app: add support for system cursors

Signed-off-by: pierre <pierre.curto@gmail.com>

.builds/freebsd.yml

@@ -3,6 +3,8 @@ image: freebsd/11.x
 packages:
  - libX11
  - libxkbcommon
+ - libXcursor
+ - libXfixes
  - wayland
  - mesa-libs
  - xorg-vfbserver

app/internal/window/GioView.java

@@ -22,6 +22,7 @@ import android.view.Choreographer;
 import android.view.KeyCharacterMap;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
+import android.view.PointerIcon;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.WindowInsets;
@@ -36,7 +37,6 @@ import android.view.inputmethod.EditorInfo;
 import java.io.UnsupportedEncodingException;
 
 public final class GioView extends SurfaceView implements Choreographer.FrameCallback {
-	private final static Object initLock = new Object();
 	private static boolean jniLoaded;
 
 	private final SurfaceHolder.Callback surfCallbacks;
@@ -124,6 +124,11 @@ public final class GioView extends SurfaceView implements Choreographer.FrameCal
 		return true;
 	}
 
+	private void setCursor(Context ctx, int id) {
+		PointerIcon pointerIcon = PointerIcon.getSystemIcon(ctx, id);
+		GioView.this.setPointerIcon(pointerIcon);
+	}
+
 	private void dispatchMotionEvent(MotionEvent event) {
 		for (int j = 0; j < event.getHistorySize(); j++) {
 			long time = event.getHistoricalEventTime(j);

app/internal/window/os_android.go

@@ -80,6 +80,7 @@ type window struct {
 	mshowTextInput     C.jmethodID
 	mhideTextInput     C.jmethodID
 	mpostFrameCallback C.jmethodID
+	msetCursor         C.jmethodID
 }
 
 // ViewEvent is sent whenever the Window's underlying Android view
@@ -202,6 +203,7 @@ func Java_org_gioui_GioView_onCreateView(env *C.JNIEnv, class C.jclass, view C.j
 		mshowTextInput:     getMethodID(env, class, "showTextInput", "()V"),
 		mhideTextInput:     getMethodID(env, class, "hideTextInput", "()V"),
 		mpostFrameCallback: getMethodID(env, class, "postFrameCallback", "()V"),
+		msetCursor:         getMethodID(env, class, "setCursor", "(Landroid/content/Context;I)V"),
 	}
 	wopts := <-mainWindow.out
 	w.callbacks = wopts.window
@@ -649,6 +651,32 @@ func (w *window) ReadClipboard() {
 	})
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	var curID int
+	switch name {
+	default:
+		fallthrough
+	case pointer.CursorDefault:
+		curID = 1000 // TYPE_ARROW
+	case pointer.CursorText:
+		curID = 1008 // TYPE_TEXT
+	case pointer.CursorPointer:
+		curID = 1002 // TYPE_HAND
+	case pointer.CursorCrossHair:
+		curID = 1007 // TYPE_CROSSHAIR
+	case pointer.CursorColResize:
+		curID = 1014 // TYPE_HORIZONTAL_DOUBLE_ARROW
+	case pointer.CursorRowResize:
+		curID = 1015 // TYPE_VERTICAL_DOUBLE_ARROW
+	case pointer.CursorNone:
+		curID = 0 // TYPE_NULL
+	}
+	runOnMain(func(env *C.JNIEnv) {
+		callVoidMethod(env, w.view, w.msetCursor,
+			jvalue(android.appCtx), jvalue(curID))
+	})
+}
+
 // Close the window. Not implemented for Android.
 func (w *window) Close() {}
 

app/internal/window/os_darwin.go

@@ -13,6 +13,9 @@ __attribute__ ((visibility ("hidden"))) void gio_releaseDisplayLink(CFTypeRef dl
 __attribute__ ((visibility ("hidden"))) int gio_startDisplayLink(CFTypeRef dl);
 __attribute__ ((visibility ("hidden"))) int gio_stopDisplayLink(CFTypeRef dl);
 __attribute__ ((visibility ("hidden"))) void gio_setDisplayLinkDisplay(CFTypeRef dl, uint64_t did);
+__attribute__ ((visibility ("hidden"))) void gio_hideCursor();
+__attribute__ ((visibility ("hidden"))) void gio_showCursor();
+__attribute__ ((visibility ("hidden"))) void gio_setCursor(NSUInteger curID);
 */
 import "C"
 import (
@@ -22,6 +25,8 @@ import (
 	"time"
 	"unicode/utf16"
 	"unsafe"
+
+	"gioui.org/io/pointer"
 )
 
 // displayLink is the state for a display link (CVDisplayLinkRef on macOS,
@@ -169,3 +174,41 @@ func gio_onFrameCallback(dl C.CFTypeRef) {
 		}
 	}
 }
+
+// windowSetCursor updates the cursor from the current one to a new one
+// and returns the new one.
+func windowSetCursor(from, to pointer.CursorName) pointer.CursorName {
+	if from == to {
+		return to
+	}
+	var curID int
+	switch to {
+	default:
+		to = pointer.CursorDefault
+		fallthrough
+	case pointer.CursorDefault:
+		curID = 1
+	case pointer.CursorText:
+		curID = 2
+	case pointer.CursorPointer:
+		curID = 3
+	case pointer.CursorCrossHair:
+		curID = 4
+	case pointer.CursorColResize:
+		curID = 5
+	case pointer.CursorRowResize:
+		curID = 6
+	case pointer.CursorNone:
+		runOnMain(func() {
+			C.gio_hideCursor()
+		})
+		return to
+	}
+	runOnMain(func() {
+		if from == pointer.CursorNone {
+			C.gio_showCursor()
+		}
+		C.gio_setCursor(C.NSUInteger(curID))
+	})
+	return to
+}

app/internal/window/os_darwin.m

@@ -20,3 +20,43 @@ void gio_nsstringGetCharacters(CFTypeRef cstr, unichar *chars, NSUInteger loc, N
 	NSString *str = (__bridge NSString *)cstr;
 	[str getCharacters:chars range:NSMakeRange(loc, length)];
 }
+
+void gio_hideCursor() {
+    @autoreleasepool {
+        [NSCursor hide];
+    }
+}
+
+void gio_showCursor() {
+    @autoreleasepool {
+        [NSCursor unhide];
+    }
+}
+
+void gio_setCursor(NSUInteger curID) {
+    @autoreleasepool {
+        switch (curID) {
+        case 1:
+            [NSCursor.arrowCursor set];
+            break;
+        case 2:
+            [NSCursor.IBeamCursor set];
+            break;
+        case 3:
+            [NSCursor.pointingHandCursor set];
+            break;
+        case 4:
+            [NSCursor.crosshairCursor set];
+            break;
+        case 5:
+            [NSCursor.resizeLeftRightCursor set];
+            break;
+        case 6:
+            [NSCursor.resizeUpDownCursor set];
+            break;
+        default:
+            [NSCursor.arrowCursor set];
+            break;
+        }
+    }
+}

app/internal/window/os_ios.go

@@ -51,6 +51,7 @@ type window struct {
 
 	layer   C.CFTypeRef
 	visible atomic.Value
+	cursor  pointer.CursorName
 
 	pointerMap []C.CFTypeRef
 }
@@ -249,6 +250,10 @@ func (w *window) SetAnimating(anim bool) {
 	}
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	w.cursor = windowSetCursor(w.cursor, name)
+}
+
 func (w *window) onKeyCommand(name string) {
 	w.w.Event(key.Event{
 		Name: name,

app/internal/window/os_js.go

@@ -426,6 +426,11 @@ func (w *window) WriteClipboard(s string) {
 	w.clipboard.Call("writeText", s)
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	style := w.cnv.Get("style")
+	style.Set("cursor", string(name))
+}
+
 func (w *window) ShowTextInput(show bool) {
 	// Run in a goroutine to avoid a deadlock if the
 	// focus change result in an event.

app/internal/window/os_macos.go

@@ -58,6 +58,7 @@ type window struct {
 	w           Callbacks
 	stage       system.Stage
 	displayLink *displayLink
+	cursor      pointer.CursorName
 
 	scale float32
 }
@@ -74,7 +75,7 @@ var launched = make(chan struct{})
 // cascadeTopLeftFromPoint.
 var nextTopLeft C.NSPoint
 
-// mustView is like lookoupView, except that it panics
+// mustView is like lookupView, except that it panics
 // if the view isn't mapped.
 func mustView(view C.CFTypeRef) *window {
 	w, ok := lookupView(view)
@@ -122,6 +123,10 @@ func (w *window) WriteClipboard(s string) {
 	})
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	w.cursor = windowSetCursor(w.cursor, name)
+}
+
 func (w *window) ShowTextInput(show bool) {}
 
 func (w *window) SetAnimating(anim bool) {
@@ -227,6 +232,7 @@ func gio_onDraw(view C.CFTypeRef) {
 func gio_onFocus(view C.CFTypeRef, focus C.BOOL) {
 	w := mustView(view)
 	w.w.Event(key.FocusEvent{Focus: focus == C.YES})
+	w.SetCursor(w.cursor)
 }
 
 //export gio_onChangeScreen

app/internal/window/os_wayland.go

@@ -764,16 +764,7 @@ func gio_onPointerEnter(data unsafe.Pointer, pointer *C.struct_wl_pointer, seria
 	s.serial = serial
 	w := callbackLoad(unsafe.Pointer(surf)).(*window)
 	s.pointerFocus = w
-	// Get images[0].
-	img := *w.cursor.cursor.images
-	buf := C.wl_cursor_image_get_buffer(img)
-	if buf == nil {
-		return
-	}
-	C.wl_pointer_set_cursor(pointer, serial, w.cursor.surf, C.int32_t(img.hotspot_x), C.int32_t(img.hotspot_y))
-	C.wl_surface_attach(w.cursor.surf, buf, 0, 0)
-	C.wl_surface_damage(w.cursor.surf, 0, 0, C.int32_t(img.width), C.int32_t(img.height))
-	C.wl_surface_commit(w.cursor.surf)
+	w.setCursor(pointer, serial)
 	w.lastPos = f32.Point{X: fromFixed(x), Y: fromFixed(y)}
 }
 
@@ -917,6 +908,50 @@ func (w *window) WriteClipboard(s string) {
 	w.disp.wakeup()
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	if name == pointer.CursorNone {
+		C.wl_pointer_set_cursor(w.disp.seat.pointer, w.serial, nil, 0, 0)
+		return
+	}
+	switch name {
+	default:
+		fallthrough
+	case pointer.CursorDefault:
+		name = "left_ptr"
+	case pointer.CursorText:
+		name = "xterm"
+	case pointer.CursorPointer:
+		name = "hand1"
+	case pointer.CursorCrossHair:
+		name = "crosshair"
+	case pointer.CursorRowResize:
+		name = "top_side"
+	case pointer.CursorColResize:
+		name = "left_side"
+	}
+	cname := C.CString(string(name))
+	defer C.free(unsafe.Pointer(cname))
+	c := C.wl_cursor_theme_get_cursor(w.cursor.theme, cname)
+	if c == nil {
+		return
+	}
+	w.cursor.cursor = c
+	w.setCursor(w.disp.seat.pointer, w.serial)
+}
+
+func (w *window) setCursor(pointer *C.struct_wl_pointer, serial C.uint32_t) {
+	// Get images[0].
+	img := *w.cursor.cursor.images
+	buf := C.wl_cursor_image_get_buffer(img)
+	if buf == nil {
+		return
+	}
+	C.wl_pointer_set_cursor(pointer, serial, w.cursor.surf, C.int32_t(img.hotspot_x), C.int32_t(img.hotspot_y))
+	C.wl_surface_attach(w.cursor.surf, buf, 0, 0)
+	C.wl_surface_damage(w.cursor.surf, 0, 0, C.int32_t(img.width), C.int32_t(img.height))
+	C.wl_surface_commit(w.cursor.surf)
+}
+
 func (w *window) resetFling() {
 	w.fling.start = false
 	w.fling.anim = fling.Animation{}

app/internal/window/os_windows.go

@@ -45,6 +45,7 @@ type window struct {
 	height      int
 	stage       system.Stage
 	pointerBtns pointer.Buttons
+	cursor      syscall.Handle
 
 	mu        sync.Mutex
 	animating bool
@@ -105,6 +106,9 @@ func NewWindow(window Callbacks, opts *Options) error {
 		windows.ShowWindow(w.hwnd, windows.SW_SHOWDEFAULT)
 		windows.SetForegroundWindow(w.hwnd)
 		windows.SetFocus(w.hwnd)
+		// Since the window class for the cursor is null,
+		// set it here to show the cursor.
+		w.SetCursor(pointer.CursorDefault)
 		if err := w.loop(); err != nil {
 			panic(err)
 		}
@@ -120,17 +124,16 @@ func initResources() error {
 		return err
 	}
 	resources.handle = hInst
-	curs, err := windows.LoadCursor(windows.IDC_ARROW)
+	c, err := loadCursor(pointer.CursorDefault)
 	if err != nil {
 		return err
 	}
-	resources.cursor = curs
+	resources.cursor = c
 	wcls := windows.WndClassEx{
 		CbSize:        uint32(unsafe.Sizeof(windows.WndClassEx{})),
 		Style:         windows.CS_HREDRAW | windows.CS_VREDRAW | windows.CS_OWNDC,
 		LpfnWndProc:   syscall.NewCallback(windowProc),
 		HInstance:     hInst,
-		HCursor:       curs,
 		LpszClassName: syscall.StringToUTF16Ptr("GioWindow"),
 	}
 	cls, err := windows.RegisterClassEx(&wcls)
@@ -299,6 +302,8 @@ func windowProc(hwnd syscall.Handle, msg uint32, wParam, lParam uintptr) uintptr
 				Y: w.minmax.maxHeight + w.deltas.height,
 			}
 		}
+	case windows.WM_SETCURSOR:
+		windows.SetCursor(w.cursor)
 	}
 
 	return windows.DefWindowProc(hwnd, msg, wParam, lParam)
@@ -552,6 +557,37 @@ func (w *window) writeClipboard(s string) error {
 	return nil
 }
 
+func (w *window) SetCursor(name pointer.CursorName) {
+	c, err := loadCursor(name)
+	if err != nil {
+		c = resources.cursor
+	}
+	w.cursor = c
+}
+
+func loadCursor(name pointer.CursorName) (syscall.Handle, error) {
+	var curID uint16
+	switch name {
+	default:
+		fallthrough
+	case pointer.CursorDefault:
+		return resources.cursor, nil
+	case pointer.CursorText:
+		curID = windows.IDC_IBEAM
+	case pointer.CursorPointer:
+		curID = windows.IDC_HAND
+	case pointer.CursorCrossHair:
+		curID = windows.IDC_CROSS
+	case pointer.CursorColResize:
+		curID = windows.IDC_SIZEWE
+	case pointer.CursorRowResize:
+		curID = windows.IDC_SIZENS
+	case pointer.CursorNone:
+		return 0, nil
+	}
+	return windows.LoadCursor(curID)
+}
+
 func (w *window) ShowTextInput(show bool) {}
 
 func (w *window) HDC() syscall.Handle {

app/internal/window/os_x11.go

@@ -7,8 +7,8 @@ package window
 /*
 #cgo openbsd CFLAGS: -I/usr/X11R6/include -I/usr/local/include
 #cgo openbsd LDFLAGS: -L/usr/X11R6/lib -L/usr/local/lib
-#cgo freebsd openbsd LDFLAGS: -lX11 -lxkbcommon -lxkbcommon-x11 -lX11-xcb
-#cgo linux pkg-config: x11 xkbcommon xkbcommon-x11 x11-xcb
+#cgo freebsd openbsd LDFLAGS: -lX11 -lxkbcommon -lxkbcommon-x11 -lX11-xcb -lXcursor -lXfixes
+#cgo linux pkg-config: x11 xkbcommon xkbcommon-x11 x11-xcb xcursor xfixes
 
 #include <stdlib.h>
 #include <locale.h>
@@ -18,6 +18,8 @@ package window
 #include <X11/Xresource.h>
 #include <X11/XKBlib.h>
 #include <X11/Xlib-xcb.h>
+#include <X11/extensions/Xfixes.h>
+#include <X11/Xcursor/Xcursor.h>
 #include <xkbcommon/xkbcommon-x11.h>
 
 */
@@ -87,6 +89,7 @@ type x11Window struct {
 		write   *string
 		content []byte
 	}
+	cursor pointer.CursorName
 }
 
 func (w *x11Window) SetAnimating(anim bool) {
@@ -112,6 +115,27 @@ func (w *x11Window) WriteClipboard(s string) {
 	w.wakeup()
 }
 
+func (w *x11Window) SetCursor(name pointer.CursorName) {
+	if name == pointer.CursorNone {
+		w.cursor = name
+		C.XFixesHideCursor(w.x, w.xw)
+		return
+	}
+	if w.cursor == pointer.CursorNone {
+		C.XFixesShowCursor(w.x, w.xw)
+	}
+	cname := C.CString(string(name))
+	defer C.free(unsafe.Pointer(cname))
+	c := C.XcursorLibraryLoadCursor(w.x, cname)
+	if c == 0 {
+		name = pointer.CursorDefault
+	}
+	w.cursor = name
+	// If c if null (i.e. name was not found),
+	// XDefineCursor will use the default cursor.
+	C.XDefineCursor(w.x, w.xw, c)
+}
+
 func (w *x11Window) ShowTextInput(show bool) {}
 
 // Close the window.

app/internal/window/window.go

@@ -9,6 +9,7 @@ import (
 
 	"gioui.org/gpu/backend"
 	"gioui.org/io/event"
+	"gioui.org/io/pointer"
 	"gioui.org/io/system"
 	"gioui.org/unit"
 )
@@ -60,6 +61,9 @@ type Driver interface {
 	// WriteClipboard requests a clipboard write.
 	WriteClipboard(s string)
 
+	// SetCursor updates the current cursor to name.
+	SetCursor(name pointer.CursorName)
+
 	// Close the window.
 	Close()
 }

app/internal/windows/windows.go

@@ -61,7 +61,12 @@ const (
 
 	CW_USEDEFAULT = -2147483648
 
-	IDC_ARROW = 32512
+	IDC_ARROW  = 32512
+	IDC_IBEAM  = 32513
+	IDC_HAND   = 32649
+	IDC_CROSS  = 32515
+	IDC_SIZENS = 32645
+	IDC_SIZEWE = 32644
 
 	INFINITE = 0xFFFFFFFF
 
@@ -146,6 +151,7 @@ const (
 	WM_PAINT         = 0x000F
 	WM_CLOSE         = 0x0010
 	WM_QUIT          = 0x0012
+	WM_SETCURSOR     = 0x0020
 	WM_SETFOCUS      = 0x0007
 	WM_KILLFOCUS     = 0x0008
 	WM_SHOWWINDOW    = 0x0018
@@ -227,6 +233,7 @@ var (
 	_ScreenToClient              = user32.NewProc("ScreenToClient")
 	_ShowWindow                  = user32.NewProc("ShowWindow")
 	_SetCapture                  = user32.NewProc("SetCapture")
+	_SetCursor                   = user32.NewProc("SetCursor")
 	_SetClipboardData            = user32.NewProc("SetClipboardData")
 	_SetForegroundWindow         = user32.NewProc("SetForegroundWindow")
 	_SetFocus                    = user32.NewProc("SetFocus")
@@ -514,6 +521,10 @@ func SetClipboardData(format uint32, mem syscall.Handle) error {
 	return nil
 }
 
+func SetCursor(h syscall.Handle) {
+	_SetCursor.Call(uintptr(h))
+}
+
 func SetTimer(hwnd syscall.Handle, nIDEvent uintptr, uElapse uint32, timerProc uintptr) error {
 	r, _, err := _SetTimer.Call(uintptr(hwnd), uintptr(nIDEvent), uintptr(uElapse), timerProc)
 	if r == 0 {

app/window.go

@@ -10,6 +10,7 @@ import (
 
 	"gioui.org/app/internal/window"
 	"gioui.org/io/event"
+	"gioui.org/io/pointer"
 	"gioui.org/io/profile"
 	"gioui.org/io/router"
 	"gioui.org/io/system"
@@ -209,6 +210,13 @@ func (w *Window) WriteClipboard(s string) {
 	})
 }
 
+// SetCursorName changes the current window cursor to name.
+func (w *Window) SetCursorName(name pointer.CursorName) {
+	go w.driverDo(func() {
+		w.driver.SetCursor(name)
+	})
+}
+
 // Close the window. The window's event loop should exit when it receives
 // system.DestroyEvent.
 //

io/pointer/pointer.go

@@ -79,9 +79,29 @@ type Source uint8
 // Buttons is a set of mouse buttons
 type Buttons uint8
 
+// CursorName is the name of a cursor.
+type CursorName string
+
 // Must match app/internal/input.areaKind
 type areaKind uint8
 
+const (
+	// CursorDefault is the default cursor.
+	CursorDefault CursorName = ""
+	// CursorText is the cursor for text.
+	CursorText CursorName = "text"
+	// CursorPointer is the cursor for a link.
+	CursorPointer CursorName = "pointer"
+	// CursorCrossHair is the cursor for precise location.
+	CursorCrossHair CursorName = "crosshair"
+	// CursorColResize is the cursor for vertical resize.
+	CursorColResize CursorName = "col-resize"
+	// CursorRowResize is the cursor for horizontal resize.
+	CursorRowResize CursorName = "row-resize"
+	// CursorNone hides the cursor. To show it again, use any other cursor.
+	CursorNone CursorName = "none"
+)
+
 const (
 	// A Cancel event is generated when the current gesture is
 	// interrupted by other handlers or the system.
@@ -242,4 +262,11 @@ func (b Buttons) String() string {
 	return strings.Join(strs, "|")
 }
 
+func (c CursorName) String() string {
+	if c == CursorDefault {
+		return "default"
+	}
+	return string(c)
+}
+
 func (Event) ImplementsEvent() {}