~eliasnaur/gio

ref: 20f9a72c1571f384fce3e09f937d00b6ce8f98e4 gio/apps/gophers/ui.go -rw-r--r-- 17.5 KiB View raw
20f9a72cElias Naur apps: update gioui.org/ui version 9 months ago
                                                                                
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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
// SPDX-License-Identifier: Unlicense OR MIT

package main

// A Gio program that displays Go contributors from GitHub. See https://gioui.org for more information.

import (
	"fmt"
	"image"
	"image/color"
	"runtime"

	"golang.org/x/image/draw"

	_ "image/jpeg"
	_ "image/png"

	_ "net/http/pprof"

	"gioui.org/ui"
	"gioui.org/ui/f32"
	"gioui.org/ui/gesture"
	"gioui.org/ui/input"
	"gioui.org/ui/key"
	"gioui.org/ui/layout"
	"gioui.org/ui/measure"
	"gioui.org/ui/pointer"
	"gioui.org/ui/system"
	"gioui.org/ui/text"
	"gioui.org/ui/widget"
	"gioui.org/ui/paint"
	"golang.org/x/exp/shiny/iconvg"

	"github.com/google/go-github/v24/github"
	"golang.org/x/image/font/gofont/gobold"
	"golang.org/x/image/font/gofont/goitalic"
	"golang.org/x/image/font/gofont/gomono"
	"golang.org/x/image/font/gofont/goregular"
	"golang.org/x/image/font/sfnt"

	"golang.org/x/exp/shiny/materialdesign/icons"
)

type UI struct {
	faces        measure.Faces
	fab          *ActionButton
	usersList    *layout.List
	users        []*user
	userClicks   []gesture.Click
	selectedUser *userPage
	edit, edit2  *text.Editor
	invalidate   func()
	fetchCommits func(u string)

	// Profiling.
	profiling   bool
	profile     system.ProfileEvent
	lastMallocs uint64
}

type userPage struct {
	config      ui.Config
	faces       measure.Faces
	invalidate  func()
	user        *user
	commitsList *layout.List
	commits     []*github.Commit
}

type user struct {
	name    string
	login   string
	company string
	avatar  image.Image
}

type icon struct {
	src  []byte
	size ui.Value

	// Cached values.
	img     image.Image
	imgSize int
}

type ActionButton struct {
	face    text.Face
	Open    bool
	icons   []*icon
	sendIco *icon
}

var fonts struct {
	regular *sfnt.Font
	bold    *sfnt.Font
	italic  *sfnt.Font
	mono    *sfnt.Font
}

var theme struct {
	text     ui.MacroOp
	tertText ui.MacroOp
	brand    ui.MacroOp
	white    ui.MacroOp
}

func colorMaterial(ops *ui.Ops, color color.RGBA) ui.MacroOp {
	var mat ui.MacroOp
	mat.Record(ops)
	paint.ColorOp{Color: color}.Add(ops)
	mat.Stop()
	return mat
}

func init() {
	fonts.regular = mustLoadFont(goregular.TTF)
	fonts.bold = mustLoadFont(gobold.TTF)
	fonts.italic = mustLoadFont(goitalic.TTF)
	fonts.mono = mustLoadFont(gomono.TTF)
	var ops ui.Ops
	theme.text = colorMaterial(&ops, rgb(0x333333))
	theme.tertText = colorMaterial(&ops, rgb(0xbbbbbb))
	theme.brand = colorMaterial(&ops, rgb(0x62798c))
	theme.white = colorMaterial(&ops, rgb(0xffffff))
}

func newUI(invalidate func(), fetchCommits func(string)) *UI {
	u := &UI{
		invalidate:   invalidate,
		fetchCommits: fetchCommits,
	}
	u.usersList = &layout.List{
		Axis: layout.Vertical,
	}
	u.fab = &ActionButton{
		face:    u.face(fonts.regular, 11),
		sendIco: &icon{src: icons.ContentSend, size: ui.Dp(24)},
		icons:   []*icon{},
	}
	u.edit2 = &text.Editor{
		Face: u.face(fonts.italic, 14),
		//Alignment: text.End,
		SingleLine:   true,
		Hint:         "Hint",
		HintMaterial: theme.tertText,
		Material:     theme.text,
	}
	u.edit2.SetText("Single line editor. Edit me!")
	u.edit = &text.Editor{
		Face:     u.face(fonts.regular, 16),
		Material: theme.text,
		//Alignment: text.End,
		//SingleLine: true,
	}
	u.edit.SetText(longTextSample)
	return u
}

func mustLoadFont(fontData []byte) *sfnt.Font {
	fnt, err := sfnt.Parse(fontData)
	if err != nil {
		panic("failed to load font")
	}
	return fnt
}

func rgb(c uint32) color.RGBA {
	return argb((0xff << 24) | c)
}

func argb(c uint32) color.RGBA {
	return color.RGBA{A: uint8(c >> 24), R: uint8(c >> 16), G: uint8(c >> 8), B: uint8(c)}
}

func (u *UI) face(f *sfnt.Font, size float32) text.Face {
	return u.faces.For(f, ui.Sp(size))
}

func (u *UI) layoutTimings(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	if !u.profiling {
		return layout.Dimens{}
	}
	for e, ok := q.Next(u); ok; e, ok = q.Next(u) {
		if e, ok := e.(system.ProfileEvent); ok {
			u.profile = e
		}
	}
	system.ProfileOp{Key: u}.Add(ops)
	var mstats runtime.MemStats
	runtime.ReadMemStats(&mstats)
	mallocs := mstats.Mallocs - u.lastMallocs
	u.lastMallocs = mstats.Mallocs
	al := layout.Align{Alignment: layout.NE}
	cs = al.Begin(ops, cs)
	in := layout.Inset{Top: ui.Dp(16)}
	cs = in.Begin(c, ops, cs)
	txt := fmt.Sprintf("m: %d %s", mallocs, u.profile.Timings)
	dims := text.Label{Material: theme.text, Face: u.face(fonts.mono, 10), Text: txt}.Layout(ops, cs)
	dims = in.End(dims)
	return al.End(dims)
}

func (u *UI) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	u.faces.Reset(c)
	for i := range u.userClicks {
		click := &u.userClicks[i]
		for _, e := range click.Events(q) {
			if e.Type == gesture.TypeClick {
				u.selectedUser = u.newUserPage(u.users[i])
			}
		}
	}
	var dims layout.Dimens
	if u.selectedUser == nil {
		dims = u.layoutUsers(c, q, ops, cs)
	} else {
		dims = u.selectedUser.Layout(c, q, ops, cs)
	}
	u.layoutTimings(c, q, ops, cs)
	return dims
}

func (u *UI) newUserPage(user *user) *userPage {
	up := &userPage{
		faces:       u.faces,
		invalidate:  u.invalidate,
		user:        user,
		commitsList: &layout.List{Axis: layout.Vertical},
	}
	u.fetchCommits(user.login)
	return up
}

func (up *userPage) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	l := up.commitsList
	if l.Dragging() {
		key.HideInputOp{}.Add(ops)
	}
	for l.Init(c, q, ops, cs, len(up.commits)); l.More(); l.Next() {
		l.Elem(up.commit(c, ops, l.Constraints(), l.Index()))
	}
	return l.Layout()
}

func (up *userPage) commit(c ui.Config, ops *ui.Ops, cs layout.Constraints, index int) layout.Dimens {
	u := up.user
	msg := up.commits[index].GetMessage()
	label := text.Label{Material: theme.text, Face: up.faces.For(fonts.regular, ui.Sp(12)), Text: msg}
	in := layout.Inset{Top: ui.Dp(16), Right: ui.Dp(8), Left: ui.Dp(8)}
	cs = in.Begin(c, ops, cs)
	f := (&layout.Flex{Axis: layout.Horizontal, MainAxisAlignment: layout.Start, CrossAxisAlignment: layout.Start}).Init(ops, cs)
	cs = f.Rigid()
	sz := c.Px(ui.Dp(48))
	cc := clipCircle{}
	cs = cc.Begin(ops, cs)
	cs = layout.RigidConstraints(cs.Constrain(image.Point{X: sz, Y: sz}))
	dims := widget.Image{Src: u.avatar, Rect: u.avatar.Bounds()}.Layout(c, ops, cs)
	dims = cc.End(dims)
	c1 := f.End(dims)
	cs = f.Flexible(1)
	cs.Width.Min = cs.Width.Max
	in2 := layout.Inset{Left: ui.Dp(8)}
	cs = in2.Begin(c, ops, cs)
	dims = label.Layout(ops, cs)
	dims = in2.End(dims)
	c2 := f.End(dims)
	dims = f.Layout(c1, c2)
	return in.End(dims)
}

func (u *UI) layoutUsers(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	st := (&layout.Stack{Alignment: layout.Start}).Init(ops, cs)
	cs = st.Rigid()
	al := layout.Align{Alignment: layout.SE}
	in := layout.UniformInset(ui.Dp(16))
	cs = in.Begin(c, ops, al.Begin(ops, cs))
	dims := u.fab.Layout(c, q, ops, cs)
	dims = al.End(in.End(dims))
	c2 := st.End(dims)

	cs = st.Expand()
	{
		f := (&layout.Flex{Axis: layout.Vertical, MainAxisAlignment: layout.Start}).Init(ops, cs)

		cs = f.Rigid()
		{
			cs.Width.Min = cs.Width.Max
			in := layout.UniformInset(ui.Dp(16))
			sz := c.Px(ui.Dp(200))
			cs = layout.RigidConstraints(cs.Constrain(image.Point{X: sz, Y: sz}))
			dims = u.edit.Layout(c, q, ops, in.Begin(c, ops, cs))
			dims = in.End(dims)
		}
		c1 := f.End(dims)

		cs = f.Rigid()
		{
			cs.Width.Min = cs.Width.Max
			in := layout.Inset{Bottom: ui.Dp(16), Left: ui.Dp(16), Right: ui.Dp(16)}
			dims = u.edit2.Layout(c, q, ops, in.Begin(c, ops, cs))
			dims = in.End(dims)
		}
		c2 := f.End(dims)

		cs = f.Rigid()
		{
			cs.Width.Min = cs.Width.Max
			s := layout.Stack{Alignment: layout.Center}
			s.Init(ops, cs)
			cs = s.Rigid()
			in := layout.Inset{Top: ui.Dp(16), Right: ui.Dp(8), Bottom: ui.Dp(8), Left: ui.Dp(8)}
			grey := colorMaterial(ops, rgb(0x888888))
			lbl := text.Label{Material: grey, Face: u.face(fonts.regular, 11), Text: "GOPHERS"}
			dims = in.End(lbl.Layout(ops, in.Begin(c, ops, cs)))
			c2 := s.End(dims)
			c1 := s.End(fill{colorMaterial(ops, rgb(0xf2f2f2))}.Layout(ops, s.Expand()))
			dims = s.Layout(c1, c2)
		}
		c3 := f.End(dims)

		cs = f.Flexible(1)
		cs.Width.Min = cs.Width.Max
		dims = u.layoutContributors(c, q, ops, cs)
		c4 := f.End(dims)
		dims = f.Layout(c1, c2, c3, c4)
	}
	c1 := st.End(dims)
	return st.Layout(c1, c2)
}

func (a *ActionButton) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	f := layout.Flex{Axis: layout.Vertical, MainAxisAlignment: layout.Start, CrossAxisAlignment: layout.End}
	f.Init(ops, cs)
	cs = f.Rigid()
	in := layout.Inset{Top: ui.Dp(4)}
	cs = in.Begin(c, ops, cs)
	dims := fab(ops, cs, a.sendIco.image(c), theme.brand, c.Px(ui.Dp(56)))
	pointer.EllipseAreaOp{Rect: image.Rectangle{Max: dims.Size}}.Add(ops)
	dims = in.End(dims)
	return f.Layout(f.End(dims))
}

func (u *UI) layoutContributors(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	l := u.usersList
	if l.Dragging() {
		key.HideInputOp{}.Add(ops)
	}
	for l.Init(c, q, ops, cs, len(u.users)); l.More(); l.Next() {
		l.Elem(u.user(c, ops, l.Constraints(), l.Index()))
	}
	return l.Layout()
}

func (u *UI) user(c ui.Config, ops *ui.Ops, cs layout.Constraints, index int) layout.Dimens {
	user := u.users[index]
	elem := layout.Flex{Axis: layout.Vertical, MainAxisAlignment: layout.Start, CrossAxisAlignment: layout.Start}
	elem.Init(ops, cs)
	cs = elem.Rigid()
	var dims layout.Dimens
	{
		in := layout.UniformInset(ui.Dp(8))
		cs = in.Begin(c, ops, cs)
		f := centerRowOpts()
		f.Init(ops, cs)
		cs = f.Rigid()
		{
			in := layout.Inset{Right: ui.Dp(8)}
			cc := clipCircle{}
			cs = cc.Begin(ops, in.Begin(c, ops, cs))
			sz := image.Point{X: c.Px(ui.Dp(48)), Y: c.Px(ui.Dp(48))}
			cs = layout.RigidConstraints(cs.Constrain(sz))
			dims = widget.Image{Src: user.avatar, Rect: user.avatar.Bounds()}.Layout(c, ops, cs)
			dims = in.End(cc.End(dims))
		}
		c1 := f.End(dims)
		cs = f.Rigid()
		{
			f := column()
			f.Init(ops, cs)
			cs = f.Rigid()
			{
				f := baseline()
				f.Init(ops, cs)
				cs = f.Rigid()
				dims = text.Label{Material: theme.text, Face: u.face(fonts.regular, 13), Text: user.name}.Layout(ops, cs)
				c1 := f.End(dims)
				cs = f.Flexible(1)
				cs.Width.Min = cs.Width.Max
				al := layout.Align{Alignment: layout.E}
				in := layout.Inset{Left: ui.Dp(2)}
				cs = in.Begin(c, ops, al.Begin(ops, cs))
				dims = text.Label{Material: theme.text, Face: u.face(fonts.regular, 10), Text: "3 hours ago"}.Layout(ops, cs)
				dims = al.End(in.End(dims))
				c2 := f.End(dims)
				dims = f.Layout(c1, c2)
			}
			c1 := f.End(dims)
			cs = f.Rigid()
			in := layout.Inset{Top: ui.Dp(4)}
			cs = in.Begin(c, ops, cs)
			dims = text.Label{Material: theme.tertText, Face: u.face(fonts.regular, 12), Text: user.company}.Layout(ops, cs)
			dims = in.End(dims)
			c2 := f.End(dims)
			dims = f.Layout(c1, c2)
		}
		c2 := f.End(dims)
		dims = f.Layout(c1, c2)
		dims = in.End(dims)
		pointer.RectAreaOp{Rect: image.Rectangle{Max: dims.Size}}.Add(ops)
		click := &u.userClicks[index]
		click.Add(ops)
	}
	c1 := elem.End(dims)
	return elem.Layout(c1)
}

type fill struct {
	material ui.MacroOp
}

func (f fill) Layout(ops *ui.Ops, cs layout.Constraints) layout.Dimens {
	d := image.Point{X: cs.Width.Max, Y: cs.Height.Max}
	dr := f32.Rectangle{
		Max: f32.Point{X: float32(d.X), Y: float32(d.Y)},
	}
	f.material.Add(ops)
	paint.PaintOp{Rect: dr}.Add(ops)
	return layout.Dimens{Size: d, Baseline: d.Y}
}

func column() layout.Flex {
	return layout.Flex{Axis: layout.Vertical, MainAxisAlignment: layout.Start, CrossAxisAlignment: layout.Start}
}

func centerRowOpts() layout.Flex {
	return layout.Flex{Axis: layout.Horizontal, MainAxisAlignment: layout.Start, CrossAxisAlignment: layout.Center}
}

func baseline() layout.Flex {
	return layout.Flex{Axis: layout.Horizontal, CrossAxisAlignment: layout.Baseline}
}

type clipCircle struct {
	m   ui.MacroOp
	ops *ui.Ops
}

func (c *clipCircle) Begin(ops *ui.Ops, cs layout.Constraints) layout.Constraints {
	c.ops = ops
	c.m.Record(ops)
	return cs
}

func (c *clipCircle) End(dims layout.Dimens) layout.Dimens {
	c.m.Stop()
	ops := c.ops
	max := dims.Size.X
	if dy := dims.Size.Y; dy > max {
		max = dy
	}
	szf := float32(max)
	rr := szf * .5
	var stack ui.StackOp
	stack.Push(ops)
	rrect(ops, szf, szf, rr, rr, rr, rr)
	c.m.Add(ops)
	stack.Pop()
	return dims
}

func fab(ops *ui.Ops, cs layout.Constraints, ico image.Image, mat ui.MacroOp, size int) layout.Dimens {
	dp := image.Point{X: (size - ico.Bounds().Dx()) / 2, Y: (size - ico.Bounds().Dy()) / 2}
	dims := image.Point{X: size, Y: size}
	rr := float32(size) * .5
	rrect(ops, float32(size), float32(size), rr, rr, rr, rr)
	mat.Add(ops)
	paint.PaintOp{Rect: f32.Rectangle{Max: f32.Point{X: float32(size), Y: float32(size)}}}.Add(ops)
	paint.ImageOp{Src: ico, Rect: ico.Bounds()}.Add(ops)
	paint.PaintOp{
		Rect: toRectF(ico.Bounds().Add(dp)),
	}.Add(ops)
	return layout.Dimens{Size: dims}
}

func toRectF(r image.Rectangle) f32.Rectangle {
	return f32.Rectangle{
		Min: f32.Point{X: float32(r.Min.X), Y: float32(r.Min.Y)},
		Max: f32.Point{X: float32(r.Max.X), Y: float32(r.Max.Y)},
	}
}

func (ic *icon) image(cfg ui.Config) image.Image {
	sz := cfg.Px(ic.size)
	if sz == ic.imgSize {
		return ic.img
	}
	m, _ := iconvg.DecodeMetadata(ic.src)
	dx, dy := m.ViewBox.AspectRatio()
	img := image.NewRGBA(image.Rectangle{Max: image.Point{X: sz, Y: int(float32(sz) * dy / dx)}})
	var ico iconvg.Rasterizer
	ico.SetDstImage(img, img.Bounds(), draw.Src)
	// Use white for icons.
	m.Palette[0] = color.RGBA{A: 0xff, R: 0xff, G: 0xff, B: 0xff}
	iconvg.Decode(&ico, ic.src, &iconvg.DecodeOptions{
		Palette: &m.Palette,
	})
	ic.img = img
	ic.imgSize = sz
	return img
}

// https://pomax.github.io/bezierinfo/#circles_cubic.
func rrect(ops *ui.Ops, width, height, se, sw, nw, ne float32) {
	w, h := float32(width), float32(height)
	const c = 0.55228475 // 4*(sqrt(2)-1)/3
	var b paint.PathBuilder
	b.Init(ops)
	b.Move(f32.Point{X: w, Y: h - se})
	b.Cube(f32.Point{X: 0, Y: se * c}, f32.Point{X: -se + se*c, Y: se}, f32.Point{X: -se, Y: se}) // SE
	b.Line(f32.Point{X: sw - w + se, Y: 0})
	b.Cube(f32.Point{X: -sw * c, Y: 0}, f32.Point{X: -sw, Y: -sw + sw*c}, f32.Point{X: -sw, Y: -sw}) // SW
	b.Line(f32.Point{X: 0, Y: nw - h + sw})
	b.Cube(f32.Point{X: 0, Y: -nw * c}, f32.Point{X: nw - nw*c, Y: -nw}, f32.Point{X: nw, Y: -nw}) // NW
	b.Line(f32.Point{X: w - ne - nw, Y: 0})
	b.Cube(f32.Point{X: ne * c, Y: 0}, f32.Point{X: ne, Y: ne - ne*c}, f32.Point{X: ne, Y: ne}) // NE
	b.End()
}

const longTextSample = `1. I learned from my grandfather, Verus, to use good manners, and to
put restraint on anger. 2. In the famous memory of my father I had a
pattern of modesty and manliness. 3. Of my mother I learned to be
pious and generous; to keep myself not only from evil deeds, but even
from evil thoughts; and to live with a simplicity which is far from
customary among the rich. 4. I owe it to my great-grandfather that I
did not attend public lectures and discussions, but had good and able
teachers at home; and I owe him also the knowledge that for things of
this nature a man should count no expense too great.

5. My tutor taught me not to favour either green or blue at the
chariot races, nor, in the contests of gladiators, to be a supporter
either of light or heavy armed. He taught me also to endure labour;
not to need many things; to serve myself without troubling others; not
to intermeddle in the affairs of others, and not easily to listen to
slanders against them.

6. Of Diognetus I had the lesson not to busy myself about vain things;
not to credit the great professions of such as pretend to work
wonders, or of sorcerers about their charms, and their expelling of
Demons and the like; not to keep quails (for fighting or divination),
nor to run after such things; to suffer freedom of speech in others,
and to apply myself heartily to philosophy. Him also I must thank for
my hearing first Bacchius, then Tandasis and Marcianus; that I wrote
dialogues in my youth, and took a liking to the philosopher's pallet
and skins, and to the other things which, by the Grecian discipline,
belong to that profession.

7. To Rusticus I owe my first apprehensions that my nature needed
reform and cure; and that I did not fall into the ambition of the
common Sophists, either by composing speculative writings or by
declaiming harangues of exhortation in public; further, that I never
strove to be admired by ostentation of great patience in an ascetic
life, or by display of activity and application; that I gave over the
study of rhetoric, poetry, and the graces of language; and that I did
not pace my house in my senatorial robes, or practise any similar
affectation. I observed also the simplicity of style in his letters,
particularly in that which he wrote to my mother from Sinuessa. I
learned from him to be easily appeased, and to be readily reconciled
with those who had displeased me or given cause of offence, so soon as
they inclined to make their peace; to read with care; not to rest
satisfied with a slight and superficial knowledge; nor quickly to
assent to great talkers. I have him to thank that I met with the
discourses of Epictetus, which he furnished me from his own library.

8. From Apollonius I learned true liberty, and tenacity of purpose; to
regard nothing else, even in the smallest degree, but reason always;
and always to remain unaltered in the agonies of pain, in the losses
of children, or in long diseases. He afforded me a living example of
how the same man can, upon occasion, be most yielding and most
inflexible. He was patient in exposition; and, as might well be seen,
esteemed his fine skill and ability in teaching others the principles
of philosophy as the least of his endowments. It was from him that I
learned how to receive from friends what are thought favours without
seeming humbled by the giver or insensible to the gift.`