Added checkbox.

Added utility methods for generating icons.

ui/checkbox.go

@@ -0,0 +1,114 @@
+package ui
+
+import (
+	"opslag.de/schobers/geom"
+)
+
+type Checkbox struct {
+	ControlBase
+
+	Selected bool
+	Text     string
+}
+
+func BuildCheckbox(text string, fn func(c *Checkbox)) *Checkbox {
+	var c = &Checkbox{Text: text}
+	if fn != nil {
+		fn(c)
+	}
+	return c
+}
+
+func (c *Checkbox) desiredSize(ctx Context) geom.PointF32 {
+	var pad = ctx.Style().Dimensions.TextPadding
+	var font = ctx.Renderer().Font(c.FontName(ctx))
+	var w, h float32 = 0, font.Height()
+	if len(c.Text) != 0 {
+		w += pad + font.WidthOf(c.Text)
+	}
+	icon, _ := ctx.Images().ScaledHeight(c.icon(ctx, false), h)
+	w += pad + icon.Width()
+	return geom.PtF32(w+pad, pad+h+pad)
+}
+
+func (c *Checkbox) icon(ctx Context, selected bool) Image {
+	if selected {
+		return GetOrCreateIcon(ctx, "ui-default-checkbox-selected", c.selectedIcon)
+	}
+	return GetOrCreateIcon(ctx, "ui-default-checkbox", c.normalIcon)
+}
+
+func (c *Checkbox) iconBorder() geom.PolygonF32 {
+	return geom.PolF32(
+		geom.PtF32(48, 80),
+		geom.PtF32(400, 80),
+		geom.PtF32(400, 432),
+		geom.PtF32(48, 432),
+	)
+}
+
+func (c *Checkbox) normalIcon() IconPixelTestFn {
+	border := c.iconBorder()
+	return func(pt geom.PointF32) bool {
+		return pt.DistanceToPolygon(border) < 48 && !pt.InPolygon(border)
+	}
+}
+
+func (c *Checkbox) selectedIcon() IconPixelTestFn {
+	border := c.iconBorder()
+	check := geom.PointsF32{
+		geom.PtF32(84, 256),
+		geom.PtF32(180, 352),
+		geom.PtF32(352, 150),
+	}
+	return func(pt geom.PointF32) bool {
+		if pt.DistanceToPolygon(border) < 48 || pt.InPolygon(border) {
+			return pt.DistanceToLines(check) > 24
+		}
+		return false
+	}
+}
+
+func (c *Checkbox) DesiredSize(ctx Context) geom.PointF32 { return c.desiredSize(ctx) }
+
+func (c *Checkbox) Handle(ctx Context, e Event) {
+	switch e := e.(type) {
+	case *MouseButtonDownEvent:
+		if e.Button == MouseButtonLeft && c.over {
+			c.Selected = !c.Selected
+		}
+	}
+	c.ControlBase.Handle(ctx, e)
+	if c.over {
+		ctx.Renderer().SetMouseCursor(MouseCursorPointer)
+	}
+}
+
+func (c *Checkbox) Render(ctx Context) {
+	var style = ctx.Style()
+	var palette = style.Palette
+	fore := c.FontColor(ctx)
+	size := c.desiredSize(ctx)
+	bounds := c.bounds
+	deltaX, deltaY := bounds.Dx()-size.X, bounds.Dy()-size.Y
+	bounds.Min.X += .5 * deltaX
+	bounds.Min.Y += .5 * deltaY
+
+	var pad = style.Dimensions.TextPadding
+	bounds = bounds.Inset(pad)
+	pos := bounds.Min
+	icon, _ := ctx.Images().ScaledHeight(c.icon(ctx, c.Selected), bounds.Dy())
+	if icon != nil {
+		iconColor := fore
+		if c.Selected {
+			iconColor = palette.Primary
+		}
+		ctx.Renderer().DrawImageOptions(icon, geom.PtF32(pos.X, pos.Y+.5*(bounds.Dy()-icon.Height())), DrawOptions{Tint: iconColor})
+		pos.X += icon.Width() + pad
+	}
+	if len(c.Text) != 0 {
+		var fontName = c.FontName(ctx)
+		var font = ctx.Renderer().Font(fontName)
+		ctx.Renderer().Text(geom.PtF32(pos.X, pos.Y+.5*(bounds.Dy()-font.Height())), fontName, fore, c.Text)
+	}
+}

ui/examples/01_basic/basic.go

@@ -55,6 +55,12 @@ func run() error {
 					ctx.Quit()
 				})
 			}), 8),
+			ui.BuildStackPanel(ui.OrientationHorizontal, func(p *ui.StackPanel) {
+				p.Children = []ui.Control{
+					&ui.Checkbox{},
+					ui.BuildCheckbox("Check me!", nil),
+				}
+			}),
 			ui.Stretch(&ui.Label{Text: "Content"}),
 			ui.StretchWidth(ui.BuildTextBox(func(b *ui.TextBox) {
 				b.Text = "Type here..."

ui/icon.go

@@ -0,0 +1,52 @@
+package ui
+
+import (
+	"image"
+	"image/color"
+
+	"opslag.de/schobers/geom"
+)
+
+type IconPixelTestFn func(geom.PointF32) bool
+
+func IconSize() geom.Point {
+	return geom.Pt(448, 512)
+}
+
+func CreateIcon(ctx Context, test IconPixelTestFn) Image {
+	icon := DrawIcon(test)
+	im, err := ctx.Renderer().CreateImage(icon)
+	if err != nil {
+		return nil
+	}
+	return im
+}
+
+func DrawIcon(test IconPixelTestFn) image.Image {
+	size := IconSize()
+	r := image.Rect(0, 0, size.X, size.Y)
+	icon := image.NewRGBA(r)
+	for y := 0; y < size.Y; y++ {
+		for x := 0; x < size.X; x++ {
+			pt := geom.PtF32(float32(x), float32(y))
+			if test(pt) {
+				icon.Set(x, y, color.White)
+			}
+		}
+	}
+	return icon
+}
+
+func GetOrCreateIcon(ctx Context, name string, testFactory func() IconPixelTestFn) Image {
+	im := ctx.Images().Image(name)
+	if im != nil {
+		return im
+	}
+	test := testFactory()
+	im = CreateIcon(ctx, test)
+	if im == nil {
+		return nil
+	}
+	ctx.Images().AddImage(name, im)
+	return im
+}