README
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img1b
Package img1b is a fork of the standard Go image package modified for 1-bit images. Images are kept packed so they take up to 8 times less memory and may be processed faster.
It provides an Image type that is in most aspects very similar to image.Paletted with palette limited to two colors.
img1b.Image implements image.PalettedImage and can be encoded with image/png and probably other encoders but that is not very efficient due to all the bit shuffling involved. Subpackage img1b/png is a modified png codec that processes whole rows which is several times faster.
Documentation
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Overview ¶
Package img1b is a fork of the standard Go image package modified for 1-bit images. Images are kept packed so they take up to 8 times less memory and may be processed faster.
There is currently no img1b.Decode. To read a PNG file use Decode from img1b/png.
Index ¶
- type Image
- func (p *Image) At(x, y int) color.Color
- func (p *Image) Bounds() image.Rectangle
- func (p *Image) ColorIndexAt(x, y int) uint8
- func (p *Image) ColorModel() color.Model
- func (p *Image) Opaque() bool
- func (p *Image) PixBitOffset(x, y int) (ofs, bit int)
- func (p *Image) SetColorIndex(x, y int, index uint8)
- func (p *Image) SubImage(r image.Rectangle) *Image
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Image ¶
type Image struct {
// Pix is a bitmap of image pixels. Bytes represent up to 8 horizontally adjacent
// pixels (there may be unused bits in the last byte of a row) with the most
// significant bit corresponding to leftmost pixel.
Pix []byte
// Stride is the Pix stride (in bytes) between vertically adjacent pixels.
Stride int
// Rect is the image's bounds.
Rect image.Rectangle
// Palette is the image's palette.
Palette color.Palette
}
Image implements the image.PalettedImage interface and is mostly analogous to image.Paletted except that Pix is a bitmap, so only color indices 0 and 1 can be used.
func (*Image) Bounds ¶
Bounds returns the domain for which At can return non-zero color. The bounds do not necessarily contain the point (0, 0).
func (*Image) ColorIndexAt ¶
ColorIndexAt returns the palette index of the pixel at (x, y).
func (*Image) ColorModel ¶
ColorModel returns the Image's color model.
func (*Image) PixBitOffset ¶
PixBitOffset returns the index of the byte of Pix that corresponds to the pixel at (x, y) and bit offset (7 for MSB) in that byte.
func (*Image) SetColorIndex ¶
SetColorIndex sets color index for the pixel at (x, y). Index should be 0 or 1.
Source Files
Directories