Howto:Creating a Font Browser using Nasal and Canvas

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Revision as of 07:06, 24 February 2020 by Hooray (Talk | contribs) (Approach)

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No easy way to browse a list of available fonts in the base package


Implement a simple font browser using Nasal and Canvas


since FlightGear uses OpenSceneGraph, and since OSG supports TXF file, we might be able use Nasal/Canvas to display a list of fonts and even preview them inside fgfs by simply rendering them as a raster image.

To see for yourself, modify the Canvas image example to point to a font file:

If this works, this can be trivially extended to show a list of all fonts including a preview, by adapting this snippet: Canvas_Snippets#Canvas_ScrollArea

Alternatively, it would be possible to render the menubar completely using the Canvas system: Howto:Making_a_Canvas_Menubar

Proof of Concept

var (width,height) = (320,160);
var title = 'Font Browser (by downpilot)';

# create a new window, dimensions are WIDTH x HEIGHT, using the dialog decoration (i.e. titlebar)
var window =[width,height],"dialog")

# adding a canvas to the new window and setting up background colors/transparency
var myCanvas = window.createCanvas().set("background","bg_color"));

# Using specific css colors would also be possible:
# myCanvas.set("background", "#ffaac0");

# creating the top-level/root group which will contain all other elements/group
var root = myCanvas.createGroup();

# path is relative to $FG_ROOT (base package)
var path = "Fonts/Helvetica.png";
# create an image child for the texture
var child = root.createChild("image")
    .setTranslation(100, 10)
    .setSize(130, 130);