commit 770c472

Allow scrolling topic left and right

Co-authored-by: delthas <delthas@dille.cc>

 1@@ -604,6 +604,8 @@ func (app *App) handleMouseEvent(ev vaxis.Mouse) {
 2 				app.win.ScrollChannelUpBy(4)
 3 			} else if x > w-app.win.MemberWidth() && y < h-memberItems*2 {
 4 				app.win.ScrollMemberUpBy(4)
 5+			} else if y == 0 {
 6+				app.win.ScrollTopicLeftBy(12)
 7 			} else {
 8 				app.win.ScrollUpBy(4)
 9 			}
10@@ -613,6 +615,8 @@ func (app *App) handleMouseEvent(ev vaxis.Mouse) {
11 				app.win.ScrollChannelDownBy(4)
12 			} else if x > w-app.win.MemberWidth() && y < h-memberItems*2 {
13 				app.win.ScrollMemberDownBy(4)
14+			} else if y == 0 {
15+				app.win.ScrollTopicRightBy(12)
16 			} else {
17 				app.win.ScrollDownBy(4)
18 			}

 1@@ -222,8 +222,9 @@ type buffer struct {
 2 	lines []Line
 3 	topic StyledString
 4 
 5-	scrollAmt int // offset in lines from the bottom
 6-	isAtTop   bool
 7+	scrollAmt   int // offset in lines from the bottom
 8+	topicOffset int // offset in clusters that are skipped when rendering topic text
 9+	isAtTop     bool
10 }
11 
12 type BufferList struct {
13@@ -747,6 +748,20 @@ func (bs *BufferList) ScrollDownHighlight() bool {
14 	return b.scrollAmt != 0
15 }
16 
17+func (bs *BufferList) ScrollTopicLeft(n int) {
18+	b := bs.cur()
19+	b.topicOffset -= n
20+
21+	if b.topicOffset < 0 {
22+		b.topicOffset = 0
23+	}
24+}
25+
26+func (bs *BufferList) ScrollTopicRight(n int) {
27+	b := bs.cur()
28+	b.topicOffset += n
29+}
30+
31 // LinesAboveOffset returns a rough approximate of the number of lines
32 // above the offset (that is, starting from the bottom of the screen,
33 // up to the first line).
34@@ -1069,6 +1084,24 @@ func (bs *BufferList) DrawTimeline(ui *UI, x0, y0, nickColWidth int) {
35 		}
36 	}
37 
38+	for b.topicOffset > 0 {
39+		sr := []rune(b.topic.string)
40+		ri := 0
41+		for i := 0; i < b.topicOffset; i++ {
42+			s, _ := firstCluster(bs.ui.vx, sr[ri:])
43+			ri += len([]rune(s))
44+		}
45+		w := stringWidth(bs.ui.vx, string(sr[ri:]))
46+		if w <= bs.tlInnerWidth+nickColWidth+9-16 {
47+			b.topicOffset -= 12
48+			if b.topicOffset < 0 {
49+				b.topicOffset = 0
50+			}
51+		} else {
52+			break
53+		}
54+	}
55+
56 	xTopic := x0
57 	{
58 		// TODO: factorize this (same code for drawing timeline)
59@@ -1076,8 +1109,14 @@ func (bs *BufferList) DrawTimeline(ui *UI, x0, y0, nickColWidth int) {
60 		var st vaxis.Style
61 		nextStyles := b.topic.styles
62 
63-		i := 0
64 		sr := []rune(b.topic.string)
65+		ri := 0
66+		for i := 0; i < b.topicOffset; i++ {
67+			s, _ := firstCluster(bs.ui.vx, sr[ri:])
68+			ri += len([]rune(s))
69+		}
70+		i := len(string(sr[:ri]))
71+		sr = sr[ri:]
72 		for len(sr) > 0 {
73 			if 0 < len(nextStyles) && nextStyles[0].Start == i {
74 				st = nextStyles[0].Style

 1@@ -350,6 +350,14 @@ func (ui *UI) ScrollMemberDownBy(n int) {
 2 	ui.memberOffset += n
 3 }
 4 
 5+func (ui *UI) ScrollTopicLeftBy(n int) {
 6+	ui.bs.ScrollTopicLeft(n)
 7+}
 8+
 9+func (ui *UI) ScrollTopicRightBy(n int) {
10+	ui.bs.ScrollTopicRight(n)
11+}
12+
13 func (ui *UI) LinesAboveOffset() int {
14 	return ui.bs.LinesAboveOffset()
15 }