package draw9 import (	"bitbucket.org/mischief/draw9/color9"	"fmt"	"image"	"io"	"strings") var ldepthToPix = []color9.Pix{	color9.GREY1,	color9.GREY2,	color9.GREY4,	color9.CMAP8,} func (d *Display) ReadImage(rd io.Reader) (*Image, error) {	d.mu.Lock()	defer d.mu.Unlock()	return d.readImage(rd)} func (d *Display) readImage(rd io.Reader) (*Image, error) {	fd := rd	hdr := make([]byte, 5*12) 	_, err := io.ReadFull(fd, hdr[:11])	if err != nil {		return nil, fmt.Errorf("reading image header: %v", err)	}	if string(hdr[:11]) == "compressed\n" {		return d.creadimage(rd)	} 	_, err = io.ReadFull(fd, hdr[11:])	if err != nil {		return nil, fmt.Errorf("reading image header: %v", err)	} 	chunk := 8192	if d != nil {		chunk = d.bufsize - 32 // a little room for header	} 	/*	 * distinguish new channel descriptor from old ldepth.	 * channel descriptors have letters as well as numbers,	 * while ldepths are a single digit formatted as %-11d.	 */	new := false	for m := 0; m < 10; m++ {		if hdr[m] != ' ' {			new = true			break		}	}	if hdr[11] != ' ' {		return nil, fmt.Errorf("readimage: bad format")	}	var pix color9.Pix	if new {		pix, err = color9.ParsePix(strings.TrimSpace(string(hdr[:12])))		if err != nil {			return nil, fmt.Errorf("readimage: %v", err)		}	} else {		ldepth := int(hdr[10]) - '0'		if ldepth < 0 || ldepth > 3 {			return nil, fmt.Errorf("readimage: bad ldepth %d", ldepth)		}		pix = ldepthToPix[ldepth]	}	r := ator(hdr[1*12:])	if r.Min.X > r.Max.X || r.Min.Y > r.Max.Y {		return nil, fmt.Errorf("readimage: bad rectangle")	} 	miny := r.Min.Y	maxy := r.Max.Y 	l := BytesPerLine(r, pix.Depth())	var i *Image	if d != nil {		i, err = d.allocImage(r, pix, false, 0)		if err != nil {			return nil, err		}	} else {		i = &Image{R: r, Pix: pix, Depth: pix.Depth()}	} 	tmp := make([]byte, chunk)	if tmp == nil {		goto Err	}	for maxy > miny {		dy := maxy - miny		if dy*l > chunk {			dy = chunk / l		}		if dy <= 0 {			err = fmt.Errorf("readimage: image too wide for buffer")			goto Err		}		n := dy * l		if _, err = io.ReadFull(fd, tmp[:n]); err != nil {			goto Err		}		if !new { /* an old image: must flip all the bits */			for i, b := range tmp[:n] {				_, _ = i, b //	tmp[i] = b ^ 0xFF			}		}		if d != nil {			if _, err = i.load(image.Rect(r.Min.X, miny, r.Max.X, miny+dy), tmp[:n]); err != nil {				goto Err			}		}		miny += dy	}	return i, nil Err:	if d != nil {		i.free()	}	return nil, err}