image.dart
3 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
/*
* Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General License for more details.
*
* You should have received a copy of the GNU Lesser General
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
part of pdf;
class PdfImage extends PdfXObject {
/// RGBA Image Data
final Uint8List image;
/// Image width
final int width;
/// Image height
final int height;
/// Image has alpha channel
final bool alpha;
String _name;
/// Process alphaChannel only
final bool alphaChannel;
/// Creates a new [PdfImage] instance.
///
/// @param imgage an [Uint8List] value
/// @param width
/// @param height
/// @param alpha if the image is transparent
/// @param alphaChannel if this is transparency mask
PdfImage(PdfDocument pdfDocument,
{@required this.image,
@required this.width,
@required this.height,
this.alpha = true,
this.alphaChannel = false})
: assert(alphaChannel == false || alpha == true),
assert(width != null),
assert(height != null),
super(pdfDocument, "/Image", isBinary: true) {
_name = "/Image$objser";
params["/Width"] = PdfStream.string(width.toString());
params["/Height"] = PdfStream.string(height.toString());
params["/BitsPerComponent"] = PdfStream.intNum(8);
params['/Name'] = PdfStream.string(_name);
if (alphaChannel == false && alpha) {
var _sMask = PdfImage(pdfDocument,
image: image,
width: width,
height: height,
alpha: alpha,
alphaChannel: true);
params["/SMask"] = PdfStream.string("${_sMask.objser} 0 R");
}
if (alphaChannel) {
params["/ColorSpace"] = PdfStream.string("/DeviceGray");
} else {
params["/ColorSpace"] = PdfStream.string("/DeviceRGB");
}
}
@override
void _prepare() {
// write the pixels to the stream
// print("Processing image ${img.width}x${img.height} pixels");
int w = width;
int h = height;
int s = w * h;
Uint8List out = Uint8List(alphaChannel ? s : s * 3);
if (alphaChannel) {
for (int i = 0; i < s; i++) {
out[i] = image[i * 4 + 3];
}
} else {
for (int i = 0; i < s; i++) {
out[i * 3] = image[i * 4];
out[i * 3 + 1] = image[i * 4 + 1];
out[i * 3 + 2] = image[i * 4 + 2];
}
}
buf.putBytes(out);
super._prepare();
}
/// Get the name
///
/// @return a String value
String get name => _name;
}