screenshot: handle transformed displays

core/cmd/dms/commands_screenshot.go

@@ -295,7 +295,14 @@ func bufferToRGBThumbnail(buf *screenshot.ShmBuffer, maxSize int, pixelFormat ui
 
 	data := buf.Data()
 	rgb := make([]byte, dstW*dstH*3)
-	swapRB := pixelFormat == uint32(screenshot.FormatARGB8888) || pixelFormat == uint32(screenshot.FormatXRGB8888) || pixelFormat == 0
+
+	var swapRB bool
+	switch pixelFormat {
+	case uint32(screenshot.FormatABGR8888), uint32(screenshot.FormatXBGR8888):
+		swapRB = false
+	default:
+		swapRB = true
+	}
 
 	for y := 0; y < dstH; y++ {
 		srcY := int(float64(y) / scale)
@@ -309,16 +316,17 @@ func bufferToRGBThumbnail(buf *screenshot.ShmBuffer, maxSize int, pixelFormat ui
 			}
 			si := srcY*buf.Stride + srcX*4
 			di := (y*dstW + x) * 3
-			if si+2 < len(data) {
-				if swapRB {
-					rgb[di+0] = data[si+2]
-					rgb[di+1] = data[si+1]
-					rgb[di+2] = data[si+0]
-				} else {
-					rgb[di+0] = data[si+0]
-					rgb[di+1] = data[si+1]
-					rgb[di+2] = data[si+2]
-				}
+			if si+3 >= len(data) {
+				continue
+			}
+			if swapRB {
+				rgb[di+0] = data[si+2]
+				rgb[di+1] = data[si+1]
+				rgb[di+2] = data[si+0]
+			} else {
+				rgb[di+0] = data[si+0]
+				rgb[di+1] = data[si+1]
+				rgb[di+2] = data[si+2]
 			}
 		}
 	}
@@ -370,7 +378,37 @@ func runScreenshotList(cmd *cobra.Command, args []string) {
 	}
 
 	for _, o := range outputs {
-		fmt.Printf("%s: %dx%d+%d+%d (scale: %d)\n",
-			o.Name, o.Width, o.Height, o.X, o.Y, o.Scale)
+		scaleStr := fmt.Sprintf("%.2f", o.FractionalScale)
+		if o.FractionalScale == float64(int(o.FractionalScale)) {
+			scaleStr = fmt.Sprintf("%d", int(o.FractionalScale))
+		}
+
+		transformStr := transformName(o.Transform)
+
+		fmt.Printf("%s: %dx%d+%d+%d scale=%s transform=%s\n",
+			o.Name, o.Width, o.Height, o.X, o.Y, scaleStr, transformStr)
+	}
+}
+
+func transformName(t int32) string {
+	switch t {
+	case 0:
+		return "normal"
+	case 1:
+		return "90"
+	case 2:
+		return "180"
+	case 3:
+		return "270"
+	case 4:
+		return "flipped"
+	case 5:
+		return "flipped-90"
+	case 6:
+		return "flipped-180"
+	case 7:
+		return "flipped-270"
+	default:
+		return fmt.Sprintf("%d", t)
 	}
 }

core/internal/screenshot/compositor.go

@@ -90,14 +90,15 @@ func SetCompositorDWL() {
 }
 
 type WindowGeometry struct {
-	X       int32
-	Y       int32
-	Width   int32
-	Height  int32
-	Output  string
-	Scale   float64
-	OutputX int32
-	OutputY int32
+	X               int32
+	Y               int32
+	Width           int32
+	Height          int32
+	Output          string
+	Scale           float64
+	OutputX         int32
+	OutputY         int32
+	OutputTransform int32
 }
 
 func GetActiveWindow() (*WindowGeometry, error) {
@@ -385,17 +386,22 @@ func GetFocusedMonitor() string {
 	return ""
 }
 
-func getOutputPosition(outputName string) (x, y int32, ok bool) {
+type outputInfo struct {
+	x, y      int32
+	transform int32
+}
+
+func getOutputInfo(outputName string) (*outputInfo, bool) {
 	display, err := client.Connect("")
 	if err != nil {
-		return 0, 0, false
+		return nil, false
 	}
 	ctx := display.Context()
 	defer ctx.Close()
 
 	registry, err := display.GetRegistry()
 	if err != nil {
-		return 0, 0, false
+		return nil, false
 	}
 
 	var outputManager *wlr_output_management.ZwlrOutputManagerV1
@@ -414,16 +420,17 @@ func getOutputPosition(outputName string) (x, y int32, ok bool) {
 	})
 
 	if err := wlhelpers.Roundtrip(display, ctx); err != nil {
-		return 0, 0, false
+		return nil, false
 	}
 
 	if outputManager == nil {
-		return 0, 0, false
+		return nil, false
 	}
 
 	type headState struct {
-		name string
-		x, y int32
+		name      string
+		x, y      int32
+		transform int32
 	}
 	heads := make(map[*wlr_output_management.ZwlrOutputHeadV1]*headState)
 	done := false
@@ -438,6 +445,9 @@ func getOutputPosition(outputName string) (x, y int32, ok bool) {
 			state.x = pe.X
 			state.y = pe.Y
 		})
+		e.Head.SetTransformHandler(func(te wlr_output_management.ZwlrOutputHeadV1TransformEvent) {
+			state.transform = te.Transform
+		})
 	})
 	outputManager.SetDoneHandler(func(e wlr_output_management.ZwlrOutputManagerV1DoneEvent) {
 		done = true
@@ -445,17 +455,21 @@ func getOutputPosition(outputName string) (x, y int32, ok bool) {
 
 	for !done {
 		if err := ctx.Dispatch(); err != nil {
-			return 0, 0, false
+			return nil, false
 		}
 	}
 
 	for _, state := range heads {
 		if state.name == outputName {
-			return state.x, state.y, true
+			return &outputInfo{
+				x:         state.x,
+				y:         state.y,
+				transform: state.transform,
+			}, true
 		}
 	}
 
-	return 0, 0, false
+	return nil, false
 }
 
 func getDWLActiveWindow() (*WindowGeometry, error) {
@@ -586,21 +600,22 @@ func getDWLActiveWindow() (*WindowGeometry, error) {
 			scale = 1.0
 		}
 
-		var outputX, outputY int32
-		if ox, oy, ok := getOutputPosition(state.name); ok {
-			outputX, outputY = ox, oy
+		geom := &WindowGeometry{
+			X:      state.x,
+			Y:      state.y,
+			Width:  state.w,
+			Height: state.h,
+			Output: state.name,
+			Scale:  scale,
 		}
 
-		return &WindowGeometry{
-			X:       state.x,
-			Y:       state.y,
-			Width:   state.w,
-			Height:  state.h,
-			Output:  state.name,
-			Scale:   scale,
-			OutputX: outputX,
-			OutputY: outputY,
-		}, nil
+		if info, ok := getOutputInfo(state.name); ok {
+			geom.OutputX = info.x
+			geom.OutputY = info.y
+			geom.OutputTransform = info.transform
+		}
+
+		return geom, nil
 	}
 
 	return nil, fmt.Errorf("no active output found")

core/internal/screenshot/encode.go

@@ -20,7 +20,13 @@ func BufferToImageWithFormat(buf *ShmBuffer, format uint32) *image.RGBA {
 	img := image.NewRGBA(image.Rect(0, 0, buf.Width, buf.Height))
 	data := buf.Data()
 
-	swapRB := format == uint32(FormatARGB8888) || format == uint32(FormatXRGB8888) || format == 0
+	var swapRB bool
+	switch format {
+	case uint32(FormatABGR8888), uint32(FormatXBGR8888):
+		swapRB = false
+	default:
+		swapRB = true
+	}
 
 	for y := 0; y < buf.Height; y++ {
 		srcOff := y * buf.Stride

core/internal/screenshot/region.go

@@ -380,19 +380,21 @@ func (r *RegionSelector) preCaptureOutput(output *WaylandOutput, pc *PreCapture,
 		return
 	}
 
+	var capturedBuf *ShmBuffer
+
 	frame.SetBufferHandler(func(e wlr_screencopy.ZwlrScreencopyFrameV1BufferEvent) {
+		if int(e.Stride) < int(e.Width)*4 {
+			log.Error("invalid stride from compositor", "stride", e.Stride, "width", e.Width)
+			return
+		}
 		buf, err := CreateShmBuffer(int(e.Width), int(e.Height), int(e.Stride))
 		if err != nil {
 			log.Error("create screen buffer failed", "err", err)
 			return
 		}
 
-		if withCursor {
-			pc.screenBuf = buf
-			pc.format = e.Format
-		} else {
-			pc.screenBufNoCursor = buf
-		}
+		capturedBuf = buf
+		pc.format = e.Format
 
 		pool, err := r.shm.CreatePool(buf.Fd(), int32(buf.Size()))
 		if err != nil {
@@ -421,6 +423,34 @@ func (r *RegionSelector) preCaptureOutput(output *WaylandOutput, pc *PreCapture,
 
 	frame.SetReadyHandler(func(e wlr_screencopy.ZwlrScreencopyFrameV1ReadyEvent) {
 		frame.Destroy()
+
+		if capturedBuf == nil {
+			onReady()
+			return
+		}
+
+		if pc.yInverted {
+			capturedBuf.FlipVertical()
+			pc.yInverted = false
+		}
+
+		if output.transform != TransformNormal {
+			invTransform := InverseTransform(output.transform)
+			transformed, err := capturedBuf.ApplyTransform(invTransform)
+			if err != nil {
+				log.Error("apply transform failed", "err", err)
+			} else if transformed != capturedBuf {
+				capturedBuf.Close()
+				capturedBuf = transformed
+			}
+		}
+
+		if withCursor {
+			pc.screenBuf = capturedBuf
+		} else {
+			pc.screenBufNoCursor = capturedBuf
+		}
+
 		onReady()
 	})
 

core/internal/screenshot/screenshot.go

@@ -324,13 +324,18 @@ func (s *Screenshoter) captureAllScreens() (*CaptureResult, error) {
 
 		outX, outY := output.x, output.y
 		scale := float64(output.scale)
-		if DetectCompositor() == CompositorHyprland {
+		switch DetectCompositor() {
+		case CompositorHyprland:
 			if hx, hy, _, _, ok := GetHyprlandMonitorGeometry(output.name); ok {
 				outX, outY = hx, hy
 			}
 			if s := GetHyprlandMonitorScale(output.name); s > 0 {
 				scale = s
 			}
+		case CompositorDWL:
+			if info, ok := getOutputInfo(output.name); ok {
+				outX, outY = info.x, info.y
+			}
 		}
 		if scale <= 0 {
 			scale = 1.0
@@ -458,13 +463,42 @@ func (s *Screenshoter) captureWholeOutput(output *WaylandOutput) (*CaptureResult
 		return nil, fmt.Errorf("capture output: %w", err)
 	}
 
-	return s.processFrame(frame, Region{
+	result, err := s.processFrame(frame, Region{
 		X:      output.x,
 		Y:      output.y,
 		Width:  output.width,
 		Height: output.height,
 		Output: output.name,
 	})
+	if err != nil {
+		return nil, err
+	}
+
+	if result.YInverted {
+		result.Buffer.FlipVertical()
+		result.YInverted = false
+	}
+
+	if output.transform == TransformNormal {
+		return result, nil
+	}
+
+	invTransform := InverseTransform(output.transform)
+	transformed, err := result.Buffer.ApplyTransform(invTransform)
+	if err != nil {
+		result.Buffer.Close()
+		return nil, fmt.Errorf("apply transform: %w", err)
+	}
+
+	if transformed != result.Buffer {
+		result.Buffer.Close()
+		result.Buffer = transformed
+	}
+
+	result.Region.Width = int32(transformed.Width)
+	result.Region.Height = int32(transformed.Height)
+
+	return result, nil
 }
 
 func (s *Screenshoter) captureAndCrop(output *WaylandOutput, region Region) (*CaptureResult, error) {
@@ -545,6 +579,10 @@ func (s *Screenshoter) captureAndCrop(output *WaylandOutput, region Region) (*Ca
 }
 
 func (s *Screenshoter) captureRegionOnOutput(output *WaylandOutput, region Region) (*CaptureResult, error) {
+	if output.transform != TransformNormal {
+		return s.captureRegionOnTransformedOutput(output, region)
+	}
+
 	scale := output.fractionalScale
 	if scale <= 0 && DetectCompositor() == CompositorHyprland {
 		scale = GetHyprlandMonitorScale(output.name)
@@ -599,6 +637,76 @@ func (s *Screenshoter) captureRegionOnOutput(output *WaylandOutput, region Regio
 	return s.processFrame(frame, region)
 }
 
+func (s *Screenshoter) captureRegionOnTransformedOutput(output *WaylandOutput, region Region) (*CaptureResult, error) {
+	result, err := s.captureWholeOutput(output)
+	if err != nil {
+		return nil, err
+	}
+
+	scale := output.fractionalScale
+	if scale <= 0 && DetectCompositor() == CompositorHyprland {
+		scale = GetHyprlandMonitorScale(output.name)
+	}
+	if scale <= 0 {
+		scale = float64(output.scale)
+	}
+	if scale <= 0 {
+		scale = 1.0
+	}
+
+	localX := int(float64(region.X-output.x) * scale)
+	localY := int(float64(region.Y-output.y) * scale)
+	w := int(float64(region.Width) * scale)
+	h := int(float64(region.Height) * scale)
+
+	if localX < 0 {
+		w += localX
+		localX = 0
+	}
+	if localY < 0 {
+		h += localY
+		localY = 0
+	}
+	if localX+w > result.Buffer.Width {
+		w = result.Buffer.Width - localX
+	}
+	if localY+h > result.Buffer.Height {
+		h = result.Buffer.Height - localY
+	}
+
+	if w <= 0 || h <= 0 {
+		result.Buffer.Close()
+		return nil, fmt.Errorf("region not visible on output")
+	}
+
+	cropped, err := CreateShmBuffer(w, h, w*4)
+	if err != nil {
+		result.Buffer.Close()
+		return nil, fmt.Errorf("create crop buffer: %w", err)
+	}
+
+	srcData := result.Buffer.Data()
+	dstData := cropped.Data()
+
+	for y := 0; y < h; y++ {
+		srcOff := (localY+y)*result.Buffer.Stride + localX*4
+		dstOff := y * cropped.Stride
+		if srcOff+w*4 <= len(srcData) && dstOff+w*4 <= len(dstData) {
+			copy(dstData[dstOff:dstOff+w*4], srcData[srcOff:srcOff+w*4])
+		}
+	}
+
+	result.Buffer.Close()
+	cropped.Format = PixelFormat(result.Format)
+
+	return &CaptureResult{
+		Buffer:    cropped,
+		Region:    region,
+		YInverted: false,
+		Format:    result.Format,
+	}, nil
+}
+
 func (s *Screenshoter) processFrame(frame *wlr_screencopy.ZwlrScreencopyFrameV1, region Region) (*CaptureResult, error) {
 	var buf *ShmBuffer
 	var pool *client.ShmPool
@@ -609,6 +717,10 @@ func (s *Screenshoter) processFrame(frame *wlr_screencopy.ZwlrScreencopyFrameV1,
 	failed := false
 
 	frame.SetBufferHandler(func(e wlr_screencopy.ZwlrScreencopyFrameV1BufferEvent) {
+		if int(e.Stride) < int(e.Width)*4 {
+			log.Error("invalid stride from compositor", "stride", e.Stride, "width", e.Width)
+			return
+		}
 		var err error
 		buf, err = CreateShmBuffer(int(e.Width), int(e.Height), int(e.Stride))
 		if err != nil {
@@ -906,16 +1018,32 @@ func ListOutputs() ([]Output, error) {
 	sc.outputsMu.Lock()
 	defer sc.outputsMu.Unlock()
 
+	compositor := DetectCompositor()
 	result := make([]Output, 0, len(sc.outputs))
 	for _, o := range sc.outputs {
-		result = append(result, Output{
-			Name:   o.name,
-			X:      o.x,
-			Y:      o.y,
-			Width:  o.width,
-			Height: o.height,
-			Scale:  o.scale,
-		})
+		out := Output{
+			Name:            o.name,
+			X:               o.x,
+			Y:               o.y,
+			Width:           o.width,
+			Height:          o.height,
+			Scale:           o.scale,
+			FractionalScale: o.fractionalScale,
+			Transform:       o.transform,
+		}
+
+		switch compositor {
+		case CompositorHyprland:
+			if hx, hy, hw, hh, ok := GetHyprlandMonitorGeometry(o.name); ok {
+				out.X, out.Y = hx, hy
+				out.Width, out.Height = hw, hh
+			}
+			if s := GetHyprlandMonitorScale(o.name); s > 0 {
+				out.FractionalScale = s
+			}
+		}
+
+		result = append(result, out)
 	}
 	return result, nil
 }

core/internal/screenshot/shm.go

@@ -11,8 +11,23 @@ const (
 	FormatXBGR8888 = shm.FormatXBGR8888
 )
 
+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
+)
+
 type ShmBuffer = shm.Buffer
 
 func CreateShmBuffer(width, height, stride int) (*ShmBuffer, error) {
 	return shm.CreateBuffer(width, height, stride)
 }
+
+func InverseTransform(transform int32) int32 {
+	return shm.InverseTransform(transform)
+}

core/internal/screenshot/types.go

@@ -32,11 +32,13 @@ func (r Region) IsEmpty() bool {
 }
 
 type Output struct {
-	Name   string
-	X, Y   int32
-	Width  int32
-	Height int32
-	Scale  int32
+	Name            string
+	X, Y            int32
+	Width           int32
+	Height          int32
+	Scale           int32
+	FractionalScale float64
+	Transform       int32
 }
 
 type Config struct {

core/internal/wayland/shm/buffer.go

@@ -137,3 +137,96 @@ func (b *Buffer) Clear() {
 func (b *Buffer) CopyFrom(src *Buffer) {
 	copy(b.data, src.data)
 }
+
+const (
+	TransformNormal     = 0
+	Transform90         = 1
+	Transform180        = 2
+	Transform270        = 3
+	TransformFlipped    = 4
+	TransformFlipped90  = 5
+	TransformFlipped180 = 6
+	TransformFlipped270 = 7
+)
+
+func (b *Buffer) ApplyTransform(transform int32) (*Buffer, error) {
+	if transform == TransformNormal {
+		return b, nil
+	}
+
+	var newW, newH int
+	switch transform {
+	case Transform90, Transform270, TransformFlipped90, TransformFlipped270:
+		newW, newH = b.Height, b.Width
+	default:
+		newW, newH = b.Width, b.Height
+	}
+
+	newBuf, err := CreateBuffer(newW, newH, newW*4)
+	if err != nil {
+		return nil, err
+	}
+	newBuf.Format = b.Format
+
+	srcData := b.data
+	dstData := newBuf.data
+
+	for sy := 0; sy < b.Height; sy++ {
+		for sx := 0; sx < b.Width; sx++ {
+			var dx, dy int
+
+			switch transform {
+			case Transform90: // 90° CCW
+				dx = sy
+				dy = b.Width - 1 - sx
+			case Transform180:
+				dx = b.Width - 1 - sx
+				dy = b.Height - 1 - sy
+			case Transform270: // 270° CCW = 90° CW
+				dx = b.Height - 1 - sy
+				dy = sx
+			case TransformFlipped:
+				dx = b.Width - 1 - sx
+				dy = sy
+			case TransformFlipped90:
+				dx = sy
+				dy = sx
+			case TransformFlipped180:
+				dx = sx
+				dy = b.Height - 1 - sy
+			case TransformFlipped270:
+				dx = b.Height - 1 - sy
+				dy = b.Width - 1 - sx
+			default:
+				dx, dy = sx, sy
+			}
+
+			si := sy*b.Stride + sx*4
+			di := dy*newBuf.Stride + dx*4
+
+			if si+3 < len(srcData) && di+3 < len(dstData) {
+				dstData[di+0] = srcData[si+0]
+				dstData[di+1] = srcData[si+1]
+				dstData[di+2] = srcData[si+2]
+				dstData[di+3] = srcData[si+3]
+			}
+		}
+	}
+
+	return newBuf, nil
+}
+
+func InverseTransform(transform int32) int32 {
+	switch transform {
+	case Transform90:
+		return Transform270
+	case Transform270:
+		return Transform90
+	case TransformFlipped90:
+		return TransformFlipped270
+	case TransformFlipped270:
+		return TransformFlipped90
+	default:
+		return transform
+	}
+}