limage - xcf/channel.go

     1  package xcf
     2  
     3  import "image"
     4  
     5  func (d *decoder) ReadChannel() *image.Gray {
     6  	width := d.ReadUint32()
     7  	height := d.ReadUint32()
     8  
     9  	d.SkipString() // name
    10  
    11  PropertyLoop:
    12  	for {
    13  		typ := d.ReadUint32()
    14  		plength := d.ReadUint32()
    15  		switch typ {
    16  		// general properties
    17  		case propEnd:
    18  			if plength != 0 {
    19  				d.SetError(ErrInvalidProperties)
    20  			}
    21  			break PropertyLoop
    22  		case propLinked:
    23  			d.SkipBoolProperty()
    24  		case propLockContent:
    25  			d.SkipBoolProperty()
    26  		case propOpacity:
    27  			if d.ReadUint32() > 255 {
    28  				d.SetError(ErrInvalidOpacity)
    29  			}
    30  		case propParasites:
    31  			d.SkipParasites(plength)
    32  		case propTattoo:
    33  			d.SkipUint32()
    34  		case propVisible:
    35  			d.SkipBoolProperty()
    36  
    37  			//channel properties
    38  		case propActiveChannel:
    39  			// active channel
    40  		case propColor:
    41  			d.SkipByte() // r
    42  			d.SkipByte() // g
    43  			d.SkipByte() // b
    44  		case propFloatColour:
    45  			d.SkipFloat32() // r
    46  			d.SkipFloat32() // g
    47  			d.SkipFloat32() // b
    48  		case propSelection:
    49  			// selected
    50  		case propShowMasked:
    51  			d.SkipBoolProperty()
    52  		default:
    53  			d.Skip(plength)
    54  		}
    55  
    56  	}
    57  
    58  	var hptr uint64
    59  	if d.mode < 2 {
    60  		hptr = uint64(d.ReadUint32())
    61  	} else {
    62  		hptr = d.ReadUint64()
    63  	}
    64  	d.Goto(hptr)
    65  
    66  	im := d.ReadImage(width, height, 2)
    67  	if im != nil {
    68  		return im.(*image.Gray) // gray
    69  	}
    70  	return nil
    71  }
    72  
    73  func (e *encoder) WriteChannel(c *image.Gray) {
    74  	b := c.Bounds()
    75  	e.WriteUint32(uint32(b.Dx()))
    76  	e.WriteUint32(uint32(b.Dy()))
    77  	e.WriteString("")
    78  
    79  	e.WriteUint32(0) // No properties
    80  	e.WriteUint32(0)
    81  
    82  	e.WriteUint32(uint32(e.pos) + 4) // hptr
    83  	e.WriteImage(c, (*encoder).grayToBuf, 1)
    84  }
    85