ui: fix classic theme drawing with gross hack

Classic theme won't draw transparent images. But new theme erases the
text if we draw ourselves, and we want the OS to draw the text so that
we have better accessibility. Support both by hacking classic theme with
a zero-sized transparent image for the indentation, while using the
transparent image normally for new theme.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 73 insertions, 46 deletions

diff --git a/ui/listview.go b/ui/listview.go
index 4416c063..afcb0ab7 100644
--- a/ui/listview.go
+++ b/ui/listview.go
@@ -9,6 +9,8 @@ import (
 	"sort"
 	"sync/atomic"
 
+	"github.com/lxn/win"
+
 	"golang.zx2c4.com/wireguard/windows/conf"
 	"golang.zx2c4.com/wireguard/windows/manager"
 
@@ -19,11 +21,9 @@ import (
 type ListModel struct {
 	walk.TableModelBase
 	walk.SorterBase
-	walk.ImageProvider
 
 	tunnels           []manager.Tunnel
 	lastObservedState map[manager.Tunnel]manager.TunnelState
-	view              *ListView
 }
 
 var cachedListViewIconsForWidthAndState = make(map[widthAndState]*walk.Bitmap)
@@ -39,49 +39,6 @@ func (t *ListModel) Value(row, col int) interface{} {
 	return t.tunnels[row].Name
 }
 
-func (t *ListModel) Image(row int) interface{} {
-	if row < 0 || row >= len(t.tunnels) {
-		return nil
-	}
-	tunnel := &t.tunnels[row]
-
-	var state manager.TunnelState
-	var ok bool
-	state, ok = t.lastObservedState[t.tunnels[row]]
-	if !ok {
-		var err error
-		state, err = tunnel.State()
-		if err != nil {
-			return nil
-		}
-		t.lastObservedState[t.tunnels[row]] = state
-	}
-	cacheKey := widthAndState{t.view.IntFrom96DPI(16), state}
-	if cacheValue, ok := cachedListViewIconsForWidthAndState[cacheKey]; ok {
-		return cacheValue
-	}
-	icon, err := iconForState(cacheKey.state, cacheKey.width)
-	if err != nil {
-		return nil
-	}
-	bitmap, err := walk.NewBitmapWithTransparentPixelsForDPI(icon.Size(), 96)
-	if err != nil {
-		return nil
-	}
-	canvas, err := walk.NewCanvasFromImage(bitmap)
-	if err != nil {
-		return nil
-	}
-	margin := t.view.IntFrom96DPI(1)
-	bounds := walk.Rectangle{X: margin, Y: margin, Height: bitmap.Size().Height - margin*2, Width: bitmap.Size().Width - margin*2}
-	if err := canvas.DrawImageStretchedPixels(icon, bounds); err != nil {
-		return nil
-	}
-	canvas.Dispose()
-	cachedListViewIconsForWidthAndState[cacheKey] = bitmap
-	return bitmap
-}
-
 func (t *ListModel) Sort(col int, order walk.SortOrder) error {
 	sort.SliceStable(t.tunnels, func(i, j int) bool {
 		return conf.TunnelNameIsLess(t.tunnels[i].Name, t.tunnels[j].Name)
@@ -124,7 +81,7 @@ func NewListView(parent walk.Container) (*ListView, error) {
 		TableView: tv,
 		model:     model,
 	}
-	model.view = tunnelsView
+	tv.SetCellStyler(tunnelsView)
 
 	disposables.Spare()
 
@@ -155,6 +112,76 @@ func (tv *ListView) CurrentTunnel() *manager.Tunnel {
 	return &tv.model.tunnels[idx]
 }
 
+var dummyBitmap *walk.Bitmap
+
+func (tv *ListView) StyleCell(style *walk.CellStyle) {
+	row := style.Row()
+	if row < 0 || row >= len(tv.model.tunnels) {
+		return
+	}
+	tunnel := &tv.model.tunnels[row]
+
+	var state manager.TunnelState
+	var ok bool
+	state, ok = tv.model.lastObservedState[tv.model.tunnels[row]]
+	if !ok {
+		var err error
+		state, err = tunnel.State()
+		if err != nil {
+			return
+		}
+		tv.model.lastObservedState[tv.model.tunnels[row]] = state
+	}
+	if win.IsAppThemed() {
+		cacheKey := widthAndState{tv.IntFrom96DPI(16), state}
+		if cacheValue, ok := cachedListViewIconsForWidthAndState[cacheKey]; ok {
+			style.Image = cacheValue
+			return
+		}
+		icon, err := iconForState(cacheKey.state, cacheKey.width)
+		if err != nil {
+			return
+		}
+		bitmap, err := walk.NewBitmapWithTransparentPixelsForDPI(tv.SizeFrom96DPI(icon.Size()), tv.DPI())
+		if err != nil {
+			return
+		}
+		canvas, err := walk.NewCanvasFromImage(bitmap)
+		if err != nil {
+			return
+		}
+		margin := tv.IntFrom96DPI(1)
+		bounds := walk.Rectangle{X: margin, Y: margin, Height: bitmap.Size().Height - 2*margin, Width: bitmap.Size().Width - 2*margin}
+		err = canvas.DrawImageStretchedPixels(icon, bounds)
+		canvas.Dispose()
+		if err != nil {
+			return
+		}
+		cachedListViewIconsForWidthAndState[cacheKey] = bitmap
+		style.Image = bitmap
+	} else {
+		if dummyBitmap == nil {
+			dummyBitmap, _ = walk.NewBitmapForDPI(tv.SizeFrom96DPI(walk.Size{}), 96)
+		}
+		style.Image = dummyBitmap
+		canvas := style.Canvas()
+		if canvas == nil {
+			return
+		}
+		margin := tv.IntFrom96DPI(1)
+		bounds := style.Bounds()
+		bounds.X = margin
+		bounds.Y += margin
+		bounds.Width = bounds.Height - 2*margin
+		bounds.Height = bounds.Width
+		icon, err := iconForState(state, style.Bounds().Width)
+		if err != nil {
+			return
+		}
+		canvas.DrawImageStretched(icon, bounds)
+	}
+}
+
 func (tv *ListView) onTunnelChange(tunnel *manager.Tunnel, state manager.TunnelState, globalState manager.TunnelState, err error) {
 	tv.Synchronize(func() {
 		idx := -1