debugui: implement spin buttons for numbers

Closes #33

Author: hajimehoshi

button.go

@@ -17,32 +17,75 @@ func (c *Context) Button(text string) EventHandler {
 	pc := caller()
 	id := c.idFromCaller(pc)
 	return c.wrapEventHandlerAndError(func() (EventHandler, error) {
-		return c.button(text, iconNone, optionAlignCenter, id)
+		return c.button(text, optionAlignCenter, id)
 	})
 }
 
-func (c *Context) iconButton(icon icon) EventHandler {
+func (c *Context) button(text string, opt option, id widgetID) (EventHandler, error) {
+	return c.widget(id, opt, nil, func(bounds image.Rectangle, wasFocused bool) EventHandler {
+		var e EventHandler
+		if c.pointing.justPressed() && c.focus == id {
+			e = &eventHandler{}
+		}
+		return e
+	}, func(bounds image.Rectangle) {
+		c.drawWidgetFrame(id, bounds, colorButton, opt)
+		if len(text) > 0 {
+			c.drawWidgetText(text, bounds, colorText, opt)
+		}
+	})
+}
+
+func (c *Context) spinButtons() (up, down EventHandler) {
 	pc := caller()
 	id := c.idFromCaller(pc)
-	return c.wrapEventHandlerAndError(func() (EventHandler, error) {
-		return c.button("", icon, optionAlignCenter, id)
+	c.idScopeFromID(id, func() {
+		upID := c.idFromString("up")
+		downID := c.idFromString("down")
+		c.GridCell(func(bounds image.Rectangle) {
+			c.setGridLayout(nil, []int{-1, -1})
+			up = c.wrapEventHandlerAndError(func() (EventHandler, error) {
+				var e EventHandler
+				var err error
+				e, err = c.spinButton(true, optionAlignCenter, upID, downID)
+				if err != nil {
+					return nil, err
+				}
+				return e, nil
+			})
+			down = c.wrapEventHandlerAndError(func() (EventHandler, error) {
+				var e EventHandler
+				var err error
+				c.idScopeFromID(id, func() {
+					e, err = c.spinButton(false, optionAlignCenter, upID, downID)
+				})
+				if err != nil {
+					return nil, err
+				}
+				return e, nil
+			})
+		})
 	})
+	return up, down
 }
 
-func (c *Context) button(text string, icon icon, opt option, id widgetID) (EventHandler, error) {
+func (c *Context) spinButton(up bool, opt option, upID, downID widgetID) (EventHandler, error) {
+	id := downID
+	if up {
+		id = upID
+	}
 	return c.widget(id, opt, nil, func(bounds image.Rectangle, wasFocused bool) EventHandler {
 		var e EventHandler
-		if c.pointing.justPressed() && c.focus == id {
+		if c.pointing.repeated() && (c.focus == upID || c.focus == downID) && c.pointing.position().In(bounds) {
 			e = &eventHandler{}
 		}
 		return e
 	}, func(bounds image.Rectangle) {
 		c.drawWidgetFrame(id, bounds, colorButton, opt)
-		if len(text) > 0 {
-			c.drawWidgetText(text, bounds, colorText, opt)
-		}
-		if icon != iconNone {
-			c.drawIcon(icon, bounds, c.style().colors[colorText])
+		icon := iconDown
+		if up {
+			icon = iconUp
 		}
+		c.drawIcon(icon, bounds, c.style().colors[colorText])
 	})
 }

draw.go

@@ -47,8 +47,7 @@ func lineHeight() int {
 type icon int
 
 const (
-	iconNone icon = iota
-	iconCheck
+	iconCheck icon = iota + 1
 	iconCollapsed
 	iconExpanded
 	iconDown
@@ -63,10 +62,6 @@ var (
 )
 
 func iconImage(icon icon) *ebiten.Image {
-	if icon == iconNone {
-		return nil
-	}
-
 	iconM.Lock()
 	defer iconM.Unlock()
 

input.go

@@ -16,6 +16,7 @@ type pointing struct {
 	touchIDs            []ebiten.TouchID
 	hasPrimaryTouchID   bool
 	primaryTouchID      ebiten.TouchID
+	duration            int
 }
 
 func (p *pointing) update() {
@@ -29,6 +30,12 @@ func (p *pointing) update() {
 		p.hasPrimaryTouchID = true
 		p.primaryTouchID = p.touchIDs[0]
 	}
+
+	if p.pressed() {
+		p.duration++
+	} else {
+		p.duration = 0
+	}
 }
 
 func (p *pointing) isTouchActive() bool {
@@ -58,3 +65,14 @@ func (p *pointing) justPressed() bool {
 	}
 	return inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft)
 }
+
+func (p *pointing) repeated() bool {
+	if p.duration == 1 {
+		return true
+	}
+	delay := ebiten.TPS() * 24 / 60
+	if p.duration < delay {
+		return false
+	}
+	return (p.duration-delay)%4 == 0
+}

textfield.go

@@ -184,11 +184,12 @@ func (c *Context) numberField(value *int, step int, id widgetID, opt option) (Ev
 		c.GridCell(func(bounds image.Rectangle) {
 			c.idScopeFromID(id, func() {
 				c.SetGridLayout(nil, []int{-1, -1})
-				c.iconButton(iconUp).On(func() {
+				up, down := c.spinButtons()
+				up.On(func() {
 					*value += step
 					e = &eventHandler{}
 				})
-				c.iconButton(iconDown).On(func() {
+				down.On(func() {
 					*value -= step
 					e = &eventHandler{}
 				})
@@ -234,11 +235,12 @@ func (c *Context) numberFieldF(value *float64, step float64, digits int, id widg
 		c.GridCell(func(bounds image.Rectangle) {
 			c.idScopeFromID(id, func() {
 				c.SetGridLayout(nil, []int{-1, -1})
-				c.iconButton(iconUp).On(func() {
+				up, down := c.spinButtons()
+				up.On(func() {
 					*value += step
 					e = &eventHandler{}
 				})
-				c.iconButton(iconDown).On(func() {
+				down.On(func() {
 					*value -= step
 					e = &eventHandler{}
 				})