Re: How to compute font size ?

Hi Chris,

Le 03/01/2019 à 06:43, 'Chris Barker' via wxPython-dev a écrit :
> On Tue, Jan 1, 2019 at 9:53 AM Nicolas Pinault <[email protected] 
> <mailto:[email protected]>> wrote:
>
>     GetFullTextExtent() is usefull but not enought.
>
>
> indeed -- there are complications that make it hard to do properly:
>
> Fonts do not, necessarily, scale directly with font size. So text in a 
> 20 pt font is not exactly twice as big as text in a 10 pt font. But 
> it's pretty close.
>
> I'm not sure I quite understand your use case, but I'd be tempted to 
> get the font size close by assuming "typical" text -- and then use the 
> actual text extent to center it.
In my function, a text (parameter of the function) is displayed centered 
in a window.  The text width is one third of the window width. The 
problem is to compute the font size to make the text the correct width.
I tried to compute the font size without success.
Using a font of size 10  then scaling it works.

Nicolas
>
> A little less precise, but easier.
>
> -CHB
>
>
>
>
>
>     I tried several methods. I ended with the following code :
>
>         def _set_overlay(self, win, text, colour=(192, 192, 192)):
>             dc = wx.ClientDC(win)
>             odc = wx.DCOverlay(self.overlay, dc)
>             odc.Clear()
>             ctx = wx.GraphicsContext.Create(dc)
>             ctx_size = ctx.GetSize()                            # Get
>     window size
>             col = wx.Colour(*colour, 128)                       # Add
>     alpha to colour
>             brush = ctx.CreateBrush(wx.Brush(wx.Colour((0,0,0,128))))
>     # Create background brush with alpha
>             fnt = wx.Font(wx.FontInfo(10).FaceName("Arial"))    #
>     Create font with size 10
>             font = ctx.CreateFont(fnt, col=col)                 #
>     Create graphics font
>     ctx.SetFont(font)                                   # Use graphics
>     font
>             txt_size = ctx.GetFullTextExtent(text)              # Get
>     text size
>             scale = (ctx_size[0] / 3) / txt_size[0]             #
>     Compute scale (text is third the width of the window)
>     fnt.Scale(scale)                                    # Scale font
>             font = ctx.CreateFont(fnt, col=col)                 #
>     Create new graphics font
>     ctx.SetFont(font)                                   # Use new
>     graphicsfont
>             txt_size = ctx.GetFullTextExtent(text)              # Get
>     new text size
>             ctx.DrawText(text, (ctx_size[0]-txt_size[0])/2,
>     (ctx_size[1]-txt_size[1])/2, brush)   # Draw text (centered)
>             del odc
>
>     So : Create a font of size 10, determine the text width with this
>     font size, scale the font, and draw with the scaled font.
>
>     Nicolas
>
>
>>
>>
>>     On Fri, Dec 28, 2018 at 2:40 PM Nicolas Pinault <[email protected]
>>     <mailto:[email protected]>> wrote:
>>
>>         Hi,
>>
>>         In my app, I have a window(a panel) where I write some text
>>         as an overlay :
>>
>>              def _set_overlay(self, win, text, colour=(192, 192, 192)):
>>                  dc = wx.ClientDC(win)
>>                  odc = wx.DCOverlay(self.overlay, dc)
>>                  odc.Clear()
>>                  ctx = wx.GraphicsContext.Create(dc)
>>                  col = wx.Colour(*colour, 128)
>>                  brush =
>>         ctx.CreateBrush(wx.Brush(wx.Colour((0,0,0,128))))
>>                  font = ctx.CreateFont(10, "ARIAL",
>>         flags=wx.FONTFLAG_DEFAULT,
>>         col=col)
>>                  ctx.SetFont(font)
>>                  ctx.DrawText(text, 10, 10, brush)
>>                  del odc
>>
>>         For now, the font size is fixed. I'd like to compute the font
>>         size to
>>         make the text half the width of the window.
>>         What is the best way to compute the font size ?
>>
>>         Regards,
>>         Nicolas
>>
>>         -- 
>>         You received this message because you are subscribed to the
>>         Google Groups "wxPython-dev" group.
>>         To unsubscribe from this group and stop receiving emails from
>>         it, send an email to
>>         [email protected]
>>         <mailto:wxPython-dev%[email protected]>.
>>         For more options, visit https://groups.google.com/d/optout.
>>
>>
>>
>>     -- 
>>
>>     Christopher Barker, Ph.D.
>>     Oceanographer
>>
>>     Emergency Response Division
>>     NOAA/NOS/OR&R            (206) 526-6959   voice
>>     7600 Sand Point Way NE   (206) 526-6329   fax
>>     Seattle, WA  98115       (206) 526-6317   main reception
>>
>>     [email protected] <mailto:[email protected]>
>>     -- 
>>     You received this message because you are subscribed to the
>>     Google Groups "wxPython-dev" group.
>>     To unsubscribe from this group and stop receiving emails from it,
>>     send an email to [email protected]
>>     <mailto:[email protected]>.
>>     For more options, visit https://groups.google.com/d/optout.
>
>     -- 
>     You received this message because you are subscribed to the Google
>     Groups "wxPython-dev" group.
>     To unsubscribe from this group and stop receiving emails from it,
>     send an email to [email protected]
>     <mailto:[email protected]>.
>     For more options, visit https://groups.google.com/d/optout.
>
>
>
> -- 
>
> Christopher Barker, Ph.D.
> Oceanographer
>
> Emergency Response Division
> NOAA/NOS/OR&R            (206) 526-6959   voice
> 7600 Sand Point Way NE   (206) 526-6329   fax
> Seattle, WA  98115       (206) 526-6317   main reception
>
> [email protected] <mailto:[email protected]>
> -- 
> You received this message because you are subscribed to the Google 
> Groups "wxPython-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send 
> an email to [email protected] 
> <mailto:[email protected]>.
> For more options, visit https://groups.google.com/d/optout.

-- 
You received this message because you are subscribed to the Google Groups "wxPython-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
For more options, visit https://groups.google.com/d/optout.