Re: Should Canvas have been Image subclass instead of Node?
I understand that Canvas has to remain a node - but I think the basic problem could be fixed in a very backward compatible way: > A future release could simply add a "CanvasImage" class which had a > GraphicsContext - then Canvas could remain, but simply embed a CanvasImage. > Though for practical purposes, I think most developers would simply use > CanvasImage with ImageView from then on. jeff On Apr 23, 2014, at 2:15 PM, Stephen F Northover wrote: > I think a graphics context on a writable image would make more sense. In any > case, Canvas is a Node and will remain one forever. > > Steve > > On 2014-04-22 6:15 PM, Jeff Martin wrote: >> I have a case where I need to draw to a canvas and reuse it in multiple >> nodes. My non-optimal work-around is to take a snapshot and use that, but it >> makes me wonder if Canvas should have been an Image subclass or if >> WritableImage should get it's own getGraphicsContext() method. >> >> jeff >
Re: Should Canvas have been Image subclass instead of Node?
I think a graphics context on a writable image would make more sense. In any case, Canvas is a Node and will remain one forever. Steve On 2014-04-22 6:15 PM, Jeff Martin wrote: I have a case where I need to draw to a canvas and reuse it in multiple nodes. My non-optimal work-around is to take a snapshot and use that, but it makes me wonder if Canvas should have been an Image subclass or if WritableImage should get it's own getGraphicsContext() method. jeff
Re: Should Canvas have been Image subclass instead of Node?
That's a nice solution - though in real world code I worry that the endDrawing
snapshotting would be triggered more often than necessary.
I still think there is no compelling reason for Canvas to be a Node, and there
is a significant drawback if you want to reuse the same Canvas many times in
your scene graph.
I think it's appropriate to think of the basic Canvas functionality as a
"Procedural Image" - it is used to create an Image from code instead of a file.
Just because the most common case might be to stuff it in an ImageView, doesn't
mean that it should be a Node for convenience. If you agree that the Image
class shouldn't be a Node, you should feel the same way about Canvas.
I also think this would be easy to fix in a backward compatible way. A future
release could simply add a "CanvasImage" class which had a GraphicsContext -
then Canvas could remain, but simply embed a CanvasImage. Though for practical
purposes, I think most developers would simply use CanvasImage with ImageView
from then on.
jeff
On Apr 23, 2014, at 10:37 AM, Scott Palmer wrote:
> Here's a quick hack based on using snapshots to make something like a
> Canvas that you can reuse in many places within the Scene. By
> subclassing WritableImage it comes out to being pretty close to what
> you were talking about. As you mentioned, using snapshots isn't
> ideal, but I wonder how far from ideal this really is? Having to
> remember to make the snapshot is just one call.
>
> public class CanvasImage extends WritableImage {
>
> private final Canvas canvas;
> private final SnapshotParameters snapshotParams;
>
> public CanvasImage(int width, int height) {
> super(width, height);
> canvas = new Canvas(width, height);
> snapshotParams = new SnapshotParameters();
> snapshotParams.setFill(Color.TRANSPARENT);
> }
>
> public GraphicsContext beginDrawing() {
> return canvas.getGraphicsContext2D();
> }
>
> public void endDrawing() {
> canvas.snapshot(snapshotParams, this);
> }
> }
>
> Cheers,
>
> Scott
>
> On Tue, Apr 22, 2014 at 7:01 PM, Scott Palmer wrote:
>> It would be great if you could get a Graphics context for drawing into a
>> WritableImage instead of having to deal with snapshots. But I suppose you
>> could build something like that based on Canvas that would update an image.
>>
>> Scott
>>
>> On Apr 22, 2014 6:52 PM, "Jeff Martin" wrote:
>>>
>>> Just by using it as an ImageView.Image.
>>>
>>> jeff
>>>
>>>
>>> On Apr 22, 2014, at 5:43 PM, John C. Turnbull
>>> wrote:
>>>
How would you (easily) use it in the scenegraph if it wasn't a Node?
-Original Message-
From: openjfx-dev [mailto:openjfx-dev-boun...@openjdk.java.net] On
Behalf Of
Jeff Martin
Sent: Wednesday, April 23, 2014 8:16 AM
To: openjfx-dev@openjdk.java.net Mailing
Subject: Should Canvas have been Image subclass instead of Node?
I have a case where I need to draw to a canvas and reuse it in multiple
nodes. My non-optimal work-around is to take a snapshot and use that,
but it
makes me wonder if Canvas should have been an Image subclass or if
WritableImage should get it's own getGraphicsContext() method.
jeff=
>>>
>>
Re: Should Canvas have been Image subclass instead of Node?
Here's a quick hack based on using snapshots to make something like a
Canvas that you can reuse in many places within the Scene. By
subclassing WritableImage it comes out to being pretty close to what
you were talking about. As you mentioned, using snapshots isn't
ideal, but I wonder how far from ideal this really is? Having to
remember to make the snapshot is just one call.
public class CanvasImage extends WritableImage {
private final Canvas canvas;
private final SnapshotParameters snapshotParams;
public CanvasImage(int width, int height) {
super(width, height);
canvas = new Canvas(width, height);
snapshotParams = new SnapshotParameters();
snapshotParams.setFill(Color.TRANSPARENT);
}
public GraphicsContext beginDrawing() {
return canvas.getGraphicsContext2D();
}
public void endDrawing() {
canvas.snapshot(snapshotParams, this);
}
}
Cheers,
Scott
On Tue, Apr 22, 2014 at 7:01 PM, Scott Palmer wrote:
> It would be great if you could get a Graphics context for drawing into a
> WritableImage instead of having to deal with snapshots. But I suppose you
> could build something like that based on Canvas that would update an image.
>
> Scott
>
> On Apr 22, 2014 6:52 PM, "Jeff Martin" wrote:
>>
>> Just by using it as an ImageView.Image.
>>
>> jeff
>>
>>
>> On Apr 22, 2014, at 5:43 PM, John C. Turnbull
>> wrote:
>>
>> > How would you (easily) use it in the scenegraph if it wasn't a Node?
>> >
>> > -Original Message-
>> > From: openjfx-dev [mailto:openjfx-dev-boun...@openjdk.java.net] On
>> > Behalf Of
>> > Jeff Martin
>> > Sent: Wednesday, April 23, 2014 8:16 AM
>> > To: openjfx-dev@openjdk.java.net Mailing
>> > Subject: Should Canvas have been Image subclass instead of Node?
>> >
>> > I have a case where I need to draw to a canvas and reuse it in multiple
>> > nodes. My non-optimal work-around is to take a snapshot and use that,
>> > but it
>> > makes me wonder if Canvas should have been an Image subclass or if
>> > WritableImage should get it's own getGraphicsContext() method.
>> >
>> > jeff=
>> >
>>
>
Re: Should Canvas have been Image subclass instead of Node?
It would be great if you could get a Graphics context for drawing into a WritableImage instead of having to deal with snapshots. But I suppose you could build something like that based on Canvas that would update an image. Scott On Apr 22, 2014 6:52 PM, "Jeff Martin" wrote: > Just by using it as an ImageView.Image. > > jeff > > > On Apr 22, 2014, at 5:43 PM, John C. Turnbull > wrote: > > > How would you (easily) use it in the scenegraph if it wasn't a Node? > > > > -Original Message- > > From: openjfx-dev [mailto:openjfx-dev-boun...@openjdk.java.net] On > Behalf Of > > Jeff Martin > > Sent: Wednesday, April 23, 2014 8:16 AM > > To: openjfx-dev@openjdk.java.net Mailing > > Subject: Should Canvas have been Image subclass instead of Node? > > > > I have a case where I need to draw to a canvas and reuse it in multiple > > nodes. My non-optimal work-around is to take a snapshot and use that, > but it > > makes me wonder if Canvas should have been an Image subclass or if > > WritableImage should get it's own getGraphicsContext() method. > > > > jeff= > > > >
Re: Should Canvas have been Image subclass instead of Node?
Just by using it as an ImageView.Image. jeff On Apr 22, 2014, at 5:43 PM, John C. Turnbull wrote: > How would you (easily) use it in the scenegraph if it wasn't a Node? > > -Original Message- > From: openjfx-dev [mailto:openjfx-dev-boun...@openjdk.java.net] On Behalf Of > Jeff Martin > Sent: Wednesday, April 23, 2014 8:16 AM > To: openjfx-dev@openjdk.java.net Mailing > Subject: Should Canvas have been Image subclass instead of Node? > > I have a case where I need to draw to a canvas and reuse it in multiple > nodes. My non-optimal work-around is to take a snapshot and use that, but it > makes me wonder if Canvas should have been an Image subclass or if > WritableImage should get it's own getGraphicsContext() method. > > jeff= >
RE: Should Canvas have been Image subclass instead of Node?
How would you (easily) use it in the scenegraph if it wasn't a Node? -Original Message- From: openjfx-dev [mailto:openjfx-dev-boun...@openjdk.java.net] On Behalf Of Jeff Martin Sent: Wednesday, April 23, 2014 8:16 AM To: openjfx-dev@openjdk.java.net Mailing Subject: Should Canvas have been Image subclass instead of Node? I have a case where I need to draw to a canvas and reuse it in multiple nodes. My non-optimal work-around is to take a snapshot and use that, but it makes me wonder if Canvas should have been an Image subclass or if WritableImage should get it's own getGraphicsContext() method. jeff=
