Animation with Timers

Hello,

I’ve searched through the examples for an animation example and found balloons.lisp. I’ve come up with the following code:

(defpackage :typing

(:use :cl :capi))

(in-package :typing)

(defparameter *typing-timer* nil)

(defun typing-display-callback (pane &optional x y w h)

(unless *typing-timer*

(setf *typing-timer* (mp:make-timer #'typing-display-callback pane)))

(with-atomic-redisplay (pane)

(gp:clear-graphics-port pane)

(gp:draw-string pane "testing" (random 800) (random 450)))

(mp:schedule-timer-relative *typing-timer* (/ 1 30)))

(defun typing ()

(let ((pane (make-instance 'output-pane

:display-callback 'typing-display-callback

:background :white

:initial-constraints

'(:visible-min-width 800 :visible-min-height 450)

:title "Typing - the game")))

(contain pane)))

I am expecting from this code the work “testing” jumping around the screen, but what I get is (usually) just a single frame and no further graphics updates, like something needs to be synched or flipped. I know the timer is running, because if I put in a (format t “.”) I see a stream of dots in the output buffer. I have searched for ways to swap or flush the buffer to screen (redisplay-all-screens) on Cocoa, as the documentation states that it is a buffered display to no avail.

Sometimes I do see what I expect, but only if I put another window obscuring part of the main window.

Any tips on how I can get animation output using CAPI?

Burton Samograd

Re: Animation with Timers

BusFactor1 wrote on Fri, 30 Dec 2016 18:06:28 -0800 (PST) 05:06:

| I've searched through the examples for an animation example and found
| balloons.lisp.  I've come up with the following code:
| ...snip...|
| (defun typing-display-callback (pane &optional x y w h)
|   (unless *typing-timer*
|     (setf *typing-timer* (mp:make-timer #'typing-display-callback pane)))
|     ...

You should invoke the typing-display-callback in the process of the pane.
For example:

  (setf *typing-timer* (mp:make-timer #'capi:apply-in-pane-process
                                 pane #'typing-display-callback
                                 (list pane))))
--
Sincerely,
Dmitry Ivanov
lisp.ystok.ru

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Re: Animation with Timers

Hi,

You've forgot to call gp:invalidate-rectangle to force display callback
to be called.

Have a look at attached slightly modified code, which works.