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<TITLE>Please title this page. (SuggestDeltas.html in FontForge)</TITLE>
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After you have generated truetype instructions to grid fit a glyph it might
to useful to look at places where those instructions yield questionable results.
In truetype a pixel is turned on if the center point of that pixel is within
the curve. If the curve is extremely close to the center point then results
are questionable
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You might want it on the other side
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Another rasterizer might round things differently and place the curve on
the wrong side.
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<IMG SRC="QGDlg.png" WIDTH="356" HEIGHT="280" ALIGN="Right">So it might be
helpful to have a command which would search the glyph for places and pixelsizes
where splines are close to the center points of pixels.
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TrueType has an instruction called DELTA which allows you to move points
only at certain pixelsizes.
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The dialog opposite will check the glyph at pointsizes 7-40, 72, 80, ...
where the screen resolution is 100 for places where a spline comes within
.01 (in pixel units) of the center of a pixel.
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<IMG SRC="QGList.png" WIDTH="441" HEIGHT="376" ALIGN="Left">The results will
look like those at right. Clicking on an entry will toggle whether that entry
is open (and its children visible) or not.
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<IMG SRC="JustOutside.png" WIDTH="132" HEIGHT="210" ALIGN="Right">If you
click on one of the bottom level entries then fontforge will open a glyph
view on that glyph, rasterize it at the current pointsize and resolution,
and indicate the offending pixel by drawing a red box around it. As you can
see, the pixel center point lies almost exactly on the spline. The closest
real point is the control point #8.
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It is possible to reorder the list... depending on what is most important.
At right data are organized by glyph, size and point. It might also be useful
to see which points in a glyph are close to problems.
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