1 package pdf417
2
3 import "math"
4
5 const (
6 minCols = 2
7 maxCols = 30
8 maxRows = 30
9 minRows = 2
10 moduleHeight = 2
11 preferred_ratio = 3.0
12 )
13
14 func calculateNumberOfRows(m, k, c int) int {
15 r := ((m + 1 + k) / c) + 1
16 if c*r >= (m + 1 + k + c) {
17 r--
18 }
19 return r
20 }
21
22 func calcDimensions(dataWords, eccWords int) (cols, rows int) {
23 ratio := 0.0
24 cols = 0
25 rows = 0
26
27 for c := minCols; c <= maxCols; c++ {
28 r := calculateNumberOfRows(dataWords, eccWords, c)
29
30 if r < minRows {
31 break
32 }
33
34 if r > maxRows {
35 continue
36 }
37
38 newRatio := float64(17*cols+69) / float64(rows*moduleHeight)
39 if rows != 0 && math.Abs(newRatio-preferred_ratio) > math.Abs(ratio-preferred_ratio) {
40 continue
41 }
42
43 ratio = newRatio
44 cols = c
45 rows = r
46 }
47
48 if rows == 0 {
49 r := calculateNumberOfRows(dataWords, eccWords, minCols)
50 if r < minRows {
51 rows = minRows
52 cols = minCols
53 }
54 }
55
56 return
57 }
58
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