Visual TrueType rasterizes one or more bitmaps whenever you compile the current glyph or the entire font. In addition, if the Grid Fit option is selected on the Options menu, Visual TrueType rasterizes bitmaps when you open a font.
Each time it rasterizes a bitmap, Visual TrueType checks for errors in the hinting. For example, if you delete an entry from the ‘cvt’ table yet one or more glyphs use that entry, the rasterizer will identify an error like this:
*** ERROR *** “”, 0 Point, Code 0 (0x0), Inst: #6
(MIRP) CVT out of range: CVT = 158, range = 0 .. 157
When it detects an error, Visual TrueType automatically opens the Font Error window, which displays text describing the problem. Before doing more hinting, you should correct the problem and recompile the glyph or font, depending on the problem. If you did not correct the problem so Visual TrueType detects another error, it appends the description of the new error after the previous text. Again, try to correct the problem and compile again, repeating until no new text appears in the Font Error window.
Note The Font Error window displays error messages only if MS Rasterizer is checked in the Visual TrueType menu.
Once you’ve fixed the problem, you can close the Font Error window, or resize it and leave it open on the screen. If you close the window, Visual TrueType re-opens it the next time it finds an error. The window contains all previous text, plus more text describing the new problem. Visual TrueType keeps appending error descriptions until you recalculate the actual memory needed by the font, a task usually done after you’ve finished all hinting (see “Reducing Memory Requirements”).
At any time, you can select and print the Font Error window to keep a record of the hinting errors (for details, see “Printing to Check Hinting Results”). If you want a record of all errors, be sure to print before recalculating memory requirements.
Otherwise, because the Font Error window is a text window, you can export its contents to a text file that you can name and save on disk (for details, see “Exporting Text”).
To close the Font Error window
1. Select the window by clicking on the window or selecting Font Errors from the View menu.
2. On the File menu, click Close, or press Ctrl + W.