~eliasnaur/gio

9793fcfcd0ac7a0d0c231d3a964d77cf7e9a9294 — Egon Elbre 7 months ago 2c5daf1
widget: add Fit and Position to Image for image placement

Signed-off-by: Egon Elbre <egonelbre@gmail.com>
1 files changed, 15 insertions(+), 7 deletions(-)

M widget/image.go
M widget/image.go => widget/image.go +15 -7
@@ 8,7 8,6 @@ import (
	"gioui.org/f32"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"gioui.org/unit"
)


@@ 17,6 16,12 @@ import (
type Image struct {
	// Src is the image to display.
	Src paint.ImageOp
	// Fit specifies how to scale the image to the constraints.
	// By default it does not do any scaling.
	Fit Fit
	// Position specifies where to position the image within
	// the constraints.
	Position layout.Direction
	// Scale is the ratio of image pixels to
	// dps. If Scale is zero Image falls back to
	// a scale that match a standard 72 DPI.


@@ 26,21 31,24 @@ type Image struct {
const defaultScale = float32(160.0 / 72.0)

func (im Image) Layout(gtx layout.Context) layout.Dimensions {
	defer op.Save(gtx.Ops).Load()

	scale := im.Scale
	if scale == 0 {
		scale = defaultScale
	}

	size := im.Src.Size()
	wf, hf := float32(size.X), float32(size.Y)
	w, h := gtx.Px(unit.Dp(wf*scale)), gtx.Px(unit.Dp(hf*scale))
	cs := gtx.Constraints
	d := cs.Constrain(image.Pt(w, h))
	stack := op.Save(gtx.Ops)

	dims := im.Fit.scale(gtx, im.Position, layout.Dimensions{Size: image.Pt(w, h)})

	pixelScale := scale * gtx.Metric.PxPerDp
	op.Affine(f32.Affine2D{}.Scale(f32.Point{}, f32.Pt(pixelScale, pixelScale))).Add(gtx.Ops)
	clip.Rect(image.Rectangle{Max: d}).Add(gtx.Ops)

	im.Src.Add(gtx.Ops)
	paint.PaintOp{}.Add(gtx.Ops)
	stack.Load()
	return layout.Dimensions{Size: d}

	return dims
}