From 960743650370838f06acae9e2dd13c5d866715cc Mon Sep 17 00:00:00 2001
From: Carlos Gutierrez <carlosg@sca.com.mx>
Date: Mon, 29 Sep 2025 13:39:40 -0700
Subject: [PATCH] fix: validate DIBv5 format before fallback to DIB in Windows
 clipboard

Previously, the clipboard reader would return errUnsupported when DIBv5
data existed but had an unsupported BitCount. This change validates the
DIBv5 format (BitCount == 32) before processing, and falls back to
readImageDib() for any DIBv5 validation failures or when DIBv5 data is
unavailable, ensuring more reliable clipboard image reading.
---
 .../internal/clipboard/clipboard_windows.go   | 80 +++++++++----------
 1 file changed, 39 insertions(+), 41 deletions(-)

diff --git a/packages/tui/internal/clipboard/clipboard_windows.go b/packages/tui/internal/clipboard/clipboard_windows.go
index 09fc1416913..e5c7892de28 100644
--- a/packages/tui/internal/clipboard/clipboard_windows.go
+++ b/packages/tui/internal/clipboard/clipboard_windows.go
@@ -108,49 +108,47 @@ func writeText(buf []byte) error {
 // if presents. The caller is responsible for opening/closing the
 // clipboard before calling this function.
 func readImage() ([]byte, error) {
-	hMem, _, err := getClipboardData.Call(cFmtDIBV5)
-	if hMem == 0 {
-		// second chance to try FmtDIB
-		return readImageDib()
-	}
-	p, _, err := gLock.Call(hMem)
-	if p == 0 {
-		return nil, err
-	}
-	defer gUnlock.Call(hMem)
-
-	// inspect header information
-	info := (*bitmapV5Header)(unsafe.Pointer(p))
-
-	// maybe deal with other formats?
-	if info.BitCount != 32 {
-		return nil, errUnsupported
-	}
-
-	var data []byte
-	sh := (*reflect.SliceHeader)(unsafe.Pointer(&data))
-	sh.Data = uintptr(p)
-	sh.Cap = int(info.Size + 4*uint32(info.Width)*uint32(info.Height))
-	sh.Len = int(info.Size + 4*uint32(info.Width)*uint32(info.Height))
-	img := image.NewRGBA(image.Rect(0, 0, int(info.Width), int(info.Height)))
-	offset := int(info.Size)
-	stride := int(info.Width)
-	for y := 0; y < int(info.Height); y++ {
-		for x := 0; x < int(info.Width); x++ {
-			idx := offset + 4*(y*stride+x)
-			xhat := (x + int(info.Width)) % int(info.Width)
-			yhat := int(info.Height) - 1 - y
-			r := data[idx+2]
-			g := data[idx+1]
-			b := data[idx+0]
-			a := data[idx+3]
-			img.SetRGBA(xhat, yhat, color.RGBA{r, g, b, a})
+	hMem, _, _ := getClipboardData.Call(cFmtDIBV5)
+	if hMem != 0 {
+		p, _, _ := gLock.Call(hMem)
+		if p != 0 {
+			defer gUnlock.Call(hMem)
+
+			// inspect header information
+			info := (*bitmapV5Header)(unsafe.Pointer(p))
+
+			// validate format
+			if info.BitCount == 32 {
+				var data []byte
+				sh := (*reflect.SliceHeader)(unsafe.Pointer(&data))
+				sh.Data = uintptr(p)
+				sh.Cap = int(info.Size + 4*uint32(info.Width)*uint32(info.Height))
+				sh.Len = int(info.Size + 4*uint32(info.Width)*uint32(info.Height))
+				img := image.NewRGBA(image.Rect(0, 0, int(info.Width), int(info.Height)))
+				offset := int(info.Size)
+				stride := int(info.Width)
+				for y := 0; y < int(info.Height); y++ {
+					for x := 0; x < int(info.Width); x++ {
+						idx := offset + 4*(y*stride+x)
+						xhat := (x + int(info.Width)) % int(info.Width)
+						yhat := int(info.Height) - 1 - y
+						r := data[idx+2]
+						g := data[idx+1]
+						b := data[idx+0]
+						a := data[idx+3]
+						img.SetRGBA(xhat, yhat, color.RGBA{r, g, b, a})
+					}
+				}
+				// always use PNG encoding.
+				var buf bytes.Buffer
+				png.Encode(&buf, img)
+				return buf.Bytes(), nil
+			}
 		}
 	}
-	// always use PNG encoding.
-	var buf bytes.Buffer
-	png.Encode(&buf, img)
-	return buf.Bytes(), nil
+
+	// Fallback to DIB format if DIBv5 is unavailable or unsupported
+	return readImageDib()
 }
 
 func readImageDib() ([]byte, error) {