path_edit.py

path_edit.py

'''
useless path editor.

tap to add a point.  tap again to add a control point.  
then, another control point, and finally another point on the curve.
existing points and control points can be dragged around, to change the curve.  

clicking save button saves an image of the path, without the handles.


'''
import ui
LINE_COLOR=(0,0,0,1)
PT_COLOR=(1,0,0,0.5)
CP_COLOR=(0,0,1,0.5)
ACTIVE_COLOR=(1,0,1,0.5)

class path_editor(ui.View):
    def __init__(self):
        self.pts=[]
        self.touch_enabled=True
        self.idx_active=None
        
    def touch_began(self,touch):
        # first, find nearby point
        xt,yt=touch.location
        self.idx_active=None
        for i,(x,y) in enumerate( self.pts):
            #simple hit check.. will find last point within 10 pix
            if (xt-x)**2+(yt-y)**2 < 20**2:
                self.idx_active=i
        if self.idx_active is None:
            self.pts.append(touch.location)
            self.idx_active=len(self.pts)-1
        self.set_needs_display()
        
    def touch_moved(self,touch):
        self.pts[self.idx_active]=touch.location
        self.set_needs_display()
        
    def touch_ended(self,touch):
        #pass
        self.idx_active=None
        self.set_needs_display()
        
    def _draw(self,show_handles=False ):
        # draw spline, optionally with handles shown
        P=ui.Path()
        if not self.pts:
            return
        #handles
        if show_handles:
            cp=0
            for i,(x,y) in enumerate(self.pts):
                if cp:
                    ui.set_color(ACTIVE_COLOR if self.idx_active==i else CP_COLOR)
                    ui.Path.oval(x-10,y-10,20,20).fill()
                else:
                    ui.set_color(PT_COLOR)
                    ui.Path.rect(x-10,y-10,20,20).stroke()
                    if self.idx_active==i:
                        ui.Path.rect(x-10,y-10,20,20).fill()
                cp=(cp+1)%3
            #draw tangent lines connecting points to handles
            i=0
            P2=ui.Path()
            ui.set_color((.5,.5,.5,.2))
            while (i+1)<len(self.pts):
                P2.move_to(*self.pts[i])
                P2.line_to(*self.pts[i+1])
                i=i+3
            i=2
            while (i+1)<len(self.pts):
                P2.move_to(*self.pts[i])
                P2.line_to(*self.pts[i+1])
                i=i+3
            P2.stroke()
        #draw curve
        P.move_to(*self.pts[0])
        i=1
        while (i+2)<len(self.pts):
            ui.set_color(LINE_COLOR)
            P.add_curve(*(self.pts[i+2]+self.pts[i]+self.pts[i+1]))
            i=i+3
        P.stroke()
        
    def draw(self):
        #called by ui system to redraw view
        self._draw(True )

    def save_img(self,sender):
        #save curve.png, and show in console.
        import StringIO, ImageFile
        
        with ui.ImageContext(self.width,self.height) as ctx:
            self._draw(False )
            img=ctx.get_image()
            img.show()
            parser=ImageFile.Parser()
            parser.feed(img.to_png())
            pil_image=parser.close()
            pil_image.save('curve.png')
    
v=path_editor()
b=ui.Button(title='save',bg_color=(.9,.9,.9))
b.frame=(0,0,50,50)
b.action=v.save_img
v.add_subview(b)
v.bg_color=(1,1,1)
v.present('sheet')