ui/image.go

83 lines
1.5 KiB
Go

package ui
import (
"fmt"
"path/filepath"
"strings"
"git.kirsle.net/apps/doodle/lib/render"
)
// ImageType for supported image formats.
type ImageType string
// Supported image formats.
const (
BMP ImageType = "bmp"
PNG = "png"
)
// Image is a widget that is backed by an image file.
type Image struct {
BaseWidget
// Configurable fields for the constructor.
Type ImageType
texture render.Texturer
}
// NewImage creates a new Image.
func NewImage(c Image) *Image {
w := &Image{
Type: c.Type,
}
if w.Type == "" {
w.Type = BMP
}
w.IDFunc(func() string {
return fmt.Sprintf(`Image<"%s">`, w.Type)
})
return w
}
// OpenImage initializes an Image with a given file name.
//
// The file extension is important and should be a supported ImageType.
func OpenImage(e render.Engine, filename string) (*Image, error) {
w := &Image{}
switch strings.ToLower(filepath.Ext(filename)) {
case ".bmp":
w.Type = BMP
case ".png":
w.Type = PNG
default:
return nil, fmt.Errorf("OpenImage: %s: not a supported image type", filename)
}
tex, err := e.LoadTexture(filename)
if err != nil {
return nil, err
}
w.texture = tex
return w, nil
}
// Compute the widget.
func (w *Image) Compute(e render.Engine) {
w.Resize(w.texture.Size())
}
// Present the widget.
func (w *Image) Present(e render.Engine, p render.Point) {
size := w.texture.Size()
dst := render.Rect{
X: p.X,
Y: p.Y,
W: size.W,
H: size.H,
}
e.Copy(w.texture, size, dst)
}