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<TITLE>Magick::TypeMetric Class</TITLE>
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<META NAME="AUTHOR" CONTENT="Bob Friesenhahn">
<META NAME="CREATED" CONTENT="20020805;17544901">
<META NAME="CHANGEDBY" CONTENT="Bob Friesenhahn">
<META NAME="CHANGED" CONTENT="20020805;17560733">
<META NAME="DESCRIPTION" CONTENT="Class to access raw image pixels.">
<META NAME="KEYWORDS" CONTENT="GraphicsMagick,Pixel,Magick++">
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<H1 ALIGN=CENTER>Magick::TypeMetric</H1>
<P>The <I>TypeMetric</I> class provides the means to pass data from
the Image class's TypeMetric method to the user. It provides
information regarding font metrics such as ascent, descent, text
width, text height, and maximum horizontal advance. The units of
these font metrics are in pixels, and that the metrics are dependent
on the current Image font (default Ghostscript's "Helvetica"),
pointsize (default 12 points), and x/y resolution (default 72 DPI)
settings.
</P>
<P>The pixel units may be converted to points (the standard
resolution-independent measure used by the typesetting industry) via
the following equation:
</P>
<BLOCKQUOTE>size_points = (size_pixels * 72)/resolution</BLOCKQUOTE>
<P>where resolution is in dots-per-inch (DPI). This means that at the
default image resolution, there is one pixel per point.
</P>
<P>Note that a font's pointsize is only a first-order approximation
of the font height (ascender + descender) in points. The relationship
between the specified pointsize and the rendered font height is
determined by the font designer.
</P>
<P>See <A HREF="http://freetype.sourceforge.net/freetype2/docs/glyphs/index.html">FreeType
Glyph Conventions</A> for a detailed description of font metrics
related issues.
</P>
<P STYLE="margin-bottom: 0cm">The methods available in the <I>TypeMetric</I>
class are shown in the following table:
</P>
<P ALIGN=CENTER STYLE="margin-bottom: 0cm"><B>TypeMetric Methods</B></P>
<TABLE WIDTH=100% BORDER=1 CELLPADDING=2 CELLSPACING=2>
<TR>
<TD>
<P ALIGN=CENTER><B>Method</B></P>
</TD>
<TD>
<P ALIGN=CENTER><B>Returns</B></P>
</TD>
<TD>
<P><B>Units</B></P>
</TD>
<TD>
<P ALIGN=CENTER><B>Signature</B></P>
</TD>
<TD>
<P ALIGN=CENTER><B>Description</B></P>
</TD>
</TR>
<TR>
<TD>
<P ALIGN=CENTER><A NAME="ascent"></A><FONT SIZE=2>ascent</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>double</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Pixels</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>void</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Returns the distance in pixels from the text
baseline to the highest/upper grid coordinate used to place an
outline point. Always a positive value.</FONT></P>
</TD>
</TR>
<TR>
<TD>
<P ALIGN=CENTER><A NAME="descent"></A><FONT SIZE=2>descent</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>double</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Pixels</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>void</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Returns the the distance in pixels from the
baseline to the lowest grid coordinate used to place an outline
point. Always a negative value.</FONT></P>
</TD>
</TR>
<TR>
<TD>
<P ALIGN=CENTER><A NAME="textWidth"></A><FONT SIZE=2>textWidth</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>double</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Pixels</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>void</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Returns text width in pixels.</FONT></P>
</TD>
</TR>
<TR>
<TD>
<P ALIGN=CENTER><A NAME="textHeight"></A><FONT SIZE=2>textHeight</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>double</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Pixels</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>void</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Returns text height in pixels.</FONT></P>
</TD>
</TR>
<TR>
<TD>
<P ALIGN=CENTER><A NAME="maxHorizontalAdvance"></A><FONT SIZE=2>maxHorizontalAdvance</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>double</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Pixels</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>void</FONT></P>
</TD>
<TD>
<P><FONT SIZE=2>Returns the maximum horizontal advance (advance
from the beginning of a character to the beginning of the next
character) in pixels.</FONT></P>
</TD>
</TR>
</TABLE>
<P><BR><BR>
</P>
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