plplot-devel

[Plplot-devel] RGBA background images

[Alan W. I. <ir...@be...>]

On 2016-02-06 10:09-0000 Phil Rosenberg wrote:

> Hi Greg

> Sorry I haven't replied earlier. Jim may have to confirm this. But
it sounds like what you are aiming to do isn't really supported by
Plplot. Basically it sounds like you are trying to add your own
graphics commands (i.e. Draw the background) part way through a
replot. Although that can work for direct drawing there is currently
no way to intercept the drawing part way through. That said i think
that for drivers where the user has access to the "canvas" this
possibly should be supported. I also think that adding some form of
drawing an rgb image would be good too. Alan do you think these are
things we should consider adding to the API?

Hi Phil:

If you are talking about the goal of having potentially different RGBA
images for each different page's background, then I really like that
long-term goal because you can get some really cool effects that way.
But I am concerned about the speed since it currently takes us an
extremely long time to display even a low-resolution image for example
20. So I encourage you to think about the image display speed issue.
For example, I presume many of our device drivers (e.g., cairo, qt,
and wxwidgets) potentially could display an image using the
(presumably fast) capabilities of the underlying pango/cairo, Qt[45],
and wxwidgets libraries.  So I think one potential way forward is to
implement that "native" image rendering capability in each of those
device drivers (and others as well whose underlying library has the
native capability).  Then plimage lets the driver render the image if
the driver advertises it has the capability, and otherwise falls back
to the extremely slow current method of displaying images.

Meanwhile, I have thought of a closely related topic concerning the
"A" in "RGBA" which I would like to discuss which is how to improve
our current methods of handling uniformly coloured semitransparent
backgrounds. But I will present my thoughts on that topic in a
separate thread so as not to hijack this one.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
__________________________

Re: [Plplot-devel] RGBA background images

[Phil R. <p.d...@gm...>]

Hi Alan
Yes, but not just as background images, as plot images too. For example I have in the past used plplot to overplot wind vectors from a weather model on satellite views of the earth. So I would want an API call where I set the world coordinates of the top left and bottom right corners of the image and plplot draws it cropped to the viewport. A similar API call for rendering to the subpage and the page would be good.

There are transparency issues that I will add to the other thread, because they only occur if the background it transparent.

Phil

-----Original Message-----
From: "Alan W. Irwin" <ir...@be...>
Sent: ‎06/‎02/‎2016 21:28
To: "Phil Rosenberg" <p.d...@gm...>
Cc: "Greg Jung" <gv...@gm...>; "Jim Dishaw" <ji...@di...>; "plp...@li..." <plp...@li...>
Subject: RGBA background images

On 2016-02-06 10:09-0000 Phil Rosenberg wrote:

> Hi Greg

> Sorry I haven't replied earlier. Jim may have to confirm this. But
it sounds like what you are aiming to do isn't really supported by
Plplot. Basically it sounds like you are trying to add your own
graphics commands (i.e. Draw the background) part way through a
replot. Although that can work for direct drawing there is currently
no way to intercept the drawing part way through. That said i think
that for drivers where the user has access to the "canvas" this
possibly should be supported. I also think that adding some form of
drawing an rgb image would be good too. Alan do you think these are
things we should consider adding to the API?

Hi Phil:

If you are talking about the goal of having potentially different RGBA
images for each different page's background, then I really like that
long-term goal because you can get some really cool effects that way.
But I am concerned about the speed since it currently takes us an
extremely long time to display even a low-resolution image for example
20. So I encourage you to think about the image display speed issue.
For example, I presume many of our device drivers (e.g., cairo, qt,
and wxwidgets) potentially could display an image using the
(presumably fast) capabilities of the underlying pango/cairo, Qt[45],
and wxwidgets libraries.  So I think one potential way forward is to
implement that "native" image rendering capability in each of those
device drivers (and others as well whose underlying library has the
native capability).  Then plimage lets the driver render the image if
the driver advertises it has the capability, and otherwise falls back
to the extremely slow current method of displaying images.

Meanwhile, I have thought of a closely related topic concerning the
"A" in "RGBA" which I would like to discuss which is how to improve
our current methods of handling uniformly coloured semitransparent
backgrounds. But I will present my thoughts on that topic in a
separate thread so as not to hijack this one.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
__________________________

Re: [Plplot-devel] RGBA background images

[Douglas H. <dh...@uc...>]

Hi all:  I achieve something like this, IE plotting on top of the image 
of a map, with perl/PDL and the plplot MEM driver.
I first use a PDL plotting routine to create an RGB memory image to pass 
to the MEM driver.

I'm not sure if this is exactly what you want, but it might help.

--Doug

On 2/6/16 2:28 PM, Alan W. Irwin wrote:
> On 2016-02-06 10:09-0000 Phil Rosenberg wrote:
>
>> Hi Greg
>> Sorry I haven't replied earlier. Jim may have to confirm this. But
> it sounds like what you are aiming to do isn't really supported by
> Plplot. Basically it sounds like you are trying to add your own
> graphics commands (i.e. Draw the background) part way through a
> replot. Although that can work for direct drawing there is currently
> no way to intercept the drawing part way through. That said i think
> that for drivers where the user has access to the "canvas" this
> possibly should be supported. I also think that adding some form of
> drawing an rgb image would be good too. Alan do you think these are
> things we should consider adding to the API?
>
> Hi Phil:
>
> If you are talking about the goal of having potentially different RGBA
> images for each different page's background, then I really like that
> long-term goal because you can get some really cool effects that way.
> But I am concerned about the speed since it currently takes us an
> extremely long time to display even a low-resolution image for example
> 20. So I encourage you to think about the image display speed issue.
> For example, I presume many of our device drivers (e.g., cairo, qt,
> and wxwidgets) potentially could display an image using the
> (presumably fast) capabilities of the underlying pango/cairo, Qt[45],
> and wxwidgets libraries.  So I think one potential way forward is to
> implement that "native" image rendering capability in each of those
> device drivers (and others as well whose underlying library has the
> native capability).  Then plimage lets the driver render the image if
> the driver advertises it has the capability, and otherwise falls back
> to the extremely slow current method of displaying images.
>
> Meanwhile, I have thought of a closely related topic concerning the
> "A" in "RGBA" which I would like to discuss which is how to improve
> our current methods of handling uniformly coloured semitransparent
> backgrounds. But I will present my thoughts on that topic in a
> separate thread so as not to hijack this one.
>
> Alan
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state
> implementation for stellar interiors (freeeos.sf.net); the Time
> Ephemerides project (timeephem.sf.net); PLplot scientific plotting
> software package (plplot.sf.net); the libLASi project
> (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
> and the Linux Brochure Project (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________
>
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