firemonkey - Delphi FMX TAnimator. How to animate a TPointF -

i have tscrollbox on form. placed onto scrollbox tlayout wider , taller device viewport horiz , vert scrollbars show , user can manually move layout.

i have gesture setup user can longpress scrollbox , layout origin (0,0).

procedure tfrmmain.scrollbox1gesture(sender: tobject;   const eventinfo: tgestureeventinfo; var handled: boolean); begin   if eventinfo.gestureid = system.uitypes.igilongtap   begin      scrollbox1.viewportposition := pointf(0, 0);      scrollbox1.realigncontent;   end; 

now works great, happens rather quickly. thought perhaps use:

tanimator.animatefloat(scrollbox1, 'scrollbox1.viewportposition.x', 0, 0.3); 

to make movement current position 0 bit more gentle, of course, that's never going work because can't assign value pointf.x or pointf.y directly (and therefore neither can animator).

so how can done? thanks

as built-in pointanimation missing, here self written one.

type   tpointanimation = class(tcustompropertyanimation)   private     fstartfloat: tpointf;     fstartfromcurrent: boolean;     fstopfloat: tpointf;   protected     procedure firstframe; override;     procedure processanimation; override;   public     constructor create(aowner: tcomponent); override;   published     property animationtype default tanimationtype.in;     property autoreverse default false;     property delay;     property duration nodefault;     property enabled default false;     property interpolation default tinterpolationtype.linear;     property inverse default false;     property loop default false;     property onfinish;     property onprocess;     property propertyname;     property startfromcurrent: boolean read fstartfromcurrent write         fstartfromcurrent default false;     property startvalue: tpointf read fstartfloat write fstartfloat stored true;     property stopvalue: tpointf read fstopfloat write fstopfloat stored true;     property trigger;     property triggerinverse;   end;  constructor tpointanimation.create(aowner: tcomponent); begin   inherited;   duration := 0.2;   fstartfloat := pointf(0, 0);   fstopfloat := pointf(0, 0); end;  procedure tpointanimation.firstframe; var   t: trttitype;   p: trttiproperty; begin   if startfromcurrent   begin     t := sharedcontext.gettype(finstance.classinfo);     if t <> nil     begin       p := t.getproperty(fpath);       if (p <> nil) , (p.propertytype.typekind = tkrecord)         startvalue := p.getvalue(finstance).astype<tpointf>;     end;   end; end;  procedure tpointanimation.processanimation; var   newpoint: tpointf;   t: trttitype;   p: trttiproperty; begin   if finstance <> nil   begin     t := sharedcontext.gettype(finstance.classinfo);     if t <> nil     begin       p := t.getproperty(fpath);       if (p <> nil) , (p.propertytype.typekind = tkrecord) begin         newpoint := pointf(interpolatesingle(fstartfloat.x, fstopfloat.x, normalizedtime),                            interpolatesingle(fstartfloat.y, fstopfloat.y, normalizedtime));         p.setvalue(finstance, tvalue.from<tpointf>(newpoint));       end;     end;   end; end; 

declare field inside forms private section

ani: tpointanimation; 

create instance during formcreate

ani := tpointanimation.create(self); ani.propertyname := 'viewportposition'; ani.startfromcurrent := true; ani.duration := 0.3; scrollbox1.addobject(ani); 

and start when needed

ani.start;