fix(viewport): scroll to last line when borders (#706)

caarlos0 · web-flow · commit 7ab08fb438e4 · 2025-01-21T19:31:03.000-03:00
If the viewport has borders, they are not currently taken into account
when calculating the viewport max y offset, which might cause the last
line to not be visible.

This is easily reproducible in `gum pager`.

Signed-off-by: Carlos Alexandro Becker &lt;caarlos0@users.noreply.github.com&gt;
diff --git a/viewport/viewport.go b/viewport/viewport.go
@@ -140,7 +140,7 @@ func (m *Model) SetContent(s string) {
 // maxYOffset returns the maximum possible value of the y-offset based on the
 // viewport's content and set height.
 func (m Model) maxYOffset() int {
-	return max(0, len(m.lines)-m.Height)
+	return max(0, len(m.lines)-m.Height+m.Style.GetVerticalFrameSize())
 }
 
 // visibleLines returns the lines that should currently be visible in the

Original file line number	Diff line number	Diff line change
`@@ -140,7 +140,7 @@ func (m *Model) SetContent(s string) {`
`140`	`140`	`// maxYOffset returns the maximum possible value of the y-offset based on the`
`141`	`141`	`// viewport's content and set height.`
`142`	`142`	`func (m Model) maxYOffset() int {`
`143`		`- return max(0, len(m.lines)-m.Height)`
	`143`	`+ return max(0, len(m.lines)-m.Height+m.Style.GetVerticalFrameSize())`
`144`	`144`	`}`
`145`	`145`
`146`	`146`	`// visibleLines returns the lines that should currently be visible in the`