Merge pull request #292 from JiepengTan/builder#570_sprite_pivot

#builder#570 sprite pivot

config.go

@@ -22,6 +22,7 @@ import (
 	"syscall"
 
 	spxfs "github.com/goplus/spx/fs"
+	"github.com/goplus/spx/internal/math32"
 )
 
 func resourceDir(resource interface{}) (fs spxfs.Dir, err error) {
@@ -233,6 +234,7 @@ type spriteConfig struct {
 	TAnimations         map[string]*aniConfig `json:"tAnimations"`
 	Visible             bool                  `json:"visible"`
 	IsDraggable         bool                  `json:"isDraggable"`
+	Pivot               math32.Vector2        `json:"pivot"`
 }
 
 func (p *spriteConfig) getCostumeIndex() int {

internal/math32/vector2.go

@@ -6,8 +6,8 @@ import (
 )
 
 type Vector2 struct {
-	X float64
-	Y float64
+	X float64 `json:"x"`
+	Y float64 `json:"y"`
 }
 
 func NewVector2(x, y float64) *Vector2 {

spgdi.go

@@ -134,6 +134,8 @@ func (p *spriteDrawInfo) updateMatrix() {
 	c := p.sprite.costumes[p.sprite.costumeIndex_]
 
 	img, centerX, centerY := c.needImage(p.sprite.g.fs)
+	centerX += p.sprite.pivot.X
+	centerY -= p.sprite.pivot.Y
 	rect := image.Rectangle{}
 	rect.Min.X = 0
 	rect.Min.Y = 0

sprite.go

@@ -61,6 +61,7 @@ type Sprite struct {
 	direction     float64
 	rotationStyle RotationStyle
 	rRect         *math32.RotatedRect
+	pivot         math32.Vector2
 
 	sayObj        *sayOrThinker
 	quoteObj      *quoter
@@ -109,8 +110,8 @@ func (p *Sprite) init(
 	p.scale = sprite.Size
 	p.direction = sprite.Heading
 	p.rotationStyle = toRotationStyle(sprite.RotationStyle)
-
 	p.isVisible = sprite.Visible
+	p.pivot = sprite.Pivot
 
 	p.animations = make(map[string]*aniConfig)