A basic class like Length should not depend on something from
frontend.
This change allows to remove several dummy implementations of
theFontMetrics().
Also output the right one depending on whether the unit is "mu" or
not. Indeed, the two macros are identical, except that \mkern only
accepts unit mu, and kern does not accept it.
With this patch, both macros accept all units, but on writing beck,
the right one is used.
* Fix spacing in lib/symbols after recent commits about math spacing, as well as
older spacing issues (e.g. \Join).
* InsetMathKern now uses the same em value as other math length commands.
What is nice is that the kerning amount now matches the ones found in the
packages definition (modulo 10mu that lyx currently adds between relations).
Testcase: $\CheckedBox\LEFTcircle\RIGHTcircle\photon\gluon\vcentcolon\dblcolon\Coloneqq\eqcolon\models\hookrightarrow\bowtie\hookleftarrow\Join\APLinv\neq$
The computation of length on screen depend in particular of the computation of the size of an em. Many places of the code used to rely on the width of the M character, which is not really correct:
http://en.wikipedia.org/wiki/Em_%28typography%29
In digital typography, the best value to use is the point size of the font.
* Implement FontMetrics::em(), which returns the value in pixels of the EM unit.
Convert code to use it.
* Introduce Length::inPixel(MetricsBase const &), which takes the textwidth and em information from the MetricsBase object. Convert code to use it.
* Fix several places where Length::inPixel is used without a proper em value.
* add mathed_font_em() helper function. It should eventually be removed like some other functions in MathSupport.
* Add dummy implementation of FontMetrics to tex2lyx for linking purposes.
- get rid of the cached Dimension. Text inset dimensions are saved in ParagraphMetrics and mathed maintain their own dimension where needed.
- width(), ascent(), descent(): deleted.
- dimension(): now needs a valid BufferView.
- metrics(): now void.
* BufferView::getCoveringInset(): simplify.
* ParagraphMetrics(): now cache inset dimensions.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@20420 a592a061-630c-0410-9148-cb99ea01b6c8
