Support mouse click (#68)

Author: magicoder10

graphics/window.go

@@ -1,6 +1,7 @@
 package graphics
 
 import (
+	"image"
 	"time"
 
 	"candy/input"
@@ -130,9 +131,11 @@ func (e EbitenWindow) pollEvents() []input.Input {
 		})
 	}
 	if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
+		x, y := ebiten.CursorPosition()
 		inputs = append(inputs, input.Input{
-			Action: input.SinglePress,
-			Device: input.MouseLeftButton,
+			Action:         input.SinglePress,
+			Device:         input.MouseLeftButton,
+			CursorPosition: image.Point{X: x, Y: y},
 		})
 	}
 	return inputs

input/input.go

@@ -2,11 +2,13 @@ package input
 
 import (
 	"fmt"
+	"image"
 )
 
 type Input struct {
-	Action action
-	Device device
+	Action         action
+	Device         device
+	CursorPosition image.Point
 }
 
 func (in Input) String() string {

ui/box.go

@@ -8,6 +8,10 @@ import (
 	"candy/ui/ptr"
 )
 
+type BoxProps struct {
+	OnClick onClickHandler
+}
+
 var _ Component = (*Box)(nil)
 
 type Box struct {
@@ -65,7 +69,10 @@ func (b Box) ComputeLeafSize(_ Constraints) Size {
 	return Size{width: width, height: height}
 }
 
-func NewBox(children []Component, style *Style) *Box {
+func NewBox(pros *BoxProps, children []Component, style *Style) *Box {
+	if pros == nil {
+		pros = &BoxProps{}
+	}
 	if style == nil {
 		style = &Style{
 			LayoutType: (*LayoutType)(ptr.Int(int(BoxLayoutType))),
@@ -79,10 +86,12 @@ func NewBox(children []Component, style *Style) *Box {
 	}
 	return &Box{
 		SharedComponent: SharedComponent{
+			name:           "Box",
 			layout:         newLayout(*style.LayoutType),
 			style:          *style,
 			children:       children,
 			childrenOffset: []Offset{},
+			events:         Events{onClick: pros.OnClick},
 		}}
 }
 

ui/button.go

@@ -7,7 +7,8 @@ import (
 )
 
 type ButtonProps struct {
-	Text *string
+	Text    *string
+	OnClick onClickHandler
 }
 
 func (b ButtonProps) getText() string {
@@ -24,11 +25,7 @@ type Button struct {
 	SharedComponent
 }
 
-func (b Button) GetName() string {
-	return "Button"
-}
-
-func (b Button) Paint(painter *Painter, destLayer draw.Image, offset Offset) {
+func (b *Button) Paint(painter *Painter, destLayer draw.Image, offset Offset) {
 	b.children[0].Paint(painter, destLayer, offset)
 }
 
@@ -62,11 +59,17 @@ func NewButton(props *ButtonProps, style *Style) *Button {
 	}
 	return &Button{
 		SharedComponent: SharedComponent{
+			name:   "Button",
 			layout: newLayout(InlineLayoutType),
 			children: []Component{
-				NewBox([]Component{
-					NewText(&TextProps{Text: props.getText()}, style),
-				}, style),
+				NewBox(
+					&BoxProps{
+						OnClick: props.OnClick,
+					}, []Component{
+						NewText(&TextProps{Text: props.getText()}, style),
+					},
+					style,
+				),
 			},
 			childrenOffset: make([]Offset, 0),
 		},

ui/component.go

@@ -1,6 +1,7 @@
 package ui
 
 import (
+	"image"
 	"image/draw"
 	"time"
 
@@ -10,6 +11,7 @@ import (
 type Component interface {
 	GetName() string
 	HandleInput(in input.Input)
+	handleInput(in input.Input, offset Offset)
 	Update(timeElapsed time.Duration)
 	getLayout() layout
 	getChildren() []Component
@@ -34,15 +36,42 @@ type Offset struct {
 }
 
 type SharedComponent struct {
+	name           string
 	layout         layout
 	style          Style
 	size           Size
 	childrenOffset []Offset
 	children       []Component
+	events         Events
 }
 
-func (s SharedComponent) HandleInput(_ input.Input) {
-	return
+func (s *SharedComponent) HandleInput(in input.Input) {
+	s.handleInput(in, Offset{
+		x: 0,
+		y: 0,
+		z: 0,
+	})
+}
+
+func (s *SharedComponent) handleInput(in input.Input, offset Offset) {
+	for index, child := range s.children {
+		child.handleInput(in, s.childrenOffset[index])
+	}
+
+	switch in.Action {
+	case input.SinglePress:
+		switch in.Device {
+		case input.MouseLeftButton:
+			rect := s.BoundingBox(offset)
+			if in.CursorPosition.In(rect) {
+				s.events.tryOnClick()
+			}
+		}
+	}
+}
+
+func (s *SharedComponent) BoundingBox(offset Offset) image.Rectangle {
+	return image.Rect(offset.x, offset.y, offset.x+s.size.width, offset.y+s.size.height)
 }
 
 func (s SharedComponent) Update(timeElapsed time.Duration) {
@@ -51,6 +80,10 @@ func (s SharedComponent) Update(timeElapsed time.Duration) {
 	}
 }
 
+func (s SharedComponent) GetName() string {
+	return s.name
+}
+
 func (s SharedComponent) getChildren() []Component {
 	return s.children
 }

ui/event.go

@@ -0,0 +1,14 @@
+package ui
+
+type onClickHandler func()
+
+type Events struct {
+	onClick onClickHandler
+}
+
+func (e *Events) tryOnClick() {
+	if e.onClick == nil {
+		return
+	}
+	e.onClick()
+}

ui/example/app.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"fmt"
+
 	"candy/assets"
 	"candy/ui"
 	"candy/ui/ptr"
@@ -13,12 +15,21 @@ type app struct {
 }
 
 func newApp(assets *assets.Assets) *app {
-	return &app{ui.NewBox([]ui.Component{
-		ui.NewButton(
-			&ui.ButtonProps{Text: ptr.String("Click")},
-			nil,
-		),
-		ui.NewText(&ui.TextProps{Text: `
+	return &app{ui.NewBox(
+		&ui.BoxProps{OnClick: func() {
+			fmt.Println("Box clicked")
+		}},
+		[]ui.Component{
+			ui.NewButton(
+				&ui.ButtonProps{
+					Text: ptr.String("Click"),
+					OnClick: func() {
+						fmt.Println("Button clicked")
+					},
+				},
+				nil,
+			),
+			ui.NewText(&ui.TextProps{Text: `
 I guess we could discuss the implications of the phrase "meant to be."
 That is if we wanted to drown ourselves in a sea of backwardly referential 
 semantics and other mumbo-jumbo. Maybe such a discussion would result in the 
@@ -27,20 +38,20 @@ seems to be, and that none of us is actually meant to be doing anything at all.
 But that's my existential underpants underpinnings showing. It's the way the 
 cookie crumbles. And now I want a cookie.
 `}, &ui.Style{FontStyle: ui.FontStyle{
-			Family:     ptr.String("Source Code Pro"),
-			Weight:     ptr.String("ExtraLight"),
-			Italic:     ptr.Bool(false),
-			Size:       ptr.Int(20),
-			LineHeight: ptr.Int(24),
-			Color: &ui.Color{
-				Red:   255,
-				Green: 255,
-				Blue:  255,
-				Alpha: 255,
-			}}}),
-		ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image3.png"}, nil),
-		ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image1.jpg"}, nil),
-		ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image2.jpg"}, nil),
-	},
+				Family:     ptr.String("Source Code Pro"),
+				Weight:     ptr.String("ExtraLight"),
+				Italic:     ptr.Bool(false),
+				Size:       ptr.Int(20),
+				LineHeight: ptr.Int(24),
+				Color: &ui.Color{
+					Red:   255,
+					Green: 255,
+					Blue:  255,
+					Alpha: 255,
+				}}}),
+			ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image3.png"}, nil),
+			ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image1.jpg"}, nil),
+			ui.NewImage(assets, &ui.ImageProps{ImagePath: "test/image2.jpg"}, nil),
+		},
 		nil)}
 }

ui/image.go

@@ -20,10 +20,6 @@ type Image struct {
 	image  image.Image
 }
 
-func (i *Image) GetName() string {
-	return "Image"
-}
-
 func (i *Image) Paint(painter *Painter, destLayer draw.Image, offset Offset) {
 	if i.image == nil {
 		return
@@ -79,6 +75,7 @@ func NewImage(assets *assets.Assets, props *ImageProps, style *Style) *Image {
 		assets: assets,
 		image:  img,
 		SharedComponent: SharedComponent{
+			name:  "Image",
 			style: *style,
 		},
 	}

ui/text.go

@@ -31,10 +31,6 @@ type Text struct {
 	shouldUpdate bool
 }
 
-func (t *Text) GetName() string {
-	return "Text"
-}
-
 func (t *Text) ComputeLeafSize(constraints Constraints) Size {
 	if len(t.props.Text) == 0 || t.fontFace == nil {
 		return Size{width: 0, height: 0}
@@ -169,6 +165,7 @@ func NewText(props *TextProps, style *Style) *Text {
 	return &Text{
 		shouldUpdate: true,
 		SharedComponent: SharedComponent{
+			name:  "Text",
 			style: *style,
 		},
 		props: *props,