screenshot: flip bits for RGB888

core/internal/colorpicker/picker.go

@@ -30,6 +30,7 @@ type Output struct {
 	height          int32
 	scale           int32
 	fractionalScale float64
+	transform       int32
 }
 
 type LayerSurface struct {
@@ -276,6 +277,7 @@ func (p *Picker) setupOutputHandlers(name uint32, output *client.Output) {
 		if o, ok := p.outputs[name]; ok {
 			o.x = e.X
 			o.y = e.Y
+			o.transform = int32(e.Transform)
 		}
 		p.outputsMu.Unlock()
 	})
@@ -485,8 +487,19 @@ func (p *Picker) captureForSurface(ls *LayerSurface) {
 	frame.SetReadyHandler(func(e wlr_screencopy.ZwlrScreencopyFrameV1ReadyEvent) {
 		ls.state.OnScreencopyReady()
 
-		logicalW, _ := ls.state.LogicalSize()
 		screenBuf := ls.state.ScreenBuffer()
+		if screenBuf != nil && ls.output.transform != TransformNormal {
+			invTransform := InverseTransform(ls.output.transform)
+			transformed, err := screenBuf.ApplyTransform(invTransform)
+			if err != nil {
+				log.Error("apply transform failed", "err", err)
+			} else if transformed != screenBuf {
+				ls.state.ReplaceScreenBuffer(transformed)
+			}
+		}
+
+		logicalW, _ := ls.state.LogicalSize()
+		screenBuf = ls.state.ScreenBuffer()
 		if logicalW > 0 && screenBuf != nil {
 			ls.output.fractionalScale = float64(screenBuf.Width) / float64(logicalW)
 		}

core/internal/colorpicker/shm.go

@@ -4,10 +4,25 @@ import "github.com/AvengeMedia/DankMaterialShell/core/internal/wayland/shm"
 
 type ShmBuffer = shm.Buffer
 
+const (
+	TransformNormal     = shm.TransformNormal
+	Transform90         = shm.Transform90
+	Transform180        = shm.Transform180
+	Transform270        = shm.Transform270
+	TransformFlipped    = shm.TransformFlipped
+	TransformFlipped90  = shm.TransformFlipped90
+	TransformFlipped180 = shm.TransformFlipped180
+	TransformFlipped270 = shm.TransformFlipped270
+)
+
 func CreateShmBuffer(width, height, stride int) (*ShmBuffer, error) {
 	return shm.CreateBuffer(width, height, stride)
 }
 
+func InverseTransform(transform int32) int32 {
+	return shm.InverseTransform(transform)
+}
+
 func GetPixelColor(buf *ShmBuffer, x, y int) Color {
 	return GetPixelColorWithFormat(buf, x, y, FormatARGB8888)
 }

core/internal/colorpicker/state.go

@@ -115,6 +115,20 @@ func (s *SurfaceState) ScreenFormat() PixelFormat {
 	return s.screenFormat
 }
 
+func (s *SurfaceState) ReplaceScreenBuffer(newBuf *ShmBuffer) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.screenBuf != nil {
+		s.screenBuf.Close()
+	}
+	s.screenBuf = newBuf
+	s.screenFormat = newBuf.Format
+
+	s.recomputeScale()
+	s.ensureRenderBuffers()
+}
+
 func (s *SurfaceState) OnScreencopyFlags(flags uint32) {
 	s.mu.Lock()
 	s.yInverted = (flags & 1) != 0

core/internal/wayland/shm/buffer.go

@@ -109,7 +109,11 @@ func (b *Buffer) ConvertTo32Bit(srcFormat PixelFormat) (*Buffer, PixelFormat, er
 
 	srcData := b.data
 	dstData := dst.data
-	isRGB := srcFormat == FormatRGB888
+
+	// DRM format names are counterintuitive on little-endian:
+	// RGB888 memory layout: B, G, R (name is logical order, not memory)
+	// BGR888 memory layout: R, G, B
+	isBGRMemory := srcFormat == FormatRGB888
 
 	for y := 0; y < b.Height; y++ {
 		srcRow := y * b.Stride
@@ -117,14 +121,16 @@ func (b *Buffer) ConvertTo32Bit(srcFormat PixelFormat) (*Buffer, PixelFormat, er
 		for x := 0; x < b.Width; x++ {
 			si := srcRow + x*3
 			di := dstRow + x*4
-			if isRGB {
+			if isBGRMemory {
-				dstData[di+0] = srcData[si+2] // B
+				// RGB888: src memory is B,G,R -> dst XRGB8888 memory B,G,R,X
-				dstData[di+1] = srcData[si+1] // G
+				dstData[di+0] = srcData[si+0]
-				dstData[di+2] = srcData[si+0] // R
+				dstData[di+1] = srcData[si+1]
+				dstData[di+2] = srcData[si+2]
 			} else {
-				dstData[di+0] = srcData[si+0] // B
+				// BGR888: src memory is R,G,B -> dst XRGB8888 memory B,G,R,X
-				dstData[di+1] = srcData[si+1] // G
+				dstData[di+0] = srcData[si+2]
-				dstData[di+2] = srcData[si+2] // R
+				dstData[di+1] = srcData[si+1]
+				dstData[di+2] = srcData[si+0]
 			}
 			dstData[di+3] = 0xFF
 		}