I am implementing plsmema as discussed, but after installing all QT5 dev
libs, plplot is not showing the memqt option to plot, which means I am
missing something. Do I have to compile from source enabling memqt perhaps
? Is there any post around that I can refer to ?
Thanks !
On Thu, Sep 5, 2019 at 8:15 PM Xavier Cardil <cardil.xav...@gmail.com>
wrote:
> That's great, thanks for the example Hazen ! I'll be implementing this in
> the following days
>
> On Thu, Sep 5, 2019 at 5:52 PM Hazen Babcock <hbabc...@mac.com> wrote:
>
>> On 9/5/19 6:16 AM, Xavier Cardil wrote:
>> > Thank you for your responses.
>> > It took me a day to realize that this might be actually the best
>> > solution, as plotting to memory will be way faster than writing to disk.
>> > As long as we can plot to memory via plsmema( ) and then retrieve it,
>> > it should be possible to convert the plot to a Numpy array ?
>> > Keras takes images as arrays as per our requirement. In matplotlib this
>> > is done behind the covers with Pillow + Numpy if I'm not wrong.
>> > Pillow can store images as arrays in memory, so it's similar to what
>> > plsmema( ) does. I mentioned RGBA encoded string instead of Numpy array
>> > because I believe Pillow stores images in memory as RGBA strings, and I
>> > was trying to find a replacement for the whole procedure ( matplotlib is
>> > terribly slow )
>> >
>> > It would be great to hear more comments from you about this, thanks !
>> >
>>
>> Here is an example (using the "memqt" driver, but "memcairo" should also
>> work).
>>
>> #!/usr/bin/env python3
>>
>> from PIL import Image
>>
>> import numpy
>> import plplot
>>
>> width = 480
>> height = 320
>> plot_buffer = numpy.zeros((height, width, 4), numpy.uint8)
>>
>> plplot.plsmema(width, height, plot_buffer)
>>
>> plplot.plstart("memqt", 1, 1)
>> plplot.plenv(0, 360, 0, 90, 0, 2)
>> plplot.plend1()
>>
>> plot_image = Image.frombytes("RGBA", (width, height), plot_buffer)
>> plot_image.save("image.png")
>>
>>
>> The final plot is available in the plot_buffer numpy array object, or in
>> the plot_image PIL/Pillow Image object.
>>
>> -Hazen
>>
>
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