[open] Easiest way to change font-size in inline scrip items

Daniel

I'm looking for a way to increase the font size in an inline script item in combination with the canvas.text() function.
I found the function canvas.set_font(style,size), but this expects you to provide a font as the first argument, while I only want to change the size. Also, it says it expects 3 arguments, while in the OpenSesame documentation only 2 are described

What would be the best way to change the font size in an inline script, without having to change anything else?

Edwin

Hi Daniel!

The standard font is (as you probably know) 'mono'. So you could just use the following:

my_canvas.set_font('mono', size) # change size to any integer you'd like

Otherwise, but this is a solution that's pretty much the same amount of trouble as the first option, add an inline_script to the main experiment sequence containing the following (Prepare phase):

global fontsize, fonttype

fonttype = 'mono' # or any preferred other type, like 'sans' or 'serif'

def fontsize(my_canvas,size):
    from openexp.canvas import canvas
    global fonttype
    my_canvas.set_font(fonttype,size)
    return my_canvas

ALTERNATIVE:

self.experiment.set("fonttype", 'mono')

Next, in inline scripts, do the following:

from openexp.canvas import canvas

global fontsize

# create canvas
my_canvas = canvas(self.experiment)

# to change fontsize
fontsize(my_canvas, size) # change size to any integer you'd like

ALTERNATIVE:

from openexp.canvas import canvas

# create canvas
my_canvas = canvas(self.experiment)

# to change fontsize
my_canvas.set_font(self.get("fonttype"), size)

Is the first option really to much of a hassle, you recon? I do think you have a point, so I would vote for a feature request (say, splitting up canvas.set_font(type,size) to canvas.set_fonttype(type) and canvas.set_fontsize(size))

Best,

Edwin

EDIT: Might prove to be difficult, since the fonttype is set using pygame.font.Font (see http://www.pygame.org/docs/ref/font.html#pygame.font.Font) in the legacy backend.

from openexp/_canvas/legacy.py (lines 271 to 283):

    def set_font(self, style, size):
    
        """
        Sets the font for subsequent drawing operations.
        
        Arguments:
        style -- A font located in the resources folder (without the .ttf
                 extension)
        size -- A font size in pixels       
        """
        
        self.font = pygame.font.Font(self.experiment.resource( \
            "%s.ttf" % style), size)

You could just change this to (or add) the following in your OpenSesame source files:

    def set_fontsize(self, size):
    
        """
        Sets the font size  for subsequent drawing operations.
        
        Arguments:
        size -- A font size in pixels       
        """
        
        style = 'mono' # or preferred style
        
        self.font = pygame.font.Font(self.experiment.resource( \
            "%s.ttf" % style), size)

Then you could use

canvas.set_fontsize(size)

sebastiaan

Hi Daniel and Edwin,

Yes, I'm afraid only more-or-less hackish solutions are possible at the moment. Perhaps it would be a good idea to change the arguments of canvas.set_font() to keywords, so that you can change only one property, while leaving the rest unchanged. The API has already changed a bit, to allow for (bold, italic, and underlined)[http://osdoc.cogsci.nl/usage/text-formatting] fonts as well.

Perhaps something like:

def set_font(self, style=None, size=None, italic=None, bold=None, underline=None):
    # Function body

This is backwards-compatible with the previous non-keyword API, but also allows you to do things like:

canvas.set_font(style='sans')
canvas.set_font(italic=True)

Regarding the mysterious 3rd argument: Python also counts the self parameter for methods, which is a bit confusing.

Cheers!
Sebastiaan

Daniel

Hi Sebastiaan and Edwin,

thanks for your replies. I didn't know the default font was mono and tried 'Arial', which it couldn't find as a ttf in the resource folder. I tried 'Mono' as well I think, but specified it with a capital M in the beginning, which OpenSesame didn't take.

About the 'self' argument: whoops, I could have known that, although OS gave the error message "only 1 of 3 arguments is specified" when i tried canvas.set_font(size=12). Since 'self' is passed through automatically, shouldn't it have said "only 2 of 3 arguments are specified" in this case?

Nevertheless, canvas.set_font('mono',50) did the trick for me and works.

sebastiaan

About the 'self' argument: whoops, I could have known that, although OS gave the error message "only 1 of 3 arguments is specified" when i tried canvas.set_font(size=12). Since 'self' is passed through automatically, shouldn't it have said "only 2 of 3 arguments are specified" in this case?

Right, that's because you're passing size as a keyword, rather than a fixed argument. If you pass the size as a non-keyword, Python indeed reports 2 arguments:

from openexp.canvas import canvas
c = canvas(exp)
c.set_font(12)

Error:

raceback (most recent call last):
  File "/home/sebastiaan/git/opensesame/libopensesame/inline_script.py", line 121, in run
    exec(self.crun)
  File "", line 4, in 
TypeError: set_font() takes at least 3 arguments (2 given)

Cheers!