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Displaying pictures using Athens

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Christopher Coat

Displaying pictures using Athens

Hi everybody,

I’m currently creating a small app to display images and move them on a screen using Athens.
I have all my image loaded on start and I use a loop to clear the screen and redraw all the elements (on different place and angle) every frames.

The problem is that with morph, everything is fine, but as soon as I place a picture on a morph the FPS drop down. Even if the picture is a small one.

Does anybody have faced the same issue ? Or is there any better way to do it ?

Thanks
Chris

Nicolai Hess

Re: Displaying pictures using Athens

2015-05-19 10:46 GMT+02:00 Christopher Coat <[hidden email]>:

Hi everybody,

Hi,

I’m currently creating a small app to display images and move them on a screen using Athens.
I have all my image loaded on start and I use a loop to clear the screen and redraw all the elements (on different place and angle) every frames.

The problem is that with morph, everything is fine, but as soon as I place a picture on a morph the FPS drop down. Even if the picture is a small one.

How do you draw the picture? Is it an ImageMorph or do you use directly Athens for drawing the image?

nicolai

Does anybody have faced the same issue ? Or is there any better way to do it ?

Thanks
Chris

Christopher Coat

Re: Displaying pictures using Athens

I’m still a beginner at Pharo and all so maybe I’ll say something wrong.

One thing I didn’t say is that I use osWindow.

I load an image as a Form and display it using that code :

"surface drawDuring:[:canvas |

canvas pathTransform translateBy: myImage position.

canvas pathTransform rotateByDegrees: anAngle.

canvas

setPaint: myImage image.

canvas drawShape: ((size x) negated @ (size y) negated corner: size).

myImage image. return the Form.

Le 19 mai 2015 à 11:41, Nicolai Hess <[hidden email]> a écrit :

2015-05-19 10:46 GMT+02:00 Christopher Coat <[hidden email]>:
Hi everybody,

Hi,

I’m currently creating a small app to display images and move them on a screen using Athens.
I have all my image loaded on start and I use a loop to clear the screen and redraw all the elements (on different place and angle) every frames.

The problem is that with morph, everything is fine, but as soon as I place a picture on a morph the FPS drop down. Even if the picture is a small one.

How do you draw the picture? Is it an ImageMorph or do you use directly Athens for drawing the image?

nicolai

Does anybody have faced the same issue ? Or is there any better way to do it ?

Thanks
Chris

Nicolai Hess

Re: Displaying pictures using Athens

2015-05-19 13:09 GMT+02:00 Christopher Coat <[hidden email]>:

I’m still a beginner at Pharo and all so maybe I’ll say something wrong.

One thing I didn’t say is that I use osWindow.
I load an image as a Form and display it using that code :

"surface drawDuring:[:canvas |
canvas pathTransform translateBy: myImage position.
canvas pathTransform rotateByDegrees: anAngle.
canvas
setPaint: myImage image.
canvas drawShape: ((size x) negated @ (size y) negated corner: size).
].
«

myImage image. return the Form.

Ok, in your drawing loop

Athens will convert the form to an AthensPaint by copying the image data - on every draw call.

You can

- create the paint once outside of the drawDuring method.

paint := surface createFormPaint: myImage image
....

"in drawDuring"

canvas setPaint:paint
....

(You will have to take care of the paint object, because it is only valid in this vm session).

- use an ImageMorph. ImageMorphs can be drawn directly as an AthensShape

morph := form asMorph

....

canvas drawShape:morph

But I don't know if using a Morph fits well with all kind of transformations. It may happen that

the morph is clipped away - I dont know for sure.

You can create the morph outside of the drawing loop, but even

canvas drawShape: myImage image asMorph

is faster than creating directly the paint from the Form in the loop.

(ImageMorphs are creating AthensPaints from its forms and they are using a cache for all paints).

nicolai

Le 19 mai 2015 à 11:41, Nicolai Hess <[hidden email]> a écrit :

2015-05-19 10:46 GMT+02:00 Christopher Coat <[hidden email]>:
Hi everybody,

Hi,

I’m currently creating a small app to display images and move them on a screen using Athens.
I have all my image loaded on start and I use a loop to clear the screen and redraw all the elements (on different place and angle) every frames.

The problem is that with morph, everything is fine, but as soon as I place a picture on a morph the FPS drop down. Even if the picture is a small one.

How do you draw the picture? Is it an ImageMorph or do you use directly Athens for drawing the image?

nicolai

Does anybody have faced the same issue ? Or is there any better way to do it ?

Thanks
Chris