Added overloads to add an image to the Images container.

ui/images.go

@@ -1,10 +1,14 @@
 package ui
 
 import (
+	"image"
+
 	"github.com/nfnt/resize"
 	"opslag.de/schobers/geom"
 )
 
+type CreateImageFn func() (image.Image, error)
+
 func ScaleImage(render Renderer, im Image, scale float32) Image {
 	w := uint(im.Width() * scale)
 	if w == 0 {
@@ -36,6 +40,23 @@ func (i *Images) AddImage(name string, im Image) {
 	i.ims[name] = im
 }
 
+func (i *Images) AddImageFn(name string, create CreateImageFn) error {
+	im, err := create()
+	if err != nil {
+		return err
+	}
+	return i.AddImageNative(name, im)
+}
+
+func (i *Images) AddImageNative(name string, im image.Image) error {
+	m, err := i.render.CreateImage(im)
+	if err != nil {
+		return err
+	}
+	i.AddImage(name, m)
+	return nil
+}
+
 func (i *Images) Destroy() {
 	for _, im := range i.ims {
 		im.Destroy()