Develop Reference

How to change the orientation of a psychopy RatingScale on the window?

I am using PsychoPy for an experiment in which participants rate some stimuli. I use visual.RatingScale. Automatically, it is placed horizontally on the screen. Does a function for changing the orientation of the rating scale exist? (I would like the rating scale to be in the vertical position) :)

Looking at the documentation (https://www.psychopy.org/api/visual/ratingscale.html, 4th paragraph) this is not possible with the actual rating scale. But from the psychopy forums it looks like there might be some user created options that could work for you if you are comfortable using the coder, and a vertical scale is crucial for your build (https://discourse.psychopy.org/t/vertical-rating-scale/1461/2). I haven't looked into this too closely but hopefully it might help

Bokeh shows plot blurred on windows

I am using bokeh for plotting. With my current settings, bokeh shows some text and lines kind of blurred (anti-aliased?). This is not really noticeable on my monitor, but on some projectors, especially when doing screenshots and inserting them into presentations, it looks weird.
As requested, a minimum working example:
from bokeh.plotting import figure, show
p = figure(plot_width=1000, plot_height=600,
title="TestTitle", x_axis_label = "Length [cm]", y_axis_label="Height [m]")
p.xaxis.axis_label_text_font_style = "normal"
p.xaxis.axis_label_text_font_size = "12pt"
show(p)
I am using Windows 7 and tried this in the current versions of Chrome and IE. Python 3.6, bokeh version 0.13.0. The first image is taken from the example, the second is taken from my real code:
I tried different figure sizes, but the problem persists - maybe I am trying the wrong ones? Anything I can do about this, except simply trying different sizes until something "works"? Setting px instead of pts seems to make it worse...

Regarding the text, it is rendered on to a raster HTML canvas, and the details of how this is done are entirely dependent on the browser canvas implementation. (FWIW things look better on any browser on OSX than the above image.) There's not anything we can to change how a specific browser renders text, and not much I can suggest except to make much bigger canvas sizes if you need to show something extremely magnified.
Regarding the aliasing of the axes and tick marks, I can't reproduce anything like that on any OSX browser (Safari, FF, or Chrome). It definitely appears to be a Windows-specific issue. It's possible there are issues that could be addressed, e.g a different HiDPI setting, or half-pixel offsets, but it would take investigation to try and determine what can be done. A Github issue with details would be appropriate, but I can't speculate when it might be addressed (we are under-resourced and no core contributors are regular windows users).

WxPython zooming technique

I am developing a wxpython project where I am drawing a diagram on to a panel that I need to be able to zoom in/out to this diagram(a directed acyclic graph in my case). I will achieve this by mouse scroll when the cursor is on the panel, however that is not a part of my question. I need an advice from an experienced person about the method I am using for zooming. So far I thought as doing,
There are lines, rectangles and texts inside rectangles within this diagram. So maybe I could increase/decrease their length/size with the chosen mouse event. But it is hard to keep it balanced because rectangles are connected with lines their angles should not change, and texts inside the rectanges should stay in the middle of them.
Other method I thought of doing is to search for a built-in zoom method. Which I heard about something like Scale. However I have some questions about this method. Will this work on vector drawings(like mine) rather than images. And will it be scaling only the panel I chose and not the whole screen ? After I hear your advice about this, I will look deeper into this, but now I am a bit clueless.
Sorry if my question is too theoretical. But I felt I needed help in the area. Thanks in advance.
Note: Zooming not necessarily applied by scrolling.
Note2: My research also led me to FloatCanvas. Is this suitable to my needs ?

Yes, from your description FloatCanvas would certainly meet your needs.
Another possibility to consider would be the wx.GraphicsContext and related classes. It is vector-based (instead of raster) and supports the use of a transformation matrix which would make zooming, rotating, etc. very easy. However, the actual drawing and management of the shapes and such would probably require more work for you than using FloatCanvas.

python matplotlib blit to axes or sides of the figure?

I'm trying to refresh some plots that I have within a gui everytime I go once through a fitting procedure. Also, these plots are within a framw which can be resized, so the axes and labels etc need to be redrawn after the resizing. So was wondering if anyone knew how to update the sides of a figure using something like plot.figure.canvas.copy_from_bbox and blit. This appears to only copy and blit the background of the graphing area (where the lines are being drawn) and not to the sides of the graph or figure (where the labels and ticks are). I have been trying to get my graphs to update by trial and error and reading mpl documentation, but so far my code has jst become horrendously complex with things like self.this_plot.canvas_of_plot..etc.etc.. .plot.figure.canvas.copy_from_bbox... which is probably far too convoluted.
I know that my language might be a little off but I've been trying to read through the matplotlb documentation and the differences between Figure, canvas, graph, plot, figure.Figure, etc. are starting to evade me. So my first and foremost question would be:
1 - How do you update the ticks and labels around a matplotlib plot.
and secondly, since I would like to have a better grasp on what the answer to this question,
2 - What is the difference between a plot, figure, canvas, etc. in regards to the area which they cover in the GUI.
Thank you very much for the help.

All this can certainly be rather confusing at first!
To begin with, if you're chaining the ticks, etc, there isn't much point in using blitting. Blitting is just a way to avoid re-drawing everything if only some things are changing. If everything is changing, there's no point in using blitting. Just re-draw the plot.
Basically, you just want fig.canvas.draw() or plt.draw()
At any rate, to answer your first question, in most cases you won't need to update them manually. If you change the axis limits, they'll update themselves. You're running into problems because you're blitting just the inside of the axes instead of redrawing the plot.
As for your second question, a good, detailed overview is the Artist Tutorial of the Matplotlib User's Guide.
In a nutshell, there are two separate layers. One deals with grouping things into the parts that you'll worry about when plotting (e.g. the figure, axes, axis, lines, etc) and another that deals with rendering and drawing in general (the canvas and renderer).
Anything you can see in a matplotlib plot is an Artist. (E.g. text, a line, the axes, and even the figure itself.) An artist a) knows how to draw itself, and b) can contain other artists.
For an artist to draw itself, it uses the renderer (a backend-specific module that you'll almost never touch directly) to draw on a FigureCanvas a.k.a. "canvas" (an abstraction around either a vector-based page or a pixel buffer). To draw everything in a figure, you call canvas.draw().
Because artists can be groups of other artists, there's a hierarchy to things. Basically, something like this (obviously, this varies):
Figure
Axes (0-many) (An axes is basically a plot)
Axis (usually two) (x-axis and y-axis)
ticks
ticklabels
axis label
background patch
title, if present
anything you've plotted, e.g. Line2D's
Hopefully that makes things a touch clearer, anyway.
If you really do want to use blitting to update the tick labels, etc, you'll need to grab and restore the full region including them. This region is a bit tricky to get, because it isn't exactly known until after draw-time (rendering text in matplotlib is more complicated than rendering other things due to latex support, etc). You can do it, and I'll be glad to give an example if it's really what you want, but it's typically not going to yield a speed advantage over just drawing everything. (The exception is if you're only updating one subplot in a figure with lots of subplots.)

What is the most performant way to implement zoom to a cairo-drawn canvas?

I have a wx.ScrolledWindow where is drawn on using cairo. I have implemented a zoom-functionality which right now redraws the whole content.
But as there will be up to 200 curves to draw I should consider a more performant solution.
I have thought of these:
Buffering images for the zoom factors -1/+1 (Memory consuming)
Using librsvg and buffer an SVG image (I have read something about this. Does librsvg work under Windows too?)
Storing the cairo.Context after drawing groups of curves, and on zoom restoring it (just an idea.. is that possible?)
Are there other possibilities, and: what is the best solution?
Thanks a lot

Not really a concrete answer to your question, but I was faced with the same problem and just switched to matplotlib where a zoom and pan function is already implemented. I am not sure though if it is super performant. I have the feeling my program was running more smoothly before.
I also tried out floatcanvas and floatcanvas2 but was not really happy with both of them.

If you're double-buffering anyway, why not do a quick bitmap scale as a "preview" while waiting for the newly redrawn vector image? I confess I don't know how to do this. But if you can make it work, it should work! :)