gui: the preview is as big as you drag it, and PDFs render to suit

1 files changed, 65 insertions, 20 deletions

diff --git a/gui/internal/ui/plan.go b/gui/internal/ui/plan.go
index f4ecb91..87afdff 100644
--- a/gui/internal/ui/plan.go
+++ b/gui/internal/ui/plan.go
@@ -40,12 +40,13 @@ type planView struct {
 
 	previewNote   *gtk.Label
 	picture       *gtk.Picture
-	pictureFrame  *gtk.ScrolledWindow
 	previewText   *gtk.TextView
 	previewScroll *gtk.ScrolledWindow
 	previewTmp    string
 	previewFor    string
+	detailPane    *gtk.Paned
 	renderedDir   string
+	previewHeight int
 	previewOff    bool
 	startSelected bool
 	menu          *gtk.Popover
@@ -128,15 +129,15 @@ func newPlanView(w *Window) *planView {
 	p.previewNote.SetEllipsize(pango.EllipsizeEnd)
 	p.previewNote.SetMaxWidthChars(20)
 	p.previewNote.AddCSSClass("dim-label")
+	// The picture fills whatever the divider leaves it. Inside a scrolled
+	// window it would be given its smallest size instead, which is what
+	// made the page a stamp (his report, 2026-09-17).
 	p.picture = gtk.NewPicture()
 	p.picture.SetCanShrink(true)
 	p.picture.SetContentFit(gtk.ContentFitContain)
 	p.picture.SetVisible(false)
-	pictureFrame := gtk.NewScrolledWindow()
-	pictureFrame.SetChild(p.picture)
-	pictureFrame.SetSizeRequest(-1, 280)
-	pictureFrame.SetVisible(false)
-	p.pictureFrame = pictureFrame
+	p.picture.SetVExpand(true)
+	p.picture.SetHExpand(true)
 	p.previewText = gtk.NewTextView()
 	p.previewText.SetEditable(false)
 	p.previewText.SetMonospace(true)
@@ -145,17 +146,28 @@ func newPlanView(w *Window) *planView {
 	p.previewText.SetTopMargin(6)
 	previewScroll := gtk.NewScrolledWindow()
 	previewScroll.SetChild(p.previewText)
-	previewScroll.SetSizeRequest(-1, 260)
 	previewScroll.SetVisible(false)
+	previewScroll.SetVExpand(true)
 	p.previewScroll = previewScroll
 
-	detailBox := gtk.NewBox(gtk.OrientationVertical, 0)
-	detailBox.Append(detailScroll)
-	detailBox.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
-	detailBox.Append(p.previewNote)
-	detailBox.Append(pictureFrame)
-	detailBox.Append(previewScroll)
-	detailBox.SetSizeRequest(340, -1)
+	previewBox := gtk.NewBox(gtk.OrientationVertical, 0)
+	previewBox.Append(p.previewNote)
+	previewBox.Append(p.picture)
+	previewBox.Append(previewScroll)
+
+	// The divider between the explanation and the preview is the size
+	// control: drag it, and the preview stays that tall (his request,
+	// 2026-09-17).
+	p.detailPane = gtk.NewPaned(gtk.OrientationVertical)
+	p.detailPane.SetStartChild(detailScroll)
+	p.detailPane.SetEndChild(previewBox)
+	p.detailPane.SetResizeStartChild(true)
+	p.detailPane.SetResizeEndChild(false)
+	p.detailPane.SetShrinkEndChild(false)
+	p.detailPane.SetVExpand(true)
+	p.detailPane.SetSizeRequest(340, -1)
+	p.detailPane.Connect("notify::position", p.rememberPreviewHeight)
+	detailBox := p.detailPane
 
 	// A pane the user can drag: on a narrow window the list needs the room,
 	// on a wide one the explanation does.
@@ -549,7 +561,7 @@ func (p *planView) showPreview(rel string) {
 		return
 	}
 	p.previewFor = path
-	p.pictureFrame.SetVisible(false)
+	p.picture.SetVisible(false)
 	p.previewScroll.SetVisible(false)
 	p.previewNote.SetText("looking at " + escape(rel) + "...")
 	if p.previewTmp == "" {
@@ -562,7 +574,7 @@ func (p *planView) showPreview(rel string) {
 	}
 	var pv model.Preview
 	runInBackground(func(ctx context.Context) error {
-		pv = model.MakePreview(ctx, path, p.previewTmp)
+		pv = model.MakePreview(ctx, path, p.previewTmp, p.previewHeight)
 		return nil
 	}, func(error) {
 		if p.previewFor != path {
@@ -573,7 +585,6 @@ func (p *planView) showPreview(rel string) {
 		case model.PreviewImage:
 			p.picture.SetFilename(pv.Image)
 			p.picture.SetVisible(true)
-			p.pictureFrame.SetVisible(true)
 			// The picture is loaded, so the page rendered for the row
 			// before it can go.
 			p.dropRendered()
@@ -588,14 +599,48 @@ func (p *planView) showPreview(rel string) {
 	})
 }
 
-// applyPrefs turns the file preview on or off, and says how a fresh plan
-// starts.
+// rememberPreviewHeight keeps what a drag of the divider chose, so the next
+// window opens the same way.
+func (p *planView) rememberPreviewHeight() {
+	height := p.detailPane.Height() - p.detailPane.Position()
+	if height < 80 || height == p.previewHeight {
+		return
+	}
+	p.previewHeight = height
+	prefs := p.w.prefs
+	prefs.PreviewHeight = height
+	p.w.prefs = prefs
+	if err := prefs.Save(); err != nil {
+		p.w.setStatus("settings: %v", err)
+	}
+}
+
+// setPreviewHeight puts the divider where a height asks for.
+func (p *planView) setPreviewHeight(height int) {
+	if height < 80 {
+		height = model.DefaultPreviewHeight
+	}
+	p.previewHeight = height
+	if total := p.detailPane.Height(); total > height+80 {
+		p.detailPane.SetPosition(total - height)
+		return
+	}
+	// Before the window is drawn there is no height to subtract from, so
+	// the end child's own request puts the divider in the right place.
+	if child := p.detailPane.EndChild(); child != nil {
+		gtk.BaseWidget(child).SetSizeRequest(-1, height)
+	}
+}
+
+// applyPrefs turns the file preview on or off, sets how tall it is, and
+// says how a fresh plan starts.
 func (p *planView) applyPrefs(prefs model.Prefs) {
 	p.previewOff = !prefs.Preview
 	p.startSelected = prefs.SelectAll
+	p.setPreviewHeight(prefs.PreviewHeight)
 	if p.previewOff {
 		p.previewFor = ""
-		p.pictureFrame.SetVisible(false)
+		p.picture.SetVisible(false)
 		p.previewScroll.SetVisible(false)
 		p.previewNote.SetText("")
 	}