Merge pull request #141 from fyne-io/feature/printscreen

Feature/printscreen

internal/ui/desk.go

@@ -227,6 +227,11 @@ func (l *desktop) registerShortcuts() {
 		func() {
 			// dummy - the wm handles app switcher
 		})
+	fynedesk.Instance().AddShortcut(&fynedesk.Shortcut{Name: "Print Window", KeyName: deskDriver.KeyPrintScreen,
+		Modifier: deskDriver.ShiftModifier},
+		l.screenshotWindow)
+	fynedesk.Instance().AddShortcut(&fynedesk.Shortcut{Name: "Print Screen", KeyName: deskDriver.KeyPrintScreen},
+		l.screenshot)
 }
 
 // Screens returns the screens provider of the current desktop environment for access to screen functionality.

internal/ui/embed_wm.go

@@ -1,6 +1,8 @@
 package ui
 
 import (
+	"image"
+
 	"fyne.io/fyne"
 
 	"fyne.io/fynedesk"
@@ -52,6 +54,10 @@ func (e *embededWM) Blank() {
 	// no-op, we don't control screen brightness
 }
 
+func (e *embededWM) Capture() image.Image {
+	return nil // would mean accessing the underling OS screen functions...
+}
+
 func (e *embededWM) Close() {
 	windows := fyne.CurrentApp().Driver().AllWindows()
 	if len(windows) > 0 {

internal/ui/screenshot.go

@@ -0,0 +1,73 @@
+package ui
+
+import (
+	"image"
+	"image/png"
+
+	"fyne.io/fyne"
+	"fyne.io/fyne/canvas"
+	"fyne.io/fyne/container"
+	"fyne.io/fyne/dialog"
+	"fyne.io/fyne/layout"
+	"fyne.io/fyne/storage"
+	"fyne.io/fyne/widget"
+)
+
+func (l *desktop) screenshot() {
+	bg := l.wm.Capture()
+	l.showCaptureSave(bg)
+}
+
+func (l *desktop) screenshotWindow() {
+	win := l.wm.TopWindow()
+	if win == nil {
+		fyne.LogError("Unable to print window with no window visible", nil)
+		return
+	}
+
+	img := win.Capture()
+	if img == nil {
+		return
+	}
+	l.showCaptureSave(img)
+}
+
+func (l *desktop) showCaptureSave(img image.Image) {
+	w := fyne.CurrentApp().NewWindow("Screenshot")
+	save := widget.NewButton("Save...", func() {
+		saveImage(img, w)
+	})
+	save.Importance = widget.HighImportance
+	buttons := container.NewHBox(
+		layout.NewSpacer(),
+		widget.NewButton("Cancel", func() {
+			w.Close()
+		}),
+		save)
+
+	preview := canvas.NewImageFromImage(img)
+	preview.FillMode = canvas.ImageFillContain
+	w.SetContent(container.NewBorder(nil, buttons, nil, nil, preview))
+	w.Resize(fyne.NewSize(480, 360))
+	w.Show()
+}
+
+func saveImage(pix image.Image, w fyne.Window) {
+	d := dialog.NewFileSave(func(write fyne.URIWriteCloser, err error) {
+		if write == nil { // cancelled
+			return
+		}
+		if err != nil {
+			dialog.ShowError(err, w)
+		}
+
+		err = png.Encode(write, pix)
+		if err != nil {
+			dialog.ShowError(err, w)
+		}
+
+		w.Close()
+	}, w)
+	d.SetFilter(storage.NewMimeTypeFileFilter([]string{"image/png"}))
+	d.Show()
+}

internal/x11/screenshot.go

@@ -0,0 +1,48 @@
+// +build linux openbsd freebsd netbsd
+
+package x11
+
+import (
+	"image"
+	"math"
+
+	"fyne.io/fyne"
+	"github.com/BurntSushi/xgb"
+	"github.com/BurntSushi/xgb/xproto"
+)
+
+// CaptureWindow allows x11 code to get the image representation of a screen area.
+// The window specified will be captured according to its bounds.
+func CaptureWindow(conn *xgb.Conn, win xproto.Window) *image.NRGBA {
+	geom, err := xproto.GetGeometry(conn, xproto.Drawable(win)).Reply()
+	if err != nil {
+		fyne.LogError("Unable to get screen geometry", err)
+		return nil
+	}
+	pix, err := xproto.GetImage(conn, xproto.ImageFormatZPixmap, xproto.Drawable(win),
+		0, 0, geom.Width, geom.Height, math.MaxUint32).Reply()
+	if err != nil {
+		fyne.LogError("Error capturing window content", err)
+		return nil
+	}
+
+	img := image.NewNRGBA(image.Rect(0, 0, int(geom.Width), int(geom.Height)))
+	i := 0
+	for y := 0; y < int(geom.Height); y++ {
+		for x := 0; x < int(geom.Width); x++ {
+			copyPixel(pix.Data, img.Pix, i)
+			i += 4
+		}
+	}
+	return img
+}
+
+func copyPixel(in []byte, out []uint8, i int) {
+	b := in[i]
+	g := in[i+1]
+	r := in[i+2]
+	out[i] = r
+	out[i+1] = g
+	out[i+2] = b
+	out[i+3] = 0xff // some colour maps / depths don't include alpha
+}

internal/x11/screenshot_test.go

@@ -0,0 +1,20 @@
+// +build linux openbsd freebsd netbsd
+
+package x11
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCopyPixel(t *testing.T) {
+	in := []byte{0xff, 0x99, 0x33, 0xff}
+	out := []uint8{0, 0, 0, 0}
+	copyPixel(in, out, 0)
+
+	assert.Equal(t, uint8(0x33), out[0])
+	assert.Equal(t, uint8(0x99), out[1])
+	assert.Equal(t, uint8(0xff), out[2])
+	assert.Equal(t, uint8(0xff), out[3])
+}

internal/x11/win/client.go

@@ -3,6 +3,8 @@
 package win
 
 import (
+	"image"
+
 	"fyne.io/fyne"
 
 	"github.com/BurntSushi/xgb/xproto"
@@ -63,6 +65,10 @@ func NewClient(win xproto.Window, wm x11.XWM) x11.XWin {
 	return c
 }
 
+func (c *client) Capture() image.Image {
+	return x11.CaptureWindow(c.wm.Conn(), c.FrameID())
+}
+
 func (c *client) ChildID() xproto.Window {
 	return c.win
 }

internal/x11/win/frame.go

@@ -231,7 +231,7 @@ func (f *frame) copyDecorationPixels(width, height, xoff, yoff uint32, img image
 			data[i] = byte(b)
 			data[i+1] = byte(g)
 			data[i+2] = byte(r)
-			data[i+3] = 0
+			data[i+3] = 0xff
 
 			i += 4
 		}

internal/x11/wm/desk.go

@@ -76,11 +76,12 @@ const (
 	moveResizeMoveKeyboard moveResizeType = 10
 	moveResizeCancel       moveResizeType = 11
 
-	keyCodeEscape = 9
-	keyCodeTab    = 23
-	keyCodeReturn = 36
-	keyCodeAlt    = 64
-	keyCodeSpace  = 65
+	keyCodeEscape      = 9
+	keyCodeTab         = 23
+	keyCodeReturn      = 36
+	keyCodeAlt         = 64
+	keyCodeSpace       = 65
+	keyCodePrintScreen = 107
 
 	keyCodeEnter = 108
 	keyCodeLeft  = 113
@@ -155,6 +156,11 @@ func (x *x11WM) Blank() {
 	}()
 }
 
+func (x *x11WM) Capture() image.Image {
+	root := x.x.RootWin()
+	return x11.CaptureWindow(x.x.Conn(), root)
+}
+
 func (x *x11WM) Close() {
 	for _, child := range x.clients {
 		child.Close()
@@ -235,6 +241,8 @@ func (x *x11WM) keyNameToCode(n fyne.KeyName) xproto.Keycode {
 	switch n {
 	case fyne.KeySpace:
 		return keyCodeSpace
+	case deskDriver.KeyPrintScreen:
+		return keyCodePrintScreen
 	case fyne.KeyTab:
 		return keyCodeTab
 	case fynedesk.KeyBrightnessDown:
@@ -265,7 +273,6 @@ func (x *x11WM) modifierToKeyMask(m deskDriver.Modifier) uint16 {
 }
 
 func (x *x11WM) runLoop() {
-	x.setupBindings()
 	conn := x.x.Conn()
 
 	for {

test/desktop.go

@@ -1,6 +1,8 @@
 package test
 
 import (
+	"image"
+
 	"fyne.io/fyne"
 	"fyne.io/fyne/test"
 
@@ -34,6 +36,11 @@ func (*Desktop) AddShortcut(shortcut *fynedesk.Shortcut, handler func()) {
 	// TODO
 }
 
+// Capture the desktop to an image. Our test code cowardly refuses to do this.
+func (*Desktop) Capture() image.Image {
+	return nil // could be implemented if required for testing
+}
+
 // ContentSizePixels returns a default value for how much space maximised apps should use
 func (*Desktop) ContentSizePixels(_ *fynedesk.Screen) (uint32, uint32) {
 	return uint32(320), uint32(240)

test/window.go

@@ -1,6 +1,10 @@
 package test
 
-import "fyne.io/fynedesk"
+import (
+	"image"
+
+	"fyne.io/fynedesk"
+)
 
 // Window is an in-memory virtual window for test purposes
 type Window struct {
@@ -16,6 +20,11 @@ func NewWindow(title string) *Window {
 	return win
 }
 
+// Capture the contents of the window. Our test code cowardly refuses to do this.
+func (w *Window) Capture() image.Image {
+	return nil // we can add this if required for testing
+}
+
 // Close this test window
 func (w *Window) Close() {
 	// no-op

window.go

@@ -1,6 +1,10 @@
 package fynedesk
 
-import "fyne.io/fyne"
+import (
+	"image"
+
+	"fyne.io/fyne"
+)
 
 // Window represents a single managed window within a window manager.
 // There may be borders or not depending on configuration.
@@ -11,16 +15,17 @@ type Window interface {
 	Maximized() bool    // Is the window Maximized?
 	TopWindow() bool    // Is this the window on top?
 
-	Close()            // Close this window and possibly the application running it
-	Focus()            // Ask this window to get input focus
-	Fullscreen()       // Request to fullscreen this window
-	Iconify()          // Request to iconify this window
-	Maximize()         // Request to resize this window to it's largest possible size
-	RaiseAbove(Window) // Raise this window above a given other window
-	RaiseToTop()       // Raise this window to the top of the stack
-	Unfullscreen()     // Request to unfullscreen this window
-	Uniconify()        // Request to restore this window and possibly children of this window from being minimized
-	Unmaximize()       // Request to restore this window to its size before being maximized
+	Capture() image.Image // Capture the contents of this window to an image
+	Close()               // Close this window and possibly the application running it
+	Focus()               // Ask this window to get input focus
+	Fullscreen()          // Request to fullscreen this window
+	Iconify()             // Request to iconify this window
+	Maximize()            // Request to resize this window to it's largest possible size
+	RaiseAbove(Window)    // Raise this window above a given other window
+	RaiseToTop()          // Raise this window to the top of the stack
+	Unfullscreen()        // Request to unfullscreen this window
+	Uniconify()           // Request to restore this window and possibly children of this window from being minimized
+	Unmaximize()          // Request to restore this window to its size before being maximized
 
 	Properties() WindowProperties // Request the properties set on this window
 }

wm.go

@@ -1,11 +1,14 @@
 package fynedesk
 
+import "image"
+
 // WindowManager describes a full window manager which may be loaded as part of the setup.
 type WindowManager interface {
 	Stack
 	AddStackListener(StackListener)
 
 	Blank()
+	Capture() image.Image // Capture the contents of the whole desktop to an image
 	Close()
 	Run()
 }