Re: [Matplotlib-users] matplotlib 3D: interpolated shading
Ben, I would be very happy to have this functionality. I think this would also make the 3D plots in the examples that matplot provides look a good deal nicer. Let me know if you have any updates on this. -Holger On Mon, Oct 3, 2011 at 21:18, Benjamin Root ben.r...@ou.edu wrote: On Fri, Sep 30, 2011 at 11:33 AM, Holger Brandsmeier holger.brandsme...@sam.math.ethz.ch wrote: Ben, On Fri, Sep 30, 2011 at 17:06, Benjamin Root ben.r...@ou.edu wrote: What values for rstride and cstride are you using? By default, plot_surface() will sample every 10th point of the data array (for performance reasons). Also, color interpoltion can be turned on by setting shade to True. I beleive I start to understand the underlying logic. If no color map is set and shading and antialiazing is set, then indeed the surface is nicely and smoothly displayed. When I provide a color map, then I seem to be able to assign one color for the whole polygon. I also find something like that in the code. In my case I want the z-coordinate to determine the color. I want to use a colormap like jet and no transparency. If I don't use the colormap argument, then I get shading, however everything is blue with shading depending on a lightsource.I don't really need a lightsource, but I would like non-constant colors per polygon. Yes, you have the logic correct (and probably better explained than I could have done). This actually was an issue raised a couple of months ago in a bit of a different context, but the solution wasn't entirely clear at that point. However, looking at the code again (remember, I didn't write it originally, and it had next to no comments), I think I see a fairly simple solution. If I allow for the user to specify a light source of None, then I could feed the data through a different function to shade the surface. I will look into doing that, but it won't make it into the v1.1.0 release (slated for tomorrow). Cheers! Ben Root -- Holger Brandsmeier, SAM, ETH Zürich http://www.sam.math.ethz.ch/people/bholger -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] matplotlib 3D: interpolated shading
Holger, for what it is worth, you can hack this fairly easily. Run the code twice once with colors, once with shading. Take the output from both as images, the convert both images to HSV, the recombine the HS components from the color version with the V component of the shaded version. I haven't done this in matplotlib, but it worked great for me in IDL. On Oct 5, 2011, at 1:23 PM, Holger Brandsmeier holger.brandsme...@sam.math.ethz.ch wrote: Ben, I would be very happy to have this functionality. I think this would also make the 3D plots in the examples that matplot provides look a good deal nicer. Let me know if you have any updates on this. -Holger On Mon, Oct 3, 2011 at 21:18, Benjamin Root ben.r...@ou.edu wrote: On Fri, Sep 30, 2011 at 11:33 AM, Holger Brandsmeier holger.brandsme...@sam.math.ethz.ch wrote: Ben, On Fri, Sep 30, 2011 at 17:06, Benjamin Root ben.r...@ou.edu wrote: What values for rstride and cstride are you using? By default, plot_surface() will sample every 10th point of the data array (for performance reasons). Also, color interpoltion can be turned on by setting shade to True. I beleive I start to understand the underlying logic. If no color map is set and shading and antialiazing is set, then indeed the surface is nicely and smoothly displayed. When I provide a color map, then I seem to be able to assign one color for the whole polygon. I also find something like that in the code. In my case I want the z-coordinate to determine the color. I want to use a colormap like jet and no transparency. If I don't use the colormap argument, then I get shading, however everything is blue with shading depending on a lightsource.I don't really need a lightsource, but I would like non-constant colors per polygon. Yes, you have the logic correct (and probably better explained than I could have done). This actually was an issue raised a couple of months ago in a bit of a different context, but the solution wasn't entirely clear at that point. However, looking at the code again (remember, I didn't write it originally, and it had next to no comments), I think I see a fairly simple solution. If I allow for the user to specify a light source of None, then I could feed the data through a different function to shade the surface. I will look into doing that, but it won't make it into the v1.1.0 release (slated for tomorrow). Cheers! Ben Root -- Holger Brandsmeier, SAM, ETH Zürich http://www.sam.math.ethz.ch/people/bholger -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
[Matplotlib-users] Alpha channel in imshow, bug or gamma correction?
Dear Lists,
I tried to draw a white block with alpha-channel gradient on top of black.
The result appears to be non-linear, and I think it is problematic.
image = ones((255, 255, 4), dtype='u1')
image[:, :, 0:3] = 255
image[:, :, 3] = arange(0, 255)[:, newaxis]
gca().set_axis_bgcolor('k')
imshow(image)
The color of the pixel with alpha = 128 is about (30, 30, 30).
We can confirm this with
cla()
image[:, :, 3] = 128
imshow(image)
On Inkscape, a white block with alpha = 128 on top of a black box gives a
final color of r,g,b=128, 128, 128.
I did a rough fit and apparently matplotlib is calculating the final pixel
brightness with (notice the original pixel is 0)
r = cr * (alpha / 255.) ** 3 , (same for g and b)
shouldn't it be r = cr * alpha / 255?
This affects matplotlib-1.0.1 and a not so recent copy of the git
master(ba4043a35d4c2).
Regards,
Yu
--
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threats, fraudulent activity and more. Splunk takes this data and makes
sense of it. Business sense. IT sense. Common sense.
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[Matplotlib-users] 3D bar chart help!
Hello List Server, I am trying to take a raster dataset, getting the center points, and the z value and trying to graph it in a 3D bar chart quite unsuccessfully. My data looks like this: XCoord = [1,2,3,4] YCoord = [1,2,3,4] ZCoord = [12,14,4,26] Those are the known locations, but there will be lots of more points when using actual data that forms a continuous surface over a small area. How do I create a 3D bar chart to represent the Z Value at each of those locations? I saw in the help that you need to create a mesh grid, but I don't understand how to do that. The help documents are vague on what the X,Y,Z values formats are as well. -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] rotating x tick labels, bold labels with axislines toolkit???
On Wed, Oct 5, 2011 at 11:50 AM, mdekauwe mdeka...@gmail.com wrote: Still haven't worked out the bold but I am sure there will be something on that page Try ax.axis[bottom].label.set_text(Test) ax.axis[bottom].label.set_weight(bold) IHTH, -JJ -- All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
