Merge pull request fyne-io#1601 from MagicalTux/custom-cursors-proposal

Proposal: Custom cursors in Fyne
lunarforge · Dec 2, 2020 · 157776c · 157776c
2 parents 5065c28 + 17ea20c
commit 157776c
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Showing 3 changed files with 63 additions and 26 deletions.
diff --git a/driver/desktop/cursor.go b/driver/desktop/cursor.go
@@ -1,11 +1,29 @@
 package desktop
 
-// Cursor represents a standard fyne cursor
-type Cursor int
+import "image"
+
+// Cursor interface is used for objects usable as cursor
+//
+// Since: 2.0.0
+type Cursor interface {
+	Image() (image.Image, int, int) // Image returns the image for the given cursor, or nil to hide the cursor
+}
+
+// StandardCursor represents a standard fyne cursor
+//
+// Since: 2.0.0
+type StandardCursor int
+
+// Image will always return nil for StandardCursor
+//
+// Since: 2.0.0
+func (d StandardCursor) Image() (image.Image, int, int) {
+	return nil, 0, 0
+}
 
 const (
 	// DefaultCursor is the default cursor typically an arrow
-	DefaultCursor Cursor = iota
+	DefaultCursor StandardCursor = iota
 	// TextCursor is the cursor often used to indicate text selection
 	TextCursor
 	// CrosshairCursor is the cursor often used to indicate bitmaps

diff --git a/internal/driver/glfw/window.go b/internal/driver/glfw/window.go
@@ -26,12 +26,12 @@ const (
 )
 
 var (
-	cursorMap    map[desktop.Cursor]*glfw.Cursor
+	cursorMap    map[desktop.StandardCursor]*glfw.Cursor
 	defaultTitle = "Fyne Application"
 )
 
 func initCursors() {
-	cursorMap = map[desktop.Cursor]*glfw.Cursor{
+	cursorMap = map[desktop.StandardCursor]*glfw.Cursor{
 		desktop.DefaultCursor:   glfw.CreateStandardCursor(glfw.ArrowCursor),
 		desktop.TextCursor:      glfw.CreateStandardCursor(glfw.IBeamCursor),
 		desktop.CrosshairCursor: glfw.CreateStandardCursor(glfw.CrosshairCursor),
@@ -52,11 +52,12 @@ type window struct {
 	decorate   bool
 	fixedSize  bool
 
-	cursor   *glfw.Cursor
-	canvas   *glCanvas
-	title    string
-	icon     fyne.Resource
-	mainmenu *fyne.MainMenu
+	cursor       desktop.Cursor
+	customCursor *glfw.Cursor
+	canvas       *glCanvas
+	title        string
+	icon         fyne.Resource
+	mainmenu     *fyne.MainMenu
 
 	clipboard fyne.Clipboard
 
@@ -558,22 +559,31 @@ func (w *window) findObjectAtPositionMatching(canvas *glCanvas, mouse fyne.Posit
 	return driver.FindObjectAtPositionMatching(mouse, matches, canvas.Overlays().Top(), canvas.menu, canvas.Content())
 }
 
-func fyneToNativeCursor(cursor desktop.Cursor) *glfw.Cursor {
-	ret, ok := cursorMap[cursor]
-	if !ok {
-		return cursorMap[desktop.DefaultCursor]
+func fyneToNativeCursor(cursor desktop.Cursor) (*glfw.Cursor, bool) {
+	switch v := cursor.(type) {
+	case desktop.StandardCursor:
+		ret, ok := cursorMap[v]
+		if !ok {
+			return cursorMap[desktop.DefaultCursor], false
+		}
+		return ret, false
+	default:
+		img, x, y := cursor.Image()
+		if img == nil {
+			return nil, true
+		}
+		return glfw.CreateCursor(img, x, y), true
 	}
-	return ret
 }
 
 func (w *window) mouseMoved(viewport *glfw.Window, xpos float64, ypos float64) {
 	w.mousePos = fyne.NewPos(internal.UnscaleInt(w.canvas, int(xpos)), internal.UnscaleInt(w.canvas, int(ypos)))
 
-	cursor := cursorMap[desktop.DefaultCursor]
+	cursor := desktop.Cursor(desktop.DefaultCursor)
+
 	obj, pos, _ := w.findObjectAtPositionMatching(w.canvas, w.mousePos, func(object fyne.CanvasObject) bool {
 		if cursorable, ok := object.(desktop.Cursorable); ok {
-			fyneCursor := cursorable.Cursor()
-			cursor = fyneToNativeCursor(fyneCursor)
+			cursor = cursorable.Cursor()
 		}
 
 		_, hover := object.(desktop.Hoverable)
@@ -582,12 +592,21 @@ func (w *window) mouseMoved(viewport *glfw.Window, xpos float64, ypos float64) {
 
 	if w.cursor != cursor {
 		// cursor has changed, store new cursor and apply change via glfw
+		rawCursor, isCustomCursor := fyneToNativeCursor(cursor)
 		w.cursor = cursor
-		if cursor == nil {
+
+		if rawCursor == nil {
 			viewport.SetInputMode(glfw.CursorMode, glfw.CursorHidden)
 		} else {
 			viewport.SetInputMode(glfw.CursorMode, glfw.CursorNormal)
-			viewport.SetCursor(cursor)
+			viewport.SetCursor(rawCursor)
+		}
+		if w.customCursor != nil {
+			w.customCursor.Destroy()
+			w.customCursor = nil
+		}
+		if isCustomCursor {
+			w.customCursor = rawCursor
 		}
 	}
 	if obj != nil && !w.objIsDragged(obj) {

diff --git a/internal/driver/glfw/window_test.go b/internal/driver/glfw/window_test.go
@@ -81,16 +81,16 @@ func TestWindow_Cursor(t *testing.T) {
 	w.SetContent(widget.NewVBox(e, h, b))
 
 	w.mouseMoved(w.viewport, 10, float64(e.Position().Y+10))
-	textCursor := cursorMap[desktop.TextCursor]
-	assert.Same(t, textCursor, w.cursor)
+	textCursor := desktop.TextCursor
+	assert.Equal(t, textCursor, w.cursor)
 
 	w.mouseMoved(w.viewport, 10, float64(h.Position().Y+10))
-	pointerCursor := cursorMap[desktop.PointerCursor]
-	assert.Same(t, pointerCursor, w.cursor)
+	pointerCursor := desktop.PointerCursor
+	assert.Equal(t, pointerCursor, w.cursor)
 
 	w.mouseMoved(w.viewport, 10, float64(b.Position().Y+10))
-	defaultCursor := cursorMap[desktop.DefaultCursor]
-	assert.Same(t, defaultCursor, w.cursor)
+	defaultCursor := desktop.DefaultCursor
+	assert.Equal(t, defaultCursor, w.cursor)
 }
 
 func TestWindow_HandleHoverable(t *testing.T) {