add open animation for pop up images

ui/widgets/imagepopup.go

@@ -0,0 +1,58 @@
+package widgets
+
+import (
+	"image"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/widget"
+)
+
+const (
+	imagePopUpLowRezDim = 128
+)
+
+type ImagePopUp struct {
+	widget.PopUp
+
+	img         image.Image
+	desiredSize fyne.Size
+	aspect      float64
+}
+
+func NewImagePopUp(img image.Image, canv fyne.Canvas, size fyne.Size) *ImagePopUp {
+	i := &ImagePopUp{
+		img:         img,
+		desiredSize: size,
+		PopUp: widget.PopUp{
+			Canvas:  canv,
+			Content: canvas.NewImageFromImage(img),
+		},
+	}
+	i.ExtendBaseWidget(i)
+	return i
+}
+
+func (i *ImagePopUp) Show() {
+	i.Content.(*canvas.Image).FillMode = canvas.ImageFillContain
+	i.Content.(*canvas.Image).ScaleMode = canvas.ImageScaleFastest
+	canvSize := i.Canvas.Size()
+	i.ShowAtPosition(fyne.NewPos(
+		canvSize.Width/2,
+		canvSize.Height/2,
+	))
+	anim := fyne.NewAnimation(canvas.DurationShort, func(f float32) {
+		if f == 1 {
+			i.Content.(*canvas.Image).ScaleMode = canvas.ImageScaleSmooth
+		}
+		size := fyne.NewSize(i.desiredSize.Width*f, i.desiredSize.Height*f)
+		i.Content.(*canvas.Image).SetMinSize(size)
+		size = i.Content.MinSize()
+		i.Resize(size)
+		i.Move(fyne.NewPos(
+			(canvSize.Width-size.Width)/2,
+			(canvSize.Height-size.Height)/2,
+		))
+	})
+	anim.Start()
+}