From 97685359be3244cedc64b10a3cab273aaa2988e4 Mon Sep 17 00:00:00 2001
From: Hubert Hirtz <hubert@hirtz.pm>
Date: Tue, 26 Oct 2021 18:41:19 +0200
Subject: Scroll up/down highlight by highlight

---
 ui/buffers.go | 30 ++++++++++++++++++++++++++++++
 ui/ui.go      |  8 ++++++++
 2 files changed, 38 insertions(+)

(limited to 'ui')

diff --git a/ui/buffers.go b/ui/buffers.go
index 0c24248..c126408 100644
--- a/ui/buffers.go
+++ b/ui/buffers.go
@@ -374,6 +374,36 @@ func (bs *BufferList) ScrollDown(n int) {
 	}
 }
 
+func (bs *BufferList) ScrollUpHighlight() bool {
+	b := &bs.list[bs.current]
+	ymin := b.scrollAmt + bs.tlHeight
+	y := 0
+	for i := len(b.lines) - 1; 0 <= i; i-- {
+		line := &b.lines[i]
+		if ymin <= y && line.Highlight {
+			b.scrollAmt = y - bs.tlHeight + 1
+			return true
+		}
+		y += len(line.NewLines(bs.tlInnerWidth)) + 1
+	}
+	return false
+}
+
+func (bs *BufferList) ScrollDownHighlight() bool {
+	b := &bs.list[bs.current]
+	yLastHighlight := 0
+	y := 0
+	for i := len(b.lines) - 1; 0 <= i && y < b.scrollAmt; i-- {
+		line := &b.lines[i]
+		if line.Highlight {
+			yLastHighlight = y
+		}
+		y += len(line.NewLines(bs.tlInnerWidth)) + 1
+	}
+	b.scrollAmt = yLastHighlight
+	return b.scrollAmt != 0
+}
+
 func (bs *BufferList) IsAtTop() bool {
 	b := &bs.list[bs.current]
 	return b.isAtTop
diff --git a/ui/ui.go b/ui/ui.go
index 7291042..ef81827 100644
--- a/ui/ui.go
+++ b/ui/ui.go
@@ -132,6 +132,14 @@ func (ui *UI) ScrollDownBy(n int) {
 	ui.bs.ScrollDown(n)
 }
 
+func (ui *UI) ScrollUpHighlight() bool {
+	return ui.bs.ScrollUpHighlight()
+}
+
+func (ui *UI) ScrollDownHighlight() bool {
+	return ui.bs.ScrollDownHighlight()
+}
+
 func (ui *UI) ScrollMemberUpBy(n int) {
 	ui.memberOffset -= n
 	if ui.memberOffset < 0 {
-- 
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