add CaptionedImage widget

2024-03-01 16:59:04 -08:00
parent c473c3ad23
commit 0c8914060e
1 changed files with 113 additions and 0 deletions
@@ -0,0 +1,113 @@
+package widgets
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/widget"
+)
+
+type Aspectable interface {
+	fyne.CanvasObject
+	Aspect() float32
+}
+
+type CaptionedImage struct {
+	widget.BaseWidget
+
+	Content Aspectable
+	Caption fyne.CanvasObject
+}
+
+var _ fyne.Widget = (*CaptionedImage)(nil)
+
+func NewCaptionedImage(content Aspectable, caption fyne.CanvasObject) *CaptionedImage {
+	c := &CaptionedImage{Content: content, Caption: caption}
+	c.ExtendBaseWidget(c)
+	return c
+}
+
+func (c *CaptionedImage) CreateRenderer() fyne.WidgetRenderer {
+	return &captionedImageRenderer{
+		ci: c,
+	}
+}
+
+type captionedImageRenderer struct {
+	ci *CaptionedImage
+}
+
+var _ fyne.WidgetRenderer = (*captionedImageRenderer)(nil)
+
+func (*captionedImageRenderer) Destroy() {
+	// intentionally blank
+}
+
+func (c *captionedImageRenderer) Layout(s fyne.Size) {
+	content := c.ci.Content
+	aspect := content.Aspect()
+	caption := c.ci.Caption
+	var captionHeight float32
+	if caption != nil {
+		captionHeight = caption.MinSize().Height
+	}
+
+	// max height that could be allocated to Content
+	contentMaxedHeight := s.Height
+	if caption != nil {
+		contentMaxedHeight -= captionHeight
+	}
+
+	// aspect ratio of Content if it were maxed out
+	maxedAspect := s.Width / contentMaxedHeight
+	if maxedAspect > aspect {
+		// Content will use full height, but not full width
+		contentW := contentMaxedHeight * aspect
+		content.Resize(fyne.NewSize(contentW, contentMaxedHeight))
+		contentX := (s.Width - contentW) / 2
+		content.Move(fyne.NewPos(contentX, 0))
+		if caption != nil {
+			caption.Resize(fyne.NewSize(s.Width, captionHeight))
+			caption.Move(fyne.NewPos(0, contentMaxedHeight))
+		}
+		return
+	}
+
+	// Content will not use full height
+	// Positioning of Content and Caption will be adjusted to center
+	contentH := s.Width / aspect
+	yStart := (s.Height - contentH - captionHeight) / 2
+	content.Resize(fyne.NewSize(s.Width, contentH))
+	content.Move(fyne.NewPos(0, yStart))
+	if caption != nil {
+		caption.Resize(fyne.NewSize(s.Width, captionHeight))
+		caption.Move(fyne.NewPos(0, yStart+contentH))
+	}
+}
+
+func (c *captionedImageRenderer) MinSize() fyne.Size {
+	objSize := c.ci.Content.MinSize()
+	if c.ci.Caption == nil {
+		return objSize
+	}
+	cptSize := c.ci.Caption.MinSize()
+	return fyne.NewSize(
+		fyne.Max(objSize.Width, cptSize.Width),
+		objSize.Height+cptSize.Height,
+	)
+}
+
+func (c *captionedImageRenderer) Objects() []fyne.CanvasObject {
+	if c.ci.Caption != nil {
+		return []fyne.CanvasObject{c.ci.Content, c.ci.Caption}
+	}
+	return []fyne.CanvasObject{c.ci.Content}
+}
+
+func (c *captionedImageRenderer) Refresh() {
+	c.ci.Content.Refresh()
+	if cap := c.ci.Caption; cap != nil {
+		cap.Refresh()
+	}
+	// aspect may have changed on Content,
+	// so we need to re-layout
+	c.Layout(c.ci.Size())
+}