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SetFScaleDisable

SetFScaleDisable Enable/disable scaling of displayed characters

#include <Fonts.h> Font Manager

void SetFScaleDisable(dontScale );

Boolean dontScale ; TRUE=disable scaling; FALSE= enable

SetFScaleDisable provides a way to draw characters at an unavailable size

without having them scaled.

dontScale is a Boolean flag specifying whether to enable or disable off-size

character scaling. It is one of:

FALSE Enables scaling (the normal status)

TRUE Disables scaling. When a font size does not exist, a larger

or smaller size font is drawn, but the space between

characters is expanded or condensed to simulate the

spacing of a scaled font.

Returns: none

Notes: When a nonexistent font size is used for drawing text, a

smaller or larger font is normally scaled to match the specified size. For

instance, the following shows two examples of 14-pt Chicago:

In the first example, the normal scaling is performed. Before the second

line was drawn, SetFScaleDisable(TRUE) was called to disable scaling.

Note that the width of the two examples is the same, but the characters of the

second are actually drawn in 12-pt, with additional spacing. Even so, the

widths are only the same because fractional widths were enabled, the font

doesn't have a font character-width table and is a member of a family

record with a family character-width table. Without all of that, there

would be no guarantee that the two examples would be equally wide.

When the nearest actual size happens to be larger rather than smaller (as

in the example above), then the characters are drawn compressed together,

even overlapping. Even so, it may be more pleasing to the eye:

SetFScaleDisable is not supported by the 64K ROM, but ASM and C

programmers have gotten the same affect by changing the byte-length global

variable FScaleDisable (at 0x0A63). We are now warned to NOT change

this variable, but to always use SetFScaleDisable. We can still examine

this address to read the current status (non-zero=scaling is disabled,

0= enabled).

There is no certainty that requesting a doubled point size or a scale factor

of 2 will get you characters with doubled widths. What you get will depend

on how QuickDraw measures and spaces the characters--especially

algorithmically-derived characters like boldface where the character

strike is one pixel wider regardless of point size. For fonts with a family

character-width table, there is no problem since character spacing is

accurately described from the table.

Condensing and expanding are more commonly performed by calling the

TextFace function with the condense or extend bit set. A technique used in

justifying lines of text is to use SpaceExtra to widen the spaces between

words.

SpaceExtra or CharExtra can also be called to make two different font

requests measure the same, or proportionaly. Normally, SpaceExtra is

adequate if you pass it the difference of the two measures (divided by the

number of spaces on the line). Use CharExtra if there aren't enough

spaces on the line or if the difference between the two measures is either

too great or too little.

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