github.com/gogpu/ui - core/popover/painter.go

func PaintPopover

PaintPopover renders a popover background with shadow.

func (p DefaultPainter) PaintPopover(canvas widget.Canvas, st *PopoverPaintState) {
	if st.Bounds.IsEmpty() {
		return
	}

	// Shadow (offset slightly down-right).
	shadowBounds := geometry.Rect{
		Min:	geometry.Pt(st.Bounds.Min.X+popShadowOffX, st.Bounds.Min.Y+popShadowOffY),
		Max:	geometry.Pt(st.Bounds.Max.X+popShadowOffX, st.Bounds.Max.Y+popShadowOffY),
	}
	canvas.DrawRoundRect(shadowBounds, popShadowColor, popRadius)

	// Background.
	canvas.DrawRoundRect(st.Bounds, popBgColor, popRadius)

	// Border.
	canvas.StrokeRoundRect(st.Bounds, popBorderColor, popRadius, popBorderWidth)
}

func PaintTooltip

PaintTooltip renders a tooltip background and text.

func (p DefaultPainter) PaintTooltip(canvas widget.Canvas, st *TooltipPaintState) {
	if st.Bounds.IsEmpty() {
		return
	}

	// Background.
	canvas.DrawRoundRect(st.Bounds, tipBgColor, tipRadius)

	// Text.
	textBounds := geometry.Rect{
		Min:	geometry.Pt(st.Bounds.Min.X+tooltipPadH, st.Bounds.Min.Y),
		Max:	geometry.Pt(st.Bounds.Max.X-tooltipPadH, st.Bounds.Max.Y),
	}
	canvas.DrawText(st.Text, textBounds, tooltipFontSz, tipTextColor, false, widget.TextAlignLeft)
}

type PopoverPaintState struct

PopoverPaintState provides the current popover state to the painter.

type PopoverPaintState struct {
	// Bounds is the popover content area bounds in window coordinates.
	Bounds	geometry.Rect

	// Placement is the resolved placement direction.
	Placement	Placement

	// ColorScheme provides theme-derived colors. Zero value means use defaults.
	ColorScheme	PopoverColorScheme
}

type TooltipPaintState struct

TooltipPaintState provides the current tooltip state to the painter.

type TooltipPaintState struct {
	// Bounds is the tooltip's bounds in window coordinates.
	Bounds	geometry.Rect

	// Text is the tooltip text to display.
	Text	string

	// Placement is the resolved placement direction.
	Placement	Placement

	// ColorScheme provides theme-derived colors. Zero value means use defaults.
	ColorScheme	TooltipColorScheme
}

type PopoverColorScheme struct

PopoverColorScheme provides theme-derived colors for popover painting.

Zero value means the painter should use its built-in defaults.

type PopoverColorScheme struct {
	Background	widget.Color
	Border		widget.Color
	Shadow		widget.Color
	ShadowBlur	float32
}

type TooltipColorScheme struct

TooltipColorScheme provides theme-derived colors for tooltip painting.

Zero value means the painter should use its built-in defaults.

type TooltipColorScheme struct {
	Background	widget.Color
	TextColor	widget.Color
	Border		widget.Color
}

type DefaultPainter struct

DefaultPainter provides a minimal fallback painter for popovers and

tooltips. It draws rounded rectangles with a subtle shadow.

type DefaultPainter struct{}

type Painter interface

Painter draws the visual representation of popovers and tooltips.

Each design system (Material 3, Fluent, Cupertino) provides its own

Painter implementation. If no Painter is set, [DefaultPainter] is used.

type Painter interface {
	// PaintPopover draws the popover background (rounded rect + shadow).
	PaintPopover(canvas widget.Canvas, state *PopoverPaintState)

	// PaintTooltip draws the tooltip background and text.
	PaintTooltip(canvas widget.Canvas, state *TooltipPaintState)
}

core/popover/painter.go

Functions