-
Notifications
You must be signed in to change notification settings - Fork 0
/
render.go
185 lines (146 loc) · 4.16 KB
/
render.go
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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
package tigrfont
import (
"image"
"image/color"
"image/draw"
xfont "golang.org/x/image/font"
"golang.org/x/image/math/fixed"
)
type missingGlyphMode int
const (
replaceMissing missingGlyphMode = 1
removeMissing missingGlyphMode = 2
)
func renderFontSheet(runes []rune, face xfont.Face, mode missingGlyphMode, watermark bool) (*image.NRGBA, int, error) {
metrics := face.Metrics()
startDot := fixed.P(0, metrics.Ascent.Ceil()+1)
drawer := xfont.Drawer{
Dst: image.NewNRGBA(image.Rect(0, 0, 1, 1)),
Src: image.White,
Face: face,
Dot: startDot,
}
// Render once to measure.
destWidthPixels, renderedRows, maxAscent, maxDescent, runesRendered := renderFontChars(runes, drawer, 1, mode, watermark)
rowHeightPixels := maxAscent + maxDescent
destHeightPixels := rowHeightPixels * renderedRows
startDot.Y = fixed.I(maxAscent)
if watermark {
// Skip initial watermark
startDot.X = fixed.I(1)
} else {
// bottom border
rowHeightPixels++
// top border
destHeightPixels += renderedRows + 1
startDot.Y += fixed.I(1)
}
// Render once more to the actual sheet size
dest := image.NewNRGBA(image.Rect(0, 0, destWidthPixels, destHeightPixels))
clear(dest)
drawer.Dst = dest
drawer.Dot = startDot
renderFontChars(runes, drawer, rowHeightPixels, mode, watermark)
if watermark {
stampWatermark(drawer.Dst, 0, 0, uint32(runesRendered), uint8(rowHeightPixels))
} else {
// left
drawVerticalDivider(drawer.Dst, 0, 1, destHeightPixels)
// top
drawHorizontalDivider(drawer.Dst, 0, destWidthPixels, 0)
}
return dest, runesRendered, nil
}
func renderFontChars(
allRunes []rune, drawer xfont.Drawer, rowHeightPixels int, mode missingGlyphMode, watermark bool,
) (totalWidth, rows, maxAscent, maxDescent, runesRendered int) {
dstMin := drawer.Dst.Bounds().Min
minGlyphY := fixed.I(10000)
maxGlyphY := fixed.I(-10000)
maxWidthPixels := fixed.I(1000)
rowHeight := fixed.I(rowHeightPixels)
yOffset := 1
if watermark {
yOffset = 0
}
rowIndex := 0
// Always start on whole pixels
drawer.Dot.X = fixed.I(drawer.Dot.X.Ceil())
for _, r := range allRunes {
s := string(r)
bounds, _, exists := drawer.Face.GlyphBounds(r)
if !exists && mode == removeMissing {
continue
}
if drawer.Dot.X >= maxWidthPixels {
drawer.Dot.X = 0
drawer.Dot.Y += rowHeight
rowIndex++
}
xStart := drawer.Dot.X.Ceil() + dstMin.X
// Skip left border / watermark
drawer.Dot.X += fixed.I(1)
if bounds.Min.Y < minGlyphY {
minGlyphY = bounds.Min.Y
}
if bounds.Max.Y > maxGlyphY {
maxGlyphY = bounds.Max.Y
}
// Glyph extends to left of box, must be shifted to the right.
if bounds.Min.X < 0 {
drawer.Dot.X += -bounds.Min.X
}
charStartX := drawer.Dot.X
// Draw the glyph. This should add "advance" to Dot.X.
drawer.DrawString(s)
width := drawer.Dot.X - charStartX
if width <= 0 {
width = fixed.I(1)
}
xEnd := xStart + width.Ceil() + 1
currentWidth := xEnd + 1
if totalWidth < currentWidth {
totalWidth = currentWidth
}
drawer.Dot.X = fixed.I(xEnd)
yStart := rowHeightPixels*rowIndex + dstMin.Y + yOffset
yEnd := yStart + rowHeightPixels
if watermark {
stampWatermark(drawer.Dst, xStart, yStart, uint32(r), uint8(width.Ceil()))
} else {
// top
drawHorizontalDivider(drawer.Dst, xStart, xEnd, yStart-1)
// right
drawVerticalDivider(drawer.Dst, xEnd, yStart, yEnd)
// bottom
drawHorizontalDivider(drawer.Dst, xStart, xEnd, yEnd-1)
}
runesRendered++
}
rows = rowIndex + 1
maxAscent = (-minGlyphY).Ceil()
maxDescent = maxGlyphY.Ceil()
return
}
func drawVerticalDivider(dest draw.Image, x, y0, y1 int) {
draw.Draw(dest, image.Rect(x, y0, x+1, y1), Border, image.Point{}, draw.Src)
}
func drawHorizontalDivider(dest draw.Image, x0, x1, y int) {
draw.Draw(dest, image.Rect(x0, y, x1, y+1), Border, image.Point{}, draw.Src)
}
func stampWatermark(dest draw.Image, x0, y0 int, big uint32, small uint8) {
mark := [7]uint8{
uint8(0b10101010),
uint8(big & 0xff),
uint8((big >> 8) & 0xff),
uint8((big >> 16) & 0xff),
uint8((big >> 24) & 0xff),
small,
uint8(0b01010101),
}
for i, m := range mark {
pixel := dest.At(x0, y0+i).(color.NRGBA)
pixel.A = m
dest.Set(x0, y0+i, pixel)
}
}