngsheet

pngsheet is a PNG file that contains a sprite sheet with animations. It additionally contains two metadata chunks, a supplementary palette in sPLT and an animation control section in zTXt with the keyword fctrl and "compression scheme" 0xFF.

For GBA rips, the sPLT section is expected to contain groups of 16 colors.

The fctrl section is structured as follows:

left:       int16
top:        int16
right:      int16
bottom:     int16
originX:    int16
originY:    int16
delay:      uint8
action:     0x00 "next" | 0x01 "loop" | 0x03 "stop"

Each animation is delimited by a non-"next" action.

Documentation

Index

• Variables
• type Animation
• type Frame
• type Info
  • func Load(f io.ReadSeeker) (image.Image, *Info, error)
  • func LoadInfo(f io.Reader) (*Info, error)

Variables

var ErrInvalidFormat = errors.New("invalid format")

Types

type Animation

type Animation struct {
	Frames    []*Frame
	IsLooping bool
}

type Frame

type Frame struct {
	Index  int
	Rect   image.Rectangle
	Origin image.Point
}

type Info

type Info struct {
	SuggestedPalettes map[string]color.Palette
	Frames            []*Frame
	Animations        []*Animation
}

func Load

func Load(f io.ReadSeeker) (image.Image, *Info, error)

func LoadInfo

func LoadInfo(f io.Reader) (*Info, error)