Function fitVariableWidth

Lib/pagebot/fonttoolbox/variablefontbuilder.py:62–153

Answers the font instance that makes string s width on the given width *w* for the given *fontSize*. The *condensedLocation* dictionary defines the most condensed font instance (optionally including the opsz) and the *wideLocation* dictionary defines the most wide font instance (optiona

(context, varFont, s, w, fontSize, condensedLocation,
        wideLocation, fixedSize=True, tracking=None, cached=True, lazy=True)

    return varFont, varFont

def fitVariableWidth(context, varFont, s, w, fontSize, condensedLocation,
        wideLocation, fixedSize=True, tracking=None, cached=True, lazy=True):
    """Answers the font instance that makes string s width on the given width
    *w* for the given *fontSize*.  The *condensedLocation* dictionary defines
    the most condensed font instance (optionally including the opsz) and the
    *wideLocation* dictionary defines the most wide font instance (optionally
    including the opsz).  The string width for s is calculated with both
    locations and then the [wdth] value is interpolated and iterated until the
    location is found where the string *s* fits width *w*). Note that
    interpolation may not be enough, as the width axis may contain non-linear
    masters.

    If the requested w outside of what is possible with two locations, then
    interations are performed to change the size. Again this cannot be done by
    simple interpolation, as the [opsz] also changes the width.  It one of the
    axes does not exist in the font, then use the default setting of the font.
    """
    # TODO: Adjusting by size change (if requested width is not possible with
    # the width limits of the font)
    # TODO: is not yet implemented.

    # Get the instances for the extreme width locations. This allows the
    # calling function to define the actual range of the [wdth] axis to be
    # user, instead of the default minValue and maxValue. E.g. for a range of
    # widths in a headline, the typographer may only want a small change before
    # the line is wrapping, instead using the full spectrum to extreme
    # condensed.
    condensedFont = getVarFontInstance(varFont, condensedLocation, cached=cached, lazy=lazy)
    wideFont = getVarFontInstance(varFont, wideLocation, cached=cached, lazy=lazy)
    # Calculate the widths of the string using these two instances.
    condensedString = context.newString(s,
                                    style=dict(font=condensedFont.path,
                                               fontSize=fontSize,
                                               tracking=tracking,
                                               textFill=blackColor))
    wideString = context.newString(s,
                               style=dict(font=wideFont.path,
                                          fontSize=fontSize,
                                          tracking=tracking,
                                          textFill=blackColor))

    # Calculate the widths of the strings.
    # TODO: Handle if these lines would wrap on the given width. In that case
    # we may want to set the wrapped first line back to it's uncondensed value,
    # to make the first wrapped line fit the width.
    condensedWidth, _ = context.textSize(condensedString)
    wideWidth, _ = context.textSize(wideString)

    # Check if the requested with is inside the boundaries of the font width axis
    # Requested width is smaller than was was possible using the extreme value
    # of [wdth] axis.
    if w < condensedWidth:
        font = condensedFont
        bs = condensedString
        location = condensedLocation
    elif w > wideWidth:
        # Requested width is larger than was was possible using the extreme
        # value of [wdth] axis.