primitives/image.go
Functions
func AccessibilityActions
func (w *ImageWidget) AccessibilityActions() []a11y.Action {
return nil
}
func AccessibilityHint
AccessibilityHint returns an empty string.
func (w *ImageWidget) AccessibilityHint() string {
return ""
}
func AccessibilityLabel
AccessibilityLabel returns the alt text.
func (w *ImageWidget) AccessibilityLabel() string {
return w.alt
}
func AccessibilityRole
AccessibilityRole returns [a11y.RoleImage].
func (w *ImageWidget) AccessibilityRole() a11y.Role {
return a11y.RoleImage
}
func AccessibilityState
AccessibilityState returns the default state.
func (w *ImageWidget) AccessibilityState() a11y.State {
return a11y.State{
Hidden: !w.IsVisible(),
}
}
func AccessibilityValue
AccessibilityValue returns an empty string.
func (w *ImageWidget) AccessibilityValue() string {
return ""
}
func Alt
Alt sets the accessibility alt text.
func (w *ImageWidget) Alt(text string) *ImageWidget {
w.alt = text
return w
}
func AltText
AltText returns the accessibility alt text.
func (w *ImageWidget) AltText() string {
return w.alt
}
func Children
Children returns nil. Image is a leaf widget.
func (w *ImageWidget) Children() []widget.Widget {
return nil
}
func Contain
Contain is a shorthand for Fit(ImageFitContain).
func (w *ImageWidget) Contain() *ImageWidget {
w.style.Fit = ImageFitContain
return w
}
func Cover
Cover is a shorthand for Fit(ImageFitCover).
func (w *ImageWidget) Cover() *ImageWidget {
w.style.Fit = ImageFitCover
return w
}
func Draw
Draw renders the image placeholder.
The current implementation draws a light gray rectangle with a centered
cross to indicate the image area. Full image rendering requires a Canvas
implementation that supports DrawImage, which will be provided by the
rendering backend.
func (w *ImageWidget) Draw(_ widget.Context, canvas widget.Canvas) {
if !w.IsVisible() {
return
}
bounds := w.Bounds()
if bounds.IsEmpty() {
return
}
// Placeholder: draw a light gray box with a cross
placeholderColor := widget.RGBA(0.9, 0.9, 0.9, 1)
crossColor := widget.RGBA(0.7, 0.7, 0.7, 1)
if w.style.Radius > 0 {
canvas.DrawRoundRect(bounds, placeholderColor, w.style.Radius)
} else {
canvas.DrawRect(bounds, placeholderColor)
}
// Draw cross
center := bounds.Center()
armLen := bounds.Width() / 4
if h := bounds.Height() / 4; h < armLen {
armLen = h
}
if armLen > 2 {
canvas.DrawLine(
geometry.Pt(center.X-armLen, center.Y-armLen),
geometry.Pt(center.X+armLen, center.Y+armLen),
crossColor, 1,
)
canvas.DrawLine(
geometry.Pt(center.X+armLen, center.Y-armLen),
geometry.Pt(center.X-armLen, center.Y+armLen),
crossColor, 1,
)
}
}
func Event
Event returns false. Image widgets do not consume events.
func (w *ImageWidget) Event(_ widget.Context, _ event.Event) bool {
return false
}
func Fill
Fill is a shorthand for Fit(ImageFitFill).
func (w *ImageWidget) Fill() *ImageWidget {
w.style.Fit = ImageFitFill
return w
}
func Fit
Fit sets the image fit mode.
func (w *ImageWidget) Fit(f ImageFit) *ImageWidget {
w.style.Fit = f
return w
}
func Image
Image creates a new image widget with the given source.
The source provides the natural pixel dimensions of the image. If source
is nil, the widget has zero natural size.
img := primitives.Image(mySource).Size(200, 150).Cover()
func Image(source ImageSource) *ImageWidget {
w := &ImageWidget{
source: source,
style: ImageStyle{
Fit: ImageFitContain,
},
}
w.SetVisible(true)
w.SetEnabled(true)
return w
}
func Layout
Layout determines the widget size based on the image source bounds, the
explicit size overrides, and the fit mode.
func (w *ImageWidget) Layout(_ widget.Context, constraints geometry.Constraints) geometry.Size {
natural := w.naturalSize()
// Apply explicit size overrides
desired := natural
if w.style.ExplicitWidth > 0 {
desired.Width = w.style.ExplicitWidth
}
if w.style.ExplicitHeight > 0 {
desired.Height = w.style.ExplicitHeight
}
// For Contain and Cover, we need to maintain aspect ratio
switch w.style.Fit {
case ImageFitContain:
if desired.Width > 0 && desired.Height > 0 {
containerMax := constraints.BiggestFinite(desired.Width, desired.Height)
desired = desired.FitIn(containerMax)
}
case ImageFitCover:
if desired.Width > 0 && desired.Height > 0 {
containerMax := constraints.BiggestFinite(desired.Width, desired.Height)
desired = desired.FillIn(containerMax)
// Clamp to container since excess is clipped
desired = desired.Min(containerMax)
}
case ImageFitFill:
// Fill stretches to available space
if constraints.HasBoundedWidth() && w.style.ExplicitWidth <= 0 {
desired.Width = constraints.MaxWidth
}
if constraints.HasBoundedHeight() && w.style.ExplicitHeight <= 0 {
desired.Height = constraints.MaxHeight
}
case ImageFitNone:
// Use natural size, will be clipped by container
}
resultSize := constraints.Constrain(desired)
w.SetBounds(geometry.FromPointSize(w.Position(), resultSize))
return resultSize
}
func Rounded
Rounded sets the border radius for clipping.
func (w *ImageWidget) Rounded(r float32) *ImageWidget {
w.style.Radius = r
return w
}
func Size
Size sets explicit width and height.
func (w *ImageWidget) Size(width, height float32) *ImageWidget {
w.style.ExplicitWidth = width
w.style.ExplicitHeight = height
return w
}
func Source
Source returns the image source.
func (w *ImageWidget) Source() ImageSource {
return w.source
}
func Style
Style returns the current image style (read-only snapshot).
func (w *ImageWidget) Style() ImageStyle {
return w.style
}
Structs
type ImageStyle struct
ImageStyle holds all visual styling for an [ImageWidget].
type ImageStyle struct {
// ExplicitWidth and ExplicitHeight override the natural image size.
// Zero means use the natural dimension.
ExplicitWidth float32
ExplicitHeight float32
Fit ImageFit
Radius float32
}
type ImageWidget struct
ImageWidget displays a raster image with configurable fit mode, optional
rounded corners, and accessibility alt text.
ImageWidget implements [widget.Widget] and [a11y.Accessible].
Create an ImageWidget with the [Image] constructor.
type ImageWidget struct {
widget.WidgetBase
style ImageStyle
source ImageSource
alt string
}
AccessibilityActions returns nil. Images have no actions.